chore: bump version to 0.2.0

Several comment and documentation strings were not updated when
Mistral Vibe support was added, leaving them out of sync with the
code. This fixes:
- update-agent-context.sh: add Generic to Supports header comment
- update-agent-context.ps1: add generic to Multi-Agent header comment
- README.md: add Mistral Vibe to CLI tool-check text

CHANGELOG.md

@@ -7,11 +7,62 @@ Recent changes to the Specify CLI and templates are documented here.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [0.2.0] - 2026-03-09
+
+### Changed
+
+- fix: sync agent list comments with actual supported agents (#1785)
+- feat(extensions): support multiple active catalogs simultaneously (#1720)
+- Pavel/add tabnine cli support (#1503)
+- Add Understanding extension to community catalog (#1778)
+- Add ralph extension to community catalog (#1780)
+- Update README with project initialization instructions (#1772)
+- feat: add review extension to community catalog (#1775)
+- Add fleet extension to community catalog (#1771)
+- Integration of Mistral vibe support into speckit (#1725)
+- fix: Remove duplicate options in specify.md (#1765)
+- fix: use global branch numbering instead of per-short-name detection (#1757)
+- Add Community Walkthroughs section to README (#1766)
+- feat(extensions): add Jira Integration to community catalog (#1764)
+- Add Azure DevOps Integration extension to community catalog (#1734)
+- Fix docs: update Antigravity link and add initialization example (#1748)
+- fix: wire after_tasks and after_implement hook events into command templates (#1702)
+- make c ignores consistent with c++ (#1747)
+- chore: bump version to 0.1.13 (#1746)
+- feat: add kiro-cli and AGENT_CONFIG consistency coverage (#1690)
+- feat: add verify extension to community catalog (#1726)
+- Add Retrospective Extension to community catalog README table (#1741)
+- fix(scripts): add empty description validation and branch checkout error handling (#1559)
+- fix: correct Copilot extension command registration (#1724)
+- fix(implement): remove Makefile from C ignore patterns (#1558)
+- Add sync extension to community catalog (#1728)
+- fix(checklist): clarify file handling behavior for append vs create (#1556)
+- fix(clarify): correct conflicting question limit from 10 to 5 (#1557)
+- chore: bump version to 0.1.12 (#1737)
+- fix: use RELEASE_PAT so tag push triggers release workflow (#1736)
+- fix: release-trigger uses release branch + PR instead of direct push to main (#1733)
+- fix: Split release process to sync pyproject.toml version with git tags (#1732)
+
+
 ## [0.1.14] - 2026-03-09
 
 ### Added
 
 - feat: add Tabnine CLI agent support
+- **Multi-Catalog Support (#1707)**: Extension catalog system now supports multiple active catalogs simultaneously via a catalog stack
+  - New `specify extension catalog list` command lists all active catalogs with name, URL, priority, and `install_allowed` status
+  - New `specify extension catalog add` and `specify extension catalog remove` commands for project-scoped catalog management
+  - Default built-in stack includes `catalog.json` (default, installable) and `catalog.community.json` (community, discovery only) — community extensions are now surfaced in search results out of the box
+  - `specify extension search` aggregates results across all active catalogs, annotating each result with source catalog
+  - `specify extension add` enforces `install_allowed` policy — extensions from discovery-only catalogs cannot be installed directly
+  - Project-level `.specify/extension-catalogs.yml` and user-level `~/.specify/extension-catalogs.yml` config files supported, with project-level taking precedence
+  - `SPECKIT_CATALOG_URL` environment variable still works for backward compatibility (replaces full stack with single catalog)
+  - All catalog URLs require HTTPS (HTTP allowed for localhost development)
+  - New `CatalogEntry` dataclass in `extensions.py` for catalog stack representation
+  - Per-URL hash-based caching for non-default catalogs; legacy cache preserved for default catalog
+  - Higher-priority catalogs win on merge conflicts (same extension id in multiple catalogs)
+  - 13 new tests covering catalog stack resolution, merge conflicts, URL validation, and `install_allowed` enforcement
+  - Updated RFC, Extension User Guide, and Extension API Reference documentation
 
 ## [0.1.13] - 2026-03-03
 

README.md

@@ -421,7 +421,7 @@ specify init . --force --ai claude
 specify init --here --force --ai claude
 ```
 
-The CLI will check if you have Claude Code, Gemini CLI, Cursor CLI, Qwen CLI, opencode, Codex CLI, Qoder CLI, Tabnine CLI, or Kiro CLI installed. If you do not, or you prefer to get the templates without checking for the right tools, use `--ignore-agent-tools` with your command:
+The CLI will check if you have Claude Code, Gemini CLI, Cursor CLI, Qwen CLI, opencode, Codex CLI, Qoder CLI, Tabnine CLI, Kiro CLI, or Mistral Vibe installed. If you do not, or you prefer to get the templates without checking for the right tools, use `--ignore-agent-tools` with your command:
 
 ```bash
 specify init <project_name> --ai claude --ignore-agent-tools

extensions/EXTENSION-API-REFERENCE.md

@@ -243,6 +243,34 @@ manager.check_compatibility(
 )  # Raises: CompatibilityError if incompatible
 ```
 
+### CatalogEntry
+
+**Module**: `specify_cli.extensions`
+
+Represents a single catalog in the active catalog stack.
+
+```python
+from specify_cli.extensions import CatalogEntry
+
+entry = CatalogEntry(
+    url="https://example.com/catalog.json",
+    name="default",
+    priority=1,
+    install_allowed=True,
+    description="Built-in catalog of installable extensions",
+)
+```
+
+**Fields**:
+
+| Field | Type | Description |
+|-------|------|-------------|
+| `url` | `str` | Catalog URL (must use HTTPS, or HTTP for localhost) |
+| `name` | `str` | Human-readable catalog name |
+| `priority` | `int` | Sort order (lower = higher priority, wins on conflicts) |
+| `install_allowed` | `bool` | Whether extensions from this catalog can be installed |
+| `description` | `str` | Optional human-readable description of the catalog (default: empty) |
+
 ### ExtensionCatalog
 
 **Module**: `specify_cli.extensions`
@@ -253,30 +281,67 @@ from specify_cli.extensions import ExtensionCatalog
 catalog = ExtensionCatalog(project_root)
 ```
 
+**Class attributes**:
+
+```python
+ExtensionCatalog.DEFAULT_CATALOG_URL    # default catalog URL
+ExtensionCatalog.COMMUNITY_CATALOG_URL  # community catalog URL
+```
+
 **Methods**:
 
 ```python
-# Fetch catalog
+# Get the ordered list of active catalogs
+entries = catalog.get_active_catalogs()  # List[CatalogEntry]
+
+# Fetch catalog (primary catalog, backward compat)
 catalog_data = catalog.fetch_catalog(force_refresh: bool = False)  # Dict
 
-# Search extensions
+# Search extensions across all active catalogs
+# Each result includes _catalog_name and _install_allowed
 results = catalog.search(
     query: Optional[str] = None,
     tag: Optional[str] = None,
     author: Optional[str] = None,
     verified_only: bool = False
-)  # Returns: List[Dict]
+)  # Returns: List[Dict]  — each dict includes _catalog_name, _install_allowed
 
-# Get extension info
+# Get extension info (searches all active catalogs)
+# Returns None if not found; includes _catalog_name and _install_allowed
 ext_info = catalog.get_extension_info(extension_id: str)  # Optional[Dict]
 
-# Check cache validity
+# Check cache validity (primary catalog)
 is_valid = catalog.is_cache_valid()  # bool
 
-# Clear cache
+# Clear all catalog caches
 catalog.clear_cache()
 ```
 
+**Result annotation fields**:
+
+Each extension dict returned by `search()` and `get_extension_info()` includes:
+
+| Field | Type | Description |
+|-------|------|-------------|
+| `_catalog_name` | `str` | Name of the source catalog |
+| `_install_allowed` | `bool` | Whether installation is allowed from this catalog |
+
+**Catalog config file** (`.specify/extension-catalogs.yml`):
+
+```yaml
+catalogs:
+  - name: "default"
+    url: "https://raw.githubusercontent.com/github/spec-kit/main/extensions/catalog.json"
+    priority: 1
+    install_allowed: true
+    description: "Built-in catalog of installable extensions"
+  - name: "community"
+    url: "https://raw.githubusercontent.com/github/spec-kit/main/extensions/catalog.community.json"
+    priority: 2
+    install_allowed: false
+    description: "Community-contributed extensions (discovery only)"
+```
+
 ### HookExecutor
 
