Add Claude Code plugin command discovery #848

crdant · 2025-11-05T02:16:24Z

What problem(s) was I solving?

Problem: CodeLayer users cannot see or use slash commands from Claude Code marketplace plugins in the CodeLayer UI.

Claude Code marketplace plugins install their commands to a different location (~/.config/claude-code/plugins/{plugin-name}/commands/), and their metadata is stored in separate JSON files (installed_plugins.json and settings.json). The daemon had no logic to discover these plugin commands.

Impact: Users installing plugins like "Superpowers" or other marketplace plugins would not see those commands available in CodeLayer, creating a disconnected experience between Claude Code and CodeLayer.

What user-facing changes did I ship?

CodeLayer will now display slash commands from installed Claude Code plugins:

Plugin commands appear in the slash command list with source: "plugin"
Commands are namespaced as /plugin-name:command-name (e.g., /superpowers:brainstorm)
Only enabled plugins' commands appear (respects user's Claude Code settings)
Nested plugin commands use colon separators (e.g., /plugin-name:config:show)
Fuzzy search works across plugin commands
Commands seamlessly integrate with existing local/global commands

No breaking changes - existing local and global commands work exactly as before.

How I implemented it

Architecture Decision: Isolated Plugin Discovery

I chose to encapsulate all plugin-specific logic in isolated functions to make the plugin system maintainable and adaptable to future changes by Anthropic:

New File: hld/api/handlers/plugins.go (122 lines)

discoverPluginCommands(configDir string) - Main discovery orchestration
scanPluginCommandsDir(dir, pluginName string) - Scans individual plugin commands
Type definitions for plugin metadata structures

Implementation Details

1. OpenAPI Schema Extension (hld/api/openapi.yaml)

Added "plugin" to the SlashCommand.source enum
Regenerated Go types → SlashCommandSourcePlugin constant

2. Plugin Discovery Logic (hld/api/handlers/plugins.go)

Discovery Flow:
1. Read $CLAUDE_CONFIG_DIR/plugins/installed_plugins.json
   - Contains plugin metadata: version, install path, git commit
2. Read $CLAUDE_CONFIG_DIR/settings.json
   - Contains enabledPlugins map (plugin-id → true/false)
3. For each enabled plugin:
   - Extract plugin name from "plugin-name@marketplace" ID
   - Scan {installPath}/commands/ for .md files
   - Create namespaced command: /plugin-name:command-name
4. Return list of plugin commands with source="plugin"

if CLAUDE_CONFIG_DIR is discovery will use ~/.claude

3. Error Handling (Graceful Degradation)

Missing installed_plugins.json → return empty list (no plugins installed)
Missing settings.json → treat all plugins as enabled (default behavior)
Malformed JSON → log warning, return empty list
Missing plugin commands directory → skip that plugin
All errors logged but don't break the entire API request

4. Integration (hld/api/handlers/sessions.go)

Added plugin discovery after global command discovery (line 1699-1721)
Plugin commands merged into same deduplication map as local/global
Maintains existing precedence: local → global → plugin (no conflicts due to namespacing)

5. Comprehensive Testing

Unit Tests (hld/api/handlers/plugins_test.go - 12 tests):

No installed plugins file
Malformed installed_plugins.json
No settings file (default enabled behavior)
Disabled plugin filtering
Enabled plugin discovery
Multiple plugins
Non-existent directories
Empty directories
Single command
Nested commands (colon separator)
Non-markdown file filtering
Multiple commands per plugin

Integration Tests (hld/daemon/daemon_slash_commands_integration_test.go):

TestPluginCommandsIntegration with 3 subtests:
- Enabled/disabled plugin filtering via settings.json
- Default behavior without settings.json (all enabled)
- Graceful handling of missing installed_plugins.json

Key Design Decisions

1. Namespace Format: /plugin-name:command

Plugin name is in the command name itself
Source field remains simple enum: "plugin" (not "plugin:name")
Easy to parse: command.name.split(':')[0].slice(1) gives plugin name

