Fix: Restore views properly, model selection for commit and pr and speed up some cli models with session resume (#801)

* Changes from fix/restoring-view * feat: Add resume query safety checks and optimize store selectors * feat: Improve session management and model normalization * refactor: Extract prompt building logic and handle file path parsing for renames
2026-03-16 21:53:07 +00:00 · 2026-02-22 10:45:45 -08:00
parent 2f071a1ba3
commit 9305ecc242
26 changed files with 761 additions and 203 deletions
--- a/apps/server/src/providers/codex-provider.ts
+++ b/apps/server/src/providers/codex-provider.ts
@@ -51,6 +51,7 @@ import { CODEX_MODELS } from './codex-models.js';

 const CODEX_COMMAND = 'codex';
 const CODEX_EXEC_SUBCOMMAND = 'exec';
+const CODEX_RESUME_SUBCOMMAND = 'resume';
 const CODEX_JSON_FLAG = '--json';
 const CODEX_MODEL_FLAG = '--model';
 const CODEX_VERSION_FLAG = '--version';
@@ -355,9 +356,14 @@ function resolveSystemPrompt(systemPrompt?: unknown): string | null {
  return null;
 }

+function buildPromptText(options: ExecuteOptions): string {
+  return typeof options.prompt === 'string'
+    ? options.prompt
+    : extractTextFromContent(options.prompt);
+}
+
 function buildCombinedPrompt(options: ExecuteOptions, systemPromptText?: string | null): string {
-  const promptText =
-    typeof options.prompt === 'string' ? options.prompt : extractTextFromContent(options.prompt);
+  const promptText = buildPromptText(options);
  const historyText = options.conversationHistory
    ? formatHistoryAsText(options.conversationHistory)
    : '';
@@ -370,6 +376,11 @@ function buildCombinedPrompt(options: ExecuteOptions, systemPromptText?: string
  return `${historyText}${systemSection}${HISTORY_HEADER}${promptText}`;
 }

+function buildResumePrompt(options: ExecuteOptions): string {
+  const promptText = buildPromptText(options);
+  return `${HISTORY_HEADER}${promptText}`;
+}
+
 function formatConfigValue(value: string | number | boolean): string {
  return String(value);
 }
@@ -793,16 +804,22 @@ export class CodexProvider extends BaseProvider {
      }
      const searchEnabled =
        codexSettings.enableWebSearch || resolveSearchEnabled(resolvedAllowedTools, restrictTools);
-      const schemaPath = await writeOutputSchemaFile(options.cwd, options.outputFormat);
-      const imageBlocks = codexSettings.enableImages ? extractImageBlocks(options.prompt) : [];
-      const imagePaths = await writeImageFiles(options.cwd, imageBlocks);
+      const isResumeQuery = Boolean(options.sdkSessionId);
+      const schemaPath = isResumeQuery
+        ? null
+        : await writeOutputSchemaFile(options.cwd, options.outputFormat);
+      const imageBlocks =
+        !isResumeQuery && codexSettings.enableImages ? extractImageBlocks(options.prompt) : [];
+      const imagePaths = isResumeQuery ? [] : await writeImageFiles(options.cwd, imageBlocks);
      const approvalPolicy =
        hasMcpServers && options.mcpAutoApproveTools !== undefined
          ? options.mcpAutoApproveTools
            ? 'never'
            : 'on-request'
          : codexSettings.approvalPolicy;
-      const promptText = buildCombinedPrompt(options, combinedSystemPrompt);
+      const promptText = isResumeQuery
+        ? buildResumePrompt(options)
+        : buildCombinedPrompt(options, combinedSystemPrompt);
      const commandPath = executionPlan.cliPath || CODEX_COMMAND;

      // Build config overrides for max turns and reasoning effort
@@ -832,21 +849,30 @@ export class CodexProvider extends BaseProvider {
      const preExecArgs: string[] = [];

      // Add additional directories with write access
-      if (codexSettings.additionalDirs && codexSettings.additionalDirs.length > 0) {
+      if (
+        !isResumeQuery &&
+        codexSettings.additionalDirs &&
+        codexSettings.additionalDirs.length > 0
+      ) {
        for (const dir of codexSettings.additionalDirs) {
          preExecArgs.push(CODEX_ADD_DIR_FLAG, dir);
        }
      }

-      // If images were written to disk, add the image directory so the CLI can access them
+      // If images were written to disk, add the image directory so the CLI can access them.
+      // Note: imagePaths is set to [] when isResumeQuery is true, so this check is sufficient.
      if (imagePaths.length > 0) {
        const imageDir = path.join(options.cwd, CODEX_INSTRUCTIONS_DIR, IMAGE_TEMP_DIR);
        preExecArgs.push(CODEX_ADD_DIR_FLAG, imageDir);
      }

      // Model is already bare (no prefix) - validated by executeQuery
+      const codexCommand = isResumeQuery
+        ? [CODEX_EXEC_SUBCOMMAND, CODEX_RESUME_SUBCOMMAND]
+        : [CODEX_EXEC_SUBCOMMAND];
+
      const args = [
-        CODEX_EXEC_SUBCOMMAND,
+        ...codexCommand,
        CODEX_YOLO_FLAG,
        CODEX_SKIP_GIT_REPO_CHECK_FLAG,
        ...preExecArgs,
@@ -855,6 +881,7 @@ export class CodexProvider extends BaseProvider {
        CODEX_JSON_FLAG,
        ...configOverrideArgs,
        ...(schemaPath ? [CODEX_OUTPUT_SCHEMA_FLAG, schemaPath] : []),
+        ...(options.sdkSessionId ? [options.sdkSessionId] : []),
        '-', // Read prompt from stdin to avoid shell escaping issues
      ];

--- a/apps/server/src/providers/copilot-provider.ts
+++ b/apps/server/src/providers/copilot-provider.ts
@@ -30,6 +30,7 @@ import {
  type CopilotRuntimeModel,
 } from '@automaker/types';
 import { createLogger, isAbortError } from '@automaker/utils';
+import { resolveModelString } from '@automaker/model-resolver';
 import { CopilotClient, type PermissionRequest } from '@github/copilot-sdk';
 import {
  normalizeTodos,
@@ -116,6 +117,12 @@ export interface CopilotError extends Error {
  suggestion?: string;
 }

+type CopilotSession = Awaited<ReturnType<CopilotClient['createSession']>>;
+type CopilotSessionOptions = Parameters<CopilotClient['createSession']>[0];
+type ResumableCopilotClient = CopilotClient & {
+  resumeSession?: (sessionId: string, options: CopilotSessionOptions) => Promise<CopilotSession>;
+};
+
 // =============================================================================
 // Tool Name Normalization
 // =============================================================================
@@ -516,7 +523,11 @@ export class CopilotProvider extends CliProvider {
    }

    const promptText = this.extractPromptText(options);
-    const bareModel = options.model || DEFAULT_BARE_MODEL;
+    // resolveModelString may return dash-separated canonical names (e.g. "claude-sonnet-4-6"),
+    // but the Copilot SDK expects dot-separated version suffixes (e.g. "claude-sonnet-4.6").
+    // Normalize by converting the last dash-separated numeric pair to dot notation.
+    const resolvedModel = resolveModelString(options.model || DEFAULT_BARE_MODEL);
+    const bareModel = resolvedModel.replace(/-(\d+)-(\d+)$/, '-$1.$2');
    const workingDirectory = options.cwd || process.cwd();

    logger.debug(
@@ -554,12 +565,14 @@ export class CopilotProvider extends CliProvider {
      });
    };

+    // Declare session outside try so it's accessible in the catch block for cleanup.
+    let session: CopilotSession | undefined;
+
    try {
      await client.start();
      logger.debug(`CopilotClient started with cwd: ${workingDirectory}`);

-      // Create session with streaming enabled for real-time events
-      const session = await client.createSession({
+      const sessionOptions: CopilotSessionOptions = {
        model: bareModel,
        streaming: true,
        // AUTONOMOUS MODE: Auto-approve all permission requests.
@@ -572,13 +585,33 @@ export class CopilotProvider extends CliProvider {
          logger.debug(`Permission request: ${request.kind}`);
          return { kind: 'approved' };
        },
-      });
+      };

