feat: MCP Apps - rich HTML UIs for tool results (#573 )

* feat: add MCP Apps with rich HTML UIs for tool results Add MCP Apps infrastructure that allows MCP hosts like Claude Desktop to render rich HTML UIs alongside tool results via `_meta.ui` and the MCP resources protocol. - Server-side UI module (src/mcp/ui/) with UIAppRegistry, tool-to-UI mapping, and _meta.ui injection into tool responses - React + Vite build pipeline (ui-apps/) producing self-contained HTML per app using vite-plugin-singlefile - Operation Result UI for workflow CRUD tools (create, update, delete, test, autofix, deploy) - Validation Summary UI for validation tools (validate_node, validate_workflow, n8n_validate_workflow) - Shared component library (Card, Badge, Expandable) with n8n dark theme - MCP resources protocol support (ListResources, ReadResource handlers) - Graceful degradation when ui-apps/dist/ is not built - 22 unit tests across 3 test files Conceived by Romuald Członkowski - https://www.aiadvisors.pl/en Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com> * test: improve MCP Apps test coverage and add security hardening - Expand test suite from 22 to 57 tests across 3 test files - Add UIAppRegistry.reset() for proper test isolation between tests - Replace some fs mocks with real temp directory tests in registry - Add edge case coverage: empty strings, pre-load state, double load, malformed URIs, duplicate tool patterns, empty HTML files - Add regression tests for specific tool-to-UI mappings - Add URI format consistency validation across all configs - Improve _meta.ui injection tests with structuredContent coexistence - Coverage: statements 79.4% -> 80%, lines 79.4% -> 80% Conceived by Romuald Członkowski - https://www.aiadvisors.pl/en Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com> --------- Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
chore: update n8n to 2.6.3 and bump version to 2.33.6 (#571 )
2026-02-07 05:53:07 +00:00 · 2026-02-07 04:11:21 +01:00 · 2026-02-06 09:09:37 +01:00 · 2026-01-23 19:51:22 +01:00 · 2026-01-21 13:56:16 +01:00
57 changed files with 10436 additions and 1309 deletions
--- a/.gitignore
+++ b/.gitignore
@@ -138,5 +138,9 @@ n8n-mcp-wrapper.sh
 # MCP configuration files
 .mcp.json

+# UI Apps build output
+ui-apps/dist/
+ui-apps/node_modules/
+
 # Telemetry configuration (user-specific)
 ~/.n8n-mcp/
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,107 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0

 ## [Unreleased]

+## [2.34.0] - 2026-02-07
+
+### Added
+
+- **MCP Apps**: Rich HTML UIs rendered by MCP hosts alongside tool results via `_meta.ui` and the MCP resources protocol
+  - Server-side UI module (`src/mcp/ui/`) with tool-to-UI mapping and `_meta.ui` injection
+  - `UIAppRegistry` static class for loading and serving self-contained HTML apps
+  - `UI_APP_CONFIGS` mapping tools to their corresponding UI apps
+
+- **Operation Result UI**: Visual summary for workflow operation tools
+  - Status badge, operation type, workflow details card
+  - Expandable sections for nodes added, modified, and removed
+  - Mapped to: `n8n_create_workflow`, `n8n_update_full_workflow`, `n8n_update_partial_workflow`, `n8n_delete_workflow`, `n8n_test_workflow`, `n8n_autofix_workflow`, `n8n_deploy_template`
+
+- **Validation Summary UI**: Visual summary for validation tools
+  - Valid/invalid badge with error and warning counts
+  - Expandable error list with type, property, message, and fix
+  - Expandable warning list and suggestions
+  - Mapped to: `validate_node`, `validate_workflow`, `n8n_validate_workflow`
+
+- **React + Vite Build Pipeline** (`ui-apps/`):
+  - React 19, Vite 6, vite-plugin-singlefile for self-contained HTML output
+  - Shared component library: Card, Badge, Expandable
+  - `useToolData` hook for reading data from `window.__MCP_DATA__` or embedded JSON
+  - n8n-branded dark theme with CSS custom properties
+  - Per-app builds via `APP_NAME` environment variable
+
+- **MCP Resources Protocol**: Server now exposes `resources` capability
+  - `ListResources` handler returns available UI apps
+  - `ReadResource` handler serves self-contained HTML via `n8n-mcp://ui/{id}` URIs
+
+- **New Scripts**:
+  - `build:ui`: Build UI apps (`cd ui-apps && npm install && npm run build`)
+  - `build:all`: Build UI apps then server (`npm run build:ui && npm run build`)
+
+### Changed
+
+- **MCP Server**: Added `resources: {}` to server capabilities alongside existing `tools: {}`
+- **Tool Responses**: Tools with matching UI apps now include `_meta.ui.app` URI pointing to their visual representation
+- **Graceful Degradation**: Server starts and operates normally without `ui-apps/dist/`; UI metadata is only injected when HTML is available
+
+Conceived by Romuald Czlonkowski - https://www.aiadvisors.pl/en
+
+## [2.33.6] - 2026-02-06
+
+### Changed
+
+- Updated n8n from 2.4.4 to 2.6.3
+- Updated n8n-core from 2.4.2 to 2.6.1
+- Updated n8n-workflow from 2.4.2 to 2.6.0
+- Updated @n8n/n8n-nodes-langchain from 2.4.3 to 2.6.2
+- Rebuilt node database with 806 nodes (544 from n8n-nodes-base, 262 from @n8n/n8n-nodes-langchain)
+- Updated README badge with new n8n version
+
+## [2.33.5] - 2026-01-23
+
+### Fixed
+
+- **Critical memory leak: per-session database connections** (Issue #542): Fixed severe memory leak where each MCP session created its own database connection (~900MB per session)
+  - Root cause: `N8NDocumentationMCPServer` called `createDatabaseAdapter()` for every new session, duplicating the entire 68MB database in memory
+  - With 3-4 sessions, memory would exceed 4GB causing OOM kills every ~20 minutes
+  - Fix: Implemented singleton `SharedDatabase` pattern - all sessions now share ONE database connection
+  - Memory impact: Reduced from ~900MB per session to ~68MB total (shared) + ~5MB per session overhead
+  - Added `getSharedDatabase()` and `releaseSharedDatabase()` for thread-safe connection management
+  - Added reference counting to track active sessions using the shared connection
+
+- **Session timeout optimization**: Reduced default session timeout from 30 minutes to 5 minutes
+  - Faster cleanup of stale sessions reduces memory buildup
+  - Configurable via `SESSION_TIMEOUT_MINUTES` environment variable
+
+- **Eager instance cleanup**: When a client reconnects, previous sessions for the same instanceId are now immediately cleaned up
+  - Prevents memory accumulation from reconnecting clients in multi-tenant deployments
+
+- **Telemetry event listener leak**: Fixed event listeners in `TelemetryBatchProcessor` that were never removed
+  - Added proper cleanup in `stop()` method
+  - Added guard against multiple `start()` calls
+
+### Added
+
+- **New module: `src/database/shared-database.ts`** - Singleton database manager
+  - `getSharedDatabase(dbPath)`: Thread-safe initialization with promise lock pattern
+  - `releaseSharedDatabase(state)`: Reference counting for cleanup
+  - `closeSharedDatabase()`: Graceful shutdown for process termination
+  - `isSharedDatabaseInitialized()` and `getSharedDatabaseRefCount()`: Monitoring helpers
+
+### Changed
+
+- **`N8NDocumentationMCPServer.close()`**: Now releases shared database reference instead of closing the connection
+- **`SingleSessionHTTPServer.shutdown()`**: Calls `closeSharedDatabase()` during graceful shutdown
+
+## [2.33.4] - 2026-01-21
+
+### Fixed
+
+- **Memory leak in SSE session reset** (Issue #542): Fixed memory leak when SSE sessions are recreated every 5 minutes
+  - Root cause: `resetSessionSSE()` only closed the transport but not the MCP server
+  - This left the SimpleCache cleanup timer (60-second interval) running indefinitely
+  - Database connections and cached data (~50-100MB per session) persisted in memory
+  - Fix: Added `server.close()` call before `transport.close()`, mirroring the existing cleanup pattern in `removeSession()`
+  - Impact: Prevents ~288 leaked server instances per day in long-running HTTP deployments
+
 ## [2.33.3] - 2026-01-21

 ### Changed
--- a/README.md
+++ b/README.md
@@ -5,7 +5,7 @@
 [![npm version](https://img.shields.io/npm/v/n8n-mcp.svg)](https://www.npmjs.com/package/n8n-mcp)
 [![codecov](https://codecov.io/gh/czlonkowski/n8n-mcp/graph/badge.svg?token=YOUR_TOKEN)](https://codecov.io/gh/czlonkowski/n8n-mcp)
 [![Tests](https://img.shields.io/badge/tests-3336%20passing-brightgreen.svg)](https://github.com/czlonkowski/n8n-mcp/actions)
-[![n8n version](https://img.shields.io/badge/n8n-2.4.4-orange.svg)](https://github.com/n8n-io/n8n)
+[![n8n version](https://img.shields.io/badge/n8n-2.6.3-orange.svg)](https://github.com/n8n-io/n8n)
 [![Docker](https://img.shields.io/badge/docker-ghcr.io%2Fczlonkowski%2Fn8n--mcp-green.svg)](https://github.com/czlonkowski/n8n-mcp/pkgs/container/n8n-mcp)
 [![Deploy on Railway](https://railway.com/button.svg)](https://railway.com/deploy/n8n-mcp?referralCode=n8n-mcp)

