feat(plugin): add dynamic skill discovery via plugin hooks

[surma]

Add Dynamic Skill Discovery via Plugin Hooks

Fixes #8304 #10148

What does this PR do?

This PR adds support for plugins to dynamically provide skills through two new hooks: skill.list and skill.load. Plugins can now register skills at runtime that will be discovered and made available to the LLM alongside static skills from .opencode/skill/ directories.

Problem Solved

Previously, skills were only loaded from static filesystem locations. Plugins had no way to dynamically provide skills based on runtime conditions. This limitation prevented use cases like:

• Loading skills specific to the current workspace/project context
• Providing skills that depend on external configuration or APIs
• Dynamic skill discovery based on environment or runtime state
• Context-aware skills that change based on user preferences or project type

Implementation

The implementation adds a skill provider registry system:

1. Provider Registration (packages/opencode/src/plugin/index.ts):

   • During plugin initialization, plugins implementing skill.list or skill.load hooks are registered as skill providers
   • Each provider is stored in a module-level registry

2. Dynamic Skill Discovery (packages/opencode/src/skill/skill.ts):

   • Skill.all() now queries all registered providers in addition to static skills
   • Skill.get() checks providers when looking up skills by name
   • Skill.loadContent() uses provider's skill.load hook to retrieve skill content
   • Provider errors are caught and logged without crashing the system

3. Hook Definitions (packages/plugin/src/index.ts):

   • skill.list: Returns array of skill metadata (name, description, location)
   • skill.load: Returns skill content for a given location string

How did you verify your code works?

1. Type Safety: bun typecheck passes without errors

2. Test Suite: bun turbo test executes successfully

3. Manual Testing:

   • Created a plugin implementing skill.list and skill.load hooks
   • Verified dynamic skills from plugin appear in the Skill tool description
   • Executed plugin-provided skills successfully
   • Confirmed static skills continue to work alongside dynamic skills
   • Tested error handling by triggering provider failures
   • Verified skills are re-discovered on each session turn

4. Code Review:

   • Follows OpenCode style guide (no any types, uses const, error handling with .catch())
   • Maintains backward compatibility with existing static skill loading
   • Properly handles multiple providers and merges results

Edge Cases Handled

• Multiple plugins can each provide skills independently
• Provider failures are logged but don't crash the system
• Static and dynamic skills are properly merged (dynamic skills can override static ones)
• Skill loading falls back to filesystem if no provider handles the location

[github-actions]

The following comment was made by an LLM, it may be inaccurate:

No duplicate PRs found