-      const sessionId = session.sessionId;
-      logger.debug(`Session created: ${sessionId}`);
+      // Resume the previous Copilot session when possible; otherwise create a fresh one.
+      const resumableClient = client as ResumableCopilotClient;
+      let sessionResumed = false;
+      if (options.sdkSessionId && typeof resumableClient.resumeSession === 'function') {
+        try {
+          session = await resumableClient.resumeSession(options.sdkSessionId, sessionOptions);
+          sessionResumed = true;
+          logger.debug(`Resumed Copilot session: ${session.sessionId}`);
+        } catch (resumeError) {
+          logger.warn(
+            `Failed to resume Copilot session "${options.sdkSessionId}", creating a new session: ${resumeError}`
+          );
+          session = await client.createSession(sessionOptions);
+        }
+      } else {
+        session = await client.createSession(sessionOptions);
+      }
+
+      // session is always assigned by this point (both branches above assign it)
+      const activeSession = session!;
+      const sessionId = activeSession.sessionId;
+      logger.debug(`Session ${sessionResumed ? 'resumed' : 'created'}: ${sessionId}`);

      // Set up event handler to push events to queue
-      session.on((event: SdkEvent) => {
+      activeSession.on((event: SdkEvent) => {
        logger.debug(`SDK event: ${event.type}`);

        if (event.type === 'session.idle') {
@@ -596,7 +629,7 @@ export class CopilotProvider extends CliProvider {
      });

      // Send the prompt (non-blocking)
-      await session.send({ prompt: promptText });
+      await activeSession.send({ prompt: promptText });

      // Process events as they arrive
      while (!sessionComplete || eventQueue.length > 0) {
@@ -604,7 +637,7 @@ export class CopilotProvider extends CliProvider {

        // Check for errors first (before processing events to avoid race condition)
        if (sessionError) {
-          await session.destroy();
+          await activeSession.destroy();
          await client.stop();
          throw sessionError;
        }
@@ -624,11 +657,19 @@ export class CopilotProvider extends CliProvider {
      }

      // Cleanup
-      await session.destroy();
+      await activeSession.destroy();
      await client.stop();
      logger.debug('CopilotClient stopped successfully');
    } catch (error) {
-      // Ensure client is stopped on error
+      // Ensure session is destroyed and client is stopped on error to prevent leaks.
+      // The session may have been created/resumed before the error occurred.
+      if (session) {
+        try {
+          await session.destroy();
+        } catch (sessionCleanupError) {
+          logger.debug(`Failed to destroy session during cleanup: ${sessionCleanupError}`);
+        }
+      }
      try {
        await client.stop();
      } catch (cleanupError) {
--- a/apps/server/src/providers/cursor-provider.ts
+++ b/apps/server/src/providers/cursor-provider.ts
@@ -450,6 +450,11 @@ export class CursorProvider extends CliProvider {
      cliArgs.push('--model', model);
    }

+    // Resume an existing chat when a provider session ID is available
+    if (options.sdkSessionId) {
+      cliArgs.push('--resume', options.sdkSessionId);
+    }
+
    // Use '-' to indicate reading prompt from stdin
    cliArgs.push('-');

--- a/apps/server/src/providers/gemini-provider.ts
+++ b/apps/server/src/providers/gemini-provider.ts
@@ -270,6 +270,11 @@ export class GeminiProvider extends CliProvider {
      cliArgs.push('--include-directories', options.cwd);
    }

+    // Resume an existing Gemini session when one is available
+    if (options.sdkSessionId) {
+      cliArgs.push('--resume', options.sdkSessionId);
+    }
+
    // Note: Gemini CLI doesn't have a --thinking-level flag.
    // Thinking capabilities are determined by the model selection (e.g., gemini-2.5-pro).
    // The model handles thinking internally based on the task complexity.
--- a/apps/server/src/routes/worktree/routes/discard-changes.ts
+++ b/apps/server/src/routes/worktree/routes/discard-changes.ts
@@ -5,12 +5,12 @@
 * 1. Discard ALL changes (when no files array is provided)
 *    - Resets staged changes (git reset HEAD)
 *    - Discards modified tracked files (git checkout .)
- *    - Removes untracked files and directories (git clean -fd)
+ *    - Removes untracked files and directories (git clean -ffd)
 *
 * 2. Discard SELECTED files (when files array is provided)
 *    - Unstages selected staged files (git reset HEAD -- <files>)
 *    - Reverts selected tracked file changes (git checkout -- <files>)
- *    - Removes selected untracked files (git clean -fd -- <files>)
+ *    - Removes selected untracked files (git clean -ffd -- <files>)
 *
 * Note: Git repository validation (isGitRepo) is handled by
 * the requireGitRepoOnly middleware in index.ts
@@ -52,6 +52,22 @@ function validateFilePath(filePath: string, worktreePath: string): boolean {
  }
 }

+/**
+ * Parse a file path from git status --porcelain output, handling renames.
+ * For renamed files (R status), git reports "old_path -> new_path" and
+ * we need the new path to match what parseGitStatus() returns in git-utils.
+ */
+function parseFilePath(rawPath: string, indexStatus: string, workTreeStatus: string): string {
+  const trimmedPath = rawPath.trim();
+  if (indexStatus === 'R' || workTreeStatus === 'R') {
+    const arrowIndex = trimmedPath.indexOf(' -> ');
+    if (arrowIndex !== -1) {
+      return trimmedPath.slice(arrowIndex + 4);
+    }
+  }
+  return trimmedPath;
+}
+
 export function createDiscardChangesHandler() {
  return async (req: Request, res: Response): Promise<void> => {
    try {
@@ -91,11 +107,16 @@ export function createDiscardChangesHandler() {

      // Parse the status output to categorize files
      // Git --porcelain format: XY PATH where X=index status, Y=worktree status
-      // Preserve the exact two-character XY status (no trim) to keep index vs worktree info
+      // For renamed files: XY OLD_PATH -> NEW_PATH
      const statusLines = status.trim().split('\n').filter(Boolean);
      const allFiles = statusLines.map((line) => {
        const fileStatus = line.substring(0, 2);
-        const filePath = line.slice(3).trim();
+        const rawPath = line.slice(3);
+        const indexStatus = fileStatus.charAt(0);
+        const workTreeStatus = fileStatus.charAt(1);
+        // Parse path consistently with parseGitStatus() in git-utils,
+        // which extracts the new path for renames
+        const filePath = parseFilePath(rawPath, indexStatus, workTreeStatus);
        return { status: fileStatus, path: filePath };
      });

@@ -122,8 +143,12 @@ export function createDiscardChangesHandler() {
        const untrackedFiles: string[] = []; // Untracked files (?)
        const warnings: string[] = [];

+        // Track which requested files were matched so we can handle unmatched ones
+        const matchedFiles = new Set<string>();
+
        for (const file of allFiles) {
          if (!filesToDiscard.has(file.path)) continue;
+          matchedFiles.add(file.path);

          // file.status is the raw two-character XY git porcelain status (no trim)
          // X = index/staging status, Y = worktree status
@@ -151,6 +176,16 @@ export function createDiscardChangesHandler() {
          }
        }

+        // Handle files from the UI that didn't match any entry in allFiles.
+        // This can happen due to timing differences between the UI loading diffs
+        // and the discard request, or path format differences.
+        // Attempt to clean unmatched files directly as untracked files.
+        for (const requestedFile of files) {
+          if (!matchedFiles.has(requestedFile)) {
+            untrackedFiles.push(requestedFile);
+          }
+        }
+
        // 1. Unstage selected staged files (using execFile to bypass shell)
        if (stagedFiles.length > 0) {
          try {
@@ -174,9 +209,10 @@ export function createDiscardChangesHandler() {
        }

        // 3. Remove selected untracked files
+        // Use -ffd (double force) to also handle nested git repositories
        if (untrackedFiles.length > 0) {
          try {
-            await execGitCommand(['clean', '-fd', '--', ...untrackedFiles], worktreePath);
+            await execGitCommand(['clean', '-ffd', '--', ...untrackedFiles], worktreePath);
          } catch (error) {
            const msg = getErrorMessage(error);
            logError(error, `Failed to clean untracked files: ${msg}`);
@@ -234,11 +270,12 @@ export function createDiscardChangesHandler() {
        }

        // 3. Remove untracked files and directories
+        // Use -ffd (double force) to also handle nested git repositories
        try {
-          await execGitCommand(['clean', '-fd'], worktreePath);
+          await execGitCommand(['clean', '-ffd', '--'], worktreePath);
        } catch (error) {
          const msg = getErrorMessage(error);
-          logError(error, `git clean -fd failed: ${msg}`);
+          logError(error, `git clean -ffd failed: ${msg}`);
          warnings.push(`Failed to remove untracked files: ${msg}`);
        }