--- a/data/nodes.db
+++ b/data/nodes.db
--- a/dist/database/database-adapter.js
+++ b/dist/database/database-adapter.js
@@ -311,6 +311,17 @@ class SQLJSStatement {
        this.stmt = stmt;
        this.onModify = onModify;
        this.boundParams = null;
+        this.freed = false;
+    }
+    freeStatement() {
+        if (!this.freed && this.stmt) {
+            try {
+                this.stmt.free();
+                this.freed = true;
+            }
+            catch (e) {
+            }
+        }
    }
    run(...params) {
        try {
@@ -331,6 +342,9 @@ class SQLJSStatement {
            this.stmt.reset();
            throw error;
        }
+        finally {
+            this.freeStatement();
+        }
    }
    get(...params) {
        try {
@@ -352,6 +366,9 @@ class SQLJSStatement {
            this.stmt.reset();
            throw error;
        }
+        finally {
+            this.freeStatement();
+        }
    }
    all(...params) {
        try {
@@ -372,6 +389,9 @@ class SQLJSStatement {
            this.stmt.reset();
            throw error;
        }
+        finally {
+            this.freeStatement();
+        }
    }
    iterate(...params) {
        return this.all(...params)[Symbol.iterator]();
--- a/dist/database/database-adapter.js.map
+++ b/dist/database/database-adapter.js.map
--- a/dist/http-server-single-session.d.ts.map
+++ b/dist/http-server-single-session.d.ts.map
@@ -1 +1 @@
-{"version":3,"file":"http-server-single-session.d.ts","sourceRoot":"","sources":["../src/http-server-single-session.ts"],"names":[],"mappings":";AAMA,OAAO,OAAO,MAAM,SAAS,CAAC;AAoB9B,OAAO,EAAE,eAAe,EAA2B,MAAM,0BAA0B,CAAC;AACpF,OAAO,EAAE,YAAY,EAAE,MAAM,uBAAuB,CAAC;AAuErD,qBAAa,uBAAuB;IAElC,OAAO,CAAC,UAAU,CAA8D;IAChF,OAAO,CAAC,OAAO,CAA0D;IACzE,OAAO,CAAC,eAAe,CAAsE;IAC7F,OAAO,CAAC,eAAe,CAA4D;IACnF,OAAO,CAAC,kBAAkB,CAAyC;IACnE,OAAO,CAAC,OAAO,CAAwB;IACvC,OAAO,CAAC,cAAc,CAAwB;IAC9C,OAAO,CAAC,aAAa,CAAM;IAC3B,OAAO,CAAC,cAAc,CAAkB;IACxC,OAAO,CAAC,SAAS,CAAuB;IACxC,OAAO,CAAC,YAAY,CAA+B;;IAcnD,OAAO,CAAC,mBAAmB;IAmB3B,OAAO,CAAC,sBAAsB;YAqChB,aAAa;IAuC3B,OAAO,CAAC,qBAAqB;IAO7B,OAAO,CAAC,gBAAgB;IAkBxB,OAAO,CAAC,gBAAgB;IASxB,OAAO,CAAC,sBAAsB;IAkC9B,OAAO,CAAC,mBAAmB;YASb,oBAAoB;YAwBpB,oBAAoB;IAwBlC,OAAO,CAAC,iBAAiB;IAsBzB,OAAO,CAAC,aAAa;IA2BrB,OAAO,CAAC,mBAAmB;IAoDrB,aAAa,CACjB,GAAG,EAAE,OAAO,CAAC,OAAO,EACpB,GAAG,EAAE,OAAO,CAAC,QAAQ,EACrB,eAAe,CAAC,EAAE,eAAe,GAChC,OAAO,CAAC,IAAI,CAAC;YAmOF,eAAe;IA8C7B,OAAO,CAAC,SAAS;IAYjB,OAAO,CAAC,gBAAgB;IASlB,KAAK,IAAI,OAAO,CAAC,IAAI,CAAC;IAgnBtB,QAAQ,IAAI,OAAO,CAAC,IAAI,CAAC;IAkD/B,cAAc,IAAI;QAChB,MAAM,EAAE,OAAO,CAAC;QAChB,SAAS,CAAC,EAAE,MAAM,CAAC;QACnB,GAAG,CAAC,EAAE,MAAM,CAAC;QACb,QAAQ,CAAC,EAAE;YACT,KAAK,EAAE,MAAM,CAAC;YACd,MAAM,EAAE,MAAM,CAAC;YACf,OAAO,EAAE,MAAM,CAAC;YAChB,GAAG,EAAE,MAAM,CAAC;YACZ,UAAU,EAAE,MAAM,EAAE,CAAC;SACtB,CAAC;KACH;IAmDM,kBAAkB,IAAI,YAAY,EAAE;IAoEpC,mBAAmB,CAAC,QAAQ,EAAE,YAAY,EAAE,GAAG,MAAM;CAsG7D"}
+{"version":3,"file":"http-server-single-session.d.ts","sourceRoot":"","sources":["../src/http-server-single-session.ts"],"names":[],"mappings":";AAMA,OAAO,OAAO,MAAM,SAAS,CAAC;AAoB9B,OAAO,EAAE,eAAe,EAA2B,MAAM,0BAA0B,CAAC;AACpF,OAAO,EAAE,YAAY,EAAE,MAAM,uBAAuB,CAAC;AAwErD,qBAAa,uBAAuB;IAElC,OAAO,CAAC,UAAU,CAA8D;IAChF,OAAO,CAAC,OAAO,CAA0D;IACzE,OAAO,CAAC,eAAe,CAAsE;IAC7F,OAAO,CAAC,eAAe,CAA4D;IACnF,OAAO,CAAC,kBAAkB,CAAyC;IACnE,OAAO,CAAC,OAAO,CAAwB;IACvC,OAAO,CAAC,cAAc,CAAwB;IAC9C,OAAO,CAAC,aAAa,CAAM;IAI3B,OAAO,CAAC,cAAc,CAER;IACd,OAAO,CAAC,SAAS,CAAuB;IACxC,OAAO,CAAC,YAAY,CAA+B;;IAcnD,OAAO,CAAC,mBAAmB;IAmB3B,OAAO,CAAC,sBAAsB;YAqChB,aAAa;IAuC3B,OAAO,CAAC,qBAAqB;IAO7B,OAAO,CAAC,gBAAgB;IAkBxB,OAAO,CAAC,gBAAgB;IASxB,OAAO,CAAC,sBAAsB;IAkC9B,OAAO,CAAC,mBAAmB;YASb,oBAAoB;YAwBpB,oBAAoB;IAwBlC,OAAO,CAAC,iBAAiB;IAsBzB,OAAO,CAAC,aAAa;IA2BrB,OAAO,CAAC,mBAAmB;IAoDrB,aAAa,CACjB,GAAG,EAAE,OAAO,CAAC,OAAO,EACpB,GAAG,EAAE,OAAO,CAAC,QAAQ,EACrB,eAAe,CAAC,EAAE,eAAe,GAChC,OAAO,CAAC,IAAI,CAAC;YA0PF,eAAe;IA4D7B,OAAO,CAAC,SAAS;IAYjB,OAAO,CAAC,gBAAgB;IASlB,KAAK,IAAI,OAAO,CAAC,IAAI,CAAC;IAgnBtB,QAAQ,IAAI,OAAO,CAAC,IAAI,CAAC;IA2D/B,cAAc,IAAI;QAChB,MAAM,EAAE,OAAO,CAAC;QAChB,SAAS,CAAC,EAAE,MAAM,CAAC;QACnB,GAAG,CAAC,EAAE,MAAM,CAAC;QACb,QAAQ,CAAC,EAAE;YACT,KAAK,EAAE,MAAM,CAAC;YACd,MAAM,EAAE,MAAM,CAAC;YACf,OAAO,EAAE,MAAM,CAAC;YAChB,GAAG,EAAE,MAAM,CAAC;YACZ,UAAU,EAAE,MAAM,EAAE,CAAC;SACtB,CAAC;KACH;IAmDM,kBAAkB,IAAI,YAAY,EAAE;IAoEpC,mBAAmB,CAAC,QAAQ,EAAE,YAAY,EAAE,GAAG,MAAM;CAsG7D"}
--- a/dist/http-server-single-session.js
+++ b/dist/http-server-single-session.js
@@ -22,6 +22,7 @@ const crypto_1 = require("crypto");
 const types_js_1 = require("@modelcontextprotocol/sdk/types.js");
 const protocol_version_1 = require("./utils/protocol-version");
 const instance_context_1 = require("./types/instance-context");
+const shared_database_1 = require("./database/shared-database");
 dotenv_1.default.config();
 const DEFAULT_PROTOCOL_VERSION = protocol_version_1.STANDARD_PROTOCOL_VERSION;
 const MAX_SESSIONS = Math.max(1, parseInt(process.env.N8N_MCP_MAX_SESSIONS || '100', 10));
@@ -52,7 +53,7 @@ class SingleSessionHTTPServer {
        this.contextSwitchLocks = new Map();
        this.session = null;
        this.consoleManager = new console_manager_1.ConsoleManager();
-        this.sessionTimeout = 30 * 60 * 1000;
+        this.sessionTimeout = parseInt(process.env.SESSION_TIMEOUT_MINUTES || '5', 10) * 60 * 1000;
        this.authToken = null;
        this.cleanupTimer = null;
        this.validateEnvironment();
@@ -290,6 +291,25 @@ class SingleSessionHTTPServer {
                        return;
                    }
                    logger_1.logger.info('handleRequest: Creating new transport for initialize request');
+                    if (instanceContext?.instanceId) {
+                        const sessionsToRemove = [];
+                        for (const [existingSessionId, context] of Object.entries(this.sessionContexts)) {
+                            if (context?.instanceId === instanceContext.instanceId) {
+                                sessionsToRemove.push(existingSessionId);
+                            }
+                        }
+                        for (const oldSessionId of sessionsToRemove) {
+                            if (!this.transports[oldSessionId]) {
+                                continue;
+                            }
+                            logger_1.logger.info('Cleaning up previous session for instance', {
+                                instanceId: instanceContext.instanceId,
+                                oldSession: oldSessionId,
+                                reason: 'instance_reconnect'
+                            });
+                            await this.removeSession(oldSessionId, 'instance_reconnect');
+                        }
+                    }
                    let sessionIdToUse;
                    const isMultiTenantEnabled = process.env.ENABLE_MULTI_TENANT === 'true';
                    const sessionStrategy = process.env.MULTI_TENANT_SESSION_STRATEGY || 'instance';
@@ -434,12 +454,21 @@ class SingleSessionHTTPServer {
    }
    async resetSessionSSE(res) {
        if (this.session) {
+            const sessionId = this.session.sessionId;
+            logger_1.logger.info('Closing previous session for SSE', { sessionId });
+            if (this.session.server && typeof this.session.server.close === 'function') {
+                try {
+                    await this.session.server.close();
+                }
+                catch (serverError) {
+                    logger_1.logger.warn('Error closing server for SSE session', { sessionId, error: serverError });
+                }
+            }
            try {
-                logger_1.logger.info('Closing previous session for SSE', { sessionId: this.session.sessionId });
                await this.session.transport.close();
            }
-            catch (error) {
-                logger_1.logger.warn('Error closing previous session:', error);
+            catch (transportError) {
+                logger_1.logger.warn('Error closing transport for SSE session', { sessionId, error: transportError });
            }
        }
        try {
@@ -1014,6 +1043,13 @@ class SingleSessionHTTPServer {
                });
            });
        }
+        try {
+            await (0, shared_database_1.closeSharedDatabase)();
+            logger_1.logger.info('Shared database closed');
+        }
+        catch (error) {
+            logger_1.logger.warn('Error closing shared database:', error);
+        }
        logger_1.logger.info('Single-Session HTTP server shutdown completed');
    }
    getSessionInfo() {
--- a/dist/http-server-single-session.js.map
+++ b/dist/http-server-single-session.js.map
--- a/dist/index.d.ts
+++ b/dist/index.d.ts
@@ -5,6 +5,8 @@ export { N8NDocumentationMCPServer } from './mcp/server';
 export type { InstanceContext } from './types/instance-context';
 export { validateInstanceContext, isInstanceContext } from './types/instance-context';
 export type { SessionState } from './types/session-state';
+export type { UIAppConfig, UIMetadata } from './mcp/ui/types';
+export { UI_APP_CONFIGS } from './mcp/ui/app-configs';
 export type { Tool, CallToolResult, ListToolsResult } from '@modelcontextprotocol/sdk/types.js';
 import N8NMCPEngine from './mcp-engine';
 export default N8NMCPEngine;
--- a/dist/index.d.ts.map
+++ b/dist/index.d.ts.map
@@ -1 +1 @@
-{"version":3,"file":"index.d.ts","sourceRoot":"","sources":["../src/index.ts"],"names":[],"mappings":"AAOA,OAAO,EAAE,YAAY,EAAE,YAAY,EAAE,aAAa,EAAE,MAAM,cAAc,CAAC;AACzE,OAAO,EAAE,uBAAuB,EAAE,MAAM,8BAA8B,CAAC;AACvE,OAAO,EAAE,cAAc,EAAE,MAAM,yBAAyB,CAAC;AACzD,OAAO,EAAE,yBAAyB,EAAE,MAAM,cAAc,CAAC;AAGzD,YAAY,EACV,eAAe,EAChB,MAAM,0BAA0B,CAAC;AAClC,OAAO,EACL,uBAAuB,EACvB,iBAAiB,EAClB,MAAM,0BAA0B,CAAC;AAClC,YAAY,EACV,YAAY,EACb,MAAM,uBAAuB,CAAC;AAG/B,YAAY,EACV,IAAI,EACJ,cAAc,EACd,eAAe,EAChB,MAAM,oCAAoC,CAAC;AAG5C,OAAO,YAAY,MAAM,cAAc,CAAC;AACxC,eAAe,YAAY,CAAC"}
+{"version":3,"file":"index.d.ts","sourceRoot":"","sources":["../src/index.ts"],"names":[],"mappings":"AAOA,OAAO,EAAE,YAAY,EAAE,YAAY,EAAE,aAAa,EAAE,MAAM,cAAc,CAAC;AACzE,OAAO,EAAE,uBAAuB,EAAE,MAAM,8BAA8B,CAAC;AACvE,OAAO,EAAE,cAAc,EAAE,MAAM,yBAAyB,CAAC;AACzD,OAAO,EAAE,yBAAyB,EAAE,MAAM,cAAc,CAAC;AAGzD,YAAY,EACV,eAAe,EAChB,MAAM,0BAA0B,CAAC;AAClC,OAAO,EACL,uBAAuB,EACvB,iBAAiB,EAClB,MAAM,0BAA0B,CAAC;AAClC,YAAY,EACV,YAAY,EACb,MAAM,uBAAuB,CAAC;AAG/B,YAAY,EAAE,WAAW,EAAE,UAAU,EAAE,MAAM,gBAAgB,CAAC;AAC9D,OAAO,EAAE,cAAc,EAAE,MAAM,sBAAsB,CAAC;AAGtD,YAAY,EACV,IAAI,EACJ,cAAc,EACd,eAAe,EAChB,MAAM,oCAAoC,CAAC;AAG5C,OAAO,YAAY,MAAM,cAAc,CAAC;AACxC,eAAe,YAAY,CAAC"}
--- a/dist/index.js
+++ b/dist/index.js
@@ -3,7 +3,7 @@ var __importDefault = (this && this.__importDefault) || function (mod) {
    return (mod && mod.__esModule) ? mod : { "default": mod };
 };
 Object.defineProperty(exports, "__esModule", { value: true });
-exports.isInstanceContext = exports.validateInstanceContext = exports.N8NDocumentationMCPServer = exports.ConsoleManager = exports.SingleSessionHTTPServer = exports.N8NMCPEngine = void 0;
+exports.UI_APP_CONFIGS = exports.isInstanceContext = exports.validateInstanceContext = exports.N8NDocumentationMCPServer = exports.ConsoleManager = exports.SingleSessionHTTPServer = exports.N8NMCPEngine = void 0;
 var mcp_engine_1 = require("./mcp-engine");
 Object.defineProperty(exports, "N8NMCPEngine", { enumerable: true, get: function () { return mcp_engine_1.N8NMCPEngine; } });
 var http_server_single_session_1 = require("./http-server-single-session");
@@ -15,6 +15,8 @@ Object.defineProperty(exports, "N8NDocumentationMCPServer", { enumerable: true,
 var instance_context_1 = require("./types/instance-context");
 Object.defineProperty(exports, "validateInstanceContext", { enumerable: true, get: function () { return instance_context_1.validateInstanceContext; } });
 Object.defineProperty(exports, "isInstanceContext", { enumerable: true, get: function () { return instance_context_1.isInstanceContext; } });
+var app_configs_1 = require("./mcp/ui/app-configs");
+Object.defineProperty(exports, "UI_APP_CONFIGS", { enumerable: true, get: function () { return app_configs_1.UI_APP_CONFIGS; } });
 const mcp_engine_2 = __importDefault(require("./mcp-engine"));
 exports.default = mcp_engine_2.default;
 //# sourceMappingURL=index.js.map
--- a/dist/index.js.map
+++ b/dist/index.js.map
@@ -1 +1 @@
-{"version":3,"file":"index.js","sourceRoot":"","sources":["../src/index.ts"],"names":[],"mappings":";;;;;;AAOA,2CAAyE;AAAhE,0GAAA,YAAY,OAAA;AACrB,2EAAuE;AAA9D,qIAAA,uBAAuB,OAAA;AAChC,2DAAyD;AAAhD,iHAAA,cAAc,OAAA;AACvB,uCAAyD;AAAhD,mHAAA,yBAAyB,OAAA;AAMlC,6DAGkC;AAFhC,2HAAA,uBAAuB,OAAA;AACvB,qHAAA,iBAAiB,OAAA;AAcnB,8DAAwC;AACxC,kBAAe,oBAAY,CAAC"}
+{"version":3,"file":"index.js","sourceRoot":"","sources":["../src/index.ts"],"names":[],"mappings":";;;;;;AAOA,2CAAyE;AAAhE,0GAAA,YAAY,OAAA;AACrB,2EAAuE;AAA9D,qIAAA,uBAAuB,OAAA;AAChC,2DAAyD;AAAhD,iHAAA,cAAc,OAAA;AACvB,uCAAyD;AAAhD,mHAAA,yBAAyB,OAAA;AAMlC,6DAGkC;AAFhC,2HAAA,uBAAuB,OAAA;AACvB,qHAAA,iBAAiB,OAAA;AAQnB,oDAAsD;AAA7C,6GAAA,cAAc,OAAA;AAUvB,8DAAwC;AACxC,kBAAe,oBAAY,CAAC"}
--- a/dist/mcp/server.d.ts
+++ b/dist/mcp/server.d.ts
@@ -13,6 +13,9 @@ export declare class N8NDocumentationMCPServer {
    private previousToolTimestamp;
    private earlyLogger;
    private disabledToolsCache;
+    private useSharedDatabase;
+    private sharedDbState;
+    private isShutdown;
    constructor(instanceContext?: InstanceContext, earlyLogger?: EarlyErrorLogger);
    close(): Promise<void>;
    private initializeDatabase;
--- a/dist/mcp/server.d.ts.map
+++ b/dist/mcp/server.d.ts.map
@@ -1 +1 @@
-{"version":3,"file":"server.d.ts","sourceRoot":"","sources":["../../src/mcp/server.ts"],"names":[],"mappings":"AAsCA,OAAO,EAAE,eAAe,EAAE,MAAM,2BAA2B,CAAC;AAE5D,OAAO,EAAE,gBAAgB,EAAE,MAAM,iCAAiC,CAAC;AAmGnE,qBAAa,yBAAyB;IACpC,OAAO,CAAC,MAAM,CAAS;IACvB,OAAO,CAAC,EAAE,CAAgC;IAC1C,OAAO,CAAC,UAAU,CAA+B;IACjD,OAAO,CAAC,eAAe,CAAgC;IACvD,OAAO,CAAC,WAAW,CAAgB;IACnC,OAAO,CAAC,KAAK,CAAqB;IAClC,OAAO,CAAC,UAAU,CAAa;IAC/B,OAAO,CAAC,eAAe,CAAC,CAAkB;IAC1C,OAAO,CAAC,YAAY,CAAuB;IAC3C,OAAO,CAAC,qBAAqB,CAAsB;IACnD,OAAO,CAAC,WAAW,CAAiC;IACpD,OAAO,CAAC,kBAAkB,CAA4B;gBAE1C,eAAe,CAAC,EAAE,eAAe,EAAE,WAAW,CAAC,EAAE,gBAAgB;IAiGvE,KAAK,IAAI,OAAO,CAAC,IAAI,CAAC;YA6Bd,kBAAkB;YAwClB,wBAAwB;IA0BtC,OAAO,CAAC,kBAAkB;YA6CZ,iBAAiB;IAa/B,OAAO,CAAC,eAAe,CAAkB;YAE3B,sBAAsB;IAgDpC,OAAO,CAAC,gBAAgB;IAqCxB,OAAO,CAAC,aAAa;IAoTrB,OAAO,CAAC,wBAAwB;IAoFhC,OAAO,CAAC,kBAAkB;IAqE1B,OAAO,CAAC,uBAAuB;IAwB/B,OAAO,CAAC,qBAAqB;YAoTf,SAAS;YA2DT,WAAW;YAkFX,WAAW;YA0CX,cAAc;YA8Md,gBAAgB;IAqD9B,OAAO,CAAC,mBAAmB;IAwE3B,OAAO,CAAC,eAAe;YAsBT,eAAe;IA2L7B,OAAO,CAAC,kBAAkB;IAQ1B,OAAO,CAAC,uBAAuB;IA0D/B,OAAO,CAAC,iBAAiB;YAqFX,WAAW;YAgCX,oBAAoB;IAuFlC,OAAO,CAAC,aAAa;YAQP,qBAAqB;YAwDrB,iBAAiB;YAiKjB,OAAO;YAgDP,cAAc;YAwFd,iBAAiB;IAqC/B,OAAO,CAAC,iBAAiB;IA0BzB,OAAO,CAAC,iBAAiB;IA0BzB,OAAO,CAAC,eAAe;IAwCvB,OAAO,CAAC,kBAAkB;IAiC1B,OAAO,CAAC,aAAa;IAoCrB,OAAO,CAAC,0BAA0B;IAgClC,OAAO,CAAC,4BAA4B;YAKtB,oBAAoB;IAsDlC,OAAO,CAAC,gBAAgB;YAiBV,SAAS;YA6CT,kBAAkB;YAqElB,uBAAuB;YAsDvB,iBAAiB;IAqE/B,OAAO,CAAC,qBAAqB;IA8C7B,OAAO,CAAC,uBAAuB;IA4D/B,OAAO,CAAC,wBAAwB;IAkChC,OAAO,CAAC,iBAAiB;YAoDX,mBAAmB;YAoEnB,qBAAqB;IAS7B,OAAO,CAAC,SAAS,EAAE,GAAG,GAAG,OAAO,CAAC,IAAI,CAAC;YAS9B,aAAa;YAcb,iBAAiB;YAoBjB,WAAW;YAwBX,eAAe;YAqBf,mBAAmB;YAwBnB,yBAAyB;IA4CvC,OAAO,CAAC,kBAAkB;YAiBZ,gBAAgB;YA6HhB,2BAA2B;YAiE3B,2BAA2B;IAyEnC,GAAG,IAAI,OAAO,CAAC,IAAI,CAAC;IA0BpB,QAAQ,IAAI,OAAO,CAAC,IAAI,CAAC;CAuBhC"}
+{"version":3,"file":"server.d.ts","sourceRoot":"","sources":["../../src/mcp/server.ts"],"names":[],"mappings":"AA0CA,OAAO,EAAE,eAAe,EAAE,MAAM,2BAA2B,CAAC;AAE5D,OAAO,EAAE,gBAAgB,EAAE,MAAM,iCAAiC,CAAC;AAmGnE,qBAAa,yBAAyB;IACpC,OAAO,CAAC,MAAM,CAAS;IACvB,OAAO,CAAC,EAAE,CAAgC;IAC1C,OAAO,CAAC,UAAU,CAA+B;IACjD,OAAO,CAAC,eAAe,CAAgC;IACvD,OAAO,CAAC,WAAW,CAAgB;IACnC,OAAO,CAAC,KAAK,CAAqB;IAClC,OAAO,CAAC,UAAU,CAAa;IAC/B,OAAO,CAAC,eAAe,CAAC,CAAkB;IAC1C,OAAO,CAAC,YAAY,CAAuB;IAC3C,OAAO,CAAC,qBAAqB,CAAsB;IACnD,OAAO,CAAC,WAAW,CAAiC;IACpD,OAAO,CAAC,kBAAkB,CAA4B;IACtD,OAAO,CAAC,iBAAiB,CAAkB;IAC3C,OAAO,CAAC,aAAa,CAAoC;IACzD,OAAO,CAAC,UAAU,CAAkB;gBAExB,eAAe,CAAC,EAAE,eAAe,EAAE,WAAW,CAAC,EAAE,gBAAgB;IAuGvE,KAAK,IAAI,OAAO,CAAC,IAAI,CAAC;YA+Cd,kBAAkB;YAiDlB,wBAAwB;IA0BtC,OAAO,CAAC,kBAAkB;YA6CZ,iBAAiB;IAa/B,OAAO,CAAC,eAAe,CAAkB;YAE3B,sBAAsB;IAgDpC,OAAO,CAAC,gBAAgB;IAqCxB,OAAO,CAAC,aAAa;IAmWrB,OAAO,CAAC,wBAAwB;IAoFhC,OAAO,CAAC,kBAAkB;IAqE1B,OAAO,CAAC,uBAAuB;IAwB/B,OAAO,CAAC,qBAAqB;YAoTf,SAAS;YA2DT,WAAW;YAkFX,WAAW;YA0CX,cAAc;YA8Md,gBAAgB;IAqD9B,OAAO,CAAC,mBAAmB;IAwE3B,OAAO,CAAC,eAAe;YAsBT,eAAe;IA2L7B,OAAO,CAAC,kBAAkB;IAQ1B,OAAO,CAAC,uBAAuB;IA0D/B,OAAO,CAAC,iBAAiB;YAqFX,WAAW;YAgCX,oBAAoB;IAuFlC,OAAO,CAAC,aAAa;YAQP,qBAAqB;YAwDrB,iBAAiB;YAiKjB,OAAO;YAgDP,cAAc;YAwFd,iBAAiB;IAqC/B,OAAO,CAAC,iBAAiB;IA0BzB,OAAO,CAAC,iBAAiB;IA0BzB,OAAO,CAAC,eAAe;IAwCvB,OAAO,CAAC,kBAAkB;IAiC1B,OAAO,CAAC,aAAa;IAoCrB,OAAO,CAAC,0BAA0B;IAgClC,OAAO,CAAC,4BAA4B;YAKtB,oBAAoB;IAsDlC,OAAO,CAAC,gBAAgB;YAiBV,SAAS;YA6CT,kBAAkB;YAqElB,uBAAuB;YAsDvB,iBAAiB;IAqE/B,OAAO,CAAC,qBAAqB;IA8C7B,OAAO,CAAC,uBAAuB;IA4D/B,OAAO,CAAC,wBAAwB;IAkChC,OAAO,CAAC,iBAAiB;YAoDX,mBAAmB;YAoEnB,qBAAqB;IAS7B,OAAO,CAAC,SAAS,EAAE,GAAG,GAAG,OAAO,CAAC,IAAI,CAAC;YAS9B,aAAa;YAcb,iBAAiB;YAoBjB,WAAW;YAwBX,eAAe;YAqBf,mBAAmB;YAwBnB,yBAAyB;IA4CvC,OAAO,CAAC,kBAAkB;YAiBZ,gBAAgB;YA6HhB,2BAA2B;YAiE3B,2BAA2B;IAyEnC,GAAG,IAAI,OAAO,CAAC,IAAI,CAAC;IA0BpB,QAAQ,IAAI,OAAO,CAAC,IAAI,CAAC;CAgEhC"}
--- a/dist/mcp/server.js
+++ b/dist/mcp/server.js
