ccc-compound

Compound — Post-Task Learning Capture

Inspired by Compound Engineering by Every.to

Each unit of work makes the next one slightly cheaper. Extract the signal, persist it, move on.

Argument: {{input}}

• No argument = capture learnings from the current session
• review = display all accumulated lessons without adding new ones
• prune = review lessons and remove outdated or irrelevant entries

---

If review

Read tasks/lessons.md and ~/.claude/learned-skills/ contents. Display a summary:

COMPOUND REVIEW

Lessons: X entries across Y categories
Learned Skills: Z entries

[grouped list of lessons by date, most recent first]

Stop here. Do not extract or persist anything.

If prune

Read tasks/lessons.md. For each entry, evaluate whether it is still relevant given the current codebase and project CLAUDE.md. Present entries to remove with rationale, then ask for confirmation before deleting.

Stop here after pruning.

---

Default: Capture Learnings

1. Review What Just Happened

Run in parallel:

• git log --oneline -10 — recent commits
• git diff --stat HEAD~3 — recent file changes

Then review the conversation context for decisions made, corrections received, and patterns discovered.

2. Extract Learnings

Organize into three categories:

Patterns Discovered:

• Code patterns that worked well (architecture, data flow, API design)
• Effective tool or library usage worth repeating
• Workflow sequences that were efficient

Mistakes & Corrections:

• What went wrong and the root cause
• What the fix was
• How to prevent this class of error in the future

Decisions & Rationale:

• Key decisions made and WHY (not just what)
• Alternatives considered and rejected
• Constraints that drove the decision

Skip any category with nothing meaningful to report.

3. Persist

• Append actionable entries to tasks/lessons.md (create the file if it does not exist). Use the format:

  ## YYYY-MM-DD — [session summary]
  
  ### Patterns
  - [pattern]
  
  ### Corrections
  - [mistake] -> [fix] -> [prevention rule]
  
  ### Decisions
  - [decision]: [rationale]
  

• If a pattern is broadly reusable, suggest adding it to the project CLAUDE.md.
• If a correction reveals a gap in existing rules, suggest a specific new rule.
• Check ~/.claude/learned-skills/ and suggest new learned skill entries if appropriate.