 **Module**: `specify_cli.extensions`
@@ -543,6 +608,39 @@ EXECUTE_COMMAND: {command}
 
 **Output**: List of installed extensions with metadata
 
+### extension catalog list
+
+**Usage**: `specify extension catalog list`
+
+Lists all active catalogs in the current catalog stack, showing name, description, URL, priority, and `install_allowed` status.
+
+### extension catalog add
+
+**Usage**: `specify extension catalog add URL [OPTIONS]`
+
+**Options**:
+
+- `--name NAME` - Catalog name (required)
+- `--priority INT` - Priority (lower = higher priority, default: 10)
+- `--install-allowed / --no-install-allowed` - Allow installs from this catalog (default: false)
+- `--description TEXT` - Optional description of the catalog
+
+**Arguments**:
+
+- `URL` - Catalog URL (must use HTTPS)
+
+Adds a catalog entry to `.specify/extension-catalogs.yml`.
+
+### extension catalog remove
+
+**Usage**: `specify extension catalog remove NAME`
+
+**Arguments**:
+
+- `NAME` - Catalog name to remove
+
+Removes a catalog entry from `.specify/extension-catalogs.yml`.
+
 ### extension add
 
 **Usage**: `specify extension add EXTENSION [OPTIONS]`
@@ -551,13 +649,13 @@ EXECUTE_COMMAND: {command}
 
 - `--from URL` - Install from custom URL
 - `--dev PATH` - Install from local directory
-- `--version VERSION` - Install specific version
-- `--no-register` - Skip command registration
 
 **Arguments**:
 
 - `EXTENSION` - Extension name or URL
 
+**Note**: Extensions from catalogs with `install_allowed: false` cannot be installed via this command.
+
 ### extension remove
 
 **Usage**: `specify extension remove EXTENSION [OPTIONS]`
@@ -575,6 +673,8 @@ EXECUTE_COMMAND: {command}
 
 **Usage**: `specify extension search [QUERY] [OPTIONS]`
 
+Searches all active catalogs simultaneously. Results include source catalog name and install_allowed status.
+
 **Options**:
 
 - `--tag TAG` - Filter by tag
@@ -589,6 +689,8 @@ EXECUTE_COMMAND: {command}
 
 **Usage**: `specify extension info EXTENSION`
 
+Shows source catalog and install_allowed status.
+
 **Arguments**:
 
 - `EXTENSION` - Extension ID

extensions/EXTENSION-USER-GUIDE.md

@@ -76,7 +76,7 @@ vim .specify/extensions/jira/jira-config.yml
 
 ## Finding Extensions
 
-**Note**: By default, `specify extension search` uses your organization's catalog (`catalog.json`). If the catalog is empty, you won't see any results. See [Extension Catalogs](#extension-catalogs) to learn how to populate your catalog from the community reference catalog.
+`specify extension search` searches **all active catalogs** simultaneously, including the community catalog by default. Results are annotated with their source catalog and install status.
 
 ### Browse All Extensions
 
@@ -84,7 +84,7 @@ vim .specify/extensions/jira/jira-config.yml
 specify extension search
 ```
 
-Shows all extensions in your organization's catalog.
+Shows all extensions across all active catalogs (default and community by default).
 
 ### Search by Keyword
 
@@ -402,13 +402,13 @@ In addition to extension-specific environment variables (`SPECKIT_{EXT_ID}_*`),
 
 | Variable | Description | Default |
 |----------|-------------|---------|
-| `SPECKIT_CATALOG_URL`       | Override the extension catalog URL | GitHub-hosted catalog |
+| `SPECKIT_CATALOG_URL`       | Override the full catalog stack with a single URL (backward compat) | Built-in default stack |
 | `GH_TOKEN` / `GITHUB_TOKEN` | GitHub API token for downloads     | None                  |
 
 #### Example: Using a custom catalog for testing
 
 ```bash
-# Point to a local or alternative catalog
+# Point to a local or alternative catalog (replaces the full stack)
 export SPECKIT_CATALOG_URL="http://localhost:8000/catalog.json"
 
 # Or use a staging catalog
@@ -419,13 +419,76 @@ export SPECKIT_CATALOG_URL="https://example.com/staging/catalog.json"
 
 ## Extension Catalogs
 
-For information about how Spec Kit's dual-catalog system works (`catalog.json` vs `catalog.community.json`), see the main [Extensions README](README.md#extension-catalogs).
+Spec Kit uses a **catalog stack** — an ordered list of catalogs searched simultaneously. By default, two catalogs are active:
+
+| Priority | Catalog | Install Allowed | Purpose |
+|----------|---------|-----------------|---------|
+| 1 | `catalog.json` (default) | ✅ Yes | Curated extensions available for installation |
+| 2 | `catalog.community.json` (community) | ❌ No (discovery only) | Browse community extensions |
+
+### Listing Active Catalogs
+
+```bash
+specify extension catalog list
+```
+
+### Adding a Catalog (Project-scoped)
+
+```bash
+# Add an internal catalog that allows installs
+specify extension catalog add \
+  --name "internal" \
+  --priority 2 \
+  --install-allowed \
+  https://internal.company.com/spec-kit/catalog.json
+
+# Add a discovery-only catalog
+specify extension catalog add \
+  --name "partner" \
+  --priority 5 \
+  https://partner.example.com/spec-kit/catalog.json
+```
+
+This creates or updates `.specify/extension-catalogs.yml`.
+
+### Removing a Catalog
+
+```bash
+specify extension catalog remove internal
+```
+
+### Manual Config File
+
+You can also edit `.specify/extension-catalogs.yml` directly:
+
+```yaml
+catalogs:
+  - name: "default"
+    url: "https://raw.githubusercontent.com/github/spec-kit/main/extensions/catalog.json"
+    priority: 1
+    install_allowed: true
+    description: "Built-in catalog of installable extensions"
+
+  - name: "internal"
+    url: "https://internal.company.com/spec-kit/catalog.json"
+    priority: 2
+    install_allowed: true
+    description: "Internal company extensions"
+
+  - name: "community"
+    url: "https://raw.githubusercontent.com/github/spec-kit/main/extensions/catalog.community.json"
+    priority: 3
+    install_allowed: false
+    description: "Community-contributed extensions (discovery only)"
+```
+
+A user-level equivalent lives at `~/.specify/extension-catalogs.yml`. Project-level config takes full precedence when it contains one or more catalog entries. An empty `catalogs: []` list falls back to built-in defaults.
 
 ## Organization Catalog Customization
 
 ### Why Customize Your Catalog
 
-Organizations customize their `catalog.json` to:
+Organizations customize their catalogs to:
 
 - **Control available extensions** - Curate which extensions your team can install
 - **Host private extensions** - Internal tools that shouldn't be public
@@ -503,24 +566,40 @@ Options for hosting your catalog:
 
 #### 3. Configure Your Environment
 
-##### Option A: Environment variable (recommended for CI/CD)
+##### Option A: Catalog stack config file (recommended)
+
+Add to `.specify/extension-catalogs.yml` in your project:
+
+```yaml
+catalogs:
+  - name: "my-org"
+    url: "https://your-org.com/spec-kit/catalog.json"
+    priority: 1
+    install_allowed: true
+```
+
+Or use the CLI:
+
+```bash
+specify extension catalog add \
+  --name "my-org" \
+  --install-allowed \
+  https://your-org.com/spec-kit/catalog.json
+```
+
+##### Option B: Environment variable (recommended for CI/CD, single-catalog)
 
 ```bash
 # In ~/.bashrc, ~/.zshrc, or CI pipeline
 export SPECKIT_CATALOG_URL="https://your-org.com/spec-kit/catalog.json"
 ```
 