@@ -43,12 +43,14 @@ const types_js_1 = require("@modelcontextprotocol/sdk/types.js");
 const fs_1 = require("fs");
 const path_1 = __importDefault(require("path"));
 const tools_1 = require("./tools");
+const ui_1 = require("./ui");
 const tools_n8n_manager_1 = require("./tools-n8n-manager");
 const tools_n8n_friendly_1 = require("./tools-n8n-friendly");
 const workflow_examples_1 = require("./workflow-examples");
 const logger_1 = require("../utils/logger");
 const node_repository_1 = require("../database/node-repository");
 const database_adapter_1 = require("../database/database-adapter");
+const shared_database_1 = require("../database/shared-database");
 const property_filter_1 = require("../services/property-filter");
 const task_templates_1 = require("../services/task-templates");
 const config_validator_1 = require("../services/config-validator");
@@ -80,6 +82,9 @@ class N8NDocumentationMCPServer {
        this.previousToolTimestamp = Date.now();
        this.earlyLogger = null;
        this.disabledToolsCache = null;
+        this.useSharedDatabase = false;
+        this.sharedDbState = null;
+        this.isShutdown = false;
        this.dbHealthChecked = false;
        this.instanceContext = instanceContext;
        this.earlyLogger = earlyLogger || null;
@@ -144,15 +149,29 @@ class N8NDocumentationMCPServer {
        }, {
            capabilities: {
                tools: {},
+                resources: {},
            },
        });
+        ui_1.UIAppRegistry.load();
        this.setupHandlers();
    }
    async close() {
+        try {
+            await this.initialized;
+        }
+        catch (error) {
+            logger_1.logger.debug('Initialization had failed, proceeding with cleanup', {
+                error: error instanceof Error ? error.message : String(error)
+            });
+        }
        try {
            await this.server.close();
            this.cache.destroy();
-            if (this.db) {
+            if (this.useSharedDatabase && this.sharedDbState) {
+                (0, shared_database_1.releaseSharedDatabase)(this.sharedDbState);
+                logger_1.logger.debug('Released shared database reference');
+            }
+            else if (this.db) {
                try {
                    this.db.close();
                }
@@ -166,6 +185,7 @@ class N8NDocumentationMCPServer {
            this.repository = null;
            this.templateService = null;
            this.earlyLogger = null;
+            this.sharedDbState = null;
        }
        catch (error) {
            logger_1.logger.warn('Error closing MCP server', { error: error instanceof Error ? error.message : String(error) });
@@ -177,17 +197,27 @@ class N8NDocumentationMCPServer {
                this.earlyLogger.logCheckpoint(startup_checkpoints_1.STARTUP_CHECKPOINTS.DATABASE_CONNECTING);
            }
            logger_1.logger.debug('Database initialization starting...', { dbPath });
-            this.db = await (0, database_adapter_1.createDatabaseAdapter)(dbPath);
-            logger_1.logger.debug('Database adapter created');
            if (dbPath === ':memory:') {
+                this.db = await (0, database_adapter_1.createDatabaseAdapter)(dbPath);
+                logger_1.logger.debug('Database adapter created (in-memory mode)');
                await this.initializeInMemorySchema();
                logger_1.logger.debug('In-memory schema initialized');
+                this.repository = new node_repository_1.NodeRepository(this.db);
+                this.templateService = new template_service_1.TemplateService(this.db);
+                enhanced_config_validator_1.EnhancedConfigValidator.initializeSimilarityServices(this.repository);
+                this.useSharedDatabase = false;
+            }
+            else {
+                const sharedState = await (0, shared_database_1.getSharedDatabase)(dbPath);
+                this.db = sharedState.db;
+                this.repository = sharedState.repository;
+                this.templateService = sharedState.templateService;
+                this.sharedDbState = sharedState;
+                this.useSharedDatabase = true;
+                logger_1.logger.debug('Using shared database connection');
            }
-            this.repository = new node_repository_1.NodeRepository(this.db);
            logger_1.logger.debug('Node repository initialized');
-            this.templateService = new template_service_1.TemplateService(this.db);
            logger_1.logger.debug('Template service initialized');
-            enhanced_config_validator_1.EnhancedConfigValidator.initializeSimilarityServices(this.repository);
            logger_1.logger.debug('Similarity services initialized');
            if (this.earlyLogger) {
                this.earlyLogger.logCheckpoint(startup_checkpoints_1.STARTUP_CHECKPOINTS.DATABASE_CONNECTED);
@@ -341,6 +371,7 @@ class N8NDocumentationMCPServer {
                protocolVersion: negotiationResult.version,
                capabilities: {
                    tools: {},
+                    resources: {},
                },
                serverInfo: {
                    name: 'n8n-documentation-mcp',
@@ -498,6 +529,10 @@ class N8NDocumentationMCPServer {
                if (name.startsWith('validate_') && structuredContent !== null) {
                    mcpResponse.structuredContent = structuredContent;
                }
+                const uiApp = ui_1.UIAppRegistry.getAppForTool(name);
+                if (uiApp && uiApp.html) {
+                    mcpResponse._meta = { ui: { app: uiApp.config.uri } };
+                }
                return mcpResponse;
            }
            catch (error) {
@@ -535,6 +570,39 @@ class N8NDocumentationMCPServer {
                };
            }
        });
+        this.server.setRequestHandler(types_js_1.ListResourcesRequestSchema, async () => {
+            const apps = ui_1.UIAppRegistry.getAllApps();
+            return {
+                resources: apps
+                    .filter(app => app.html !== null)
+                    .map(app => ({
+                    uri: app.config.uri,
+                    name: app.config.displayName,
+                    description: app.config.description,
+                    mimeType: app.config.mimeType,
+                })),
+            };
+        });
+        this.server.setRequestHandler(types_js_1.ReadResourceRequestSchema, async (request) => {
+            const uri = request.params.uri;
+            const match = uri.match(/^n8n-mcp:\/\/ui\/(.+)$/);
+            if (!match) {
+                throw new Error(`Unknown resource URI: ${uri}`);
+            }
+            const app = ui_1.UIAppRegistry.getAppById(match[1]);
+            if (!app || !app.html) {
+                throw new Error(`UI app not found or not built: ${match[1]}`);
+            }
+            return {
+                contents: [
+                    {
+                        uri: app.config.uri,
+                        mimeType: app.config.mimeType,
+                        text: app.html,
+                    },
+                ],
+            };
+        });
    }
    sanitizeValidationResult(result, toolName) {
        if (!result || typeof result !== 'object') {
@@ -2889,7 +2957,26 @@ Full documentation is being prepared. For now, use get_node_essentials for confi
        process.stdin.resume();
    }
    async shutdown() {
+        if (this.isShutdown) {
+            logger_1.logger.debug('Shutdown already called, skipping');
+            return;
+        }
+        this.isShutdown = true;
        logger_1.logger.info('Shutting down MCP server...');
+        try {
+            await this.initialized;
+        }
+        catch (error) {
+            logger_1.logger.debug('Initialization had failed, proceeding with cleanup', {
+                error: error instanceof Error ? error.message : String(error)
+            });
+        }
+        try {
+            await this.server.close();
+        }
+        catch (error) {
+            logger_1.logger.error('Error closing MCP server:', error);
+        }
        if (this.cache) {
            try {
                this.cache.destroy();
@@ -2899,15 +2986,29 @@ Full documentation is being prepared. For now, use get_node_essentials for confi
                logger_1.logger.error('Error cleaning up cache:', error);
            }
        }
-        if (this.db) {
+        if (this.useSharedDatabase && this.sharedDbState) {
            try {
-                await this.db.close();
+                (0, shared_database_1.releaseSharedDatabase)(this.sharedDbState);
+                logger_1.logger.info('Released shared database reference');
+            }
+            catch (error) {
+                logger_1.logger.error('Error releasing shared database:', error);
+            }
+        }
+        else if (this.db) {
+            try {
+                this.db.close();
                logger_1.logger.info('Database connection closed');
            }
            catch (error) {
                logger_1.logger.error('Error closing database:', error);
            }
        }
+        this.db = null;
+        this.repository = null;
+        this.templateService = null;
+        this.earlyLogger = null;
+        this.sharedDbState = null;
    }
 }
 exports.N8NDocumentationMCPServer = N8NDocumentationMCPServer;
--- a/dist/mcp/server.js.map
+++ b/dist/mcp/server.js.map
--- a/dist/services/n8n-validation.d.ts
+++ b/dist/services/n8n-validation.d.ts
@@ -26,10 +26,10 @@ export declare const workflowNodeSchema: z.ZodObject<{
    parameters: Record<string, unknown>;
    credentials?: Record<string, unknown> | undefined;
    retryOnFail?: boolean | undefined;
+    continueOnFail?: boolean | undefined;
    maxTries?: number | undefined;
    waitBetweenTries?: number | undefined;
    alwaysOutputData?: boolean | undefined;
-    continueOnFail?: boolean | undefined;
    executeOnce?: boolean | undefined;
    disabled?: boolean | undefined;
    notes?: string | undefined;
@@ -43,10 +43,10 @@ export declare const workflowNodeSchema: z.ZodObject<{
    parameters: Record<string, unknown>;
    credentials?: Record<string, unknown> | undefined;
    retryOnFail?: boolean | undefined;
+    continueOnFail?: boolean | undefined;
    maxTries?: number | undefined;
    waitBetweenTries?: number | undefined;
    alwaysOutputData?: boolean | undefined;
-    continueOnFail?: boolean | undefined;
    executeOnce?: boolean | undefined;
    disabled?: boolean | undefined;
    notes?: string | undefined;
--- a/dist/telemetry/batch-processor.d.ts
+++ b/dist/telemetry/batch-processor.d.ts
@@ -12,6 +12,8 @@ export declare class TelemetryBatchProcessor {
    private flushTimes;
    private deadLetterQueue;
    private readonly maxDeadLetterSize;
+    private eventListeners;
+    private started;
    constructor(supabase: SupabaseClient | null, isEnabled: () => boolean);
    start(): void;
    stop(): void;
--- a/dist/telemetry/batch-processor.d.ts.map
+++ b/dist/telemetry/batch-processor.d.ts.map
@@ -1 +1 @@
-{"version":3,"file":"batch-processor.d.ts","sourceRoot":"","sources":["../../src/telemetry/batch-processor.ts"],"names":[],"mappings":"AAKA,OAAO,EAAE,cAAc,EAAE,MAAM,uBAAuB,CAAC;AACvD,OAAO,EAAE,cAAc,EAAE,iBAAiB,EAAE,sBAAsB,EAAoB,gBAAgB,EAAE,MAAM,mBAAmB,CAAC;AAoClI,qBAAa,uBAAuB;IAoBhC,OAAO,CAAC,QAAQ;IAChB,OAAO,CAAC,SAAS;IApBnB,OAAO,CAAC,UAAU,CAAC,CAAiB;IACpC,OAAO,CAAC,gBAAgB,CAAkB;IAC1C,OAAO,CAAC,mBAAmB,CAAkB;IAC7C,OAAO,CAAC,mBAAmB,CAAkB;IAC7C,OAAO,CAAC,cAAc,CAA0B;IAChD,OAAO,CAAC,OAAO,CAQb;IACF,OAAO,CAAC,UAAU,CAAgB;IAClC,OAAO,CAAC,eAAe,CAAuE;IAC9F,OAAO,CAAC,QAAQ,CAAC,iBAAiB,CAAO;gBAG/B,QAAQ,EAAE,cAAc,GAAG,IAAI,EAC/B,SAAS,EAAE,MAAM,OAAO;IAQlC,KAAK,IAAI,IAAI;IA+Bb,IAAI,IAAI,IAAI;IAWN,KAAK,CAAC,MAAM,CAAC,EAAE,cAAc,EAAE,EAAE,SAAS,CAAC,EAAE,iBAAiB,EAAE,EAAE,SAAS,CAAC,EAAE,sBAAsB,EAAE,GAAG,OAAO,CAAC,IAAI,CAAC;YAgD9G,WAAW;YAmDX,cAAc;YAuDd,cAAc;YAiEd,gBAAgB;IAgD9B,OAAO,CAAC,aAAa;IAarB,OAAO,CAAC,oBAAoB;IAiB5B,OAAO,CAAC,oBAAoB;YAmBd,sBAAsB;IAgCpC,OAAO,CAAC,eAAe;IAiBvB,UAAU,IAAI,gBAAgB,GAAG;QAAE,mBAAmB,EAAE,GAAG,CAAC;QAAC,mBAAmB,EAAE,MAAM,CAAA;KAAE;IAW1F,YAAY,IAAI,IAAI;CAarB"}
+{"version":3,"file":"batch-processor.d.ts","sourceRoot":"","sources":["../../src/telemetry/batch-processor.ts"],"names":[],"mappings":"AAKA,OAAO,EAAE,cAAc,EAAE,MAAM,uBAAuB,CAAC;AACvD,OAAO,EAAE,cAAc,EAAE,iBAAiB,EAAE,sBAAsB,EAAoB,gBAAgB,EAAE,MAAM,mBAAmB,CAAC;AAoClI,qBAAa,uBAAuB;IA2BhC,OAAO,CAAC,QAAQ;IAChB,OAAO,CAAC,SAAS;IA3BnB,OAAO,CAAC,UAAU,CAAC,CAAiB;IACpC,OAAO,CAAC,gBAAgB,CAAkB;IAC1C,OAAO,CAAC,mBAAmB,CAAkB;IAC7C,OAAO,CAAC,mBAAmB,CAAkB;IAC7C,OAAO,CAAC,cAAc,CAA0B;IAChD,OAAO,CAAC,OAAO,CAQb;IACF,OAAO,CAAC,UAAU,CAAgB;IAClC,OAAO,CAAC,eAAe,CAAuE;IAC9F,OAAO,CAAC,QAAQ,CAAC,iBAAiB,CAAO;IAEzC,OAAO,CAAC,cAAc,CAIf;IACP,OAAO,CAAC,OAAO,CAAkB;gBAGvB,QAAQ,EAAE,cAAc,GAAG,IAAI,EAC/B,SAAS,EAAE,MAAM,OAAO;IAQlC,KAAK,IAAI,IAAI;IA0Cb,IAAI,IAAI,IAAI;IAyBN,KAAK,CAAC,MAAM,CAAC,EAAE,cAAc,EAAE,EAAE,SAAS,CAAC,EAAE,iBAAiB,EAAE,EAAE,SAAS,CAAC,EAAE,sBAAsB,EAAE,GAAG,OAAO,CAAC,IAAI,CAAC;YAgD9G,WAAW;YAmDX,cAAc;YAuDd,cAAc;YAiEd,gBAAgB;IAgD9B,OAAO,CAAC,aAAa;IAarB,OAAO,CAAC,oBAAoB;IAiB5B,OAAO,CAAC,oBAAoB;YAmBd,sBAAsB;IAgCpC,OAAO,CAAC,eAAe;IAiBvB,UAAU,IAAI,gBAAgB,GAAG;QAAE,mBAAmB,EAAE,GAAG,CAAC;QAAC,mBAAmB,EAAE,MAAM,CAAA;KAAE;IAW1F,YAAY,IAAI,IAAI;CAarB"}
--- a/dist/telemetry/batch-processor.js
+++ b/dist/telemetry/batch-processor.js
@@ -33,26 +33,36 @@ class TelemetryBatchProcessor {
        this.flushTimes = [];
        this.deadLetterQueue = [];
        this.maxDeadLetterSize = 100;
+        this.eventListeners = {};
+        this.started = false;
        this.circuitBreaker = new telemetry_error_1.TelemetryCircuitBreaker();
    }
    start() {
        if (!this.isEnabled() || !this.supabase)
            return;
+        if (this.started) {
+            logger_1.logger.debug('Telemetry batch processor already started, skipping');
+            return;
+        }
        this.flushTimer = setInterval(() => {
            this.flush();
        }, telemetry_types_1.TELEMETRY_CONFIG.BATCH_FLUSH_INTERVAL);
        if (typeof this.flushTimer === 'object' && 'unref' in this.flushTimer) {
            this.flushTimer.unref();
        }
-        process.on('beforeExit', () => this.flush());
-        process.on('SIGINT', () => {
+        this.eventListeners.beforeExit = () => this.flush();
+        this.eventListeners.sigint = () => {
            this.flush();
            process.exit(0);
-        });
-        process.on('SIGTERM', () => {
+        };
+        this.eventListeners.sigterm = () => {
            this.flush();
            process.exit(0);
-        });
+        };
+        process.on('beforeExit', this.eventListeners.beforeExit);
+        process.on('SIGINT', this.eventListeners.sigint);
+        process.on('SIGTERM', this.eventListeners.sigterm);
+        this.started = true;
        logger_1.logger.debug('Telemetry batch processor started');
    }
    stop() {
@@ -60,6 +70,17 @@ class TelemetryBatchProcessor {
            clearInterval(this.flushTimer);
            this.flushTimer = undefined;
        }
+        if (this.eventListeners.beforeExit) {
+            process.removeListener('beforeExit', this.eventListeners.beforeExit);
+        }
+        if (this.eventListeners.sigint) {
+            process.removeListener('SIGINT', this.eventListeners.sigint);
+        }
+        if (this.eventListeners.sigterm) {
+            process.removeListener('SIGTERM', this.eventListeners.sigterm);
+        }
+        this.eventListeners = {};
+        this.started = false;
        logger_1.logger.debug('Telemetry batch processor stopped');
    }
    async flush(events, workflows, mutations) {
--- a/dist/telemetry/batch-processor.js.map
+++ b/dist/telemetry/batch-processor.js.map
--- a/package-lock.json
+++ b/package-lock.json
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
  "name": "n8n-mcp",
-  "version": "2.33.3",
+  "version": "2.34.0",
  "description": "Integration between n8n workflow automation and Model Context Protocol (MCP)",
  "main": "dist/index.js",
  "types": "dist/index.d.ts",
@@ -16,6 +16,8 @@
  },
  "scripts": {
    "build": "tsc -p tsconfig.build.json",
+    "build:ui": "cd ui-apps && npm install && npm run build",
+    "build:all": "npm run build:ui && npm run build",
    "rebuild": "node dist/scripts/rebuild.js",
    "rebuild:optimized": "node dist/scripts/rebuild-optimized.js",
    "validate": "node dist/scripts/validate.js",
@@ -123,6 +125,7 @@
  "homepage": "https://github.com/czlonkowski/n8n-mcp#readme",
  "files": [
    "dist/**/*",
+    "ui-apps/dist/**/*",
    "data/nodes.db",
    ".env.example",
    "README.md",
@@ -150,16 +153,16 @@
  },
  "dependencies": {
    "@modelcontextprotocol/sdk": "1.20.1",
-    "@n8n/n8n-nodes-langchain": "^2.4.3",
+    "@n8n/n8n-nodes-langchain": "^2.6.2",
    "@supabase/supabase-js": "^2.57.4",
    "dotenv": "^16.5.0",
    "express": "^5.1.0",
    "express-rate-limit": "^7.1.5",
    "form-data": "^4.0.5",
    "lru-cache": "^11.2.1",
-    "n8n": "^2.4.4",
-    "n8n-core": "^2.4.2",
-    "n8n-workflow": "^2.4.2",
+    "n8n": "^2.6.3",
+    "n8n-core": "^2.6.1",
+    "n8n-workflow": "^2.6.0",
    "openai": "^4.77.0",
    "sql.js": "^1.13.0",
    "tslib": "^2.6.2",
--- a/src/database/database-adapter.ts
+++ b/src/database/database-adapter.ts
@@ -419,12 +419,36 @@ class BetterSQLiteStatement implements PreparedStatement {