--- a/apps/server/src/services/agent-executor-types.ts
+++ b/apps/server/src/services/agent-executor-types.ts
@@ -29,6 +29,7 @@ export interface AgentExecutionOptions {
  credentials?: Credentials;
  claudeCompatibleProvider?: ClaudeCompatibleProvider;
  mcpServers?: Record<string, unknown>;
+  sdkSessionId?: string;
  sdkOptions?: {
    maxTurns?: number;
    allowedTools?: string[];
--- a/apps/server/src/services/agent-executor.ts
+++ b/apps/server/src/services/agent-executor.ts
@@ -93,6 +93,7 @@ export class AgentExecutor {
      credentials,
      claudeCompatibleProvider,
      mcpServers,
+      sdkSessionId,
      sdkOptions,
    } = options;
    const { content: promptContent } = await buildPromptWithImages(
@@ -129,6 +130,7 @@ export class AgentExecutor {
      thinkingLevel: options.thinkingLevel,
      credentials,
      claudeCompatibleProvider,
+      sdkSessionId,
    };
    const featureDirForOutput = getFeatureDir(projectPath, featureId);
    const outputPath = path.join(featureDirForOutput, 'agent-output.md');
@@ -217,6 +219,9 @@ export class AgentExecutor {
    try {
      const stream = provider.executeQuery(executeOptions);
      streamLoop: for await (const msg of stream) {
+        if (msg.session_id && msg.session_id !== options.sdkSessionId) {
+          options.sdkSessionId = msg.session_id;
+        }
        receivedAnyStreamMessage = true;
        appendRawEvent(msg);
        if (abortController.signal.aborted) {
@@ -385,6 +390,9 @@ export class AgentExecutor {
        taskCompleteDetected = false;

      for await (const msg of taskStream) {
+        if (msg.session_id && msg.session_id !== options.sdkSessionId) {
+          options.sdkSessionId = msg.session_id;
+        }
        if (msg.type === 'assistant' && msg.message?.content) {
          for (const b of msg.message.content) {
            if (b.type === 'text') {
@@ -599,6 +607,9 @@ export class AgentExecutor {
          for await (const msg of provider.executeQuery(
            this.buildExecOpts(options, revPrompt, sdkOptions?.maxTurns ?? DEFAULT_MAX_TURNS)
          )) {
+            if (msg.session_id && msg.session_id !== options.sdkSessionId) {
+              options.sdkSessionId = msg.session_id;
+            }
            if (msg.type === 'assistant' && msg.message?.content)
              for (const b of msg.message.content)
                if (b.type === 'text') {
@@ -698,6 +709,7 @@ export class AgentExecutor {
          : undefined,
      credentials: o.credentials,
      claudeCompatibleProvider: o.claudeCompatibleProvider,
+      sdkSessionId: o.sdkSessionId,
    };
  }

@@ -717,6 +729,9 @@ export class AgentExecutor {
    for await (const msg of provider.executeQuery(
      this.buildExecOpts(options, contPrompt, options.sdkOptions?.maxTurns ?? DEFAULT_MAX_TURNS)
    )) {
+      if (msg.session_id && msg.session_id !== options.sdkSessionId) {
+        options.sdkSessionId = msg.session_id;
+      }
      if (msg.type === 'assistant' && msg.message?.content)
        for (const b of msg.message.content) {
          if (b.type === 'text') {
--- a/apps/server/src/services/agent-service.ts
+++ b/apps/server/src/services/agent-service.ts
@@ -329,12 +329,6 @@ export class AgentService {
      timestamp: new Date().toISOString(),
    };

-    // Build conversation history from existing messages BEFORE adding current message
-    const conversationHistory = session.messages.map((msg) => ({
-      role: msg.role,
-      content: msg.content,
-    }));
-
    session.messages.push(userMessage);
    session.isRunning = true;
    session.abortController = new AbortController();
@@ -406,6 +400,7 @@ export class AgentService {
        }
      }

+      let combinedSystemPrompt: string | undefined;
      // Load project context files (CLAUDE.md, CODE_QUALITY.md, etc.) and memory files
      // Use the user's message as task context for smart memory selection
      const contextResult = await loadContextFiles({
@@ -423,7 +418,7 @@ export class AgentService {

      // Build combined system prompt with base prompt and context files
      const baseSystemPrompt = await this.getSystemPrompt();
-      const combinedSystemPrompt = contextFilesPrompt
+      combinedSystemPrompt = contextFilesPrompt
        ? `${contextFilesPrompt}\n\n${baseSystemPrompt}`
        : baseSystemPrompt;

@@ -513,6 +508,14 @@ export class AgentService {
        : stripProviderPrefix(effectiveModel);

      // Build options for provider
+      const conversationHistory = session.messages
+        .slice(0, -1)
+        .map((msg) => ({
+          role: msg.role,
+          content: msg.content,
+        }))
+        .filter((msg) => msg.content.trim().length > 0);
+
      const options: ExecuteOptions = {
        prompt: '', // Will be set below based on images
        model: bareModel, // Bare model ID (e.g., "gpt-5.1-codex-max", "composer-1")
@@ -522,7 +525,8 @@ export class AgentService {
        maxTurns: maxTurns,
        allowedTools: allowedTools,
        abortController: session.abortController!,
-        conversationHistory: conversationHistory.length > 0 ? conversationHistory : undefined,
+        conversationHistory:
+          conversationHistory && conversationHistory.length > 0 ? conversationHistory : undefined,
        settingSources: settingSources.length > 0 ? settingSources : undefined,
        sdkSessionId: session.sdkSessionId, // Pass SDK session ID for resuming
        mcpServers: Object.keys(mcpServers).length > 0 ? mcpServers : undefined, // Pass MCP servers configuration
--- a/apps/server/tests/unit/providers/codex-provider.test.ts
+++ b/apps/server/tests/unit/providers/codex-provider.test.ts
@@ -170,6 +170,30 @@ describe('codex-provider.ts', () => {
      expect(call.args).toContain('--json');
    });

+    it('uses exec resume when sdkSessionId is provided', async () => {
+      vi.mocked(spawnJSONLProcess).mockReturnValue((async function* () {})());
+
+      await collectAsyncGenerator(
+        provider.executeQuery({
+          prompt: 'Continue',
+          model: 'gpt-5.2',
+          cwd: '/tmp',
+          sdkSessionId: 'codex-session-123',
+          outputFormat: { type: 'json_schema', schema: { type: 'object', properties: {} } },
+          codexSettings: { additionalDirs: ['/extra/dir'] },
+        })
+      );
+
+      const call = vi.mocked(spawnJSONLProcess).mock.calls[0][0];
+      expect(call.args[0]).toBe('exec');
+      expect(call.args[1]).toBe('resume');
+      expect(call.args).toContain('codex-session-123');
+      expect(call.args).toContain('--json');
+      // Resume queries must not include --output-schema or --add-dir
+      expect(call.args).not.toContain('--output-schema');
+      expect(call.args).not.toContain('--add-dir');
+    });
+
    it('overrides approval policy when MCP auto-approval is enabled', async () => {
      // Note: With full-permissions always on (--dangerously-bypass-approvals-and-sandbox),
      // approval policy is bypassed, not configured via --config
--- a/apps/server/tests/unit/providers/copilot-provider.test.ts
+++ b/apps/server/tests/unit/providers/copilot-provider.test.ts
@@ -1,17 +1,35 @@
 import { describe, it, expect, vi, beforeEach, afterEach } from 'vitest';
 import { CopilotProvider, CopilotErrorCode } from '@/providers/copilot-provider.js';
+import { collectAsyncGenerator } from '../../utils/helpers.js';
+import { CopilotClient } from '@github/copilot-sdk';
+
+const createSessionMock = vi.fn();
+const resumeSessionMock = vi.fn();
+
+function createMockSession(sessionId = 'test-session') {
+  let eventHandler: ((event: any) => void) | null = null;
+  return {
+    sessionId,
+    send: vi.fn().mockImplementation(async () => {
+      if (eventHandler) {
+        eventHandler({ type: 'assistant.message', data: { content: 'hello' } });
+        eventHandler({ type: 'session.idle' });
+      }
+    }),
+    destroy: vi.fn().mockResolvedValue(undefined),
+    on: vi.fn().mockImplementation((handler: (event: any) => void) => {
+      eventHandler = handler;
+    }),
+  };
+}