-##### Option B: Per-project configuration
-
-Create `.env` or set in your shell before running spec-kit commands:
-
-```bash
-SPECKIT_CATALOG_URL="https://your-org.com/spec-kit/catalog.json" specify extension search
-```
-
 #### 4. Verify Configuration
 
 ```bash
+# List active catalogs
+specify extension catalog list
+
 # Search should now show your catalog's extensions
 specify extension search
 

extensions/RFC-EXTENSION-SYSTEM.md

@@ -868,7 +868,7 @@ Spec Kit uses two catalog files with different purposes:
 
 - **Purpose**: Organization's curated catalog of approved extensions
 - **Default State**: Empty by design - users populate with extensions they trust
-- **Usage**: Default catalog used by `specify extension` CLI commands
+- **Usage**: Primary catalog (priority 1, `install_allowed: true`) in the default stack
 - **Control**: Organizations maintain their own fork/version for their teams
 
 #### Community Reference Catalog (`catalog.community.json`)
@@ -879,16 +879,16 @@ Spec Kit uses two catalog files with different purposes:
 - **Verification**: Community extensions may have `verified: false` initially
 - **Status**: Active - open for community contributions
 - **Submission**: Via Pull Request following the Extension Publishing Guide
-- **Usage**: Browse to discover extensions, then copy to your `catalog.json`
+- **Usage**: Secondary catalog (priority 2, `install_allowed: false`) in the default stack — discovery only
 
-**How It Works:**
+**How It Works (default stack):**
 
-1. **Discover**: Browse `catalog.community.json` to find available extensions
+1. **Discover**: `specify extension search` searches both catalogs — community extensions appear automatically
-2. **Review**: Evaluate extensions for security, quality, and organizational fit
+2. **Review**: Evaluate community extensions for security, quality, and organizational fit
-3. **Curate**: Copy approved extension entries from community catalog to your `catalog.json`
+3. **Curate**: Copy approved entries from community catalog to your `catalog.json`, or add to `.specify/extension-catalogs.yml` with `install_allowed: true`
-4. **Install**: Use `specify extension add <name>` (pulls from your curated catalog)
+4. **Install**: Use `specify extension add <name>` — only allowed from `install_allowed: true` catalogs
 
-This approach gives organizations full control over which extensions are available to their teams while maintaining a shared community resource for discovery.
+This approach gives organizations full control over which extensions can be installed while still providing community discoverability out of the box.
 
 ### Catalog Format
 
@@ -961,30 +961,92 @@ specify extension info jira
 
 ### Custom Catalogs
 
-**⚠️ FUTURE FEATURE - NOT YET IMPLEMENTED**
+Spec Kit supports a **catalog stack** — an ordered list of catalogs that the CLI merges and searches across. This allows organizations to maintain their own org-approved extensions alongside an internal catalog and community discovery, all at once.
 
-The following catalog management commands are proposed design concepts but are not yet available in the current implementation:
+#### Catalog Stack Resolution
 
-```bash
+The active catalog stack is resolved in this order (first match wins):
-# Add custom catalog (FUTURE - NOT AVAILABLE)
-specify extension add-catalog https://internal.company.com/spec-kit/catalog.json
 
-# Set as default (FUTURE - NOT AVAILABLE)
+1. **`SPECKIT_CATALOG_URL` environment variable** — single catalog replacing all defaults (backward compat)
-specify extension set-catalog --default https://internal.company.com/spec-kit/catalog.json
+2. **Project-level `.specify/extension-catalogs.yml`** — full control for the project
+3. **User-level `~/.specify/extension-catalogs.yml`** — personal defaults
+4. **Built-in default stack** — `catalog.json` (install_allowed: true) + `catalog.community.json` (install_allowed: false)
 
-# List catalogs (FUTURE - NOT AVAILABLE)
+#### Default Built-in Stack
-specify extension catalogs
+
+When no config file exists, the CLI uses:
+
+| Priority | Catalog | install_allowed | Purpose |
+|----------|---------|-----------------|---------|
+| 1 | `catalog.json` (default) | `true` | Curated extensions available for installation |
+| 2 | `catalog.community.json` (community) | `false` | Discovery only — browse but not install |
+
+This means `specify extension search` surfaces community extensions out of the box, while `specify extension add` is still restricted to entries from catalogs with `install_allowed: true`.
+
+#### `.specify/extension-catalogs.yml` Config File
+
+```yaml
+catalogs:
+  - name: "default"
+    url: "https://raw.githubusercontent.com/github/spec-kit/main/extensions/catalog.json"
+    priority: 1          # Highest — only approved entries can be installed
+    install_allowed: true
+    description: "Built-in catalog of installable extensions"
+
+  - name: "internal"
+    url: "https://internal.company.com/spec-kit/catalog.json"
+    priority: 2
+    install_allowed: true
+    description: "Internal company extensions"
+
+  - name: "community"
+    url: "https://raw.githubusercontent.com/github/spec-kit/main/extensions/catalog.community.json"
+    priority: 3          # Lowest — discovery only, not installable
+    install_allowed: false
+    description: "Community-contributed extensions (discovery only)"
 ```
 
-**Proposed catalog priority** (future design):
+A user-level equivalent lives at `~/.specify/extension-catalogs.yml`. When a project-level config is present with one or more catalog entries, it takes full control and the built-in defaults are not applied. An empty `catalogs: []` list is treated the same as no config file, falling back to defaults.
 
-1. Project-specific catalog (`.specify/extension-catalogs.yml`) - *not implemented*
+#### Catalog CLI Commands
-2. User-level catalog (`~/.specify/extension-catalogs.yml`) - *not implemented*
-3. Default GitHub catalog
 
-#### Current Implementation: SPECKIT_CATALOG_URL
+```bash
+# List active catalogs with name, URL, priority, and install_allowed
+specify extension catalog list
 