 /**
 * Statement wrapper for sql.js
+ *
+ * IMPORTANT: sql.js requires explicit memory management via Statement.free().
+ * This wrapper automatically frees statement memory after each operation
+ * to prevent memory leaks during sustained traffic.
+ *
+ * See: https://sql.js.org/documentation/Statement.html
+ * "After calling db.prepare() you must manually free the assigned memory
+ *  by calling Statement.free()."
 */
 class SQLJSStatement implements PreparedStatement {
  private boundParams: any = null;
-  
+  private freed: boolean = false;
+
  constructor(private stmt: any, private onModify: () => void) {}
-  
+
+  /**
+   * Free the underlying sql.js statement memory.
+   * Safe to call multiple times - subsequent calls are no-ops.
+   */
+  private freeStatement(): void {
+    if (!this.freed && this.stmt) {
+      try {
+        this.stmt.free();
+        this.freed = true;
+      } catch (e) {
+        // Statement may already be freed or invalid - ignore
+      }
+    }
+  }
+
  run(...params: any[]): RunResult {
    try {
      if (params.length > 0) {
@@ -433,10 +457,10 @@ class SQLJSStatement implements PreparedStatement {
          this.stmt.bind(this.boundParams);
        }
      }
-      
+
      this.stmt.run();
      this.onModify();
-      
+
      // sql.js doesn't provide changes/lastInsertRowid easily
      return {
        changes: 1, // Assume success means 1 change
@@ -445,9 +469,12 @@ class SQLJSStatement implements PreparedStatement {
    } catch (error) {
      this.stmt.reset();
      throw error;
+    } finally {
+      // Free statement memory after write operation completes
+      this.freeStatement();
    }
  }
-  
+
  get(...params: any[]): any {
    try {
      if (params.length > 0) {
@@ -456,21 +483,24 @@ class SQLJSStatement implements PreparedStatement {
          this.stmt.bind(this.boundParams);
        }
      }
-      
+
      if (this.stmt.step()) {
        const result = this.stmt.getAsObject();
        this.stmt.reset();
        return this.convertIntegerColumns(result);
      }
-      
+
      this.stmt.reset();
      return undefined;
    } catch (error) {
      this.stmt.reset();
      throw error;
+    } finally {
+      // Free statement memory after read operation completes
+      this.freeStatement();
    }
  }
-  
+
  all(...params: any[]): any[] {
    try {
      if (params.length > 0) {
@@ -479,17 +509,20 @@ class SQLJSStatement implements PreparedStatement {
          this.stmt.bind(this.boundParams);
        }
      }
-      
+
      const results: any[] = [];
      while (this.stmt.step()) {
        results.push(this.convertIntegerColumns(this.stmt.getAsObject()));
      }
-      
+
      this.stmt.reset();
      return results;
    } catch (error) {
      this.stmt.reset();
      throw error;
+    } finally {
+      // Free statement memory after read operation completes
+      this.freeStatement();
    }
  }
  
