Authoring a built-in Blue Spec sub-skill (development workspace)

The end-user command @spec/commands/bluespec.specialize.md writes into a scaffolded target project: .bluespec/skills/<name>.md and .bluespec/skills.json. Neither path exists here. This repo is the Blue Spec source, where built-in sub-skills live in spec/skills/<name>.md and the catalog is a hardcoded TypeScript array, not a runtime JSON file. There is also no "user" registry: a built-in is registered in code, compiled, scaffolded, and tested.

So you reuse the command's authoring discipline (terrain, defense-only gate, template, tags, reconcile-never-append) but override every output path to the native layout, and you update the registration points the end-user command never has to.

Step 1: Run the command's authoring steps, with redirected paths

Read and follow @spec/commands/bluespec.specialize.md in full. Its authoring steps hold unchanged. The one thing that does not is where files are read and written, since the command targets a scaffolded project and you are in the source. Remap every path it names:

One path it names stays put: a hook reference inside the .md body keeps the ./.bluespec/hooks/<x>.mjs form, because that body ships verbatim to the end user and must point at their scaffolded path, not the source.

Step 2: Decide the category (group)

Every built-in belongs to a category (group), which is how npx blue-spec add --skills <category> bundles it into a target project. Categories live in SKILL_GROUPS in src/hooks/skills/groups.ts.

• A language sub-skill goes under its language key (python under python, and so on).
• A sub-skill about an application-security risk OWASP tracks goes under owasp.
• Match the sub-skill to the category that actually describes it. If none fits, that is a signal a new category may be needed, adding a SkillGroup to SKILL_GROUPS (key, label, description). Ask the user before inventing one, do not force an unrelated module into owasp to avoid the question.

The end-user skills.json has no groups field by default, but the built-in catalog entry does. Set it.

Step 3: Write and register, then verify

A new built-in is not done when the .md exists. Touch each of these:

Required (a sub-skill is broken without these)

1. Write the authored module to `spec/skills/<name>.md` (Step 1). src/core/assets.ts reads spec/skills/ by directory listing, so the file loads automatically once it is on disk, with no code change.
2. Add the BuiltinSkillEntry { name, tags, groups } to `src/hooks/skills/catalog.ts`. Without this row the file scaffolds, but the skills hook never lists it and add --skills cannot bundle it.
3. Add a SkillGroup to `src/hooks/skills/groups.ts`, but only when you introduced a new category.

Tests (the suite asserts the catalog and the docs stay in sync)

1. `test/integration/skills/skills.test.ts` iterates SKILLS_CATALOG (e.g. "never repeats the name inside its own tags"), so a new entry is exercised automatically. Check that no count-based or hardcoded-list assertion now fails.
2. `test/e2e/init/skills-hook.test.ts` and `test/e2e/init/manage-cli.test.ts` assert scaffold and listing behavior, sometimes by sub-skill name. Update any hardcoded expectation that should now include the new one.
3. `test/integration/cli/manifest.test.ts` and `test/integration/cli/scaffold-groups.test.ts` reference specific skill paths like .bluespec/skills/regex.md. Update them only when your change alters what a given category scaffolds.
4. Run the full suite: npm test. Its pretest hook runs scripts/build.sh first, so the compiled lib/hooks/*.mjs the e2e tests exercise are rebuilt automatically, no separate build step needed. All green before you call it done.

Documentation (the built-in catalog is enumerated by hand in the website)

1. Add a row to the "set that ships with Blue Spec" table in `website/docs/commands/skills.mdx` (around line 48), giving the built-in its category and focus. This table is maintained by hand and drifts silently when a built-in is missing.
2. The example listing output in `website/docs/hooks/skills.mdx` (# => regex: ...) is illustrative. Update it only when it should showcase the new one.
3. Update `README.md` only when it enumerates built-ins.

Not touched

• src/core/skills-catalog.ts (the _empty user_ catalog factory), src/hooks/skills/discover.ts (reads the _user's_ .bluespec/skills.json), and .bluespec/skills.json itself: these are the end-user registry. A built-in never writes there.

Quick checklist

[ ] spec/skills/<name>.md            authored from spec/templates/specialize-template.md (reconciled on a refine)
[ ] src/hooks/skills/catalog.ts      BuiltinSkillEntry added { name, tags, groups }
[ ] src/hooks/skills/groups.ts       only if a new category was introduced
[ ] tests updated + npm test green
[ ] website/docs/commands/skills.mdx table row added

Summary to the user

As Step 8 of the command: state the name, tags, category, what it covers, and that the detect and verify phases now load it on demand once shipped (end users import it with @.bluespec/skills/<name>.md). Note it shadows any same-named entry on a refine. Suggest a commit such as `feat: add specialization in <name> defense`, matching the wording the existing built-ins use, as a suggestion, not a mandate.