-**The currently available method** for using custom catalogs is the `SPECKIT_CATALOG_URL` environment variable:
+# Add a catalog (project-scoped)
+specify extension catalog add --name "internal" --install-allowed \
+  https://internal.company.com/spec-kit/catalog.json
+
+# Add a discovery-only catalog
+specify extension catalog add --name "community" \
+  https://raw.githubusercontent.com/github/spec-kit/main/extensions/catalog.community.json
+
+# Remove a catalog
+specify extension catalog remove internal
+
+# Show which catalog an extension came from
+specify extension info jira
+# → Source catalog: default
+```
+
+#### Merge Conflict Resolution
+
+When the same extension `id` appears in multiple catalogs, the higher-priority (lower priority number) catalog wins. Extensions from lower-priority catalogs with the same `id` are ignored.
+
+#### `install_allowed: false` Behavior
+
+Extensions from discovery-only catalogs are shown in `specify extension search` results but cannot be installed directly:
+
+```
+⚠  'linear' is available in the 'community' catalog but installation is not allowed from that catalog.
+
+To enable installation, add 'linear' to an approved catalog (install_allowed: true) in .specify/extension-catalogs.yml.
+```
+
+#### `SPECKIT_CATALOG_URL` (Backward Compatibility)
+
+The `SPECKIT_CATALOG_URL` environment variable still works — it is treated as a single `install_allowed: true` catalog, **replacing both defaults** for full backward compatibility:
 
 ```bash
 # Point to your organization's catalog

pyproject.toml

@@ -1,6 +1,6 @@
 [project]
 name = "specify-cli"
-version = "0.1.14"
+version = "0.2.0"
 description = "Specify CLI, part of GitHub Spec Kit. A tool to bootstrap your projects for Spec-Driven Development (SDD)."
 requires-python = ">=3.11"
 dependencies = [

scripts/bash/update-agent-context.sh

@@ -30,7 +30,7 @@
 #
 # 5. Multi-Agent Support
 #    - Handles agent-specific file paths and naming conventions
-#    - Supports: Claude, Gemini, Copilot, Cursor, Qwen, opencode, Codex, Windsurf, Kilo Code, Auggie CLI, Roo Code, CodeBuddy CLI, Qoder CLI, Amp, SHAI, Tabnine CLI, Kiro CLI, Mistral Vibe or Antigravity
+#    - Supports: Claude, Gemini, Copilot, Cursor, Qwen, opencode, Codex, Windsurf, Kilo Code, Auggie CLI, Roo Code, CodeBuddy CLI, Qoder CLI, Amp, SHAI, Tabnine CLI, Kiro CLI, Mistral Vibe, Antigravity or Generic
 #    - Can update single agents or all existing agent files
 #    - Creates default Claude file if no agent files exist
 #

scripts/powershell/update-agent-context.ps1

@@ -9,7 +9,7 @@ Mirrors the behavior of scripts/bash/update-agent-context.sh:
  2. Plan Data Extraction
  3. Agent File Management (create from template or update existing)
  4. Content Generation (technology stack, recent changes, timestamp)
- 5. Multi-Agent Support (claude, gemini, copilot, cursor-agent, qwen, opencode, codex, windsurf, kilocode, auggie, roo, codebuddy, amp, shai, tabnine, kiro-cli, agy, bob, vibe, qodercli)
+ 5. Multi-Agent Support (claude, gemini, copilot, cursor-agent, qwen, opencode, codex, windsurf, kilocode, auggie, roo, codebuddy, amp, shai, tabnine, kiro-cli, agy, bob, vibe, qodercli, generic)
 
 .PARAMETER AgentType
 Optional agent key to update a single agent. If omitted, updates all existing agent files (creating a default Claude file if none exist).

src/specify_cli/__init__.py

@@ -1772,6 +1772,13 @@ extension_app = typer.Typer(
 )
 app.add_typer(extension_app, name="extension")
 
+catalog_app = typer.Typer(
+    name="catalog",
+    help="Manage extension catalogs",
+    add_completion=False,
+)
+extension_app.add_typer(catalog_app, name="catalog")
+
 
 def get_speckit_version() -> str:
     """Get current spec-kit version."""
@@ -1837,6 +1844,181 @@ def extension_list(
         console.print("  [cyan]specify extension add <name>[/cyan]")
 
 
+@catalog_app.command("list")
+def catalog_list():
+    """List all active extension catalogs."""
+    from .extensions import ExtensionCatalog, ValidationError
+
+    project_root = Path.cwd()
+
+    specify_dir = project_root / ".specify"
+    if not specify_dir.exists():
+        console.print("[red]Error:[/red] Not a spec-kit project (no .specify/ directory)")
+        console.print("Run this command from a spec-kit project root")
+        raise typer.Exit(1)
+
+    catalog = ExtensionCatalog(project_root)
+
+    try:
+        active_catalogs = catalog.get_active_catalogs()
+    except ValidationError as e:
+        console.print(f"[red]Error:[/red] {e}")
+        raise typer.Exit(1)
+
+    console.print("\n[bold cyan]Active Extension Catalogs:[/bold cyan]\n")
+    for entry in active_catalogs:
+        install_str = (
+            "[green]install allowed[/green]"
+            if entry.install_allowed
+            else "[yellow]discovery only[/yellow]"
+        )
+        console.print(f"  [bold]{entry.name}[/bold] (priority {entry.priority})")
+        if entry.description:
+            console.print(f"     {entry.description}")
+        console.print(f"     URL: {entry.url}")
+        console.print(f"     Install: {install_str}")
+        console.print()
+
+    config_path = project_root / ".specify" / "extension-catalogs.yml"
+    user_config_path = Path.home() / ".specify" / "extension-catalogs.yml"
+    if os.environ.get("SPECKIT_CATALOG_URL"):
+        console.print("[dim]Catalog configured via SPECKIT_CATALOG_URL environment variable.[/dim]")
+    else:
+        try:
+            proj_loaded = config_path.exists() and catalog._load_catalog_config(config_path) is not None
+        except ValidationError:
+            proj_loaded = False
+        if proj_loaded:
+            console.print(f"[dim]Config: {config_path.relative_to(project_root)}[/dim]")
+        else:
+            try:
+                user_loaded = user_config_path.exists() and catalog._load_catalog_config(user_config_path) is not None
+            except ValidationError:
+                user_loaded = False
+            if user_loaded:
+                console.print("[dim]Config: ~/.specify/extension-catalogs.yml[/dim]")
+            else:
+                console.print("[dim]Using built-in default catalog stack.[/dim]")
+                console.print(
+                    "[dim]Add .specify/extension-catalogs.yml to customize.[/dim]"
+                )
+
+
+@catalog_app.command("add")
+def catalog_add(
+    url: str = typer.Argument(help="Catalog URL (must use HTTPS)"),
+    name: str = typer.Option(..., "--name", help="Catalog name"),
+    priority: int = typer.Option(10, "--priority", help="Priority (lower = higher priority)"),
+    install_allowed: bool = typer.Option(
+        False, "--install-allowed/--no-install-allowed",
+        help="Allow extensions from this catalog to be installed",
+    ),
+    description: str = typer.Option("", "--description", help="Description of the catalog"),
+):
+    """Add a catalog to .specify/extension-catalogs.yml."""
+    from .extensions import ExtensionCatalog, ValidationError
+
+    project_root = Path.cwd()
+
+    specify_dir = project_root / ".specify"
+    if not specify_dir.exists():
+        console.print("[red]Error:[/red] Not a spec-kit project (no .specify/ directory)")
+        console.print("Run this command from a spec-kit project root")
+        raise typer.Exit(1)
+
+    # Validate URL
+    tmp_catalog = ExtensionCatalog(project_root)
+    try:
+        tmp_catalog._validate_catalog_url(url)
+    except ValidationError as e:
+        console.print(f"[red]Error:[/red] {e}")
+        raise typer.Exit(1)
+
+    config_path = specify_dir / "extension-catalogs.yml"
+
+    # Load existing config
+    if config_path.exists():
+        try:
+            config = yaml.safe_load(config_path.read_text()) or {}
+        except Exception as e:
+            console.print(f"[red]Error:[/red] Failed to read {config_path}: {e}")
+            raise typer.Exit(1)
+    else:
+        config = {}
+
+    catalogs = config.get("catalogs", [])
+    if not isinstance(catalogs, list):
+        console.print("[red]Error:[/red] Invalid catalog config: 'catalogs' must be a list.")
+        raise typer.Exit(1)
+
+    # Check for duplicate name
+    for existing in catalogs:
+        if isinstance(existing, dict) and existing.get("name") == name:
+            console.print(f"[yellow]Warning:[/yellow] A catalog named '{name}' already exists.")
+            console.print("Use 'specify extension catalog remove' first, or choose a different name.")
+            raise typer.Exit(1)
+
+    catalogs.append({
+        "name": name,
+        "url": url,
+        "priority": priority,
+        "install_allowed": install_allowed,
+        "description": description,
+    })
+
+    config["catalogs"] = catalogs
+    config_path.write_text(yaml.dump(config, default_flow_style=False, sort_keys=False))
+
+    install_label = "install allowed" if install_allowed else "discovery only"
+    console.print(f"\n[green]✓[/green] Added catalog '[bold]{name}[/bold]' ({install_label})")
+    console.print(f"  URL: {url}")
+    console.print(f"  Priority: {priority}")
+    console.print(f"\nConfig saved to {config_path.relative_to(project_root)}")
+
+
+@catalog_app.command("remove")
+def catalog_remove(
+    name: str = typer.Argument(help="Catalog name to remove"),
+):
+    """Remove a catalog from .specify/extension-catalogs.yml."""
+    project_root = Path.cwd()
+
+    specify_dir = project_root / ".specify"
+    if not specify_dir.exists():
+        console.print("[red]Error:[/red] Not a spec-kit project (no .specify/ directory)")
+        console.print("Run this command from a spec-kit project root")
+        raise typer.Exit(1)
+
+    config_path = specify_dir / "extension-catalogs.yml"
+    if not config_path.exists():
+        console.print("[red]Error:[/red] No catalog config found. Nothing to remove.")
+        raise typer.Exit(1)
+
+    try:
+        config = yaml.safe_load(config_path.read_text()) or {}
+    except Exception:
+        console.print("[red]Error:[/red] Failed to read catalog config.")
+        raise typer.Exit(1)
+
+    catalogs = config.get("catalogs", [])
+    if not isinstance(catalogs, list):
+        console.print("[red]Error:[/red] Invalid catalog config: 'catalogs' must be a list.")
+        raise typer.Exit(1)
+    original_count = len(catalogs)
+    catalogs = [c for c in catalogs if isinstance(c, dict) and c.get("name") != name]
+
+    if len(catalogs) == original_count:
+        console.print(f"[red]Error:[/red] Catalog '{name}' not found.")
+        raise typer.Exit(1)
+
+    config["catalogs"] = catalogs