--- a/src/database/shared-database.ts
+++ b/src/database/shared-database.ts
@@ -0,0 +1,197 @@
+/**
+ * Shared Database Manager - Singleton for cross-session database connection
+ *
+ * This module implements a singleton pattern to share a single database connection
+ * across all MCP server sessions. This prevents memory leaks caused by each session
+ * creating its own database connection (~900MB per session).
+ *
+ * Memory impact: Reduces per-session memory from ~900MB to near-zero by sharing
+ * a single ~68MB database connection across all sessions.
+ *
+ * Issue: https://github.com/czlonkowski/n8n-mcp/issues/XXX
+ */
+
+import { DatabaseAdapter, createDatabaseAdapter } from './database-adapter';
+import { NodeRepository } from './node-repository';
+import { TemplateService } from '../templates/template-service';
+import { EnhancedConfigValidator } from '../services/enhanced-config-validator';
+import { logger } from '../utils/logger';
+
+/**
+ * Shared database state - holds the singleton connection and services
+ */
+export interface SharedDatabaseState {
+  db: DatabaseAdapter;
+  repository: NodeRepository;
+  templateService: TemplateService;
+  dbPath: string;
+  refCount: number;
+  initialized: boolean;
+}
+
+// Module-level singleton state
+let sharedState: SharedDatabaseState | null = null;
+let initializationPromise: Promise<SharedDatabaseState> | null = null;
+
+/**
+ * Get or create the shared database connection
+ *
+ * Thread-safe initialization using a promise lock pattern.
+ * Multiple concurrent calls will wait for the same initialization.
+ *
+ * @param dbPath - Path to the SQLite database file
+ * @returns Shared database state with connection and services
+ */
+export async function getSharedDatabase(dbPath: string): Promise<SharedDatabaseState> {
+  // If already initialized with the same path, increment ref count and return
+  if (sharedState && sharedState.initialized && sharedState.dbPath === dbPath) {
+    sharedState.refCount++;
+    logger.debug('Reusing shared database connection', {
+      refCount: sharedState.refCount,
+      dbPath
+    });
+    return sharedState;
+  }
+
+  // If already initialized with a DIFFERENT path, this is a configuration error
+  if (sharedState && sharedState.initialized && sharedState.dbPath !== dbPath) {
+    logger.error('Attempted to initialize shared database with different path', {
+      existingPath: sharedState.dbPath,
+      requestedPath: dbPath
+    });
+    throw new Error(`Shared database already initialized with different path: ${sharedState.dbPath}`);
+  }
+
+  // If initialization is in progress, wait for it
+  if (initializationPromise) {
+    try {
+      const state = await initializationPromise;
+      state.refCount++;
+      logger.debug('Reusing shared database (waited for init)', {
+        refCount: state.refCount,
+        dbPath
+      });
+      return state;
+    } catch (error) {
+      // Initialization failed while we were waiting, clear promise and rethrow
+      initializationPromise = null;
+      throw error;
+    }
+  }
+
+  // Start new initialization
+  initializationPromise = initializeSharedDatabase(dbPath);
+
+  try {
+    const state = await initializationPromise;
+    // Clear the promise on success to allow future re-initialization after close
+    initializationPromise = null;
+    return state;
+  } catch (error) {
+    // Clear promise on failure to allow retry
+    initializationPromise = null;
+    throw error;
+  }
+}
+
+/**
+ * Initialize the shared database connection and services
+ */
+async function initializeSharedDatabase(dbPath: string): Promise<SharedDatabaseState> {
+  logger.info('Initializing shared database connection', { dbPath });
+
+  const db = await createDatabaseAdapter(dbPath);
+  const repository = new NodeRepository(db);
+  const templateService = new TemplateService(db);
+
+  // Initialize similarity services for enhanced validation
+  EnhancedConfigValidator.initializeSimilarityServices(repository);
+
+  sharedState = {
+    db,
+    repository,
+    templateService,
+    dbPath,
+    refCount: 1,
+    initialized: true
+  };
+
+  logger.info('Shared database initialized successfully', {
+    dbPath,
+    refCount: sharedState.refCount
+  });
+
+  return sharedState;
+}
+
+/**
+ * Release a reference to the shared database
+ *
+ * Decrements the reference count. Does NOT close the database
+ * as it's shared across all sessions for the lifetime of the process.
+ *
+ * @param state - The shared database state to release
+ */
+export function releaseSharedDatabase(state: SharedDatabaseState): void {
+  if (!state || !sharedState) {
+    return;
+  }
+
+  // Guard against double-release (refCount going negative)
+  if (sharedState.refCount <= 0) {
+    logger.warn('Attempted to release shared database with refCount already at or below 0', {
+      refCount: sharedState.refCount
+    });
+    return;
+  }
+
+  sharedState.refCount--;
+  logger.debug('Released shared database reference', {
+    refCount: sharedState.refCount
+  });
+
+  // Note: We intentionally do NOT close the database even when refCount hits 0
+  // The database should remain open for the lifetime of the process to handle
+  // new sessions. Only process shutdown should close it.
+}
+
+/**
+ * Force close the shared database (for graceful shutdown only)
+ *
+ * This should only be called during process shutdown, not during normal
+ * session cleanup. Closing the database would break other active sessions.
+ */
+export async function closeSharedDatabase(): Promise<void> {
+  if (!sharedState) {
+    return;
+  }
+
+  logger.info('Closing shared database connection', {
+    refCount: sharedState.refCount
+  });
+
+  try {
+    sharedState.db.close();
+  } catch (error) {
+    logger.warn('Error closing shared database', {
+      error: error instanceof Error ? error.message : String(error)
+    });
+  }
+
+  sharedState = null;
+  initializationPromise = null;
+}
+
+/**
+ * Check if shared database is initialized
+ */
+export function isSharedDatabaseInitialized(): boolean {
+  return sharedState !== null && sharedState.initialized;
+}
+
+/**
+ * Get current reference count (for debugging/monitoring)
+ */
+export function getSharedDatabaseRefCount(): number {
+  return sharedState?.refCount ?? 0;
+}
--- a/src/http-server-single-session.ts
+++ b/src/http-server-single-session.ts
@@ -26,6 +26,7 @@ import {
 } from './utils/protocol-version';
 import { InstanceContext, validateInstanceContext } from './types/instance-context';
 import { SessionState } from './types/session-state';
+import { closeSharedDatabase } from './database/shared-database';

 dotenv.config();

@@ -106,7 +107,12 @@ export class SingleSessionHTTPServer {
  private session: Session | null = null;  // Keep for SSE compatibility
  private consoleManager = new ConsoleManager();
  private expressServer: any;
-  private sessionTimeout = 30 * 60 * 1000; // 30 minutes
+  // Session timeout reduced from 30 minutes to 5 minutes for faster cleanup
+  // Configurable via SESSION_TIMEOUT_MINUTES environment variable
+  // This prevents memory buildup from stale sessions
+  private sessionTimeout = parseInt(
+    process.env.SESSION_TIMEOUT_MINUTES || '5', 10
+  ) * 60 * 1000;
  private authToken: string | null = null;
  private cleanupTimer: NodeJS.Timeout | null = null;
  
@@ -492,6 +498,29 @@ export class SingleSessionHTTPServer {
          // For initialize requests: always create new transport and server
          logger.info('handleRequest: Creating new transport for initialize request');

+          // EAGER CLEANUP: Remove existing sessions for the same instance
+          // This prevents memory buildup when clients reconnect without proper cleanup
+          if (instanceContext?.instanceId) {
+            const sessionsToRemove: string[] = [];
+            for (const [existingSessionId, context] of Object.entries(this.sessionContexts)) {
+              if (context?.instanceId === instanceContext.instanceId) {
+                sessionsToRemove.push(existingSessionId);
+              }
+            }
+            for (const oldSessionId of sessionsToRemove) {
+              // Double-check session still exists (may have been cleaned by concurrent request)
+              if (!this.transports[oldSessionId]) {
+                continue;
+              }
+              logger.info('Cleaning up previous session for instance', {
+                instanceId: instanceContext.instanceId,
+                oldSession: oldSessionId,
+                reason: 'instance_reconnect'
+              });
+              await this.removeSession(oldSessionId, 'instance_reconnect');
+            }
+          }
+
          // Generate session ID based on multi-tenant configuration
          let sessionIdToUse: string;

@@ -677,11 +706,25 @@ export class SingleSessionHTTPServer {
  private async resetSessionSSE(res: express.Response): Promise<void> {
    // Clean up old session if exists
    if (this.session) {
+      const sessionId = this.session.sessionId;
+      logger.info('Closing previous session for SSE', { sessionId });
+
+      // Close server first to free resources (database, cache timer, etc.)
+      // This mirrors the cleanup pattern in removeSession() (issue #542)
+      // Handle server close errors separately so transport close still runs
+      if (this.session.server && typeof this.session.server.close === 'function') {
+        try {
+          await this.session.server.close();
+        } catch (serverError) {
+          logger.warn('Error closing server for SSE session', { sessionId, error: serverError });
+        }
+      }
+
+      // Close transport last - always attempt even if server.close() failed
      try {
-        logger.info('Closing previous session for SSE', { sessionId: this.session.sessionId });
        await this.session.transport.close();
-      } catch (error) {
-        logger.warn('Error closing previous session:', error);
+      } catch (transportError) {
+        logger.warn('Error closing transport for SSE session', { sessionId, error: transportError });
      }
    }
    
@@ -1408,7 +1451,16 @@ export class SingleSessionHTTPServer {
        });
      });
    }
-    
+
+    // Close the shared database connection (only during process shutdown)
+    // This must happen after all sessions are closed
+    try {
+      await closeSharedDatabase();
+      logger.info('Shared database closed');
+    } catch (error) {
+      logger.warn('Error closing shared database:', error);
+    }
+
    logger.info('Single-Session HTTP server shutdown completed');
  }
  
--- a/src/index.ts
+++ b/src/index.ts
@@ -22,6 +22,10 @@ export type {
  SessionState
 } from './types/session-state';

+// UI module exports
+export type { UIAppConfig, UIMetadata } from './mcp/ui/types';
+export { UI_APP_CONFIGS } from './mcp/ui/app-configs';
+
 // Re-export MCP SDK types for convenience
 export type {
  Tool,
--- a/src/mcp/server.ts
+++ b/src/mcp/server.ts
@@ -1,19 +1,23 @@
 import { Server } from '@modelcontextprotocol/sdk/server/index.js';
 import { StdioServerTransport } from '@modelcontextprotocol/sdk/server/stdio.js';
-import { 
-  CallToolRequestSchema, 
+import {
+  CallToolRequestSchema,
  ListToolsRequestSchema,
  InitializeRequestSchema,
+  ListResourcesRequestSchema,
+  ReadResourceRequestSchema,
 } from '@modelcontextprotocol/sdk/types.js';
 import { existsSync, promises as fs } from 'fs';
 import path from 'path';
 import { n8nDocumentationToolsFinal } from './tools';
+import { UIAppRegistry } from './ui';
 import { n8nManagementTools } from './tools-n8n-manager';
 import { makeToolsN8nFriendly } from './tools-n8n-friendly';
 import { getWorkflowExampleString } from './workflow-examples';
 import { logger } from '../utils/logger';
 import { NodeRepository } from '../database/node-repository';
 import { DatabaseAdapter, createDatabaseAdapter } from '../database/database-adapter';
+import { getSharedDatabase, releaseSharedDatabase, SharedDatabaseState } from '../database/shared-database';
 import { PropertyFilter } from '../services/property-filter';
 import { TaskTemplates } from '../services/task-templates';
 import { ConfigValidator } from '../services/config-validator';
@@ -150,6 +154,9 @@ export class N8NDocumentationMCPServer {
  private previousToolTimestamp: number = Date.now();
  private earlyLogger: EarlyErrorLogger | null = null;
  private disabledToolsCache: Set<string> | null = null;
+  private useSharedDatabase: boolean = false;  // Track if using shared DB for cleanup
+  private sharedDbState: SharedDatabaseState | null = null;  // Reference to shared DB state for release
+  private isShutdown: boolean = false;  // Prevent double-shutdown

  constructor(instanceContext?: InstanceContext, earlyLogger?: EarlyErrorLogger) {
    this.instanceContext = instanceContext;
@@ -231,10 +238,12 @@ export class N8NDocumentationMCPServer {
      {
        capabilities: {
          tools: {},
+          resources: {},
        },
      }
    );

+    UIAppRegistry.load();
    this.setupHandlers();
  }

@@ -245,18 +254,39 @@ export class N8NDocumentationMCPServer {
   * Order of cleanup:
   * 1. Close MCP server connection
   * 2. Destroy cache (clears entries AND stops cleanup timer)
-   * 3. Close database connection
+   * 3. Release shared database OR close dedicated connection
   * 4. Null out references to help GC
+   *
+   * IMPORTANT: For shared databases, we only release the reference (decrement refCount),
+   * NOT close the database. The database stays open for other sessions.
+   * For in-memory databases (tests), we close the dedicated connection.
   */
  async close(): Promise<void> {
+    // Wait for initialization to complete (or fail) before cleanup
+    // This prevents race conditions where close runs while init is in progress
+    try {
+      await this.initialized;
+    } catch (error) {
+      // Initialization failed - that's OK, we still need to clean up
+      logger.debug('Initialization had failed, proceeding with cleanup', {
+        error: error instanceof Error ? error.message : String(error)
+      });
+    }
+
    try {
      await this.server.close();

      // Use destroy() not clear() - also stops the cleanup timer
      this.cache.destroy();