 // Mock the Copilot SDK
 vi.mock('@github/copilot-sdk', () => ({
  CopilotClient: vi.fn().mockImplementation(() => ({
    start: vi.fn().mockResolvedValue(undefined),
    stop: vi.fn().mockResolvedValue(undefined),
-    createSession: vi.fn().mockResolvedValue({
-      sessionId: 'test-session',
-      send: vi.fn().mockResolvedValue(undefined),
-      destroy: vi.fn().mockResolvedValue(undefined),
-      on: vi.fn(),
-    }),
+    createSession: createSessionMock,
+    resumeSession: resumeSessionMock,
  })),
 }));

@@ -49,6 +67,16 @@ describe('copilot-provider.ts', () => {

  beforeEach(() => {
    vi.clearAllMocks();
+    vi.mocked(CopilotClient).mockImplementation(function () {
+      return {
+        start: vi.fn().mockResolvedValue(undefined),
+        stop: vi.fn().mockResolvedValue(undefined),
+        createSession: createSessionMock,
+        resumeSession: resumeSessionMock,
+      } as any;
+    });
+    createSessionMock.mockResolvedValue(createMockSession());
+    resumeSessionMock.mockResolvedValue(createMockSession('resumed-session'));

    // Mock fs.existsSync for CLI path validation
    vi.mocked(fs.existsSync).mockReturnValue(true);
@@ -514,4 +542,45 @@ describe('copilot-provider.ts', () => {
      expect(todoInput.todos[0].status).toBe('completed');
    });
  });
+
+  describe('executeQuery resume behavior', () => {
+    it('uses resumeSession when sdkSessionId is provided', async () => {
+      const results = await collectAsyncGenerator(
+        provider.executeQuery({
+          prompt: 'Hello',
+          model: 'claude-sonnet-4.6',
+          cwd: '/tmp/project',
+          sdkSessionId: 'session-123',
+        })
+      );
+
+      expect(resumeSessionMock).toHaveBeenCalledWith(
+        'session-123',
+        expect.objectContaining({ model: 'claude-sonnet-4.6', streaming: true })
+      );
+      expect(createSessionMock).not.toHaveBeenCalled();
+      expect(results.some((msg) => msg.session_id === 'resumed-session')).toBe(true);
+    });
+
+    it('falls back to createSession when resumeSession fails', async () => {
+      resumeSessionMock.mockRejectedValueOnce(new Error('session not found'));
+      createSessionMock.mockResolvedValueOnce(createMockSession('fresh-session'));
+
+      const results = await collectAsyncGenerator(
+        provider.executeQuery({
+          prompt: 'Hello',
+          model: 'claude-sonnet-4.6',
+          cwd: '/tmp/project',
+          sdkSessionId: 'stale-session',
+        })
+      );
+
+      expect(resumeSessionMock).toHaveBeenCalledWith(
+        'stale-session',
+        expect.objectContaining({ model: 'claude-sonnet-4.6', streaming: true })
+      );
+      expect(createSessionMock).toHaveBeenCalledTimes(1);
+      expect(results.some((msg) => msg.session_id === 'fresh-session')).toBe(true);
+    });
+  });
 });
--- a/apps/server/tests/unit/providers/cursor-provider.test.ts
+++ b/apps/server/tests/unit/providers/cursor-provider.test.ts
@@ -0,0 +1,39 @@
+import { describe, it, expect } from 'vitest';
+import { CursorProvider } from '@/providers/cursor-provider.js';
+
+describe('cursor-provider.ts', () => {
+  describe('buildCliArgs', () => {
+    it('adds --resume when sdkSessionId is provided', () => {
+      const provider = Object.create(CursorProvider.prototype) as CursorProvider & {
+        cliPath?: string;
+      };
+      provider.cliPath = '/usr/local/bin/cursor-agent';
+
+      const args = provider.buildCliArgs({
+        prompt: 'Continue the task',
+        model: 'gpt-5',
+        cwd: '/tmp/project',
+        sdkSessionId: 'cursor-session-123',
+      });
+
+      const resumeIndex = args.indexOf('--resume');
+      expect(resumeIndex).toBeGreaterThan(-1);
+      expect(args[resumeIndex + 1]).toBe('cursor-session-123');
+    });
+
+    it('does not add --resume when sdkSessionId is omitted', () => {
+      const provider = Object.create(CursorProvider.prototype) as CursorProvider & {
+        cliPath?: string;
+      };
+      provider.cliPath = '/usr/local/bin/cursor-agent';
+
+      const args = provider.buildCliArgs({
+        prompt: 'Start a new task',
+        model: 'gpt-5',
+        cwd: '/tmp/project',
+      });
+
+      expect(args).not.toContain('--resume');
+    });
+  });
+});
--- a/apps/server/tests/unit/providers/gemini-provider.test.ts
+++ b/apps/server/tests/unit/providers/gemini-provider.test.ts
@@ -0,0 +1,35 @@
+import { describe, it, expect, beforeEach } from 'vitest';
+import { GeminiProvider } from '@/providers/gemini-provider.js';
+
+describe('gemini-provider.ts', () => {
+  let provider: GeminiProvider;
+
+  beforeEach(() => {
+    provider = new GeminiProvider();
+  });
+
+  describe('buildCliArgs', () => {
+    it('should include --resume when sdkSessionId is provided', () => {
+      const args = provider.buildCliArgs({
+        prompt: 'Hello',
+        model: '2.5-flash',
+        cwd: '/tmp/project',
+        sdkSessionId: 'gemini-session-123',
+      });
+
+      const resumeIndex = args.indexOf('--resume');
+      expect(resumeIndex).toBeGreaterThan(-1);
+      expect(args[resumeIndex + 1]).toBe('gemini-session-123');
+    });
+
+    it('should not include --resume when sdkSessionId is missing', () => {
+      const args = provider.buildCliArgs({
+        prompt: 'Hello',
+        model: '2.5-flash',
+        cwd: '/tmp/project',
+      });
+
+      expect(args).not.toContain('--resume');
+    });
+  });
+});
--- a/apps/server/tests/unit/services/agent-service.test.ts
+++ b/apps/server/tests/unit/services/agent-service.test.ts
@@ -303,6 +303,36 @@ describe('agent-service.ts', () => {

      expect(fs.writeFile).toHaveBeenCalled();
    });
+
+    it('should include context/history preparation for Gemini requests', async () => {
+      let capturedOptions: any;
+      const mockProvider = {
+        getName: () => 'gemini',
+        executeQuery: async function* (options: any) {
+          capturedOptions = options;
+          yield {
+            type: 'result',
+            subtype: 'success',
+          };
+        },
+      };
+
+      vi.mocked(ProviderFactory.getProviderForModelName).mockReturnValue('gemini');
+      vi.mocked(ProviderFactory.getProviderForModel).mockReturnValue(mockProvider as any);
+      vi.mocked(promptBuilder.buildPromptWithImages).mockResolvedValue({
+        content: 'Hello',
+        hasImages: false,
+      });
+
+      await service.sendMessage({
+        sessionId: 'session-1',
+        message: 'Hello',
+        model: 'gemini-2.5-flash',
+      });
+
+      expect(contextLoader.loadContextFiles).toHaveBeenCalled();
+      expect(capturedOptions).toBeDefined();
+    });
  });

  describe('stopExecution', () => {
--- a/apps/ui/src/components/views/agent-view.tsx
+++ b/apps/ui/src/components/views/agent-view.tsx
@@ -1,6 +1,5 @@
 import { useState, useCallback, useRef, useEffect } from 'react';
 import { useAppStore } from '@/store/app-store';
-import type { PhaseModelEntry } from '@automaker/types';
 import { useElectronAgent } from '@/hooks/use-electron-agent';
 import { SessionManager } from '@/components/session-manager';

@@ -46,8 +45,6 @@ export function AgentView() {
    return () => window.removeEventListener('resize', updateVisibility);
  }, []);

-  const [modelSelection, setModelSelection] = useState<PhaseModelEntry>({ model: 'claude-sonnet' });
-
  // Input ref for auto-focus
  const inputRef = useRef<HTMLTextAreaElement>(null);

@@ -57,10 +54,12 @@ export function AgentView() {
  const createSessionInFlightRef = useRef(false);

  // Session management hook - scoped to current worktree
-  const { currentSessionId, handleSelectSession } = useAgentSession({
-    projectPath: currentProject?.path,
-    workingDirectory: effectiveWorkingDirectory,
-  });
+  // Also handles model selection persistence per session
+  const { currentSessionId, handleSelectSession, modelSelection, setModelSelection } =
+    useAgentSession({
+      projectPath: currentProject?.path,
+      workingDirectory: effectiveWorkingDirectory,
+    });