+    config_path.write_text(yaml.dump(config, default_flow_style=False, sort_keys=False))
+
+    console.print(f"[green]✓[/green] Removed catalog '{name}'")
+    if not catalogs:
+        console.print("\n[dim]No catalogs remain in config. Built-in defaults will be used.[/dim]")
+
+
 @extension_app.command("add")
 def extension_add(
     extension: str = typer.Argument(help="Extension name or path"),
@@ -1925,6 +2107,19 @@ def extension_add(
                     console.print("  specify extension search")
                     raise typer.Exit(1)
 
+                # Enforce install_allowed policy
+                if not ext_info.get("_install_allowed", True):
+                    catalog_name = ext_info.get("_catalog_name", "community")
+                    console.print(
+                        f"[red]Error:[/red] '{extension}' is available in the "
+                        f"'{catalog_name}' catalog but installation is not allowed from that catalog."
+                    )
+                    console.print(
+                        f"\nTo enable installation, add '{extension}' to an approved catalog "
+                        f"(install_allowed: true) in .specify/extension-catalogs.yml."
+                    )
+                    raise typer.Exit(1)
+
                 # Download extension ZIP
                 console.print(f"Downloading {ext_info['name']} v{ext_info.get('version', 'unknown')}...")
                 zip_path = catalog.download_extension(extension)
@@ -2069,6 +2264,15 @@ def extension_search(
                 tags_str = ", ".join(ext['tags'])
                 console.print(f"  [dim]Tags:[/dim] {tags_str}")
 
+            # Source catalog
+            catalog_name = ext.get("_catalog_name", "")
+            install_allowed = ext.get("_install_allowed", True)
+            if catalog_name:
+                if install_allowed:
+                    console.print(f"  [dim]Catalog:[/dim] {catalog_name}")
+                else:
+                    console.print(f"  [dim]Catalog:[/dim] {catalog_name} [yellow](discovery only — not installable)[/yellow]")
+
             # Stats
             stats = []
             if ext.get('downloads') is not None:
@@ -2082,8 +2286,15 @@ def extension_search(
             if ext.get('repository'):
                 console.print(f"  [dim]Repository:[/dim] {ext['repository']}")
 
-            # Install command
+            # Install command (show warning if not installable)
-            console.print(f"\n  [cyan]Install:[/cyan] specify extension add {ext['id']}")
+            if install_allowed:
+                console.print(f"\n  [cyan]Install:[/cyan] specify extension add {ext['id']}")
+            else:
+                console.print(f"\n  [yellow]⚠[/yellow]  Not directly installable from '{catalog_name}'.")
+                console.print(
+                    f"  Add to an approved catalog with install_allowed: true, "
+                    f"or install from a ZIP URL: specify extension add {ext['id']} --from <zip-url>"
+                )
             console.print()
 
     except ExtensionError as e:
@@ -2132,6 +2343,12 @@ def extension_info(
         # Author and License
         console.print(f"[dim]Author:[/dim] {ext_info.get('author', 'Unknown')}")
         console.print(f"[dim]License:[/dim] {ext_info.get('license', 'Unknown')}")
+
+        # Source catalog
+        if ext_info.get("_catalog_name"):
+            install_allowed = ext_info.get("_install_allowed", True)
+            install_note = "" if install_allowed else " [yellow](discovery only)[/yellow]"
+            console.print(f"[dim]Source catalog:[/dim] {ext_info['_catalog_name']}{install_note}")
         console.print()
 
         # Requirements
@@ -2188,12 +2405,21 @@ def extension_info(
 
         # Installation status and command
         is_installed = manager.registry.is_installed(ext_info['id'])
+        install_allowed = ext_info.get("_install_allowed", True)
         if is_installed:
             console.print("[green]✓ Installed[/green]")
             console.print(f"\nTo remove: specify extension remove {ext_info['id']}")
-        else:
+        elif install_allowed:
             console.print("[yellow]Not installed[/yellow]")
             console.print(f"\n[cyan]Install:[/cyan] specify extension add {ext_info['id']}")
+        else:
+            catalog_name = ext_info.get("_catalog_name", "community")
+            console.print("[yellow]Not installed[/yellow]")
+            console.print(
+                f"\n[yellow]⚠[/yellow]  '{ext_info['id']}' is available in the '{catalog_name}' catalog "
+                f"but not in your approved catalog. Add it to .specify/extension-catalogs.yml "
+                f"with install_allowed: true to enable installation."
+            )
 
     except ExtensionError as e:
         console.print(f"\n[red]Error:[/red] {e}")

src/specify_cli/extensions.py

@@ -8,9 +8,11 @@ without bloating the core framework.
 
 import json
 import hashlib
+import os
 import tempfile
 import zipfile
 import shutil
+from dataclasses import dataclass
 from pathlib import Path
 from typing import Optional, Dict, List, Any
 from datetime import datetime, timezone
@@ -36,6 +38,16 @@ class CompatibilityError(ExtensionError):
     pass
 
 
+@dataclass
+class CatalogEntry:
+    """Represents a single catalog entry in the catalog stack."""
+    url: str
+    name: str
+    priority: int
+    install_allowed: bool
+    description: str = ""
+
+
 class ExtensionManifest:
     """Represents and validates an extension manifest (extension.yml)."""
 
@@ -976,6 +988,7 @@ class ExtensionCatalog:
     """Manages extension catalog fetching, caching, and searching."""
 
     DEFAULT_CATALOG_URL = "https://raw.githubusercontent.com/github/spec-kit/main/extensions/catalog.json"
+    COMMUNITY_CATALOG_URL = "https://raw.githubusercontent.com/github/spec-kit/main/extensions/catalog.community.json"
     CACHE_DURATION = 3600  # 1 hour in seconds
 
     def __init__(self, project_root: Path):
@@ -990,43 +1003,109 @@ class ExtensionCatalog:
         self.cache_file = self.cache_dir / "catalog.json"
         self.cache_metadata_file = self.cache_dir / "catalog-metadata.json"
 
-    def get_catalog_url(self) -> str:
+    def _validate_catalog_url(self, url: str) -> None:
-        """Get catalog URL from config or use default.
+        """Validate that a catalog URL uses HTTPS (localhost HTTP allowed).
 
-        Checks in order:
+        Args:
-        1. SPECKIT_CATALOG_URL environment variable
+            url: URL to validate
-        2. Default catalog URL
-
-        Returns:
-            URL to fetch catalog from
 
         Raises:
-            ValidationError: If custom URL is invalid (non-HTTPS)
+            ValidationError: If URL is invalid or uses non-HTTPS scheme
         """
-        import os
-        import sys
         from urllib.parse import urlparse
 
-        # Environment variable override (useful for testing)
+        parsed = urlparse(url)
+        is_localhost = parsed.hostname in ("localhost", "127.0.0.1", "::1")
+        if parsed.scheme != "https" and not (parsed.scheme == "http" and is_localhost):
+            raise ValidationError(
+                f"Catalog URL must use HTTPS (got {parsed.scheme}://). "
+                "HTTP is only allowed for localhost."
+            )
+        if not parsed.netloc:
+            raise ValidationError("Catalog URL must be a valid URL with a host.")
+
+    def _load_catalog_config(self, config_path: Path) -> Optional[List[CatalogEntry]]:
+        """Load catalog stack configuration from a YAML file.
+
+        Args:
+            config_path: Path to extension-catalogs.yml
+
+        Returns:
+            Ordered list of CatalogEntry objects, or None if file doesn't exist
+            or contains no valid catalog entries.
+
+        Raises:
+            ValidationError: If any catalog entry has an invalid URL,
+                the file cannot be parsed, or a priority value is invalid.
+        """
+        if not config_path.exists():
+            return None
+        try:
+            data = yaml.safe_load(config_path.read_text()) or {}
+        except (yaml.YAMLError, OSError) as e:
+            raise ValidationError(
+                f"Failed to read catalog config {config_path}: {e}"
+            )
+        catalogs_data = data.get("catalogs", [])
+        if not catalogs_data:
+            return None
+        if not isinstance(catalogs_data, list):
+            raise ValidationError(
+                f"Invalid catalog config: 'catalogs' must be a list, got {type(catalogs_data).__name__}"
+            )
+        entries: List[CatalogEntry] = []
+        for idx, item in enumerate(catalogs_data):
+            if not isinstance(item, dict):
+                raise ValidationError(
+                    f"Invalid catalog entry at index {idx}: expected a mapping, got {type(item).__name__}"
+                )
+            url = str(item.get("url", "")).strip()
+            if not url:
+                continue
+            self._validate_catalog_url(url)
+            try:
+                priority = int(item.get("priority", idx + 1))
+            except (TypeError, ValueError):
+                raise ValidationError(
+                    f"Invalid priority for catalog '{item.get('name', idx + 1)}': "
+                    f"expected integer, got {item.get('priority')!r}"
+                )
+            raw_install = item.get("install_allowed", False)
+            if isinstance(raw_install, str):
+                install_allowed = raw_install.strip().lower() in ("true", "yes", "1")
+            else:
+                install_allowed = bool(raw_install)
+            entries.append(CatalogEntry(
+                url=url,
+                name=str(item.get("name", f"catalog-{idx + 1}")),
+                priority=priority,
+                install_allowed=install_allowed,
+                description=str(item.get("description", "")),
+            ))
+        entries.sort(key=lambda e: e.priority)
+        return entries if entries else None
+
+    def get_active_catalogs(self) -> List[CatalogEntry]:
+        """Get the ordered list of active catalogs.
+
+        Resolution order:
+        1. SPECKIT_CATALOG_URL env var — single catalog replacing all defaults
+        2. Project-level .specify/extension-catalogs.yml
+        3. User-level ~/.specify/extension-catalogs.yml
+        4. Built-in default stack (default + community)
+
+        Returns:
+            List of CatalogEntry objects sorted by priority (ascending)
+
+        Raises:
+            ValidationError: If a catalog URL is invalid