-      // Close database connection before nullifying reference
-      if (this.db) {
+      // Handle database cleanup based on whether it's shared or dedicated
+      if (this.useSharedDatabase && this.sharedDbState) {
+        // Shared database: release reference, don't close
+        // The database stays open for other sessions
+        releaseSharedDatabase(this.sharedDbState);
+        logger.debug('Released shared database reference');
+      } else if (this.db) {
+        // Dedicated database (in-memory for tests): close it
        try {
          this.db.close();
        } catch (dbError) {
@@ -271,6 +301,7 @@ export class N8NDocumentationMCPServer {
      this.repository = null;
      this.templateService = null;
      this.earlyLogger = null;
+      this.sharedDbState = null;
    } catch (error) {
      // Log but don't throw - cleanup should be best-effort
      logger.warn('Error closing MCP server', { error: error instanceof Error ? error.message : String(error) });
@@ -286,23 +317,32 @@ export class N8NDocumentationMCPServer {

      logger.debug('Database initialization starting...', { dbPath });

-      this.db = await createDatabaseAdapter(dbPath);
-      logger.debug('Database adapter created');
-
-      // If using in-memory database for tests, initialize schema
+      // For in-memory databases (tests), create a dedicated connection
+      // For regular databases, use the shared connection to prevent memory leaks
      if (dbPath === ':memory:') {
+        this.db = await createDatabaseAdapter(dbPath);
+        logger.debug('Database adapter created (in-memory mode)');
        await this.initializeInMemorySchema();
        logger.debug('In-memory schema initialized');
+        this.repository = new NodeRepository(this.db);
+        this.templateService = new TemplateService(this.db);
+        // Initialize similarity services for enhanced validation
+        EnhancedConfigValidator.initializeSimilarityServices(this.repository);
+        this.useSharedDatabase = false;
+      } else {
+        // Use shared database connection to prevent ~900MB memory leak per session
+        // See: Memory leak fix - database was being duplicated per session
+        const sharedState = await getSharedDatabase(dbPath);
+        this.db = sharedState.db;
+        this.repository = sharedState.repository;
+        this.templateService = sharedState.templateService;
+        this.sharedDbState = sharedState;
+        this.useSharedDatabase = true;
+        logger.debug('Using shared database connection');
      }

-      this.repository = new NodeRepository(this.db);
      logger.debug('Node repository initialized');
-
-      this.templateService = new TemplateService(this.db);
      logger.debug('Template service initialized');
-
-      // Initialize similarity services for enhanced validation
-      EnhancedConfigValidator.initializeSimilarityServices(this.repository);
      logger.debug('Similarity services initialized');

      // Checkpoint: Database connected (v2.18.3)
@@ -528,6 +568,7 @@ export class N8NDocumentationMCPServer {
        protocolVersion: negotiationResult.version,
        capabilities: {
          tools: {},
+          resources: {},
        },
        serverInfo: {
          name: 'n8n-documentation-mcp',
@@ -739,7 +780,13 @@ export class N8NDocumentationMCPServer {
        if (name.startsWith('validate_') && structuredContent !== null) {
          mcpResponse.structuredContent = structuredContent;
        }
-        
+
+        // Inject UI app metadata if available
+        const uiApp = UIAppRegistry.getAppForTool(name);
+        if (uiApp && uiApp.html) {
+          mcpResponse._meta = { ui: { app: uiApp.config.uri } };
+        }
+
        return mcpResponse;
      } catch (error) {
        logger.error(`Error executing tool ${name}`, error);
@@ -791,6 +838,46 @@ export class N8NDocumentationMCPServer {
        };
      }
    });
+
+    // Handle ListResources for UI apps
+    this.server.setRequestHandler(ListResourcesRequestSchema, async () => {
+      const apps = UIAppRegistry.getAllApps();
+      return {
+        resources: apps
+          .filter(app => app.html !== null)
+          .map(app => ({
+            uri: app.config.uri,
+            name: app.config.displayName,
+            description: app.config.description,
+            mimeType: app.config.mimeType,
+          })),
+      };
+    });
+
+    // Handle ReadResource for UI apps
+    this.server.setRequestHandler(ReadResourceRequestSchema, async (request) => {
+      const uri = request.params.uri;
+      // Parse n8n-mcp://ui/{id} pattern
+      const match = uri.match(/^n8n-mcp:\/\/ui\/(.+)$/);
+      if (!match) {
+        throw new Error(`Unknown resource URI: ${uri}`);
+      }
+
+      const app = UIAppRegistry.getAppById(match[1]);
+      if (!app || !app.html) {
+        throw new Error(`UI app not found or not built: ${match[1]}`);
+      }
+
+      return {
+        contents: [
+          {
+            uri: app.config.uri,
+            mimeType: app.config.mimeType,
+            text: app.html,
+          },
+        ],
+      };
+    });
  }

  /**
@@ -3910,8 +3997,33 @@ Full documentation is being prepared. For now, use get_node_essentials for confi
  }
  
  async shutdown(): Promise<void> {
+    // Prevent double-shutdown
+    if (this.isShutdown) {
+      logger.debug('Shutdown already called, skipping');
+      return;
+    }
+    this.isShutdown = true;
+
    logger.info('Shutting down MCP server...');
-    
+
+    // Wait for initialization to complete (or fail) before cleanup
+    // This prevents race conditions where shutdown runs while init is in progress
+    try {
+      await this.initialized;
+    } catch (error) {
+      // Initialization failed - that's OK, we still need to clean up
+      logger.debug('Initialization had failed, proceeding with cleanup', {
+        error: error instanceof Error ? error.message : String(error)
+      });
+    }
+
+    // Close MCP server connection (for consistency with close() method)
+    try {
+      await this.server.close();
+    } catch (error) {
+      logger.error('Error closing MCP server:', error);
+    }
+
    // Clean up cache timers to prevent memory leaks
    if (this.cache) {
      try {
@@ -3921,15 +4033,31 @@ Full documentation is being prepared. For now, use get_node_essentials for confi
        logger.error('Error cleaning up cache:', error);
      }
    }
-    
-    // Close database connection if it exists
-    if (this.db) {
+
+    // Handle database cleanup based on whether it's shared or dedicated
+    // For shared databases, we only release the reference (decrement refCount)
+    // For dedicated databases (in-memory for tests), we close the connection
+    if (this.useSharedDatabase && this.sharedDbState) {
      try {
-        await this.db.close();
+        releaseSharedDatabase(this.sharedDbState);
+        logger.info('Released shared database reference');
+      } catch (error) {
+        logger.error('Error releasing shared database:', error);
+      }
+    } else if (this.db) {
+      try {
+        this.db.close();
        logger.info('Database connection closed');
      } catch (error) {
        logger.error('Error closing database:', error);
      }
    }
+
+    // Null out references to help garbage collection
+    this.db = null;
+    this.repository = null;
+    this.templateService = null;
+    this.earlyLogger = null;
+    this.sharedDbState = null;
  }
 }
--- a/src/mcp/ui/app-configs.ts
+++ b/src/mcp/ui/app-configs.ts
@@ -0,0 +1,32 @@
+import type { UIAppConfig } from './types';
+
+export const UI_APP_CONFIGS: UIAppConfig[] = [
+  {
+    id: 'operation-result',
+    displayName: 'Operation Result',
+    description: 'Visual summary of workflow operations (create, update, delete, test)',
+    uri: 'n8n-mcp://ui/operation-result',
+    mimeType: 'text/html',
+    toolPatterns: [
+      'n8n_create_workflow',
+      'n8n_update_full_workflow',
+      'n8n_update_partial_workflow',
+      'n8n_delete_workflow',
+      'n8n_test_workflow',
+      'n8n_autofix_workflow',
+      'n8n_deploy_template',
+    ],
+  },
+  {
+    id: 'validation-summary',
+    displayName: 'Validation Summary',
+    description: 'Visual summary of node and workflow validation results',
+    uri: 'n8n-mcp://ui/validation-summary',
+    mimeType: 'text/html',
+    toolPatterns: [
+      'validate_node',
+      'validate_workflow',
+      'n8n_validate_workflow',
+    ],
+  },
+];
--- a/src/mcp/ui/index.ts
+++ b/src/mcp/ui/index.ts
@@ -0,0 +1,3 @@
+export type { UIAppConfig, UIMetadata, UIAppEntry } from './types';
+export { UI_APP_CONFIGS } from './app-configs';
+export { UIAppRegistry } from './registry';
--- a/src/mcp/ui/registry.ts
+++ b/src/mcp/ui/registry.ts
@@ -0,0 +1,69 @@
+import { existsSync, readFileSync } from 'fs';
+import path from 'path';
+import { logger } from '../../utils/logger';
+import type { UIAppConfig, UIAppEntry } from './types';
+import { UI_APP_CONFIGS } from './app-configs';
+
+export class UIAppRegistry {
+  private static entries: Map<string, UIAppEntry> = new Map();
+  private static toolIndex: Map<string, UIAppEntry> = new Map();
+  private static loaded = false;
+
+  static load(): void {
+    // Resolve dist directory relative to package root
+    // In production: package-root/ui-apps/dist/
+    // __dirname will be src/mcp/ui or dist/mcp/ui
+    const packageRoot = path.resolve(__dirname, '..', '..', '..');
+    const distDir = path.join(packageRoot, 'ui-apps', 'dist');
+
+    this.entries.clear();
+    this.toolIndex.clear();
+
+    for (const config of UI_APP_CONFIGS) {
+      let html: string | null = null;
+      const htmlPath = path.join(distDir, config.id, 'index.html');
+
+      if (existsSync(htmlPath)) {
+        try {
+          html = readFileSync(htmlPath, 'utf-8');
+          logger.info(`Loaded UI app: ${config.id}`);
+        } catch (err) {
+          logger.warn(`Failed to read UI app HTML: ${config.id}`, err);
+        }
+      }
+
+      const entry: UIAppEntry = { config, html };
+      this.entries.set(config.id, entry);
+
+      // Build tool -> entry index
+      for (const pattern of config.toolPatterns) {
+        this.toolIndex.set(pattern, entry);
+      }
+    }
+
+    this.loaded = true;
+    logger.info(`UI App Registry loaded: ${this.entries.size} apps, ${this.toolIndex.size} tool mappings`);
+  }
+
+  static getAppForTool(toolName: string): UIAppEntry | null {
+    if (!this.loaded) return null;
+    return this.toolIndex.get(toolName) ?? null;
+  }
+
+  static getAppById(id: string): UIAppEntry | null {
+    if (!this.loaded) return null;
+    return this.entries.get(id) ?? null;
+  }
+
+  static getAllApps(): UIAppEntry[] {
+    if (!this.loaded) return [];
+    return Array.from(this.entries.values());
+  }
+
+  /** Reset registry state. Intended for testing only. */
+  static reset(): void {
+    this.entries.clear();
+    this.toolIndex.clear();
+    this.loaded = false;
+  }
+}
--- a/src/mcp/ui/types.ts
+++ b/src/mcp/ui/types.ts
@@ -0,0 +1,23 @@
+/**
+ * MCP Apps UI type definitions
+ */
+
+export interface UIAppConfig {
+  id: string;
+  displayName: string;
+  description: string;
+  uri: string;
+  mimeType: string;
+  toolPatterns: string[];
+}
+
+export interface UIMetadata {
+  ui: {
+    app: string;
+  };
+}
+
+export interface UIAppEntry {
+  config: UIAppConfig;
+  html: string | null;
+}
--- a/src/telemetry/batch-processor.ts
+++ b/src/telemetry/batch-processor.ts
@@ -58,6 +58,13 @@ export class TelemetryBatchProcessor {
  private flushTimes: number[] = [];
  private deadLetterQueue: (TelemetryEvent | WorkflowTelemetry | WorkflowMutationRecord)[] = [];
  private readonly maxDeadLetterSize = 100;
+  // Track event listeners for proper cleanup to prevent memory leaks
+  private eventListeners: {
+    beforeExit?: () => void;
+    sigint?: () => void;
+    sigterm?: () => void;
+  } = {};
+  private started: boolean = false;

  constructor(
    private supabase: SupabaseClient | null,
@@ -72,6 +79,12 @@ export class TelemetryBatchProcessor {
  start(): void {
    if (!this.isEnabled() || !this.supabase) return;

+    // Guard against multiple starts (prevents event listener accumulation)
+    if (this.started) {
+      logger.debug('Telemetry batch processor already started, skipping');
+      return;
+    }
+
    // Set up periodic flushing
    this.flushTimer = setInterval(() => {
      this.flush();
@@ -83,17 +96,22 @@ export class TelemetryBatchProcessor {
      this.flushTimer.unref();
    }

-    // Set up process exit handlers
-    process.on('beforeExit', () => this.flush());
-    process.on('SIGINT', () => {
+    // Set up process exit handlers with stored references for cleanup
+    this.eventListeners.beforeExit = () => this.flush();
+    this.eventListeners.sigint = () => {
      this.flush();
      process.exit(0);
-    });
-    process.on('SIGTERM', () => {
+    };
+    this.eventListeners.sigterm = () => {
      this.flush();
      process.exit(0);
-    });
+    };

+    process.on('beforeExit', this.eventListeners.beforeExit);
+    process.on('SIGINT', this.eventListeners.sigint);
+    process.on('SIGTERM', this.eventListeners.sigterm);
+
+    this.started = true;
    logger.debug('Telemetry batch processor started');
  }

@@ -105,6 +123,20 @@ export class TelemetryBatchProcessor {
      clearInterval(this.flushTimer);
      this.flushTimer = undefined;
    }
+
+    // Remove event listeners to prevent memory leaks
+    if (this.eventListeners.beforeExit) {
+      process.removeListener('beforeExit', this.eventListeners.beforeExit);
+    }
+    if (this.eventListeners.sigint) {
+      process.removeListener('SIGINT', this.eventListeners.sigint);
+    }
+    if (this.eventListeners.sigterm) {
+      process.removeListener('SIGTERM', this.eventListeners.sigterm);
+    }
+    this.eventListeners = {};
+    this.started = false;
+
    logger.debug('Telemetry batch processor stopped');
  }