  // Use the Electron agent hook (only if we have a session)
  const {
--- a/apps/ui/src/components/views/agent-view/hooks/use-agent-session.ts
+++ b/apps/ui/src/components/views/agent-view/hooks/use-agent-session.ts
@@ -1,9 +1,14 @@
 import { useState, useCallback, useEffect, useRef } from 'react';
 import { createLogger } from '@automaker/utils/logger';
+import type { PhaseModelEntry } from '@automaker/types';
 import { useAppStore } from '@/store/app-store';
+import { useShallow } from 'zustand/react/shallow';

 const logger = createLogger('AgentSession');

+// Default model selection when none is persisted
+const DEFAULT_MODEL_SELECTION: PhaseModelEntry = { model: 'claude-sonnet' };
+
 interface UseAgentSessionOptions {
  projectPath: string | undefined;
  workingDirectory?: string; // Current worktree path for per-worktree session persistence
@@ -12,14 +17,31 @@ interface UseAgentSessionOptions {
 interface UseAgentSessionResult {
  currentSessionId: string | null;
  handleSelectSession: (sessionId: string | null) => void;
+  // Model selection persistence
+  modelSelection: PhaseModelEntry;
+  setModelSelection: (model: PhaseModelEntry) => void;
 }

 export function useAgentSession({
  projectPath,
  workingDirectory,
 }: UseAgentSessionOptions): UseAgentSessionResult {
-  const { setLastSelectedSession, getLastSelectedSession } = useAppStore();
+  const {
+    setLastSelectedSession,
+    getLastSelectedSession,
+    setAgentModelForSession,
+    getAgentModelForSession,
+  } = useAppStore(
+    useShallow((state) => ({
+      setLastSelectedSession: state.setLastSelectedSession,
+      getLastSelectedSession: state.getLastSelectedSession,
+      setAgentModelForSession: state.setAgentModelForSession,
+      getAgentModelForSession: state.getAgentModelForSession,
+    }))
+  );
  const [currentSessionId, setCurrentSessionId] = useState<string | null>(null);
+  const [modelSelection, setModelSelectionState] =
+    useState<PhaseModelEntry>(DEFAULT_MODEL_SELECTION);

  // Track if initial session has been loaded
  const initialSessionLoadedRef = useRef(false);
@@ -27,6 +49,22 @@ export function useAgentSession({
  // Use workingDirectory as the persistence key so sessions are scoped per worktree
  const persistenceKey = workingDirectory || projectPath;

+  /**
+   * Fetch persisted model for sessionId and update local state, or fall back to default.
+   */
+  const restoreModelForSession = useCallback(
+    (sessionId: string) => {
+      const persistedModel = getAgentModelForSession(sessionId);
+      if (persistedModel) {
+        logger.debug('Restoring model selection for session:', sessionId, persistedModel);
+        setModelSelectionState(persistedModel);
+      } else {
+        setModelSelectionState(DEFAULT_MODEL_SELECTION);
+      }
+    },
+    [getAgentModelForSession]
+  );
+
  // Handle session selection with persistence
  const handleSelectSession = useCallback(
    (sessionId: string | null) => {
@@ -35,16 +73,52 @@ export function useAgentSession({
      if (persistenceKey) {
        setLastSelectedSession(persistenceKey, sessionId);
      }
+      // Restore model selection for this session if available
+      if (sessionId) {
+        restoreModelForSession(sessionId);
+      }
    },
-    [persistenceKey, setLastSelectedSession]
+    [persistenceKey, setLastSelectedSession, restoreModelForSession]
  );

+  // Wrapper for setModelSelection that also persists
+  const setModelSelection = useCallback(
+    (model: PhaseModelEntry) => {
+      setModelSelectionState(model);
+      // Persist model selection for current session.
+      // If currentSessionId is null (no active session), we only update local state
+      // and skip persistence — this is intentional because the model picker should be
+      // disabled (or hidden) in the UI whenever there is no active session, so this
+      // path is only reached if the UI allows selection before a session is established.
+      if (currentSessionId) {
+        setAgentModelForSession(currentSessionId, model);
+      }
+    },
+    [currentSessionId, setAgentModelForSession]
+  );
+
+  // Track the previous persistence key to detect actual changes
+  const prevPersistenceKeyRef = useRef(persistenceKey);
+
  // Restore last selected session when switching to Agent view or when worktree changes
  useEffect(() => {
-    if (!persistenceKey) {
-      // No project, reset
-      setCurrentSessionId(null);
+    // Detect if persistenceKey actually changed (worktree/project switch)
+    const persistenceKeyChanged = prevPersistenceKeyRef.current !== persistenceKey;
+
+    if (persistenceKeyChanged) {
+      // Reset state when switching worktree/project
+      prevPersistenceKeyRef.current = persistenceKey;
      initialSessionLoadedRef.current = false;
+      setCurrentSessionId(null);
+      setModelSelectionState(DEFAULT_MODEL_SELECTION);
+
+      if (!persistenceKey) {
+        // No project, nothing to restore
+        return;
+      }
+    }
+
+    if (!persistenceKey) {
      return;
    }

@@ -54,19 +128,17 @@ export function useAgentSession({

    const lastSessionId = getLastSelectedSession(persistenceKey);
    if (lastSessionId) {
-      logger.info('Restoring last selected session:', lastSessionId);
+      logger.debug('Restoring last selected session:', lastSessionId);
      setCurrentSessionId(lastSessionId);
+      // Also restore model selection for this session
+      restoreModelForSession(lastSessionId);
    }
-  }, [persistenceKey, getLastSelectedSession]);
-
-  // Reset when worktree/project changes - clear current session and allow restore
-  useEffect(() => {
-    initialSessionLoadedRef.current = false;
-    setCurrentSessionId(null);
-  }, [persistenceKey]);
+  }, [persistenceKey, getLastSelectedSession, restoreModelForSession]);

  return {
    currentSessionId,
    handleSelectSession,
+    modelSelection,
+    setModelSelection,
  };
 }
--- a/apps/ui/src/components/views/board-view.tsx
+++ b/apps/ui/src/components/views/board-view.tsx
@@ -116,7 +116,6 @@ export function BoardView() {
    setPendingPlanApproval,
    updateFeature,
    batchUpdateFeatures,
-    getCurrentWorktree,
    setCurrentWorktree,
    getWorktrees,
    setWorktrees,
@@ -135,7 +134,6 @@ export function BoardView() {
      setPendingPlanApproval: state.setPendingPlanApproval,
      updateFeature: state.updateFeature,
      batchUpdateFeatures: state.batchUpdateFeatures,
-      getCurrentWorktree: state.getCurrentWorktree,
      setCurrentWorktree: state.setCurrentWorktree,
      getWorktrees: state.getWorktrees,
      setWorktrees: state.setWorktrees,
@@ -444,9 +442,17 @@ export function BoardView() {
    [batchResetBranchFeatures]
  );

-  // Get current worktree info (path) for filtering features
-  // This needs to be before useBoardActions so we can pass currentWorktreeBranch
-  const currentWorktreeInfo = currentProject ? getCurrentWorktree(currentProject.path) : null;
+  const currentProjectPath = currentProject?.path;
+
+  // Get current worktree info (path/branch) for filtering features.
+  // Subscribe to the selected project's current worktree value directly so worktree
+  // switches trigger an immediate re-render and instant kanban/list re-filtering.
+  const currentWorktreeInfo = useAppStore(
+    useCallback(
+      (s) => (currentProjectPath ? (s.currentWorktreeByProject[currentProjectPath] ?? null) : null),
+      [currentProjectPath]
+    )
+  );
  const currentWorktreePath = currentWorktreeInfo?.path ?? null;