+        """
+        import sys
+
+        # 1. SPECKIT_CATALOG_URL env var replaces all defaults for backward compat
         if env_value := os.environ.get("SPECKIT_CATALOG_URL"):
             catalog_url = env_value.strip()
-            parsed = urlparse(catalog_url)
+            self._validate_catalog_url(catalog_url)
-
-            # Require HTTPS for security (prevent man-in-the-middle attacks)
-            # Allow http://localhost for local development/testing
-            is_localhost = parsed.hostname in ("localhost", "127.0.0.1", "::1")
-            if parsed.scheme != "https" and not (parsed.scheme == "http" and is_localhost):
-                raise ValidationError(
-                    f"Invalid SPECKIT_CATALOG_URL: must use HTTPS (got {parsed.scheme}://). "
-                    "HTTP is only allowed for localhost."
-                )
-
-            if not parsed.netloc:
-                raise ValidationError(
-                    "Invalid SPECKIT_CATALOG_URL: must be a valid URL with a host."
-                )
-
-            # Warn users when using a non-default catalog (once per instance)
             if catalog_url != self.DEFAULT_CATALOG_URL:
                 if not getattr(self, "_non_default_catalog_warning_shown", False):
                     print(
@@ -1035,11 +1114,163 @@ class ExtensionCatalog:
                         file=sys.stderr,
                     )
                     self._non_default_catalog_warning_shown = True
+            return [CatalogEntry(url=catalog_url, name="custom", priority=1, install_allowed=True, description="Custom catalog via SPECKIT_CATALOG_URL")]
 
-            return catalog_url
+        # 2. Project-level config overrides all defaults
+        project_config_path = self.project_root / ".specify" / "extension-catalogs.yml"
+        catalogs = self._load_catalog_config(project_config_path)
+        if catalogs is not None:
+            return catalogs
 
-        # TODO: Support custom catalogs from .specify/extension-catalogs.yml
+        # 3. User-level config
-        return self.DEFAULT_CATALOG_URL
+        user_config_path = Path.home() / ".specify" / "extension-catalogs.yml"
+        catalogs = self._load_catalog_config(user_config_path)
+        if catalogs is not None:
+            return catalogs
+
+        # 4. Built-in default stack
+        return [
+            CatalogEntry(url=self.DEFAULT_CATALOG_URL, name="default", priority=1, install_allowed=True, description="Built-in catalog of installable extensions"),
+            CatalogEntry(url=self.COMMUNITY_CATALOG_URL, name="community", priority=2, install_allowed=False, description="Community-contributed extensions (discovery only)"),
+        ]
+
+    def get_catalog_url(self) -> str:
+        """Get the primary catalog URL.
+
+        Returns the URL of the highest-priority catalog. Kept for backward
+        compatibility. Use get_active_catalogs() for full multi-catalog support.
+
+        Returns:
+            URL of the primary catalog
+
+        Raises:
+            ValidationError: If a catalog URL is invalid
+        """
+        active = self.get_active_catalogs()
+        return active[0].url if active else self.DEFAULT_CATALOG_URL
+
+    def _fetch_single_catalog(self, entry: CatalogEntry, force_refresh: bool = False) -> Dict[str, Any]:
+        """Fetch a single catalog with per-URL caching.
+
+        For the DEFAULT_CATALOG_URL, uses legacy cache files (self.cache_file /
+        self.cache_metadata_file) for backward compatibility. For all other URLs,
+        uses URL-hash-based cache files in self.cache_dir.
+
+        Args:
+            entry: CatalogEntry describing the catalog to fetch
+            force_refresh: If True, bypass cache
+
+        Returns:
+            Catalog data dictionary
+
+        Raises:
+            ExtensionError: If catalog cannot be fetched or has invalid format
+        """
+        import urllib.request
+        import urllib.error
+
+        # Determine cache file paths (backward compat for default catalog)
+        if entry.url == self.DEFAULT_CATALOG_URL:
+            cache_file = self.cache_file
+            cache_meta_file = self.cache_metadata_file
+            is_valid = not force_refresh and self.is_cache_valid()
+        else:
+            url_hash = hashlib.sha256(entry.url.encode()).hexdigest()[:16]
+            cache_file = self.cache_dir / f"catalog-{url_hash}.json"
+            cache_meta_file = self.cache_dir / f"catalog-{url_hash}-metadata.json"
+            is_valid = False
+            if not force_refresh and cache_file.exists() and cache_meta_file.exists():
+                try:
+                    metadata = json.loads(cache_meta_file.read_text())
+                    cached_at = datetime.fromisoformat(metadata.get("cached_at", ""))
+                    if cached_at.tzinfo is None:
+                        cached_at = cached_at.replace(tzinfo=timezone.utc)
+                    age = (datetime.now(timezone.utc) - cached_at).total_seconds()
+                    is_valid = age < self.CACHE_DURATION
+                except (json.JSONDecodeError, ValueError, KeyError, TypeError):
+                    # If metadata is invalid or missing expected fields, treat cache as invalid
+                    pass
+
+        # Use cache if valid
+        if is_valid:
+            try:
+                return json.loads(cache_file.read_text())
+            except json.JSONDecodeError:
+                pass
+
+        # Fetch from network
+        try:
+            with urllib.request.urlopen(entry.url, timeout=10) as response:
+                catalog_data = json.loads(response.read())
+
+            if "schema_version" not in catalog_data or "extensions" not in catalog_data:
+                raise ExtensionError(f"Invalid catalog format from {entry.url}")
+
+            # Save to cache
+            self.cache_dir.mkdir(parents=True, exist_ok=True)
+            cache_file.write_text(json.dumps(catalog_data, indent=2))
+            cache_meta_file.write_text(json.dumps({
+                "cached_at": datetime.now(timezone.utc).isoformat(),
+                "catalog_url": entry.url,
+            }, indent=2))
+
+            return catalog_data
+
+        except urllib.error.URLError as e:
+            raise ExtensionError(f"Failed to fetch catalog from {entry.url}: {e}")
+        except json.JSONDecodeError as e:
+            raise ExtensionError(f"Invalid JSON in catalog from {entry.url}: {e}")
+
+    def _get_merged_extensions(self, force_refresh: bool = False) -> List[Dict[str, Any]]:
+        """Fetch and merge extensions from all active catalogs.
+
+        Higher-priority (lower priority number) catalogs win on conflicts
+        (same extension id in two catalogs). Each extension dict is annotated with:
+          - _catalog_name: name of the source catalog
+          - _install_allowed: whether installation is allowed from this catalog
+
+        Catalogs that fail to fetch are skipped. Raises ExtensionError only if
+        ALL catalogs fail.
+
+        Args:
+            force_refresh: If True, bypass all caches
+
+        Returns:
+            List of merged extension dicts
+
+        Raises:
+            ExtensionError: If all catalogs fail to fetch
+        """
+        import sys
+
+        active_catalogs = self.get_active_catalogs()
+        merged: Dict[str, Dict[str, Any]] = {}
+        any_success = False
+
+        for catalog_entry in active_catalogs:
+            try:
+                catalog_data = self._fetch_single_catalog(catalog_entry, force_refresh)
+                any_success = True
+            except ExtensionError as e:
+                print(
+                    f"Warning: Could not fetch catalog '{catalog_entry.name}': {e}",
+                    file=sys.stderr,
+                )
+                continue
+
+            for ext_id, ext_data in catalog_data.get("extensions", {}).items():
+                if ext_id not in merged:  # Higher-priority catalog wins
+                    merged[ext_id] = {
+                        **ext_data,
+                        "id": ext_id,
+                        "_catalog_name": catalog_entry.name,
+                        "_install_allowed": catalog_entry.install_allowed,
+                    }
+
+        if not any_success and active_catalogs:
+            raise ExtensionError("Failed to fetch any extension catalog")
+
+        return list(merged.values())
 
     def is_cache_valid(self) -> bool:
         """Check if cached catalog is still valid.
@@ -1053,9 +1284,11 @@ class ExtensionCatalog:
         try:
             metadata = json.loads(self.cache_metadata_file.read_text())
             cached_at = datetime.fromisoformat(metadata.get("cached_at", ""))
+            if cached_at.tzinfo is None:
+                cached_at = cached_at.replace(tzinfo=timezone.utc)
             age_seconds = (datetime.now(timezone.utc) - cached_at).total_seconds()
             return age_seconds < self.CACHE_DURATION
-        except (json.JSONDecodeError, ValueError, KeyError):
+        except (json.JSONDecodeError, ValueError, KeyError, TypeError):
             return False
 
     def fetch_catalog(self, force_refresh: bool = False) -> Dict[str, Any]:
@@ -1116,7 +1349,7 @@ class ExtensionCatalog:
         author: Optional[str] = None,
         verified_only: bool = False,
     ) -> List[Dict[str, Any]]:
-        """Search catalog for extensions.
+        """Search catalog for extensions across all active catalogs.
 
         Args:
             query: Search query (searches name, description, tags)
@@ -1125,14 +1358,16 @@ class ExtensionCatalog:
             verified_only: If True, show only verified extensions
 
         Returns:
-            List of matching extension metadata
+            List of matching extension metadata, each annotated with
+            ``_catalog_name`` and ``_install_allowed`` from its source catalog.
         """
-        catalog = self.fetch_catalog()
+        all_extensions = self._get_merged_extensions()
-        extensions = catalog.get("extensions", {})
 
         results = []
 
-        for ext_id, ext_data in extensions.items():
+        for ext_data in all_extensions:
+            ext_id = ext_data["id"]
+
             # Apply filters
             if verified_only and not ext_data.get("verified", False):
                 continue
@@ -1158,25 +1393,26 @@ class ExtensionCatalog:
                 if query_lower not in searchable_text:
                     continue
 
-            results.append({"id": ext_id, **ext_data})
+            results.append(ext_data)
 