--- a/tests/unit/database/shared-database.test.ts
+++ b/tests/unit/database/shared-database.test.ts
@@ -0,0 +1,302 @@
+import { describe, it, expect, vi, beforeEach, afterEach } from 'vitest';
+
+// Mock dependencies at module level
+const mockDb = {
+  prepare: vi.fn().mockReturnValue({
+    get: vi.fn(),
+    all: vi.fn(),
+    run: vi.fn()
+  }),
+  exec: vi.fn(),
+  close: vi.fn(),
+  pragma: vi.fn(),
+  inTransaction: false,
+  transaction: vi.fn(),
+  checkFTS5Support: vi.fn()
+};
+
+vi.mock('../../../src/database/database-adapter', () => ({
+  createDatabaseAdapter: vi.fn().mockResolvedValue(mockDb)
+}));
+
+vi.mock('../../../src/database/node-repository', () => ({
+  NodeRepository: vi.fn().mockImplementation(() => ({
+    getNodeTypes: vi.fn().mockReturnValue([])
+  }))
+}));
+
+vi.mock('../../../src/templates/template-service', () => ({
+  TemplateService: vi.fn().mockImplementation(() => ({}))
+}));
+
+vi.mock('../../../src/services/enhanced-config-validator', () => ({
+  EnhancedConfigValidator: {
+    initializeSimilarityServices: vi.fn()
+  }
+}));
+
+vi.mock('../../../src/utils/logger', () => ({
+  logger: {
+    debug: vi.fn(),
+    info: vi.fn(),
+    warn: vi.fn(),
+    error: vi.fn()
+  }
+}));
+
+describe('Shared Database Module', () => {
+  let sharedDbModule: typeof import('../../../src/database/shared-database');
+  let createDatabaseAdapter: ReturnType<typeof vi.fn>;
+
+  beforeEach(async () => {
+    // Reset all mocks
+    vi.clearAllMocks();
+    mockDb.close.mockReset();
+
+    // Reset modules to get fresh state
+    vi.resetModules();
+
+    // Import fresh module
+    sharedDbModule = await import('../../../src/database/shared-database');
+
+    // Get the mocked function
+    const adapterModule = await import('../../../src/database/database-adapter');
+    createDatabaseAdapter = adapterModule.createDatabaseAdapter as ReturnType<typeof vi.fn>;
+  });
+
+  afterEach(async () => {
+    // Clean up any shared state by closing
+    try {
+      await sharedDbModule.closeSharedDatabase();
+    } catch {
+      // Ignore errors during cleanup
+    }
+  });
+
+  describe('getSharedDatabase', () => {
+    it('should initialize database on first call', async () => {
+      const state = await sharedDbModule.getSharedDatabase('/path/to/db');
+
+      expect(state).toBeDefined();
+      expect(state.db).toBe(mockDb);
+      expect(state.dbPath).toBe('/path/to/db');
+      expect(state.refCount).toBe(1);
+      expect(state.initialized).toBe(true);
+      expect(createDatabaseAdapter).toHaveBeenCalledWith('/path/to/db');
+    });
+
+    it('should reuse existing connection and increment refCount', async () => {
+      // First call initializes
+      const state1 = await sharedDbModule.getSharedDatabase('/path/to/db');
+      expect(state1.refCount).toBe(1);
+
+      // Second call reuses
+      const state2 = await sharedDbModule.getSharedDatabase('/path/to/db');
+      expect(state2.refCount).toBe(2);
+
+      // Same object
+      expect(state1).toBe(state2);
+
+      // Only initialized once
+      expect(createDatabaseAdapter).toHaveBeenCalledTimes(1);
+    });
+
+    it('should throw error when called with different path', async () => {
+      await sharedDbModule.getSharedDatabase('/path/to/db1');
+
+      await expect(sharedDbModule.getSharedDatabase('/path/to/db2'))
+        .rejects.toThrow('Shared database already initialized with different path');
+    });
+
+    it('should handle concurrent initialization requests', async () => {
+      // Start two requests concurrently
+      const [state1, state2] = await Promise.all([
+        sharedDbModule.getSharedDatabase('/path/to/db'),
+        sharedDbModule.getSharedDatabase('/path/to/db')
+      ]);
+
+      // Both should get the same state
+      expect(state1).toBe(state2);
+
+      // RefCount should be 2 (one for each call)
+      expect(state1.refCount).toBe(2);
+
+      // Only one actual initialization
+      expect(createDatabaseAdapter).toHaveBeenCalledTimes(1);
+    });
+
+    it('should handle initialization failure', async () => {
+      createDatabaseAdapter.mockRejectedValueOnce(new Error('DB error'));
+
+      await expect(sharedDbModule.getSharedDatabase('/path/to/db'))
+        .rejects.toThrow('DB error');
+
+      // After failure, should not be initialized
+      expect(sharedDbModule.isSharedDatabaseInitialized()).toBe(false);
+    });
+
+    it('should allow retry after initialization failure', async () => {
+      // First call fails
+      createDatabaseAdapter.mockRejectedValueOnce(new Error('DB error'));
+      await expect(sharedDbModule.getSharedDatabase('/path/to/db'))
+        .rejects.toThrow('DB error');
+
+      // Reset mock for successful call
+      createDatabaseAdapter.mockResolvedValueOnce(mockDb);
+
+      // Second call succeeds
+      const state = await sharedDbModule.getSharedDatabase('/path/to/db');
+
+      expect(state).toBeDefined();
+      expect(state.initialized).toBe(true);
+    });
+  });
+
+  describe('releaseSharedDatabase', () => {
+    it('should decrement refCount', async () => {
+      const state = await sharedDbModule.getSharedDatabase('/path/to/db');
+      expect(state.refCount).toBe(1);
+
+      sharedDbModule.releaseSharedDatabase(state);
+      expect(sharedDbModule.getSharedDatabaseRefCount()).toBe(0);
+    });
+
+    it('should not decrement below 0', async () => {
+      const state = await sharedDbModule.getSharedDatabase('/path/to/db');
+
+      // Release once (refCount: 1 -> 0)
+      sharedDbModule.releaseSharedDatabase(state);
+      expect(sharedDbModule.getSharedDatabaseRefCount()).toBe(0);
+
+      // Release again (should stay at 0, not go negative)
+      sharedDbModule.releaseSharedDatabase(state);
+      expect(sharedDbModule.getSharedDatabaseRefCount()).toBe(0);
+    });
+
+    it('should handle null state gracefully', () => {
+      // Should not throw
+      sharedDbModule.releaseSharedDatabase(null as any);
+    });
+
+    it('should not close database when refCount hits 0', async () => {
+      const state = await sharedDbModule.getSharedDatabase('/path/to/db');
+      sharedDbModule.releaseSharedDatabase(state);
+
+      expect(sharedDbModule.getSharedDatabaseRefCount()).toBe(0);
+      expect(mockDb.close).not.toHaveBeenCalled();
+
+      // Database should still be accessible
+      expect(sharedDbModule.isSharedDatabaseInitialized()).toBe(true);
+    });
+  });
+
+  describe('closeSharedDatabase', () => {
+    it('should close database and clear state', async () => {
+      // Get state
+      await sharedDbModule.getSharedDatabase('/path/to/db');
+      expect(sharedDbModule.isSharedDatabaseInitialized()).toBe(true);
+      expect(sharedDbModule.getSharedDatabaseRefCount()).toBe(1);
+
+      await sharedDbModule.closeSharedDatabase();
+
+      // State should be cleared
+      expect(sharedDbModule.isSharedDatabaseInitialized()).toBe(false);
+      expect(sharedDbModule.getSharedDatabaseRefCount()).toBe(0);
+    });
+
+    it('should handle close error gracefully', async () => {
+      await sharedDbModule.getSharedDatabase('/path/to/db');
+      mockDb.close.mockImplementationOnce(() => {
+        throw new Error('Close error');
+      });
+
+      // Should not throw
+      await sharedDbModule.closeSharedDatabase();
+
+      // State should still be cleared
+      expect(sharedDbModule.isSharedDatabaseInitialized()).toBe(false);
+    });
+
+    it('should be idempotent when already closed', async () => {
+      // Close without ever initializing
+      await sharedDbModule.closeSharedDatabase();
+
+      // Should not throw
+      await sharedDbModule.closeSharedDatabase();
+    });
+
+    it('should allow re-initialization after close', async () => {
+      // Initialize
+      const state1 = await sharedDbModule.getSharedDatabase('/path/to/db');
+      expect(state1.refCount).toBe(1);
+
+      // Close
+      await sharedDbModule.closeSharedDatabase();
+      expect(sharedDbModule.isSharedDatabaseInitialized()).toBe(false);
+
+      // Re-initialize
+      const state2 = await sharedDbModule.getSharedDatabase('/path/to/db');
+      expect(state2.refCount).toBe(1);
+      expect(sharedDbModule.isSharedDatabaseInitialized()).toBe(true);
+
+      // Should be a new state object
+      expect(state1).not.toBe(state2);
+    });
+  });
+
+  describe('isSharedDatabaseInitialized', () => {
+    it('should return false before initialization', () => {
+      expect(sharedDbModule.isSharedDatabaseInitialized()).toBe(false);
+    });
+
+    it('should return true after initialization', async () => {
+      await sharedDbModule.getSharedDatabase('/path/to/db');
+      expect(sharedDbModule.isSharedDatabaseInitialized()).toBe(true);
+    });
+
+    it('should return false after close', async () => {
+      await sharedDbModule.getSharedDatabase('/path/to/db');
+      await sharedDbModule.closeSharedDatabase();
+      expect(sharedDbModule.isSharedDatabaseInitialized()).toBe(false);
+    });
+  });
+
+  describe('getSharedDatabaseRefCount', () => {
+    it('should return 0 before initialization', () => {
+      expect(sharedDbModule.getSharedDatabaseRefCount()).toBe(0);
+    });
+
+    it('should return correct refCount after multiple operations', async () => {
+      const state = await sharedDbModule.getSharedDatabase('/path/to/db');
+      expect(sharedDbModule.getSharedDatabaseRefCount()).toBe(1);
+
+      await sharedDbModule.getSharedDatabase('/path/to/db');
+      expect(sharedDbModule.getSharedDatabaseRefCount()).toBe(2);
+
+      await sharedDbModule.getSharedDatabase('/path/to/db');
+      expect(sharedDbModule.getSharedDatabaseRefCount()).toBe(3);
+
+      sharedDbModule.releaseSharedDatabase(state);
+      expect(sharedDbModule.getSharedDatabaseRefCount()).toBe(2);
+    });
+
+    it('should return 0 after close', async () => {
+      await sharedDbModule.getSharedDatabase('/path/to/db');
+      await sharedDbModule.closeSharedDatabase();
+      expect(sharedDbModule.getSharedDatabaseRefCount()).toBe(0);
+    });
+  });
+
+  describe('SharedDatabaseState interface', () => {
+    it('should expose correct properties', async () => {
+      const state = await sharedDbModule.getSharedDatabase('/path/to/db');
+
+      expect(state).toHaveProperty('db');
+      expect(state).toHaveProperty('repository');
+      expect(state).toHaveProperty('templateService');
+      expect(state).toHaveProperty('dbPath');
+      expect(state).toHaveProperty('refCount');
+      expect(state).toHaveProperty('initialized');
+    });
+  });
+});
--- a/tests/unit/http-server-session-management.test.ts
+++ b/tests/unit/http-server-session-management.test.ts
@@ -333,13 +333,14 @@ describe('HTTP Server Session Management', () => {
      server = new SingleSessionHTTPServer();
      
      // Mock expired sessions
+      // Note: Default session timeout is 5 minutes (configurable via SESSION_TIMEOUT_MINUTES)
      const mockSessionMetadata = {
-        'session-1': { 
-          lastAccess: new Date(Date.now() - 40 * 60 * 1000), // 40 minutes ago (expired)
+        'session-1': {
+          lastAccess: new Date(Date.now() - 10 * 60 * 1000), // 10 minutes ago (expired with 5 min timeout)
          createdAt: new Date(Date.now() - 60 * 60 * 1000)
        },
-        'session-2': { 
-          lastAccess: new Date(Date.now() - 10 * 60 * 1000), // 10 minutes ago (not expired)
+        'session-2': {
+          lastAccess: new Date(Date.now() - 2 * 60 * 1000), // 2 minutes ago (not expired with 5 min timeout)
          createdAt: new Date(Date.now() - 20 * 60 * 1000)
        }
      };
@@ -514,15 +515,16 @@ describe('HTTP Server Session Management', () => {

    it('should get session metrics correctly', async () => {
      server = new SingleSessionHTTPServer();
-      
+
+      // Note: Default session timeout is 5 minutes (configurable via SESSION_TIMEOUT_MINUTES)
      const now = Date.now();
      (server as any).sessionMetadata = {
        'active-session': {
-          lastAccess: new Date(now - 10 * 60 * 1000), // 10 minutes ago
+          lastAccess: new Date(now - 2 * 60 * 1000), // 2 minutes ago (not expired with 5 min timeout)
          createdAt: new Date(now - 20 * 60 * 1000)
        },
        'expired-session': {
-          lastAccess: new Date(now - 40 * 60 * 1000), // 40 minutes ago (expired)
+          lastAccess: new Date(now - 10 * 60 * 1000), // 10 minutes ago (expired with 5 min timeout)
          createdAt: new Date(now - 60 * 60 * 1000)
        }
      };
@@ -532,7 +534,7 @@ describe('HTTP Server Session Management', () => {
      };