2. Config Directory Detection

Uses existing CLAUDE_CONFIG_DIR environment variable logic
Falls back to ~/.claude (macOS/Linux standard)
Leverages existing expandTilde() helper function

3. Isolation Pattern

All plugin logic in separate plugins.go file
Can be updated independently if Anthropic changes plugin format
No pollution of main session handler logic

How to verify it

I have ensured make check test passes

Verification Results:

✓ Format check passed
✓ Vet check passed
✓ Lint check passed
✓ Unit tests passed (424 tests)
✓ Unit tests with race detection passed (424 tests)
✓ Integration tests passed (50 tests)
✓ Integration tests with race detection passed (50 tests)

Test Coverage:

12 new unit tests for plugin discovery (all passing)
3 new integration test scenarios (all passing)
0 failing tests
0 lint issues

Manual Testing (optional but recommended):

With real Claude Code plugins installed:

# Start daemon
cd hld && make build && ./hld

# Query plugin commands
curl "http://127.0.0.1:5188/api/v1/slash-commands?working_dir=$(pwd)" | \
  jq '.data[] | select(.source == "plugin")'

# Test fuzzy search
curl "http://127.0.0.1:5188/api/v1/slash-commands?working_dir=$(pwd)&query=brain" | \
  jq '.data[] | select(.source == "plugin")'

Description for the changelog

Added: Claude Code marketplace plugin commands now appear in CodeLayer's slash command list. Plugin commands are discovered from ~/.config/claude-code/plugins/ and respect enabled/disabled state from Claude Code settings. Commands are namespaced as /plugin-name:command-name.

A picture of a cute animal (not mandatory but encouraged)

Technical Notes

Files Modified:

hld/api/openapi.yaml - Added "plugin" to source enum
hld/api/server.gen.go - Auto-generated constant
hld/api/handlers/sessions.go - Added plugin discovery call (24 lines)
hld/daemon/daemon_slash_commands_integration_test.go - Added integration test (274 lines)
hld/go.mod / hld/go.sum - Added test mock dependencies

Files Created:

hld/api/handlers/plugins.go - Plugin discovery implementation (122 lines)
hld/api/handlers/plugins_test.go - Comprehensive unit tests (250+ lines)

Implementation Plan: thoughts/shared/plans/2025-01-08-plugin-command-discovery.md
Research Document: docs/research/2025-11-04-codelayer-slash-command-loading.md

Total Changes: +635 lines, -156 lines across 6 modified + 2 new files

Important

Adds discovery and display of Claude Code marketplace plugin commands in CodeLayer UI, with new logic in plugins.go and comprehensive testing.

Behavior:
- Adds discovery of slash commands from Claude Code marketplace plugins in hld/api/handlers/plugins.go.
- Commands are namespaced as /plugin-name:command-name and appear with source: "plugin".
- Only enabled plugins' commands are shown, respecting settings.json.
- Supports nested commands with colon separators.
- Integrates with existing local/global commands without breaking changes.
Implementation:
- New file plugins.go for plugin command discovery logic.
- Updates openapi.yaml to add "plugin" to SlashCommand.source enum.
- Modifies sessions.go to include plugin command discovery.
Testing:
- Adds unit tests in plugins_test.go for various scenarios including missing files and malformed JSON.
- Adds integration tests in daemon_slash_commands_integration_test.go for plugin command discovery.
Misc:
- Updates go.mod and go.sum for new dependencies.

^{This description was created by}^{for c354296. You can customize this summary. It will automatically update as commits are pushed.}

Add "plugin" as a third source type alongside "local" and "global" in the SlashCommand schema. This enables the API to distinguish commands from Claude Code marketplace plugins.

Add discovery of slash commands from Claude Code marketplace plugins. Reads installed_plugins.json and settings.json to find enabled plugins and scans their commands directories. Plugin commands are namespaced as /plugin-name:command-name and respect enabled/disabled state. Gracefully handles missing or malformed plugin metadata files.

