extensions

Context

Receives:

• Agent/skill name and target phase from user

Reads:

• The agent/skill file
• wiki/extensions/<phase>.md (if exists)

Produces:

• Updated wiki/extensions/<phase>.md

Procedure

1. Accept input

Get agent/skill name and target phase from user.

2. Validate phase

Extendable phases: router, diagnose, craft, verify.

Reject with explanation: sketch, blueprint, retro, explore -- "single-agent or conversational -- no dispatch point for extensions."

3. Validate extension type

• Agent extensions: all extendable phases (router, diagnose, craft, verify).
• Skill extensions: craft only. Reject for other phases -- "only craft supports skill extensions because it's the only phase where extensions do work, not just report findings."

4. Locate the file

Search in order:

Type	Project path	User path
Agents	.claude/agents/	~/.claude/agents/
Skills	.claude/skills/	~/.claude/skills/

If not found, tell user where to create it.

5. Assess fit

Read the agent/skill file. Check for these structural markers per phase:

• Router extensions: file must contain ## Key Findings, ## Relevant Files, ## Open Questions sections (or equivalent output format). Check: does the file define an output template matching this structure?
• Diagnose extensions: file must define investigation output with classification support. Check: does it produce findings that feed into the routing decision?
• Craft agent extensions: file must define pass/fail output per check. Check: does the output format include structured findings (not prose)?
• Craft skill extensions: file must have YAML frontmatter with name:. Check: does it follow the standard SKILL.md format with a Procedure section?
• Verify extensions: file must define severity-tagged findings (P0-P3) with file:line references. Check: does the output format match the code-reviewer's finding structure (Severity, File/line, Observed, Expected, Why)?

If format doesn't match: show the user what's missing and suggest specific additions. Do not silently register an extension with incompatible output.

6. Check extension cap

Phase	Framework agents	Extension cap
Router	2 (code + docs explorer)	2
Diagnose	0	2
Craft	0	2 agents + 2 skills
Verify	1 (unified code-reviewer)	3

If cap reached: reject, suggest replacing an existing extension.

7. Write extension manifest

Create or update wiki/extensions/<phase>.md:

---
phase: [phase name]
date_updated: [YYYY-MM-DD]
---
agents:
  - name: [agent-name]
    source: project | user

# craft only:
skills:
  - name: [skill-name]
    source: project | user

Output

Updated wiki/extensions/<phase>.md.

References

• references/registry.md -- Extension types, integration points, output contracts, and examples per phase

Gotchas

• All extensions are always-on -- no per-task toggling or conditional triggers.
• Lightweight craft skips extensions entirely.
• Extension caps are evolvable -- /propose can recommend raising a cap if retros show gaps.
• Agent extensions must use the same evidence-based finding format as framework agents.