         return results
 
     def get_extension_info(self, extension_id: str) -> Optional[Dict[str, Any]]:
         """Get detailed information about a specific extension.
 
+        Searches all active catalogs in priority order.
+
         Args:
             extension_id: ID of the extension
 
         Returns:
-            Extension metadata or None if not found
+            Extension metadata (annotated with ``_catalog_name`` and
+            ``_install_allowed``) or None if not found.
         """
-        catalog = self.fetch_catalog()
+        all_extensions = self._get_merged_extensions()
-        extensions = catalog.get("extensions", {})
+        for ext_data in all_extensions:
-
+            if ext_data["id"] == extension_id:
-        if extension_id in extensions:
+                return ext_data
-            return {"id": extension_id, **extensions[extension_id]}
-
         return None
 
     def download_extension(self, extension_id: str, target_dir: Optional[Path] = None) -> Path:
@@ -1236,11 +1472,18 @@ class ExtensionCatalog:
             raise ExtensionError(f"Failed to save extension ZIP: {e}")
 
     def clear_cache(self):
-        """Clear the catalog cache."""
+        """Clear the catalog cache (both legacy and URL-hash-based files)."""
         if self.cache_file.exists():
             self.cache_file.unlink()
         if self.cache_metadata_file.exists():
             self.cache_metadata_file.unlink()
+        # Also clear any per-URL hash-based cache files
+        if self.cache_dir.exists():
+            for extra_cache in self.cache_dir.glob("catalog-*.json"):
+                if extra_cache != self.cache_file:
+                    extra_cache.unlink(missing_ok=True)
+            for extra_meta in self.cache_dir.glob("catalog-*-metadata.json"):
+                extra_meta.unlink(missing_ok=True)
 
 
 class ConfigManager:

tests/test_extensions.py

@@ -6,6 +6,7 @@ Tests cover:
 - Extension registry operations
 - Extension manager installation/removal
 - Command registration
+- Catalog stack (multi-catalog support)
 """
 
 import pytest
@@ -16,6 +17,7 @@ from pathlib import Path
 from datetime import datetime, timezone
 
 from specify_cli.extensions import (
+    CatalogEntry,
     ExtensionManifest,
     ExtensionRegistry,
     ExtensionManager,
@@ -880,10 +882,29 @@ class TestExtensionCatalog:
 
     def test_search_all_extensions(self, temp_dir):
         """Test searching all extensions without filters."""
+        import yaml as yaml_module
+
         project_dir = temp_dir / "project"
         project_dir.mkdir()
         (project_dir / ".specify").mkdir()
 
+        # Use a single-catalog config so community extensions don't interfere
+        config_path = project_dir / ".specify" / "extension-catalogs.yml"
+        with open(config_path, "w") as f:
+            yaml_module.dump(
+                {
+                    "catalogs": [
+                        {
+                            "name": "test-catalog",
+                            "url": ExtensionCatalog.DEFAULT_CATALOG_URL,
+                            "priority": 1,
+                            "install_allowed": True,
+                        }
+                    ]
+                },
+                f,
+            )
+
         catalog = ExtensionCatalog(project_dir)
 
         # Create mock catalog
@@ -929,10 +950,29 @@ class TestExtensionCatalog:
 
     def test_search_by_query(self, temp_dir):
         """Test searching by query text."""
+        import yaml as yaml_module
+
         project_dir = temp_dir / "project"
         project_dir.mkdir()
         (project_dir / ".specify").mkdir()
 
+        # Use a single-catalog config so community extensions don't interfere
+        config_path = project_dir / ".specify" / "extension-catalogs.yml"
+        with open(config_path, "w") as f:
+            yaml_module.dump(
+                {
+                    "catalogs": [
+                        {
+                            "name": "test-catalog",
+                            "url": ExtensionCatalog.DEFAULT_CATALOG_URL,
+                            "priority": 1,
+                            "install_allowed": True,
+                        }
+                    ]
+                },
+                f,
+            )
+
         catalog = ExtensionCatalog(project_dir)
 
         # Create mock catalog
@@ -974,10 +1014,29 @@ class TestExtensionCatalog:
 
     def test_search_by_tag(self, temp_dir):
         """Test searching by tag."""
+        import yaml as yaml_module
+
         project_dir = temp_dir / "project"
         project_dir.mkdir()
         (project_dir / ".specify").mkdir()
 
+        # Use a single-catalog config so community extensions don't interfere
+        config_path = project_dir / ".specify" / "extension-catalogs.yml"
+        with open(config_path, "w") as f:
+            yaml_module.dump(
+                {
+                    "catalogs": [
+                        {
+                            "name": "test-catalog",
+                            "url": ExtensionCatalog.DEFAULT_CATALOG_URL,
+                            "priority": 1,
+                            "install_allowed": True,
+                        }
+                    ]
+                },
+                f,
+            )
+
         catalog = ExtensionCatalog(project_dir)
 
         # Create mock catalog
@@ -1026,10 +1085,29 @@ class TestExtensionCatalog:
 
     def test_search_verified_only(self, temp_dir):
         """Test searching verified extensions only."""
+        import yaml as yaml_module
+
         project_dir = temp_dir / "project"
         project_dir.mkdir()
         (project_dir / ".specify").mkdir()
 
+        # Use a single-catalog config so community extensions don't interfere
+        config_path = project_dir / ".specify" / "extension-catalogs.yml"
+        with open(config_path, "w") as f:
+            yaml_module.dump(
+                {
+                    "catalogs": [
+                        {
+                            "name": "test-catalog",
+                            "url": ExtensionCatalog.DEFAULT_CATALOG_URL,
+                            "priority": 1,
+                            "install_allowed": True,
+                        }
+                    ]
+                },
+                f,
+            )
+
         catalog = ExtensionCatalog(project_dir)
 
         # Create mock catalog
@@ -1071,10 +1149,29 @@ class TestExtensionCatalog:
 
     def test_get_extension_info(self, temp_dir):
         """Test getting specific extension info."""
+        import yaml as yaml_module
+
         project_dir = temp_dir / "project"
         project_dir.mkdir()
         (project_dir / ".specify").mkdir()
 
+        # Use a single-catalog config so community extensions don't interfere
+        config_path = project_dir / ".specify" / "extension-catalogs.yml"
+        with open(config_path, "w") as f:
+            yaml_module.dump(
+                {
+                    "catalogs": [
+                        {
+                            "name": "test-catalog",
+                            "url": ExtensionCatalog.DEFAULT_CATALOG_URL,
+                            "priority": 1,
+                            "install_allowed": True,
+                        }
+                    ]
+                },
+                f,
+            )
+
         catalog = ExtensionCatalog(project_dir)
 
         # Create mock catalog
@@ -1133,3 +1230,371 @@ class TestExtensionCatalog:
 
         assert not catalog.cache_file.exists()
         assert not catalog.cache_metadata_file.exists()
+
+
+# ===== CatalogEntry Tests =====
+
+class TestCatalogEntry:
+    """Test CatalogEntry dataclass."""
+
+    def test_catalog_entry_creation(self):
+        """Test creating a CatalogEntry."""
+        entry = CatalogEntry(
+            url="https://example.com/catalog.json",
+            name="test",
+            priority=1,
+            install_allowed=True,
+        )
+        assert entry.url == "https://example.com/catalog.json"
+        assert entry.name == "test"
+        assert entry.priority == 1
+        assert entry.install_allowed is True
+
+
+# ===== Catalog Stack Tests =====
+
+class TestCatalogStack:
+    """Test multi-catalog stack support."""
+
+    def _make_project(self, temp_dir: Path) -> Path:
+        """Create a minimal spec-kit project directory."""
+        project_dir = temp_dir / "project"
+        project_dir.mkdir()
+        (project_dir / ".specify").mkdir()
+        return project_dir
+
+    def _write_catalog_config(self, project_dir: Path, catalogs: list) -> None:
+        """Write extension-catalogs.yml to project .specify dir."""
+        import yaml as yaml_module
+
+        config_path = project_dir / ".specify" / "extension-catalogs.yml"
+        with open(config_path, "w") as f:
+            yaml_module.dump({"catalogs": catalogs}, f)
+
+    def _write_valid_cache(
+        self, catalog: ExtensionCatalog, extensions: dict, url: str = "http://test.com"
+    ) -> None:
+        """Populate the primary cache file with mock extension data."""
+        catalog_data = {"schema_version": "1.0", "extensions": extensions}
+        catalog.cache_dir.mkdir(parents=True, exist_ok=True)
+        catalog.cache_file.write_text(json.dumps(catalog_data))
+        catalog.cache_metadata_file.write_text(
+            json.dumps(
+                {
+                    "cached_at": datetime.now(timezone.utc).isoformat(),
+                    "catalog_url": url,
+                }
+            )
+        )
+
+    # --- get_active_catalogs ---
+
+    def test_default_stack(self, temp_dir):
+        """Default stack includes default and community catalogs."""
+        project_dir = self._make_project(temp_dir)
+        catalog = ExtensionCatalog(project_dir)
+
+        entries = catalog.get_active_catalogs()
+
+        assert len(entries) == 2
+        assert entries[0].url == ExtensionCatalog.DEFAULT_CATALOG_URL
+        assert entries[0].name == "default"
+        assert entries[0].priority == 1
+        assert entries[0].install_allowed is True
+        assert entries[1].url == ExtensionCatalog.COMMUNITY_CATALOG_URL
+        assert entries[1].name == "community"
+        assert entries[1].priority == 2
+        assert entries[1].install_allowed is False
+
+    def test_env_var_overrides_default_stack(self, temp_dir, monkeypatch):
+        """SPECKIT_CATALOG_URL replaces the entire default stack."""
+        project_dir = self._make_project(temp_dir)
+        custom_url = "https://example.com/catalog.json"