Add 12 unit tests covering plugin discovery edge cases: - Missing/malformed metadata files - Enabled/disabled plugin filtering - Nested commands and namespacing - Multiple plugins Add integration test with 3 scenarios validating end-to-end behavior.

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1. hld/api/server.gen.go:1

Draft comment:
This file is auto-generated by oapi-codegen (v2.5.1); please avoid manual modifications. Ensure that the new constant for SlashCommandSourcePlugin is correctly integrated with the rest of the system.
Reason this comment was not posted:
Confidence changes required: 0% <= threshold 50% None

2. hld/daemon/daemon_slash_commands_integration_test.go:195

Draft comment:
Prefer using the api.SlashCommandSourceLocal constant (and similarly for 'global') instead of literal strings ('local', 'global') in assertions for better maintainability and consistency.
Reason this comment was not posted:
Comment was not on a location in the diff, so it can't be submitted as a review comment.

3. hld/daemon/daemon_slash_commands_integration_test.go:630

Draft comment:
When removing the installed_plugins.json file (using os.Remove), consider checking and ignoring errors if the file does not exist. This can improve robustness in test cleanup.
Reason this comment was not posted:
Comment looked like it was already resolved.

4. hld/go.mod:5

Draft comment:
The go.mod file updates (including replace directives and dependency versions) appear intentional. Please double‐check that these dependency version bumps (e.g., for github.com/golang/mock) are expected.
Reason this comment was not posted:
Comment was not on a location in the diff, so it can't be submitted as a review comment.

5. hld/go.sum:1

Draft comment:
The go.sum file reflects updated dependency checksums. They seem consistent with the go.mod changes; no issues noted.
Reason this comment was not posted:
Confidence changes required: 0% <= threshold 50% None

Workflow ID: wflow_btR2tdcTJ52P8wnY

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K-Mistele · 2025-11-05T04:02:17Z

Thanks for the PR @crdant !

Plugins are still considered to be in beta by anthropic right now so I am hesitant to merge something that depends on what the Claude code team considers an unstable API

Will discuss internally and let you know where we wind up on this

crdant · 2025-11-05T12:13:10Z

Plugins are still considered to be in beta by anthropic right now so I am hesitant to merge something that depends on what the Claude code team considers an unstable API

Makes a lot of sense.

This PR and my last one have a common theme. hld is in the loop for autocompleting slash commands, so as soon as I type / and don't see a command I expect I'm back to the terminal until I have time to create a PR, get it approved, and install a new release.

This whack-a-mole game isn't the best thing for me as a user or for your team as creators. Perhaps there's a better approach I can't see to stay aligned so the / makes the same recommendations either in or out of CodeLayer.

dexhorthy · 2025-11-05T20:08:44Z

Appreciate both sides of this convo, and thanks chuck for the PR!

@K-Mistele is this something we could drop in an opt-in “experimental features” thing?

I would guess Claude will continue to launch beta features that ppl wanna use and we should weigh the tradeoffs of not supporting them

crdant · 2025-11-11T16:16:37Z

@K-Mistele @dexhorthy if the experimental feature model makes sense, I can imagine I wouldn't be too hard for me to wrap it and contribute the whole thing.

crdant added 3 commits November 4, 2025 21:14

feat: add plugin source type to slash command API

42a1cc3

Add "plugin" as a third source type alongside "local" and "global" in the SlashCommand schema. This enables the API to distinguish commands from Claude Code marketplace plugins.

crdant changed the title ~~feat: Add Claude Code plugin command discovery~~ Add Claude Code plugin command discovery Nov 5, 2025

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Add Claude Code plugin command discovery #848

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crdant commented Nov 5, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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What problem(s) was I solving?

What user-facing changes did I ship?

How I implemented it

Architecture Decision: Isolated Plugin Discovery

Implementation Details

Key Design Decisions

How to verify it

Description for the changelog

A picture of a cute animal (not mandatory but encouraged)

Technical Notes

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K-Mistele commented Nov 5, 2025

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crdant commented Nov 5, 2025 •

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