Extending

Add a skill

Add a narrow entry to src/skills.js or register project-local skills through the native filesystem provider. Keep the body actionable and branch-specific. Do not duplicate the entire methodology in every skill.

Add a deterministic check

Implement a pure helper in src/core/index.js, test it with owned JSON fixtures, and have fullstack_check return pass, warn, or unknown. Never turn missing capability into a pass.

Add a capability adapter

Prefer a separate Cordis package/service only when two real consumers need the seam. Query the installed Inspect contract or read the authoritative package declaration first. Declare hard dependencies with inject, use ctx.get for optional capabilities, keep effects Fiber-owned, and return only lossless JSON across model-facing tools.

Add UI

Only add a Client package when a visible, interactive page surface is requested and a stable Slot contract is available. Query the actual Slot tree and props first. V0.1 has no Client UI because the existing Harness conversation, tool, plan, trajectory, and approval UIs already present the native surfaces.

Versioning

The old package version remains immutable. Add a new package version under the same Plugin identity, then update the profile overlay; preserve rollback paths and re-run mount/unit/integration checks.