+        monkeypatch.setenv("SPECKIT_CATALOG_URL", custom_url)
+
+        catalog = ExtensionCatalog(project_dir)
+        entries = catalog.get_active_catalogs()
+
+        assert len(entries) == 1
+        assert entries[0].url == custom_url
+        assert entries[0].install_allowed is True
+
+    def test_env_var_invalid_url_raises(self, temp_dir, monkeypatch):
+        """SPECKIT_CATALOG_URL with http:// (non-localhost) raises ValidationError."""
+        project_dir = self._make_project(temp_dir)
+        monkeypatch.setenv("SPECKIT_CATALOG_URL", "http://example.com/catalog.json")
+
+        catalog = ExtensionCatalog(project_dir)
+        with pytest.raises(ValidationError, match="HTTPS"):
+            catalog.get_active_catalogs()
+
+    def test_project_config_overrides_defaults(self, temp_dir):
+        """Project-level extension-catalogs.yml overrides default stack."""
+        project_dir = self._make_project(temp_dir)
+        self._write_catalog_config(
+            project_dir,
+            [
+                {
+                    "name": "custom",
+                    "url": "https://example.com/catalog.json",
+                    "priority": 1,
+                    "install_allowed": True,
+                }
+            ],
+        )
+
+        catalog = ExtensionCatalog(project_dir)
+        entries = catalog.get_active_catalogs()
+
+        assert len(entries) == 1
+        assert entries[0].url == "https://example.com/catalog.json"
+        assert entries[0].name == "custom"
+
+    def test_project_config_sorted_by_priority(self, temp_dir):
+        """Catalog entries are sorted by priority (ascending)."""
+        project_dir = self._make_project(temp_dir)
+        self._write_catalog_config(
+            project_dir,
+            [
+                {
+                    "name": "secondary",
+                    "url": "https://example.com/secondary.json",
+                    "priority": 5,
+                    "install_allowed": False,
+                },
+                {
+                    "name": "primary",
+                    "url": "https://example.com/primary.json",
+                    "priority": 1,
+                    "install_allowed": True,
+                },
+            ],
+        )
+
+        catalog = ExtensionCatalog(project_dir)
+        entries = catalog.get_active_catalogs()
+
+        assert len(entries) == 2
+        assert entries[0].name == "primary"
+        assert entries[1].name == "secondary"
+
+    def test_project_config_invalid_url_raises(self, temp_dir):
+        """Project config with HTTP (non-localhost) URL raises ValidationError."""
+        project_dir = self._make_project(temp_dir)
+        self._write_catalog_config(
+            project_dir,
+            [
+                {
+                    "name": "bad",
+                    "url": "http://example.com/catalog.json",
+                    "priority": 1,
+                    "install_allowed": True,
+                }
+            ],
+        )
+
+        catalog = ExtensionCatalog(project_dir)
+        with pytest.raises(ValidationError, match="HTTPS"):
+            catalog.get_active_catalogs()
+
+    def test_empty_project_config_falls_back_to_defaults(self, temp_dir):
+        """Empty catalogs list in config falls back to default stack."""
+        import yaml as yaml_module
+
+        project_dir = self._make_project(temp_dir)
+        config_path = project_dir / ".specify" / "extension-catalogs.yml"
+        with open(config_path, "w") as f:
+            yaml_module.dump({"catalogs": []}, f)
+
+        catalog = ExtensionCatalog(project_dir)
+        entries = catalog.get_active_catalogs()
+
+        # Falls back to default stack
+        assert len(entries) == 2
+        assert entries[0].url == ExtensionCatalog.DEFAULT_CATALOG_URL
+
+    # --- _load_catalog_config ---
+
+    def test_load_catalog_config_missing_file(self, temp_dir):
+        """Returns None when config file doesn't exist."""
+        project_dir = self._make_project(temp_dir)
+        catalog = ExtensionCatalog(project_dir)
+
+        result = catalog._load_catalog_config(project_dir / ".specify" / "nonexistent.yml")
+        assert result is None
+
+    def test_load_catalog_config_localhost_allowed(self, temp_dir):
+        """Localhost HTTP URLs are allowed in config."""
+        project_dir = self._make_project(temp_dir)
+        self._write_catalog_config(
+            project_dir,
+            [
+                {
+                    "name": "local",
+                    "url": "http://localhost:8000/catalog.json",
+                    "priority": 1,
+                    "install_allowed": True,
+                }
+            ],
+        )
+
+        catalog = ExtensionCatalog(project_dir)
+        entries = catalog.get_active_catalogs()
+
+        assert len(entries) == 1
+        assert entries[0].url == "http://localhost:8000/catalog.json"
+
+    # --- Merge conflict resolution ---
+
+    def test_merge_conflict_higher_priority_wins(self, temp_dir):
+        """When same extension id is in two catalogs, higher priority wins."""
+        project_dir = self._make_project(temp_dir)
+
+        # Write project config with two catalogs
+        self._write_catalog_config(
+            project_dir,
+            [
+                {
+                    "name": "primary",
+                    "url": ExtensionCatalog.DEFAULT_CATALOG_URL,
+                    "priority": 1,
+                    "install_allowed": True,
+                },
+                {
+                    "name": "secondary",
+                    "url": ExtensionCatalog.COMMUNITY_CATALOG_URL,
+                    "priority": 2,
+                    "install_allowed": False,
+                },
+            ],
+        )
+
+        catalog = ExtensionCatalog(project_dir)
+
+        # Write primary cache with jira v2.0.0
+        primary_data = {
+            "schema_version": "1.0",
+            "extensions": {
+                "jira": {
+                    "name": "Jira Integration",
+                    "id": "jira",
+                    "version": "2.0.0",
+                    "description": "Primary Jira",
+                }
+            },
+        }
+        catalog.cache_dir.mkdir(parents=True, exist_ok=True)
+        catalog.cache_file.write_text(json.dumps(primary_data))
+        catalog.cache_metadata_file.write_text(
+            json.dumps({"cached_at": datetime.now(timezone.utc).isoformat(), "catalog_url": "http://test.com"})
+        )
+
+        # Write secondary cache (URL-hash-based) with jira v1.0.0 (should lose)
+        import hashlib
+
+        url_hash = hashlib.sha256(ExtensionCatalog.COMMUNITY_CATALOG_URL.encode()).hexdigest()[:16]
+        secondary_cache = catalog.cache_dir / f"catalog-{url_hash}.json"
+        secondary_meta = catalog.cache_dir / f"catalog-{url_hash}-metadata.json"
+        secondary_data = {
+            "schema_version": "1.0",
+            "extensions": {
+                "jira": {
+                    "name": "Jira Integration Community",
+                    "id": "jira",
+                    "version": "1.0.0",
+                    "description": "Community Jira",
+                },
+                "linear": {
+                    "name": "Linear",
+                    "id": "linear",
+                    "version": "0.9.0",
+                    "description": "Linear from secondary",
+                },
+            },
+        }
+        secondary_cache.write_text(json.dumps(secondary_data))
+        secondary_meta.write_text(
+            json.dumps({"cached_at": datetime.now(timezone.utc).isoformat(), "catalog_url": ExtensionCatalog.COMMUNITY_CATALOG_URL})
+        )
+
+        results = catalog.search()
+        jira_results = [r for r in results if r["id"] == "jira"]
+        assert len(jira_results) == 1
+        # Primary catalog wins
+        assert jira_results[0]["version"] == "2.0.0"
+        assert jira_results[0]["_catalog_name"] == "primary"
+        assert jira_results[0]["_install_allowed"] is True
+
+        # linear comes from secondary
+        linear_results = [r for r in results if r["id"] == "linear"]
+        assert len(linear_results) == 1
+        assert linear_results[0]["_catalog_name"] == "secondary"
+        assert linear_results[0]["_install_allowed"] is False
+
+    def test_install_allowed_false_from_get_extension_info(self, temp_dir):
+        """get_extension_info includes _install_allowed from source catalog."""
+        project_dir = self._make_project(temp_dir)
+
+        # Single catalog that is install_allowed=False
+        self._write_catalog_config(
+            project_dir,
+            [
+                {
+                    "name": "discovery",
+                    "url": ExtensionCatalog.DEFAULT_CATALOG_URL,
+                    "priority": 1,
+                    "install_allowed": False,
+                }
+            ],
+        )
+
+        catalog = ExtensionCatalog(project_dir)
+        self._write_valid_cache(
+            catalog,
+            {
+                "jira": {
+                    "name": "Jira Integration",
+                    "id": "jira",
+                    "version": "1.0.0",
+                    "description": "Jira integration",
+                }
+            },
+        )
+
+        info = catalog.get_extension_info("jira")
+        assert info is not None
+        assert info["_install_allowed"] is False
+        assert info["_catalog_name"] == "discovery"
+
+    def test_search_results_include_catalog_metadata(self, temp_dir):
+        """Search results include _catalog_name and _install_allowed."""
+        project_dir = self._make_project(temp_dir)
+        self._write_catalog_config(
+            project_dir,
+            [
+                {
+                    "name": "org",
+                    "url": ExtensionCatalog.DEFAULT_CATALOG_URL,
+                    "priority": 1,
+                    "install_allowed": True,
+                }
+            ],
+        )
+
+        catalog = ExtensionCatalog(project_dir)
+        self._write_valid_cache(
+            catalog,
+            {
+                "jira": {
+                    "name": "Jira Integration",
+                    "id": "jira",
+                    "version": "1.0.0",
+                    "description": "Jira integration",
+                }
+            },
+        )
+
+        results = catalog.search()
+        assert len(results) == 1
+        assert results[0]["_catalog_name"] == "org"
+        assert results[0]["_install_allowed"] is True