retrospective

name	retrospective
description	After completing a significant task or experiment, extract lessons learned and update the project knowledge base. Captures what worked, what failed, and what to remember for next time.
argument-hint	["task-description"]
disable-model-invocation	true
allowed-tools	Read, Edit, Write, Bash, Grep, Glob

Retrospective: Capture Lessons Learned

After completing "$ARGUMENTS", extract insights and update the project knowledge base.

Steps

1. Gather context: Read recent changes, results, and any errors encountered during the task. Look at:

   • Recent git commits: git log --oneline -10
   • Modified files: git diff --name-only HEAD~5
   • Any error logs in logs/
   • Result files if experiment-related

2. Extract lessons in these categories:

   What worked — approaches, tools, or patterns that were effective What failed — approaches that were tried and didn't work, with WHY Surprises — unexpected findings or behaviors For next time — specific recommendations for similar future tasks

3. Update knowledge base:

   If there are failed approaches: Append to docs/failures.md following the existing format:

   ### Title
   **When**: Date
   **What happened**: Description
   **Root cause**: Why it failed
   **Fix/workaround**: What to do instead
   

   If there's a decision: Append to docs/decisions.jsonl using the established schema.

   If there are experiment findings: Consider whether docs/findings.md needs updating.

4. Summarize the retrospective in 3-5 bullet points for the user.

Rules

• Be specific. "It was hard" is not useful. "XGBoost training fails with >100k samples on MPS due to memory limit" is useful.
• Include exact error messages or config values when relevant.
• Failed attempts with details are MORE valuable than successes — they prevent repeated mistakes.
• Don't update files unless there's genuinely new information to capture.