  // Select worktrees for the current project directly from the store.
@@ -455,7 +461,6 @@ export function BoardView() {
  // object, causing unnecessary re-renders that cascaded into selectedWorktree →
  // useAutoMode → refreshStatus → setAutoModeRunning → store update → re-render loop
  // that could trigger React error #185 on initial project open).
-  const currentProjectPath = currentProject?.path;
  const worktrees = useAppStore(
    useCallback(
      (s) =>
--- a/apps/ui/src/components/views/board-view/dialogs/commit-worktree-dialog.tsx
+++ b/apps/ui/src/components/views/board-view/dialogs/commit-worktree-dialog.tsx
@@ -1,4 +1,4 @@
-import { useState, useEffect, useMemo, useCallback } from 'react';
+import { useState, useEffect, useMemo, useCallback, useRef } from 'react';
 import {
  Dialog,
  DialogContent,
@@ -30,13 +30,17 @@ import {
  ChevronDown,
  ChevronRight,
  Upload,
+  RefreshCw,
 } from 'lucide-react';
 import { Spinner } from '@/components/ui/spinner';
 import { getElectronAPI } from '@/lib/electron';
+import { getHttpApiClient } from '@/lib/http-api-client';
 import { toast } from 'sonner';
 import { useAppStore } from '@/store/app-store';
+import { resolveModelString } from '@automaker/model-resolver';
 import { cn } from '@/lib/utils';
 import { TruncatedFilePath } from '@/components/ui/truncated-file-path';
+import { ModelOverrideTrigger, useModelOverride } from '@/components/shared';
 import type { FileStatus, MergeStateInfo } from '@/types/electron';
 import { parseDiff, type ParsedFileDiff } from '@/lib/diff-utils';

@@ -206,6 +210,11 @@ export function CommitWorktreeDialog({
  const [error, setError] = useState<string | null>(null);
  const enableAiCommitMessages = useAppStore((state) => state.enableAiCommitMessages);

+  // Commit message model override
+  const commitModelOverride = useModelOverride({ phase: 'commitMessageModel' });
+  const { effectiveModel: commitEffectiveModel, effectiveModelEntry: commitEffectiveModelEntry } =
+    commitModelOverride;
+
  // File selection state
  const [files, setFiles] = useState<FileStatus[]>([]);
  const [diffContent, setDiffContent] = useState('');
@@ -532,6 +541,46 @@ export function CommitWorktreeDialog({
    }
  };

+  // Generate AI commit message
+  const generateCommitMessage = useCallback(async () => {
+    if (!worktree) return;
+
+    setIsGenerating(true);
+    try {
+      const resolvedCommitModel = resolveModelString(commitEffectiveModel);
+      const api = getHttpApiClient();
+      const result = await api.worktree.generateCommitMessage(
+        worktree.path,
+        resolvedCommitModel,
+        commitEffectiveModelEntry?.thinkingLevel,
+        commitEffectiveModelEntry?.providerId
+      );
+
+      if (result.success && result.message) {
+        setMessage(result.message);
+      } else {
+        console.warn('Failed to generate commit message:', result.error);
+        toast.error('Failed to generate commit message', {
+          description: result.error || 'Unknown error',
+        });
+      }
+    } catch (err) {
+      console.warn('Error generating commit message:', err);
+      toast.error('Failed to generate commit message', {
+        description: err instanceof Error ? err.message : 'Unknown error',
+      });
+    } finally {
+      setIsGenerating(false);
+    }
+  }, [worktree, commitEffectiveModel, commitEffectiveModelEntry]);
+
+  // Keep a stable ref to generateCommitMessage so the open-dialog effect
+  // doesn't re-fire (and erase user edits) when the model override changes.
+  const generateCommitMessageRef = useRef(generateCommitMessage);
+  useEffect(() => {
+    generateCommitMessageRef.current = generateCommitMessage;
+  });
+
  // Generate AI commit message when dialog opens (if enabled)
  useEffect(() => {
    if (open && worktree) {
@@ -543,45 +592,7 @@ export function CommitWorktreeDialog({
        return;
      }

-      setIsGenerating(true);
-      let cancelled = false;
-
-      const generateMessage = async () => {
-        try {
-          const api = getElectronAPI();
-          if (!api?.worktree?.generateCommitMessage) {
-            if (!cancelled) {
-              setIsGenerating(false);
-            }
-            return;
-          }
-
-          const result = await api.worktree.generateCommitMessage(worktree.path);
-
-          if (cancelled) return;
-
-          if (result.success && result.message) {
-            setMessage(result.message);
-          } else {
-            console.warn('Failed to generate commit message:', result.error);
-            setMessage('');
-          }
-        } catch (err) {
-          if (cancelled) return;
-          console.warn('Error generating commit message:', err);
-          setMessage('');
-        } finally {
-          if (!cancelled) {
-            setIsGenerating(false);
-          }
-        }
-      };
-
-      generateMessage();
-
-      return () => {
-        cancelled = true;
-      };
+      generateCommitMessageRef.current();
    }
  }, [open, worktree, enableAiCommitMessages]);

@@ -589,12 +600,12 @@ export function CommitWorktreeDialog({

  const allSelected = selectedFiles.size === files.length && files.length > 0;

-  // Prevent the dialog from being dismissed while a push is in progress.
+  // Prevent the dialog from being dismissed while a push or generation is in progress.
  // Overlay clicks and Escape key both route through onOpenChange(false); we
-  // intercept those here so the UI stays open until the push completes.
+  // intercept those here so the UI stays open until the operation completes.
  const handleOpenChange = (nextOpen: boolean) => {
-    if (!nextOpen && isPushing) {
-      // Ignore close requests during an active push.
+    if (!nextOpen && (isLoading || isPushing || isGenerating)) {
+      // Ignore close requests during an active commit, push, or generation.
      return;
    }
    onOpenChange(nextOpen);
@@ -813,15 +824,46 @@ export function CommitWorktreeDialog({

          {/* Commit Message */}
          <div className="grid gap-1.5">
-            <Label htmlFor="commit-message" className="flex items-center gap-2">
-              Commit Message
-              {isGenerating && (
-                <span className="flex items-center gap-1 text-xs text-muted-foreground">
-                  <Sparkles className="w-3 h-3 animate-pulse" />
-                  Generating...
-                </span>
-              )}
-            </Label>
+            <div className="flex items-center justify-between">
+              <Label htmlFor="commit-message" className="flex items-center gap-2">
+                Commit Message
+                {isGenerating && (
+                  <span className="flex items-center gap-1 text-xs text-muted-foreground">
+                    <Sparkles className="w-3 h-3 animate-pulse" />
+                    Generating...
+                  </span>
+                )}
+              </Label>
+              <div className="flex items-center gap-1">
+                {enableAiCommitMessages && (
+                  <>
+                    <Button
+                      variant="ghost"
+                      size="sm"
+                      onClick={generateCommitMessage}
+                      disabled={isGenerating || isLoading}
+                      className="h-6 px-2 text-xs"
+                      title="Regenerate commit message"
+                    >
+                      {isGenerating ? (
+                        <Spinner size="xs" className="mr-1" />
+                      ) : (
+                        <RefreshCw className="w-3 h-3 mr-1" />
+                      )}
+                      Regenerate
+                    </Button>
+                    <ModelOverrideTrigger
+                      currentModelEntry={commitModelOverride.effectiveModelEntry}
+                      onModelChange={commitModelOverride.setOverride}
+                      phase="commitMessageModel"
+                      isOverridden={commitModelOverride.isOverridden}
+                      size="sm"
+                      variant="icon"
+                    />
+                  </>
+                )}
+              </div>
+            </div>
            <Textarea
              id="commit-message"
              placeholder={
--- a/apps/ui/src/components/views/board-view/dialogs/create-pr-dialog.tsx
+++ b/apps/ui/src/components/views/board-view/dialogs/create-pr-dialog.tsx
@@ -26,6 +26,7 @@ import { getElectronAPI } from '@/lib/electron';
 import { getHttpApiClient } from '@/lib/http-api-client';
 import { toast } from 'sonner';
 import { useWorktreeBranches } from '@/hooks/queries';
+import { ModelOverrideTrigger, useModelOverride } from '@/components/shared';

 interface RemoteInfo {
  name: string;
@@ -92,6 +93,9 @@ export function CreatePRDialog({
  // Generate description state
  const [isGeneratingDescription, setIsGeneratingDescription] = useState(false);

