Add custom Copilot skills support for domain-specific planning

[Copilot]

Copilot SDK v0.1.24-preview.0 added skillDirectories and disabledSkills options for custom skills. This enables users to provide domain-specific context (e.g., "web-app", "data-pipeline") that improves WBS generation accuracy.

Implementation

Skill loading: Skills are read from .github/skills/*.yaml on startup. Simple regex parsing extracts the name field; malformed files are logged and skipped.

SDK integration: Skills are passed per-session via SessionConfig, not client initialization:

const sessionConfig: SessionConfigWithSkills = {
  model: currentModel,
  streaming: true,
  skillDirectories: ['/path/to/.github/skills'],
  disabledSkills: ['skill-name']  // optional
};
session = await copilot.createSession(sessionConfig);

UI: Refine screen now has Skills view (⇥ to cycle Tree → Batches → Skills). Users toggle skills on/off with Space. Active skills are serialized with the plan.

Planner integration: During WBS generation, enabled skill names are appended to the user content sent to Copilot:

if (activeSkills?.length > 0) {
  userContent += `\n\nActive custom skills: ${enabledSkills.join(', ')}`;
}

Skills Directory

Skills are stored in .github/skills/ directory, making them part of the repository's GitHub configuration alongside workflows and other GitHub-specific files. This location:

• Makes skills discoverable and version-controlled with the repository
• Follows GitHub conventions for repository configuration
• Allows skills to be shared across team members automatically

Example Skills

Two skills included as templates in .github/skills/:

• web-app: Frontend/backend/database/deployment task patterns
• data-pipeline: ETL extraction/transformation/loading/monitoring patterns

Each YAML defines instructions and examples that guide Copilot's task breakdown logic.

Data Model

interface SkillConfig {
  name: string;
  enabled: boolean;
}

interface Plan {
  // ... existing fields
  skills?: SkillConfig[];  // tracks which skills were active
}

Original prompt

---

This section details on the original issue you should resolve

<issue_title>[enhancement] Support Custom Copilot Skills for Domain-Specific Planning and Execution</issue_title>
<issue_description>## Background

The Copilot SDK v0.1.24-preview.0 release added support for custom skills across all SDK implementations:

• skillDirectories option: Allows developers to specify directories containing custom skill definitions (PR colindembovsky/planeteer#57 merged in v0.1.24-preview.0)
• disabledSkills option: Provides control over which built-in or custom skills are active
• Skill E2E tests: New test coverage ensures skills work reliably (PR colindembovsky/planeteer#69 by Steve Sanderson)

Release notes: v0.1.24-preview.0

Proposal

Extend Planeteer to support custom Copilot skills, enabling users to define domain-specific planning and execution behaviors. For example:

• A "web-app" skill that knows to break down web projects into frontend, backend, database, and deployment tasks
• A "data-pipeline" skill that structures ETL workflows with validation and monitoring
• A "mobile-app" skill that generates iOS/Android-specific task breakdowns

Implementation approach:

1. Add skillDirectories and disabledSkills options to src/services/copilot.ts when initializing SDK sessions
2. Create a .planeteer/skills/ directory structure where users can drop skill definition files
3. Update src/services/planner.ts to pass skill context to Copilot during clarification and breakdown phases
4. Add a "Skills" section to the refine screen (src/screens/refine.tsx) showing which skills are active
5. Document skill creation in README.md with example skill definitions

Benefit

• Customization: Teams can encode their own best practices and project structures as reusable skills
• Domain expertise: Skills provide context that improves Copilot's planning accuracy for specific types of projects
• Efficiency: Well-crafted skills reduce the need for manual refinement in the breakdown phase
• Ecosystem: Users can share skills with the community, building a library of domain-specific templates

Acceptance Criteria

• src/services/copilot.ts passes skillDirectories option to SDK when creating sessions
• .planeteer/skills/ directory is created on first run if it doesn't exist
• Sample skill definition file included in repository (e.g., example-web-app-skill.yaml)
• Active skills displayed in refine screen with option to toggle on/off
• Planner prompts (src/services/planner.ts) reference skill names when generating WBS
• Unit tests verify skill configuration is passed correctly to SDK
• README documents skill file format and provides 2+ examples
• Error handling for malformed skill files (graceful degradation)

AI generated by Weekly Enhancement Suggestions

Comments on the Issue (you are @copilot in this section)

• Fixes [enhancement] Support Custom Copilot Skills for Domain-Specific Planning and Execution #10

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[colindembovsky]

@copilot Update the skills location to default to ./github/skills instead of ./planeteer/skills

[Copilot]

@copilot Update the skills location to default to ./github/skills instead of ./planeteer/skills

Updated skills location from .planeteer/skills to .github/skills in commit f061152.

Changes:

• SKILLS_DIR constant updated in src/services/copilot.ts
• Example skill files moved to .github/skills/
• All documentation references updated in README.md
• UI message updated in refine screen

New directory structure:

.github/
└── skills/
    ├── example-data-pipeline-skill.yaml
    └── example-web-app-skill.yaml

All tests passing ✓