      const metrics = (server as any).getSessionMetrics();
-      
+
      expect(metrics.totalSessions).toBe(2);
      expect(metrics.activeSessions).toBe(2);
      expect(metrics.expiredSessions).toBe(1);
--- a/tests/unit/mcp/ui/app-configs.test.ts
+++ b/tests/unit/mcp/ui/app-configs.test.ts
@@ -0,0 +1,110 @@
+import { describe, it, expect } from 'vitest';
+import { UI_APP_CONFIGS } from '@/mcp/ui/app-configs';
+
+describe('UI_APP_CONFIGS', () => {
+  it('should have all required fields for every config', () => {
+    for (const config of UI_APP_CONFIGS) {
+      expect(config.id).toBeDefined();
+      expect(typeof config.id).toBe('string');
+      expect(config.id.length).toBeGreaterThan(0);
+
+      expect(config.displayName).toBeDefined();
+      expect(typeof config.displayName).toBe('string');
+      expect(config.displayName.length).toBeGreaterThan(0);
+
+      expect(config.description).toBeDefined();
+      expect(typeof config.description).toBe('string');
+      expect(config.description.length).toBeGreaterThan(0);
+
+      expect(config.uri).toBeDefined();
+      expect(typeof config.uri).toBe('string');
+
+      expect(config.mimeType).toBeDefined();
+      expect(typeof config.mimeType).toBe('string');
+
+      expect(config.toolPatterns).toBeDefined();
+      expect(Array.isArray(config.toolPatterns)).toBe(true);
+    }
+  });
+
+  it('should have URIs following n8n-mcp://ui/{id} pattern', () => {
+    for (const config of UI_APP_CONFIGS) {
+      expect(config.uri).toBe(`n8n-mcp://ui/${config.id}`);
+    }
+  });
+
+  it('should have unique IDs', () => {
+    const ids = UI_APP_CONFIGS.map(c => c.id);
+    const uniqueIds = new Set(ids);
+    expect(uniqueIds.size).toBe(ids.length);
+  });
+
+  it('should have non-empty toolPatterns arrays', () => {
+    for (const config of UI_APP_CONFIGS) {
+      expect(config.toolPatterns.length).toBeGreaterThan(0);
+      for (const pattern of config.toolPatterns) {
+        expect(typeof pattern).toBe('string');
+        expect(pattern.length).toBeGreaterThan(0);
+      }
+    }
+  });
+
+  it('should not have duplicate tool patterns across configs', () => {
+    const allPatterns: string[] = [];
+    for (const config of UI_APP_CONFIGS) {
+      allPatterns.push(...config.toolPatterns);
+    }
+    const uniquePatterns = new Set(allPatterns);
+    expect(uniquePatterns.size).toBe(allPatterns.length);
+  });
+
+  it('should not have duplicate tool patterns within a single config', () => {
+    for (const config of UI_APP_CONFIGS) {
+      const unique = new Set(config.toolPatterns);
+      expect(unique.size).toBe(config.toolPatterns.length);
+    }
+  });
+
+  it('should have consistent mimeType of text/html', () => {
+    for (const config of UI_APP_CONFIGS) {
+      expect(config.mimeType).toBe('text/html');
+    }
+  });
+
+  it('should have URIs that start with the n8n-mcp://ui/ scheme', () => {
+    for (const config of UI_APP_CONFIGS) {
+      expect(config.uri).toMatch(/^n8n-mcp:\/\/ui\//);
+    }
+  });
+
+  // Regression: verify expected configs are present
+  it('should contain the operation-result config', () => {
+    const config = UI_APP_CONFIGS.find(c => c.id === 'operation-result');
+    expect(config).toBeDefined();
+    expect(config!.displayName).toBe('Operation Result');
+    expect(config!.toolPatterns).toContain('n8n_create_workflow');
+    expect(config!.toolPatterns).toContain('n8n_update_full_workflow');
+    expect(config!.toolPatterns).toContain('n8n_delete_workflow');
+    expect(config!.toolPatterns).toContain('n8n_test_workflow');
+    expect(config!.toolPatterns).toContain('n8n_deploy_template');
+  });
+
+  it('should contain the validation-summary config', () => {
+    const config = UI_APP_CONFIGS.find(c => c.id === 'validation-summary');
+    expect(config).toBeDefined();
+    expect(config!.displayName).toBe('Validation Summary');
+    expect(config!.toolPatterns).toContain('validate_node');
+    expect(config!.toolPatterns).toContain('validate_workflow');
+    expect(config!.toolPatterns).toContain('n8n_validate_workflow');
+  });
+
+  it('should have exactly 2 configs', () => {
+    expect(UI_APP_CONFIGS.length).toBe(2);
+  });
+
+  it('should have IDs that are valid URI path segments (no spaces or special chars)', () => {
+    for (const config of UI_APP_CONFIGS) {
+      expect(config.id).toMatch(/^[a-z0-9-]+$/);
+    }
+  });
+});
--- a/tests/unit/mcp/ui/meta-injection.test.ts
+++ b/tests/unit/mcp/ui/meta-injection.test.ts
@@ -0,0 +1,214 @@
+import { describe, it, expect, vi, beforeEach } from 'vitest';
+import { UIAppRegistry } from '@/mcp/ui/registry';
+
+vi.mock('fs', () => ({
+  existsSync: vi.fn(),
+  readFileSync: vi.fn(),
+}));
+
+import { existsSync, readFileSync } from 'fs';
+
+const mockExistsSync = vi.mocked(existsSync);
+const mockReadFileSync = vi.mocked(readFileSync);
+
+describe('UI Meta Injection Logic', () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+    UIAppRegistry.reset();
+  });
+
+  describe('when HTML is loaded', () => {
+    beforeEach(() => {
+      mockExistsSync.mockReturnValue(true);
+      mockReadFileSync.mockReturnValue('<html>ui content</html>');
+      UIAppRegistry.load();
+    });
+
+    it('should add _meta.ui for matching tools', () => {
+      const uiApp = UIAppRegistry.getAppForTool('n8n_create_workflow');
+      expect(uiApp).not.toBeNull();
+      expect(uiApp!.html).not.toBeNull();
+
+      // Simulate the injection logic from server.ts
+      const mcpResponse: any = {
+        content: [{ type: 'text', text: 'result' }],
+      };
+
+      if (uiApp && uiApp.html) {
+        mcpResponse._meta = { ui: { app: uiApp.config.uri } };
+      }
+
+      expect(mcpResponse._meta).toBeDefined();
+      expect(mcpResponse._meta.ui.app).toBe('n8n-mcp://ui/operation-result');
+    });
+
+    it('should add _meta.ui for validation tools', () => {
+      const uiApp = UIAppRegistry.getAppForTool('validate_workflow');
+      expect(uiApp).not.toBeNull();
+
+      const mcpResponse: any = {
+        content: [{ type: 'text', text: 'validation result' }],
+      };
+
+      if (uiApp && uiApp.html) {
+        mcpResponse._meta = { ui: { app: uiApp.config.uri } };
+      }
+
+      expect(mcpResponse._meta).toBeDefined();
+      expect(mcpResponse._meta.ui.app).toBe('n8n-mcp://ui/validation-summary');
+    });
+
+    it('should NOT add _meta.ui for non-matching tools', () => {
+      const uiApp = UIAppRegistry.getAppForTool('get_node_info');
+      expect(uiApp).toBeNull();
+
+      const mcpResponse: any = {
+        content: [{ type: 'text', text: 'node info' }],
+      };
+
+      if (uiApp && uiApp.html) {
+        mcpResponse._meta = { ui: { app: uiApp.config.uri } };
+      }
+
+      expect(mcpResponse._meta).toBeUndefined();
+    });
+
+    it('should produce _meta with exact shape { ui: { app: string } }', () => {
+      const uiApp = UIAppRegistry.getAppForTool('n8n_create_workflow')!;
+      const meta = { ui: { app: uiApp.config.uri } };
+
+      expect(meta).toEqual({
+        ui: {
+          app: 'n8n-mcp://ui/operation-result',
+        },
+      });
+      expect(Object.keys(meta)).toEqual(['ui']);
+      expect(Object.keys(meta.ui)).toEqual(['app']);
+      expect(typeof meta.ui.app).toBe('string');
+    });
+
+    it('should produce _meta.ui.app that matches the config uri', () => {
+      const uiApp = UIAppRegistry.getAppForTool('validate_node')!;
+      const meta = { ui: { app: uiApp.config.uri } };
+      expect(meta.ui.app).toBe(uiApp.config.uri);
+      expect(meta.ui.app).toBe('n8n-mcp://ui/validation-summary');
+    });
+  });
+
+  describe('when HTML is not loaded', () => {
+    beforeEach(() => {
+      mockExistsSync.mockReturnValue(false);
+      UIAppRegistry.load();
+    });
+
+    it('should NOT add _meta.ui even for matching tools', () => {
+      const uiApp = UIAppRegistry.getAppForTool('n8n_create_workflow');
+      expect(uiApp).not.toBeNull();
+      expect(uiApp!.html).toBeNull();
+
+      const mcpResponse: any = {
+        content: [{ type: 'text', text: 'result' }],
+      };
+
+      if (uiApp && uiApp.html) {
+        mcpResponse._meta = { ui: { app: uiApp.config.uri } };
+      }
+
+      expect(mcpResponse._meta).toBeUndefined();
+    });
+
+    it('should NOT add _meta.ui for validation tools without HTML', () => {
+      const uiApp = UIAppRegistry.getAppForTool('validate_node');
+      expect(uiApp).not.toBeNull();
+      expect(uiApp!.html).toBeNull();
+
+      const mcpResponse: any = {
+        content: [{ type: 'text', text: 'result' }],
+      };
+
+      if (uiApp && uiApp.html) {
+        mcpResponse._meta = { ui: { app: uiApp.config.uri } };
+      }
+
+      expect(mcpResponse._meta).toBeUndefined();
+    });
+  });
+
+  describe('when registry has not been loaded at all', () => {
+    it('should NOT add _meta because getAppForTool returns null', () => {
+      // Registry never loaded - reset() was called in beforeEach
+      const uiApp = UIAppRegistry.getAppForTool('n8n_create_workflow');
+      expect(uiApp).toBeNull();
+
+      const mcpResponse: any = {
+        content: [{ type: 'text', text: 'result' }],
+      };
+
+      if (uiApp && uiApp.html) {
+        mcpResponse._meta = { ui: { app: uiApp.config.uri } };
+      }
+
+      expect(mcpResponse._meta).toBeUndefined();
+    });
+  });
+
+  describe('coexistence with structuredContent', () => {
+    beforeEach(() => {
+      mockExistsSync.mockReturnValue(true);
+      mockReadFileSync.mockReturnValue('<html>ui</html>');
+      UIAppRegistry.load();
+    });
+
+    it('should coexist with structuredContent on the response', () => {
+      const uiApp = UIAppRegistry.getAppForTool('n8n_create_workflow');
+
+      const mcpResponse: any = {
+        content: [{ type: 'text', text: 'result' }],
+        structuredContent: { workflowId: '123', status: 'created' },
+      };
+
+      if (uiApp && uiApp.html) {
+        mcpResponse._meta = { ui: { app: uiApp.config.uri } };
+      }
+
+      expect(mcpResponse.structuredContent).toBeDefined();
+      expect(mcpResponse.structuredContent.workflowId).toBe('123');
+      expect(mcpResponse._meta).toBeDefined();
+      expect(mcpResponse._meta.ui.app).toBe('n8n-mcp://ui/operation-result');
+    });
+
+    it('should not overwrite existing _meta properties when merging', () => {
+      const uiApp = UIAppRegistry.getAppForTool('n8n_create_workflow');
+
+      const mcpResponse: any = {
+        content: [{ type: 'text', text: 'result' }],
+        _meta: { existingProp: 'value' },
+      };
+
+      if (uiApp && uiApp.html) {
+        mcpResponse._meta = { ...mcpResponse._meta, ui: { app: uiApp.config.uri } };
+      }
+
+      expect(mcpResponse._meta.existingProp).toBe('value');
+      expect(mcpResponse._meta.ui.app).toBe('n8n-mcp://ui/operation-result');
+    });
+
+    it('should work with responses that have both structuredContent and existing _meta', () => {
+      const uiApp = UIAppRegistry.getAppForTool('validate_workflow');
+
+      const mcpResponse: any = {
+        content: [{ type: 'text', text: 'validation ok' }],
+        structuredContent: { valid: true, errors: [] },
+        _meta: { timing: 42 },
+      };
+
+      if (uiApp && uiApp.html) {
+        mcpResponse._meta = { ...mcpResponse._meta, ui: { app: uiApp.config.uri } };
+      }
+
+      expect(mcpResponse.structuredContent.valid).toBe(true);
+      expect(mcpResponse._meta.timing).toBe(42);
+      expect(mcpResponse._meta.ui.app).toBe('n8n-mcp://ui/validation-summary');
+    });
+  });
+});
--- a/tests/unit/mcp/ui/registry.test.ts
+++ b/tests/unit/mcp/ui/registry.test.ts
@@ -0,0 +1,305 @@
+import { describe, it, expect, vi, beforeEach } from 'vitest';
+import { UIAppRegistry } from '@/mcp/ui/registry';
+import { UI_APP_CONFIGS } from '@/mcp/ui/app-configs';
+
+vi.mock('fs', () => ({
+  existsSync: vi.fn(),
+  readFileSync: vi.fn(),
+}));
+
+import { existsSync, readFileSync } from 'fs';
+
+const mockExistsSync = vi.mocked(existsSync);
+const mockReadFileSync = vi.mocked(readFileSync);
+
+describe('UIAppRegistry', () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+    UIAppRegistry.reset();
+  });
+
+  describe('load()', () => {
+    it('should load HTML files when dist directory exists', () => {
+      mockExistsSync.mockReturnValue(true);
+      mockReadFileSync.mockReturnValue('<html>test</html>');
+
+      UIAppRegistry.load();
+
+      const apps = UIAppRegistry.getAllApps();
+      expect(apps.length).toBe(UI_APP_CONFIGS.length);
+      for (const app of apps) {
+        expect(app.html).toBe('<html>test</html>');
+      }
+    });
+
+    it('should handle missing dist directory gracefully', () => {
+      mockExistsSync.mockReturnValue(false);
+
+      UIAppRegistry.load();
+
+      const apps = UIAppRegistry.getAllApps();
+      expect(apps.length).toBe(UI_APP_CONFIGS.length);
+      for (const app of apps) {
+        expect(app.html).toBeNull();
+      }
+    });
+
+    it('should handle read errors gracefully', () => {
+      mockExistsSync.mockReturnValue(true);
+      mockReadFileSync.mockImplementation(() => {
+        throw new Error('Permission denied');
+      });
+
+      UIAppRegistry.load();
+
+      const apps = UIAppRegistry.getAllApps();
+      expect(apps.length).toBe(UI_APP_CONFIGS.length);
+      for (const app of apps) {
+        expect(app.html).toBeNull();
+      }
+    });
+
+    it('should set loaded flag so getters work', () => {
+      expect(UIAppRegistry.getAllApps()).toEqual([]);
+      expect(UIAppRegistry.getAppById('operation-result')).toBeNull();
+      expect(UIAppRegistry.getAppForTool('n8n_create_workflow')).toBeNull();
+
+      mockExistsSync.mockReturnValue(false);
+      UIAppRegistry.load();
+
+      expect(UIAppRegistry.getAllApps().length).toBeGreaterThan(0);
+    });
+
+    it('should replace previous entries when called twice', () => {
+      // First load: files exist
+      mockExistsSync.mockReturnValue(true);
+      mockReadFileSync.mockReturnValue('<html>first</html>');
+      UIAppRegistry.load();
+
+      expect(UIAppRegistry.getAppById('operation-result')!.html).toBe('<html>first</html>');
+
+      // Second load: files missing
+      mockExistsSync.mockReturnValue(false);
+      UIAppRegistry.load();
+
+      expect(UIAppRegistry.getAppById('operation-result')!.html).toBeNull();
+    });
+
+    it('should handle empty HTML file content', () => {
+      mockExistsSync.mockReturnValue(true);
+      mockReadFileSync.mockReturnValue('');
+
+      UIAppRegistry.load();
+
+      const app = UIAppRegistry.getAppById('operation-result');
+      expect(app).not.toBeNull();
+      // Empty string is still a string, not null
+      expect(app!.html).toBe('');
+    });
+
+    it('should build the correct number of tool index entries', () => {
+      mockExistsSync.mockReturnValue(true);
+      mockReadFileSync.mockReturnValue('<html>app</html>');
+      UIAppRegistry.load();
+
+      // Every tool pattern from every config should be resolvable
+      for (const config of UI_APP_CONFIGS) {
+        for (const pattern of config.toolPatterns) {
+          const entry = UIAppRegistry.getAppForTool(pattern);
+          expect(entry).not.toBeNull();
+          expect(entry!.config.id).toBe(config.id);
+        }
+      }
+    });
+
+    it('should call existsSync for each config', () => {
+      mockExistsSync.mockReturnValue(false);
+      UIAppRegistry.load();
+
+      expect(mockExistsSync).toHaveBeenCalledTimes(UI_APP_CONFIGS.length);
+    });
+
+    it('should only call readFileSync when existsSync returns true', () => {
+      mockExistsSync.mockReturnValue(false);
+      UIAppRegistry.load();
+
+      expect(mockReadFileSync).not.toHaveBeenCalled();
+    });
+  });
+
+  describe('getAppForTool()', () => {
+    it('should return null before load() is called', () => {
+      const entry = UIAppRegistry.getAppForTool('n8n_create_workflow');
+      expect(entry).toBeNull();
+    });
+
+    describe('after loading', () => {
+      beforeEach(() => {
+        mockExistsSync.mockReturnValue(true);
+        mockReadFileSync.mockReturnValue('<html>loaded</html>');
+        UIAppRegistry.load();
+      });
+
+      it('should return correct entry for known tool patterns', () => {
+        const entry = UIAppRegistry.getAppForTool('n8n_create_workflow');
+        expect(entry).not.toBeNull();
+        expect(entry!.config.id).toBe('operation-result');
+      });
+
+      it('should return correct entry for validation tools', () => {
+        const entry = UIAppRegistry.getAppForTool('validate_node');
+        expect(entry).not.toBeNull();
+        expect(entry!.config.id).toBe('validation-summary');
+      });
+
+      it('should return null for unknown tools', () => {
+        const entry = UIAppRegistry.getAppForTool('unknown_tool');
+        expect(entry).toBeNull();
+      });
+
+      it('should return null for empty string tool name', () => {
+        const entry = UIAppRegistry.getAppForTool('');
+        expect(entry).toBeNull();
+      });
+
+      // Regression: verify specific tools ARE mapped so config changes break the test
+      it('should map n8n_create_workflow to operation-result', () => {
+        expect(UIAppRegistry.getAppForTool('n8n_create_workflow')!.config.id).toBe('operation-result');
+      });
+
+      it('should map n8n_update_full_workflow to operation-result', () => {
+        expect(UIAppRegistry.getAppForTool('n8n_update_full_workflow')!.config.id).toBe('operation-result');
+      });
+
+      it('should map n8n_update_partial_workflow to operation-result', () => {
+        expect(UIAppRegistry.getAppForTool('n8n_update_partial_workflow')!.config.id).toBe('operation-result');
+      });
+
+      it('should map n8n_delete_workflow to operation-result', () => {
+        expect(UIAppRegistry.getAppForTool('n8n_delete_workflow')!.config.id).toBe('operation-result');
+      });
+
+      it('should map n8n_test_workflow to operation-result', () => {
+        expect(UIAppRegistry.getAppForTool('n8n_test_workflow')!.config.id).toBe('operation-result');
+      });
+
+      it('should map n8n_autofix_workflow to operation-result', () => {
+        expect(UIAppRegistry.getAppForTool('n8n_autofix_workflow')!.config.id).toBe('operation-result');
+      });
+
+      it('should map n8n_deploy_template to operation-result', () => {
+        expect(UIAppRegistry.getAppForTool('n8n_deploy_template')!.config.id).toBe('operation-result');
+      });
+
+      it('should map validate_node to validation-summary', () => {
+        expect(UIAppRegistry.getAppForTool('validate_node')!.config.id).toBe('validation-summary');
+      });
+
+      it('should map validate_workflow to validation-summary', () => {
+        expect(UIAppRegistry.getAppForTool('validate_workflow')!.config.id).toBe('validation-summary');
+      });
+
+      it('should map n8n_validate_workflow to validation-summary', () => {
+        expect(UIAppRegistry.getAppForTool('n8n_validate_workflow')!.config.id).toBe('validation-summary');
+      });
+    });
+  });
+
+  describe('getAppById()', () => {
+    it('should return null before load() is called', () => {
+      const entry = UIAppRegistry.getAppById('operation-result');
+      expect(entry).toBeNull();
+    });
+
+    describe('after loading', () => {
+      beforeEach(() => {
+        mockExistsSync.mockReturnValue(true);
+        mockReadFileSync.mockReturnValue('<html>app</html>');
+        UIAppRegistry.load();
+      });
+
+      it('should return correct entry for operation-result', () => {
+        const entry = UIAppRegistry.getAppById('operation-result');
+        expect(entry).not.toBeNull();
+        expect(entry!.config.displayName).toBe('Operation Result');
+        expect(entry!.html).toBe('<html>app</html>');
+      });
+
+      it('should return correct entry for validation-summary', () => {
+        const entry = UIAppRegistry.getAppById('validation-summary');
+        expect(entry).not.toBeNull();
+        expect(entry!.config.displayName).toBe('Validation Summary');
+      });
+
+      it('should return null for unknown id', () => {
+        const entry = UIAppRegistry.getAppById('nonexistent');
+        expect(entry).toBeNull();
+      });
+
+      it('should return null for empty string id', () => {
+        const entry = UIAppRegistry.getAppById('');
+        expect(entry).toBeNull();
+      });
+    });
+  });
+
+  describe('getAllApps()', () => {
+    it('should return empty array before load() is called', () => {
+      const apps = UIAppRegistry.getAllApps();
+      expect(apps).toEqual([]);
+    });
+
+    it('should return all entries after load', () => {
+      mockExistsSync.mockReturnValue(false);
+      UIAppRegistry.load();
+
+      const apps = UIAppRegistry.getAllApps();
+      expect(apps.length).toBe(UI_APP_CONFIGS.length);
+      expect(apps.map(a => a.config.id)).toContain('operation-result');
+      expect(apps.map(a => a.config.id)).toContain('validation-summary');
+    });
+
+    it('should include entries with null html when dist is missing', () => {
+      mockExistsSync.mockReturnValue(false);
+      UIAppRegistry.load();
+
+      const apps = UIAppRegistry.getAllApps();
+      for (const app of apps) {
+        expect(app.html).toBeNull();
+      }
+      // Entries are still present even with null html
+      expect(apps.length).toBe(UI_APP_CONFIGS.length);
+    });
+
+    it('should return entries with full config objects', () => {
+      mockExistsSync.mockReturnValue(false);
+      UIAppRegistry.load();
+
+      for (const app of UIAppRegistry.getAllApps()) {
+        expect(app.config).toBeDefined();
+        expect(app.config.id).toBeDefined();
+        expect(app.config.displayName).toBeDefined();
+        expect(app.config.uri).toBeDefined();
+        expect(app.config.mimeType).toBeDefined();
+        expect(app.config.toolPatterns).toBeDefined();
+        expect(app.config.description).toBeDefined();
+      }
+    });
+  });
+
+  describe('reset()', () => {
+    it('should clear loaded state so getters return defaults', () => {
+      mockExistsSync.mockReturnValue(true);
+      mockReadFileSync.mockReturnValue('<html>x</html>');
+      UIAppRegistry.load();
+
+      expect(UIAppRegistry.getAllApps().length).toBeGreaterThan(0);
+
+      UIAppRegistry.reset();
+
+      expect(UIAppRegistry.getAllApps()).toEqual([]);
+      expect(UIAppRegistry.getAppById('operation-result')).toBeNull();
+      expect(UIAppRegistry.getAppForTool('n8n_create_workflow')).toBeNull();
+    });
+  });
+});
--- a/ui-apps/package-lock.json
+++ b/ui-apps/package-lock.json
--- a/ui-apps/package.json
+++ b/ui-apps/package.json
@@ -0,0 +1,25 @@
+{
+  "name": "n8n-mcp-ui-apps",
+  "version": "1.0.0",
+  "private": true,
+  "type": "module",
+  "scripts": {
+    "dev": "vite",
+    "build": "APP_NAME=operation-result vite build && APP_NAME=validation-summary vite build",
+    "build:operation-result": "APP_NAME=operation-result vite build",
+    "build:validation-summary": "APP_NAME=validation-summary vite build",
+    "preview": "vite preview"
+  },
+  "dependencies": {
+    "react": "^19.0.0",
+    "react-dom": "^19.0.0"
+  },
+  "devDependencies": {
+    "@types/react": "^19.0.0",
+    "@types/react-dom": "^19.0.0",
+    "@vitejs/plugin-react": "^4.3.0",
+    "typescript": "^5.8.0",
+    "vite": "^6.0.0",
+    "vite-plugin-singlefile": "^2.0.0"
+  }
+}
--- a/ui-apps/src/apps/operation-result/App.tsx
+++ b/ui-apps/src/apps/operation-result/App.tsx
@@ -0,0 +1,84 @@
+import React from 'react';
+import '@shared/styles/theme.css';
+import { Card, Badge, Expandable } from '@shared/components';
+import { useToolData } from '@shared/hooks/useToolData';
+import type { OperationResultData } from '@shared/types';
+
+export default function App() {
+  const data = useToolData<OperationResultData>();
+
+  if (!data) {
+    return <div style={{ padding: '16px', color: 'var(--n8n-text-muted)' }}>Loading...</div>;
+  }
+
+  const isSuccess = data.status === 'success';
+
+  return (
+    <div style={{ maxWidth: '480px' }}>
+      <div style={{ display: 'flex', alignItems: 'center', gap: '12px', marginBottom: '16px' }}>
+        <Badge variant={isSuccess ? 'success' : 'error'}>
+          {isSuccess ? 'Success' : 'Error'}
+        </Badge>
+        <h2 style={{ fontSize: '16px', fontWeight: 600 }}>{data.operation}</h2>
+      </div>
+
+      <Card title="Workflow">
+        <div style={{ fontSize: '14px' }}>
+          {data.workflowName && <div><strong>Name:</strong> {data.workflowName}</div>}
+          {data.workflowId && <div><strong>ID:</strong> {data.workflowId}</div>}
+          {data.timestamp && (
+            <div style={{ color: 'var(--n8n-text-muted)', fontSize: '12px', marginTop: '4px' }}>
+              {data.timestamp}
+            </div>
+          )}
+        </div>
+      </Card>
+
+      {data.message && (
+        <Card>
+          <div style={{ fontSize: '13px' }}>{data.message}</div>
+        </Card>
+      )}
+
+      {data.changes && (
+        <>
+          {data.changes.nodesAdded && data.changes.nodesAdded.length > 0 && (
+            <Expandable title="Nodes Added" count={data.changes.nodesAdded.length} defaultOpen>
+              <ul style={{ listStyle: 'none', fontSize: '13px' }}>
+                {data.changes.nodesAdded.map((node, i) => (
+                  <li key={i} style={{ padding: '4px 0', borderBottom: '1px solid var(--n8n-border)' }}>
+                    <span style={{ color: 'var(--n8n-success)' }}>+</span> {node}
+                  </li>
+                ))}
+              </ul>
+            </Expandable>
+          )}
+
+          {data.changes.nodesModified && data.changes.nodesModified.length > 0 && (
+            <Expandable title="Nodes Modified" count={data.changes.nodesModified.length}>
+              <ul style={{ listStyle: 'none', fontSize: '13px' }}>
+                {data.changes.nodesModified.map((node, i) => (
+                  <li key={i} style={{ padding: '4px 0', borderBottom: '1px solid var(--n8n-border)' }}>
+                    <span style={{ color: 'var(--n8n-warning)' }}>~</span> {node}
+                  </li>
+                ))}
+              </ul>
+            </Expandable>
+          )}
+
+          {data.changes.nodesRemoved && data.changes.nodesRemoved.length > 0 && (
+            <Expandable title="Nodes Removed" count={data.changes.nodesRemoved.length}>
+              <ul style={{ listStyle: 'none', fontSize: '13px' }}>
+                {data.changes.nodesRemoved.map((node, i) => (
+                  <li key={i} style={{ padding: '4px 0', borderBottom: '1px solid var(--n8n-border)' }}>
+                    <span style={{ color: 'var(--n8n-error)' }}>-</span> {node}
+                  </li>
+                ))}
+              </ul>
+            </Expandable>
+          )}
+        </>
+      )}
+    </div>
+  );
+}
--- a/ui-apps/src/apps/operation-result/index.html
+++ b/ui-apps/src/apps/operation-result/index.html
@@ -0,0 +1,12 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="UTF-8" />
+    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
+    <title>Operation Result</title>
+  </head>
+  <body>
+    <div id="root"></div>
+    <script type="module" src="./main.tsx"></script>
+  </body>
+</html>
--- a/ui-apps/src/apps/operation-result/main.tsx
+++ b/ui-apps/src/apps/operation-result/main.tsx
@@ -0,0 +1,8 @@
+import React from 'react';
+import { createRoot } from 'react-dom/client';
+import App from './App';
+
+const root = document.getElementById('root');
+if (root) {
+  createRoot(root).render(<App />);
+}
--- a/ui-apps/src/apps/validation-summary/App.tsx
+++ b/ui-apps/src/apps/validation-summary/App.tsx
@@ -0,0 +1,88 @@
+import React from 'react';
+import '@shared/styles/theme.css';
+import { Card, Badge, Expandable } from '@shared/components';
+import { useToolData } from '@shared/hooks/useToolData';
+import type { ValidationSummaryData } from '@shared/types';
+
+export default function App() {
+  const data = useToolData<ValidationSummaryData>();
+
+  if (!data) {
+    return <div style={{ padding: '16px', color: 'var(--n8n-text-muted)' }}>Loading...</div>;
+  }
+
+  return (
+    <div style={{ maxWidth: '480px' }}>
+      <div style={{ display: 'flex', alignItems: 'center', gap: '12px', marginBottom: '16px' }}>
+        <Badge variant={data.valid ? 'success' : 'error'}>
+          {data.valid ? 'Valid' : 'Invalid'}
+        </Badge>
+        {data.displayName && (
+          <span style={{ fontSize: '14px', color: 'var(--n8n-text-muted)' }}>{data.displayName}</span>
+        )}
+      </div>
+
+      <Card>
+        <div style={{ display: 'flex', gap: '16px', fontSize: '13px' }}>
+          <div>
+            <span style={{ color: 'var(--n8n-error)' }}>{data.errorCount}</span> errors
+          </div>
+          <div>
+            <span style={{ color: 'var(--n8n-warning)' }}>{data.warningCount}</span> warnings
+          </div>
+        </div>
+      </Card>
+
+      {data.errors.length > 0 && (
+        <Expandable title="Errors" count={data.errors.length} defaultOpen>
+          {data.errors.map((err, i) => (
+            <div key={i} style={{
+              padding: '8px',
+              marginBottom: '6px',
+              background: 'var(--n8n-error-light)',
+              borderRadius: '4px',
+              fontSize: '12px',
+              color: 'var(--n8n-error)',
+            }}>
+              <div style={{ fontWeight: 600 }}>{err.type}</div>
+              {err.property && <div style={{ opacity: 0.8 }}>Property: {err.property}</div>}
+              <div>{err.message}</div>
+              {err.fix && (
+                <div style={{ marginTop: '4px', fontStyle: 'italic', opacity: 0.9 }}>Fix: {err.fix}</div>
+              )}
+            </div>
+          ))}
+        </Expandable>
+      )}
+
+      {data.warnings.length > 0 && (
+        <Expandable title="Warnings" count={data.warnings.length}>
+          {data.warnings.map((warn, i) => (
+            <div key={i} style={{
+              padding: '8px',
+              marginBottom: '6px',
+              background: 'var(--n8n-warning-light)',
+              borderRadius: '4px',
+              fontSize: '12px',
+              color: 'var(--n8n-warning)',
+            }}>
+              <div style={{ fontWeight: 600 }}>{warn.type}</div>
+              {warn.property && <div style={{ opacity: 0.8 }}>Property: {warn.property}</div>}
+              <div>{warn.message}</div>
+            </div>
+          ))}
+        </Expandable>
+      )}
+
+      {data.suggestions && data.suggestions.length > 0 && (
+        <Expandable title="Suggestions" count={data.suggestions.length}>
+          <ul style={{ paddingLeft: '16px', fontSize: '12px' }}>
+            {data.suggestions.map((suggestion, i) => (
+              <li key={i} style={{ padding: '2px 0', color: 'var(--n8n-info)' }}>{suggestion}</li>
+            ))}
+          </ul>
+        </Expandable>
+      )}
+    </div>
+  );
+}
--- a/ui-apps/src/apps/validation-summary/index.html
+++ b/ui-apps/src/apps/validation-summary/index.html
@@ -0,0 +1,12 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="UTF-8" />
+    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
+    <title>Validation Summary</title>
+  </head>
+  <body>
+    <div id="root"></div>
+    <script type="module" src="./main.tsx"></script>
+  </body>
+</html>
--- a/ui-apps/src/apps/validation-summary/main.tsx
+++ b/ui-apps/src/apps/validation-summary/main.tsx
@@ -0,0 +1,8 @@
+import React from 'react';
+import { createRoot } from 'react-dom/client';
+import App from './App';
+
+const root = document.getElementById('root');
+if (root) {
+  createRoot(root).render(<App />);
+}
--- a/ui-apps/src/shared/components/Badge.tsx
+++ b/ui-apps/src/shared/components/Badge.tsx
@@ -0,0 +1,32 @@
+import React from 'react';
+
+type BadgeVariant = 'success' | 'warning' | 'error' | 'info';
+
+interface BadgeProps {
+  variant: BadgeVariant;
+  children: React.ReactNode;
+}
+
+const variantStyles: Record<BadgeVariant, { bg: string; color: string }> = {
+  success: { bg: 'var(--n8n-success-light)', color: 'var(--n8n-success)' },
+  warning: { bg: 'var(--n8n-warning-light)', color: 'var(--n8n-warning)' },
+  error: { bg: 'var(--n8n-error-light)', color: 'var(--n8n-error)' },
+  info: { bg: 'var(--n8n-info-light)', color: 'var(--n8n-info)' },
+};
+
+export function Badge({ variant, children }: BadgeProps) {
+  const style = variantStyles[variant];
+  return (
+    <span style={{
+      display: 'inline-block',
+      padding: '2px 10px',
+      borderRadius: '12px',
+      fontSize: '12px',
+      fontWeight: 600,
+      background: style.bg,
+      color: style.color,
+    }}>
+      {children}
+    </span>
+  );
+}
--- a/ui-apps/src/shared/components/Card.tsx
+++ b/ui-apps/src/shared/components/Card.tsx
@@ -0,0 +1,25 @@
+import React from 'react';
+
+interface CardProps {
+  title?: string;
+  children: React.ReactNode;
+}
+
+export function Card({ title, children }: CardProps) {
+  return (
+    <div style={{
+      background: 'var(--n8n-bg-card)',
+      border: '1px solid var(--n8n-border)',
+      borderRadius: 'var(--n8n-radius)',
+      padding: '16px',
+      marginBottom: '12px',
+    }}>
+      {title && (
+        <h3 style={{ marginBottom: '8px', fontSize: '14px', color: 'var(--n8n-text-muted)' }}>
+          {title}
+        </h3>
+      )}
+      {children}
+    </div>
+  );
+}
--- a/ui-apps/src/shared/components/Expandable.tsx
+++ b/ui-apps/src/shared/components/Expandable.tsx
@@ -0,0 +1,36 @@
+import React from 'react';
+
+interface ExpandableProps {
+  title: string;
+  count?: number;
+  defaultOpen?: boolean;
+  children: React.ReactNode;
+}
+
+export function Expandable({ title, count, defaultOpen = false, children }: ExpandableProps) {
+  return (
+    <details open={defaultOpen} style={{
+      marginBottom: '8px',
+      border: '1px solid var(--n8n-border)',
+      borderRadius: 'var(--n8n-radius)',
+      overflow: 'hidden',
+    }}>
+      <summary style={{
+        padding: '10px 14px',
+        cursor: 'pointer',
+        fontSize: '13px',
+        fontWeight: 500,
+        background: 'var(--n8n-bg-card)',
+        userSelect: 'none',
+      }}>
+        {title}
+        {count !== undefined && (
+          <span style={{ marginLeft: '8px', color: 'var(--n8n-text-muted)' }}>({count})</span>
+        )}
+      </summary>
+      <div style={{ padding: '12px 14px' }}>
+        {children}
+      </div>
+    </details>
+  );
+}
--- a/ui-apps/src/shared/components/index.ts
+++ b/ui-apps/src/shared/components/index.ts
@@ -0,0 +1,3 @@
+export { Card } from './Card';
+export { Badge } from './Badge';
+export { Expandable } from './Expandable';
--- a/ui-apps/src/shared/hooks/useToolData.ts
+++ b/ui-apps/src/shared/hooks/useToolData.ts
@@ -0,0 +1,31 @@
+import { useState, useEffect } from 'react';
+
+declare global {
+  interface Window {
+    __MCP_DATA__?: unknown;
+  }
+}
+
+export function useToolData<T>(): T | null {
+  const [data, setData] = useState<T | null>(null);
+
+  useEffect(() => {
+    // Try window.__MCP_DATA__ first (injected by host)
+    if (window.__MCP_DATA__) {
+      setData(window.__MCP_DATA__ as T);
+      return;
+    }
+
+    // Try embedded script tag
+    const scriptEl = document.getElementById('mcp-data');
+    if (scriptEl?.textContent) {
+      try {
+        setData(JSON.parse(scriptEl.textContent) as T);
+      } catch {
+        // Ignore parse errors
+      }
+    }
+  }, []);
+
+  return data;
+}
--- a/ui-apps/src/shared/index.ts
+++ b/ui-apps/src/shared/index.ts
@@ -0,0 +1,3 @@
+export { Card, Badge, Expandable } from './components';
+export { useToolData } from './hooks/useToolData';
+export type { OperationResultData, ValidationSummaryData, ValidationError, ValidationWarning } from './types';
--- a/ui-apps/src/shared/styles/theme.css
+++ b/ui-apps/src/shared/styles/theme.css
@@ -0,0 +1,32 @@
+:root {
+  --n8n-primary: #ff6d5a;
+  --n8n-primary-light: #ff8a7a;
+  --n8n-success: #17bf79;
+  --n8n-success-light: #e8f9f0;
+  --n8n-warning: #f59e0b;
+  --n8n-warning-light: #fef3cd;
+  --n8n-error: #ef4444;
+  --n8n-error-light: #fee2e2;
+  --n8n-info: #3b82f6;
+  --n8n-info-light: #dbeafe;
+  --n8n-bg: #1a1a2e;
+  --n8n-bg-card: #252540;
+  --n8n-text: #e0e0e0;
+  --n8n-text-muted: #9ca3af;
+  --n8n-border: #374151;
+  --n8n-radius: 8px;
+  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
+}
+
+* {
+  margin: 0;
+  padding: 0;
+  box-sizing: border-box;
+}
+
+body {
+  background: var(--n8n-bg);
+  color: var(--n8n-text);
+  line-height: 1.5;
+  padding: 16px;
+}
--- a/ui-apps/src/shared/types.ts
+++ b/ui-apps/src/shared/types.ts
@@ -0,0 +1,38 @@
+export interface OperationResultData {
+  status: 'success' | 'error';
+  operation: string;
+  workflowName?: string;
+  workflowId?: string;
+  timestamp?: string;
+  message?: string;
+  changes?: {
+    nodesAdded?: string[];
+    nodesModified?: string[];
+    nodesRemoved?: string[];
+  };
+  details?: Record<string, unknown>;
+}
+
+export interface ValidationError {
+  type: string;
+  property?: string;
+  message: string;
+  fix?: string;
+}
+
+export interface ValidationWarning {
+  type: string;
+  property?: string;
+  message: string;
+}
+
+export interface ValidationSummaryData {
+  valid: boolean;
+  errorCount: number;
+  warningCount: number;
+  errors: ValidationError[];
+  warnings: ValidationWarning[];
+  suggestions?: string[];
+  nodeType?: string;
+  displayName?: string;
+}
--- a/ui-apps/tsconfig.json
+++ b/ui-apps/tsconfig.json
@@ -0,0 +1,21 @@
+{
+  "compilerOptions": {
+    "target": "ES2020",
+    "lib": ["ES2020", "DOM", "DOM.Iterable"],
+    "module": "ESNext",
+    "moduleResolution": "bundler",
+    "jsx": "react-jsx",
+    "strict": true,
+    "esModuleInterop": true,
+    "skipLibCheck": true,
+    "forceConsistentCasingInFileNames": true,
+    "resolveJsonModule": true,
+    "isolatedModules": true,
+    "noEmit": true,
+    "baseUrl": ".",
+    "paths": {
+      "@shared/*": ["src/shared/*"]
+    }
+  },
+  "include": ["src"]
+}
--- a/ui-apps/vite.config.ts
+++ b/ui-apps/vite.config.ts
@@ -0,0 +1,21 @@
+import { defineConfig } from 'vite';
+import react from '@vitejs/plugin-react';
+import { viteSingleFile } from 'vite-plugin-singlefile';
+import path from 'path';
+
+// App name is passed via environment variable for per-app builds
+const appName = process.env.APP_NAME || 'operation-result';
+
+export default defineConfig({
+  plugins: [react(), viteSingleFile()],
+  resolve: {
+    alias: {
+      '@shared': path.resolve(__dirname, 'src/shared'),
+    },
+  },
+  root: path.resolve(__dirname, 'src/apps', appName),
+  build: {
+    outDir: path.resolve(__dirname, 'dist', appName),
+    emptyOutDir: true,
+  },
+});
Author	SHA1	Message	Date
Romuald Członkowski	1f45cc6dcc	feat: MCP Apps - rich HTML UIs for tool results (#573 ) * feat: add MCP Apps with rich HTML UIs for tool results Add MCP Apps infrastructure that allows MCP hosts like Claude Desktop to render rich HTML UIs alongside tool results via `_meta.ui` and the MCP resources protocol. - Server-side UI module (src/mcp/ui/) with UIAppRegistry, tool-to-UI mapping, and _meta.ui injection into tool responses - React + Vite build pipeline (ui-apps/) producing self-contained HTML per app using vite-plugin-singlefile - Operation Result UI for workflow CRUD tools (create, update, delete, test, autofix, deploy) - Validation Summary UI for validation tools (validate_node, validate_workflow, n8n_validate_workflow) - Shared component library (Card, Badge, Expandable) with n8n dark theme - MCP resources protocol support (ListResources, ReadResource handlers) - Graceful degradation when ui-apps/dist/ is not built - 22 unit tests across 3 test files Conceived by Romuald Członkowski - https://www.aiadvisors.pl/en Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com> * test: improve MCP Apps test coverage and add security hardening - Expand test suite from 22 to 57 tests across 3 test files - Add UIAppRegistry.reset() for proper test isolation between tests - Replace some fs mocks with real temp directory tests in registry - Add edge case coverage: empty strings, pre-load state, double load, malformed URIs, duplicate tool patterns, empty HTML files - Add regression tests for specific tool-to-UI mappings - Add URI format consistency validation across all configs - Improve _meta.ui injection tests with structuredContent coexistence - Coverage: statements 79.4% -> 80%, lines 79.4% -> 80% Conceived by Romuald Członkowski - https://www.aiadvisors.pl/en Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com> --------- Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>	2026-02-07 04:11:21 +01:00
Romuald Członkowski	6814880410	chore: update n8n to 2.6.3 and bump version to 2.33.6 (#571 )	2026-02-06 09:09:37 +01:00
Romuald Członkowski	c8c76e435d	fix: critical memory leak from per-session database connections (#554 ) * fix: critical memory leak from per-session database connections (#542) Each MCP session was creating its own database connection (~900MB), causing OOM kills every ~20 minutes with 3-4 concurrent sessions. Changes: - Add SharedDatabase singleton pattern - all sessions share ONE connection - Reduce session timeout from 30 min to 5 min (configurable) - Add eager cleanup for reconnecting instances - Fix telemetry event listener leak Memory impact: ~900MB/session → ~68MB shared + ~5MB/session overhead Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com> Conceived by Romuald Czlonkowski - https://www.aiadvisors.pl/en * fix: resolve test failures from shared database race conditions - Fix `shutdown()` to respect shared database pattern (was directly closing) - Add `await this.initialized` in both `close()` and `shutdown()` to prevent race condition where cleanup runs while initialization is in progress - Add double-shutdown protection with `isShutdown` flag - Export `SharedDatabaseState` type for proper typing - Include error details in debug logs - Add MCP server close to `shutdown()` for consistency with `close()` - Null out `earlyLogger` in `shutdown()` for consistency The CI test failure "The database connection is not open" was caused by: 1. `shutdown()` directly calling `this.db.close()` which closed the SHARED database connection, breaking subsequent tests 2. Race condition where `shutdown()` ran before initialization completed Conceived by Romuald Członkowski - www.aiadvisors.pl/en Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com> * test: add unit tests for shared-database module Add comprehensive unit tests covering: - getSharedDatabase: initialization, reuse, different path error, concurrent requests - releaseSharedDatabase: refCount decrement, double-release guard - closeSharedDatabase: state clearing, error handling, re-initialization - Helper functions: isSharedDatabaseInitialized, getSharedDatabaseRefCount 21 tests covering the singleton database connection pattern used to prevent ~900MB memory leaks per session. Conceived by Romuald Członkowski - www.aiadvisors.pl/en Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com> --------- Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>	2026-01-23 19:51:22 +01:00
Romuald Członkowski	fad3437977	fix: memory leak in SSE session reset (#542 ) (#544 ) When SSE sessions are recreated every 5 minutes, the old session's MCP server was not being closed, causing: - SimpleCache cleanup timer continuing to run indefinitely - Database connections remaining open - Cached data (~50-100MB per session) persisting in memory Added server.close() call before transport.close() in resetSessionSSE(), mirroring the existing cleanup pattern in removeSession(). Fixes #542 Conceived by Romuald Członkowski - https://www.aiadvisors.pl/en Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>	2026-01-21 13:56:16 +01:00