+  // PR description model override
+  const prDescriptionModelOverride = useModelOverride({ phase: 'prDescriptionModel' });
+
  // Use React Query for branch fetching - only enabled when dialog is open
  const { data: branchesData, isLoading: isLoadingBranches } = useWorktreeBranches(
    open ? worktree?.path : undefined,
@@ -306,7 +310,13 @@ export function CreatePRDialog({
        resolvedRef !== baseBranch && resolvedRef.includes('/')
          ? resolvedRef.substring(resolvedRef.indexOf('/') + 1)
          : resolvedRef;
-      const result = await api.worktree.generatePRDescription(worktree.path, branchNameForApi);
+      const result = await api.worktree.generatePRDescription(
+        worktree.path,
+        branchNameForApi,
+        prDescriptionModelOverride.effectiveModel,
+        prDescriptionModelOverride.effectiveModelEntry.thinkingLevel,
+        prDescriptionModelOverride.effectiveModelEntry.providerId
+      );

      if (result.success) {
        if (result.title) {
@@ -587,30 +597,40 @@ export function CreatePRDialog({
              <div className="grid gap-2">
                <div className="flex items-center justify-between">
                  <Label htmlFor="pr-title">PR Title</Label>
-                  <Button
-                    variant="ghost"
-                    size="sm"
-                    onClick={handleGenerateDescription}
-                    disabled={isGeneratingDescription || isLoading}
-                    className="h-6 px-2 text-xs"
-                    title={
-                      worktree.hasChanges
-                        ? 'Generate title and description from commits and uncommitted changes'
-                        : 'Generate title and description from commits'
-                    }
-                  >
-                    {isGeneratingDescription ? (
-                      <>
-                        <Spinner size="xs" className="mr-1" />
-                        Generating...
-                      </>
-                    ) : (
-                      <>
-                        <Sparkles className="w-3 h-3 mr-1" />
-                        Generate with AI
-                      </>
-                    )}
-                  </Button>
+                  <div className="flex items-center gap-1">
+                    <Button
+                      variant="ghost"
+                      size="sm"
+                      onClick={handleGenerateDescription}
+                      disabled={isGeneratingDescription || isLoading}
+                      className="h-6 px-2 text-xs"
+                      title={
+                        worktree.hasChanges
+                          ? 'Generate title and description from commits and uncommitted changes'
+                          : 'Generate title and description from commits'
+                      }
+                    >
+                      {isGeneratingDescription ? (
+                        <>
+                          <Spinner size="xs" className="mr-1" />
+                          Generating...
+                        </>
+                      ) : (
+                        <>
+                          <Sparkles className="w-3 h-3 mr-1" />
+                          Generate with AI
+                        </>
+                      )}
+                    </Button>
+                    <ModelOverrideTrigger
+                      currentModelEntry={prDescriptionModelOverride.effectiveModelEntry}
+                      onModelChange={prDescriptionModelOverride.setOverride}
+                      phase="prDescriptionModel"
+                      isOverridden={prDescriptionModelOverride.isOverridden}
+                      size="sm"
+                      variant="icon"
+                    />
+                  </div>
                </div>
                <Input
                  id="pr-title"
--- a/apps/ui/src/hooks/use-settings-sync.ts
+++ b/apps/ui/src/hooks/use-settings-sync.ts
@@ -109,6 +109,7 @@ const SETTINGS_FIELDS_TO_SYNC = [
  'projectHistory',
  'projectHistoryIndex',
  'lastSelectedSessionByProject',
+  'agentModelBySession',
  'currentWorktreeByProject',
  // Codex CLI Settings
  'codexAutoLoadAgents',
@@ -173,6 +174,17 @@ function getSettingsFieldValue(
    }
    return persistedSettings;
  }
+  if (field === 'agentModelBySession') {
+    // Cap to the 50 most-recently-inserted session entries to prevent unbounded growth.
+    // agentModelBySession grows by one entry per agent session — without pruning this
+    // will bloat settings.json, every debounced sync payload, and the localStorage cache.
+    const map = appState.agentModelBySession as Record<string, unknown>;
+    const MAX_ENTRIES = 50;
+    const entries = Object.entries(map);
+    if (entries.length <= MAX_ENTRIES) return map;
+    // Keep the last MAX_ENTRIES entries (insertion-order approximation for recency)
+    return Object.fromEntries(entries.slice(-MAX_ENTRIES));
+  }
  return appState[field as keyof typeof appState];
 }

@@ -806,6 +818,13 @@ export async function refreshSettingsFromServer(): Promise<boolean> {
      projectHistory: serverSettings.projectHistory,
      projectHistoryIndex: serverSettings.projectHistoryIndex,
      lastSelectedSessionByProject: serverSettings.lastSelectedSessionByProject,
+      agentModelBySession: serverSettings.agentModelBySession
+        ? Object.fromEntries(
+            Object.entries(serverSettings.agentModelBySession as Record<string, unknown>).map(
+              ([sessionId, entry]) => [sessionId, migratePhaseModelEntry(entry)]
+            )
+          )
+        : currentAppState.agentModelBySession,
      // Sanitize: only restore entries with path === null (main branch).
      // Non-null paths may reference deleted worktrees, causing crash loops.
      currentWorktreeByProject: sanitizeWorktreeByProject(
--- a/apps/ui/src/lib/http-api-client.ts
+++ b/apps/ui/src/lib/http-api-client.ts
@@ -2204,10 +2204,32 @@ export class HttpApiClient implements ElectronAPI {
      }),
    commit: (worktreePath: string, message: string, files?: string[]) =>
      this.post('/api/worktree/commit', { worktreePath, message, files }),
-    generateCommitMessage: (worktreePath: string) =>
-      this.post('/api/worktree/generate-commit-message', { worktreePath }),
-    generatePRDescription: (worktreePath: string, baseBranch?: string) =>
-      this.post('/api/worktree/generate-pr-description', { worktreePath, baseBranch }),
+    generateCommitMessage: (
+      worktreePath: string,
+      model?: string,
+      thinkingLevel?: string,
+      providerId?: string
+    ) =>
+      this.post('/api/worktree/generate-commit-message', {
+        worktreePath,
+        model,
+        thinkingLevel,
+        providerId,
+      }),
+    generatePRDescription: (
+      worktreePath: string,
+      baseBranch?: string,
+      model?: string,
+      thinkingLevel?: string,
+      providerId?: string
+    ) =>
+      this.post('/api/worktree/generate-pr-description', {
+        worktreePath,
+        baseBranch,
+        model,
+        thinkingLevel,
+        providerId,
+      }),
    push: (worktreePath: string, force?: boolean, remote?: string, autoResolve?: boolean) =>
      this.post('/api/worktree/push', { worktreePath, force, remote, autoResolve }),
    sync: (worktreePath: string, remote?: string) =>
--- a/apps/ui/src/lib/settings-utils.ts
+++ b/apps/ui/src/lib/settings-utils.ts
@@ -3,10 +3,14 @@
 */

 /**
- * Drop currentWorktreeByProject entries with non-null paths.
- * Non-null paths reference worktree directories that may have been deleted,
- * and restoring them causes crash loops (board renders invalid worktree
- * -> error boundary reloads -> restores same stale path).
+ * Validate and sanitize currentWorktreeByProject entries.
+ *
+ * Keeps all valid entries (both main branch and feature worktrees).
+ * The validation against actual worktrees happens in use-worktrees.ts
+ * which resets to main branch if the selected worktree no longer exists.
+ *
+ * Only drops entries with invalid structure (not an object, missing/invalid
+ * path or branch).
 */
 export function sanitizeWorktreeByProject(
  raw: Record<string, { path: string | null; branch: string }> | undefined
@@ -14,11 +18,13 @@ export function sanitizeWorktreeByProject(
  if (!raw) return {};
  const sanitized: Record<string, { path: string | null; branch: string }> = {};
  for (const [projectPath, worktree] of Object.entries(raw)) {
+    // Only validate structure - keep both null (main) and non-null (worktree) paths
+    // Runtime validation in use-worktrees.ts handles deleted worktrees
    if (
      typeof worktree === 'object' &&
      worktree !== null &&
-      'path' in worktree &&
-      worktree.path === null
+      typeof worktree.branch === 'string' &&
+      (worktree.path === null || typeof worktree.path === 'string')
    ) {
      sanitized[projectPath] = worktree;
    }
--- a/apps/ui/src/store/app-store.ts
+++ b/apps/ui/src/store/app-store.ts
@@ -275,6 +275,7 @@ const initialState: AppState = {
  collapsedNavSections: cachedUI.collapsedNavSections,
  mobileSidebarHidden: false,
  lastSelectedSessionByProject: {},
+  agentModelBySession: {},
  theme: getStoredTheme() || 'dark',
  fontFamilySans: getStoredFontSans(),
  fontFamilyMono: getStoredFontMono(),
@@ -962,11 +963,15 @@ export const useAppStore = create<AppState & AppActions>()((set, get) => ({
      ),
    })),
  deleteChatSession: (sessionId) =>
-    set((state) => ({
-      chatSessions: state.chatSessions.filter((s) => s.id !== sessionId),
-      currentChatSession:
-        state.currentChatSession?.id === sessionId ? null : state.currentChatSession,
-    })),
+    set((state) => {
+      const { [sessionId]: _removed, ...remainingAgentModels } = state.agentModelBySession;
+      return {
+        chatSessions: state.chatSessions.filter((s) => s.id !== sessionId),
+        currentChatSession:
+          state.currentChatSession?.id === sessionId ? null : state.currentChatSession,
+        agentModelBySession: remainingAgentModels,
+      };
+    }),
  setChatHistoryOpen: (open) => set({ chatHistoryOpen: open }),
  toggleChatHistory: () => set((state) => ({ chatHistoryOpen: !state.chatHistoryOpen })),

@@ -1598,6 +1603,16 @@ export const useAppStore = create<AppState & AppActions>()((set, get) => ({
    })),
  getLastSelectedSession: (projectPath) => get().lastSelectedSessionByProject[projectPath] ?? null,

+  // Agent model selection actions
+  setAgentModelForSession: (sessionId, model) =>
+    set((state) => ({
+      agentModelBySession: {
+        ...state.agentModelBySession,
+        [sessionId]: model,
+      },
+    })),
+  getAgentModelForSession: (sessionId) => get().agentModelBySession[sessionId] ?? null,
+
  // Board Background actions
  setBoardBackground: (projectPath, imagePath) =>
    set((state) => ({
--- a/apps/ui/src/store/types/state-types.ts
+++ b/apps/ui/src/store/types/state-types.ts
@@ -83,6 +83,8 @@ export interface AppState {

  // Agent Session state (per-project, keyed by project path)
  lastSelectedSessionByProject: Record<string, string>; // projectPath -> sessionId
+  // Agent model selection (per-session, keyed by sessionId)
+  agentModelBySession: Record<string, PhaseModelEntry>; // sessionId -> model selection

  // Theme
  theme: ThemeMode;
@@ -669,6 +671,9 @@ export interface AppActions {
  // Agent Session actions
  setLastSelectedSession: (projectPath: string, sessionId: string | null) => void;
  getLastSelectedSession: (projectPath: string) => string | null;
+  // Agent model selection actions
+  setAgentModelForSession: (sessionId: string, model: PhaseModelEntry) => void;
+  getAgentModelForSession: (sessionId: string) => PhaseModelEntry | null;

  // Board Background actions
  setBoardBackground: (projectPath: string, imagePath: string | null) => void;
--- a/apps/ui/src/store/ui-cache-store.ts
+++ b/apps/ui/src/store/ui-cache-store.ts
@@ -81,6 +81,38 @@ export const useUICacheStore = create<UICacheState & UICacheActions>()(
  )
 );

+/**
+ * Check whether an unknown value is a valid cached worktree entry.
+ * Accepts objects with a non-empty string branch and a path that is null or a string.
+ */
+function isValidCachedWorktreeEntry(
+  worktree: unknown
+): worktree is { path: string | null; branch: string } {
+  return (
+    typeof worktree === 'object' &&
+    worktree !== null &&
+    typeof (worktree as Record<string, unknown>).branch === 'string' &&
+    ((worktree as Record<string, unknown>).branch as string).trim().length > 0 &&
+    ((worktree as Record<string, unknown>).path === null ||
+      typeof (worktree as Record<string, unknown>).path === 'string')
+  );
+}
+
+/**
+ * Filter a raw worktree map, discarding entries that fail structural validation.
+ */
+function sanitizeCachedWorktreeByProject(
+  raw: Record<string, unknown>
+): Record<string, { path: string | null; branch: string }> {
+  const sanitized: Record<string, { path: string | null; branch: string }> = {};
+  for (const [key, worktree] of Object.entries(raw)) {
+    if (isValidCachedWorktreeEntry(worktree)) {
+      sanitized[key] = worktree;
+    }
+  }
+  return sanitized;
+}
+
 /**
 * Sync critical UI state from the main app store to the UI cache.
 * Call this whenever the app store changes to keep the cache up to date.
@@ -114,24 +146,14 @@ export function syncUICache(appState: {
    update.cachedCollapsedNavSections = appState.collapsedNavSections;
  }
  if ('currentWorktreeByProject' in appState && appState.currentWorktreeByProject) {
-    // Sanitize on write: only persist entries where path is null (main branch).
-    // Non-null paths point to worktree directories on disk that may be deleted
-    // while the app is not running. Persisting stale paths can cause crash loops
-    // on restore (the board renders with an invalid selection, the error boundary
-    // reloads, which restores the same bad cache). This mirrors the sanitization
-    // in restoreFromUICache() for defense-in-depth.
-    const sanitized: Record<string, { path: string | null; branch: string }> = {};
-    for (const [projectPath, worktree] of Object.entries(appState.currentWorktreeByProject)) {
-      if (
-        typeof worktree === 'object' &&
-        worktree !== null &&
-        'path' in worktree &&
-        worktree.path === null
-      ) {
-        sanitized[projectPath] = worktree;
-      }
-    }
-    update.cachedCurrentWorktreeByProject = sanitized;
+    // Persist all valid worktree selections (both main branch and feature worktrees).
+    // Validation against actual worktrees happens at restore time in:
+    // 1. restoreFromUICache() - early restore with validation
+    // 2. use-worktrees.ts - runtime validation that resets to main if deleted
+    // This allows users to have their feature worktree selection persist across refreshes.
+    update.cachedCurrentWorktreeByProject = sanitizeCachedWorktreeByProject(
+      appState.currentWorktreeByProject as Record<string, unknown>
+    );
  }

  if (Object.keys(update).length > 0) {
@@ -178,33 +200,18 @@ export function restoreFromUICache(
  // Restore last selected worktree per project so the board doesn't
  // reset to main branch after PWA memory eviction or tab discard.
  //
-  // IMPORTANT: Only restore entries where path is null (main branch selection).
-  // Non-null paths point to worktree directories on disk that may have been
-  // deleted while the PWA was evicted. Restoring a stale worktree path causes
-  // the board to render with an invalid selection, and if the server can't
-  // validate it fast enough, the app enters an unrecoverable crash loop
-  // (the error boundary reloads, which restores the same bad cache).
-  // Main branch (path=null) is always valid and safe to restore.
+  // Restore all valid worktree selections (both main branch and feature worktrees).
+  // The validation effect in use-worktrees.ts will handle resetting to main branch
+  // if the cached worktree no longer exists when worktree data loads.
  if (
    cache.cachedCurrentWorktreeByProject &&
    Object.keys(cache.cachedCurrentWorktreeByProject).length > 0
  ) {
-    const sanitized: Record<string, { path: string | null; branch: string }> = {};
-    for (const [projectPath, worktree] of Object.entries(cache.cachedCurrentWorktreeByProject)) {
-      if (
-        typeof worktree === 'object' &&
-        worktree !== null &&
-        'path' in worktree &&
-        worktree.path === null
-      ) {
-        // Main branch selection — always safe to restore
-        sanitized[projectPath] = worktree;
-      }
-      // Non-null paths are dropped; the app will re-discover actual worktrees
-      // from the server and the validation effect in use-worktrees will handle
-      // resetting to main if the cached worktree no longer exists.
-      // Null/malformed entries are also dropped to prevent crashes.
-    }
+    // Validate structure only - keep both null (main) and non-null (worktree) paths
+    // Runtime validation in use-worktrees.ts handles deleted worktrees gracefully
+    const sanitized = sanitizeCachedWorktreeByProject(
+      cache.cachedCurrentWorktreeByProject as Record<string, unknown>
+    );
    if (Object.keys(sanitized).length > 0) {
      stateUpdate.currentWorktreeByProject = sanitized;
    }
--- a/apps/ui/src/types/electron.d.ts
+++ b/apps/ui/src/types/electron.d.ts
@@ -959,7 +959,12 @@ export interface WorktreeAPI {
  }>;

  // Generate an AI commit message from git diff
-  generateCommitMessage: (worktreePath: string) => Promise<{
+  generateCommitMessage: (
+    worktreePath: string,
+    model?: string,
+    thinkingLevel?: string,
+    providerId?: string
+  ) => Promise<{
    success: boolean;
    message?: string;
    error?: string;
@@ -968,7 +973,10 @@ export interface WorktreeAPI {
  // Generate an AI PR title and description from branch diff
  generatePRDescription: (
    worktreePath: string,
-    baseBranch?: string
+    baseBranch?: string,
+    model?: string,
+    thinkingLevel?: string,
+    providerId?: string
  ) => Promise<{
    success: boolean;
    title?: string;