Retrospective
When To Activate
- Multi-step implementations (3+ distinct phases)
- Debugging sessions that found the root cause
- Experiments or spikes that reached a conclusion
- Tasks where you tried multiple approaches
User signals completion:
- "That worked"
- "Done" / "Finished" / "Ship it"
- "Can you summarize what we did?"
- Explicit request for retrospective
Instructions
Step 1: Capture Failed Attempts First
Document what DIDN'T work before it fades from memory:
## Failed Attempts
| Approach | Why It Failed | Time Spent |
|----------|---------------|------------|
| [First thing tried] | [Specific reason] | [Estimate] |
| [Second thing tried] | [Specific reason] | [Estimate] |
Be specific about WHY it failed. "Didn't work" is useless. "Race condition between auth callback and state update" is useful.
Step 2: Document The Working Solution
## What Worked
**Final approach:** [One sentence summary]
**Key insight:** [The "aha" moment that unlocked the solution]
**Implementation:**
1. [Step 1]
2. [Step 2]
3. [Step 3]
Step 3: Extract Learnings
## Learnings
**Would do differently:**
- [What you'd change next time]
**Surprised by:**
- [Unexpected discoveries]
**Reusable patterns:**
- [Anything worth extracting into a skill or snippet]
Step 4: Create Artifact (Optional)
If the learnings are significant, offer to create:
- A skill (if pattern will recur) → invoke
learn-from-this - A snippet (if code is reusable)
- A doc (if context is project-specific)
Output Format
# Retrospective: [Task Name]
## Failed Attempts
| Approach | Why It Failed | Time Spent |
|----------|---------------|------------|
| ... | ... | ... |
## What Worked
**Final approach:** ...
**Key insight:** ...
**Implementation:**
1. ...
## Learnings
**Would do differently:**
- ...
**Surprised by:**
- ...
**Reusable patterns:**
- ...
---
*Generated: [timestamp]*
Examples
Example: Debugging Session
# Retrospective: Fix Login Race Condition
## Failed Attempts
| Approach | Why It Failed | Time Spent |
|----------|---------------|------------|
| Added setTimeout delay | Worked locally, flaky in prod | 20 min |
| Moved auth check earlier | Still raced with state hydration | 15 min |
| Added loading state | Masked the bug, didn't fix it | 10 min |
## What Worked
**Final approach:** Used auth state machine with explicit "initializing" state
**Key insight:** The bug wasn't timing - it was a missing state. Auth had
three states (logged-in, logged-out, unknown) but code only handled two.
**Implementation:**
1. Added AuthState enum with INITIALIZING state
2. Protected routes check for INITIALIZING, show skeleton
3. Auth callback sets state atomically after validation
## Learnings
**Would do differently:**
- Check for missing states FIRST before adding timing hacks
**Surprised by:**
- The "loading" state we added was actually correct, just incomplete
**Reusable patterns:**
- State machines for auth (avoid boolean flags)
Example: Feature Implementation
# Retrospective: Add CSV Export
## Failed Attempts
| Approach | Why It Failed | Time Spent |
|----------|---------------|------------|
| Client-side blob generation | Crashed on 10k+ rows | 30 min |
| Streaming response | CORS issues with download | 20 min |
## What Worked
**Final approach:** Server generates CSV, returns signed URL, client redirects
**Key insight:** Don't fight the browser. Redirecting to a file URL is the
native download UX.
**Implementation:**
1. POST /api/export triggers server-side generation
2. CSV written to temp storage with 5-min expiry
3. Return signed URL
4. Client does window.location = url
## Learnings
**Would do differently:**
- Start with server-side for any "export" feature
**Surprised by:**
- Signed URLs are trivial with modern cloud storage
**Reusable patterns:**
- Export pattern: generate server-side, return URL, redirect
NEVER
- Skip the Failed Attempts section (it's the most valuable part)
- Write vague failure reasons ("didn't work", "broken", "issues")
- Document only successes (survivorship bias)
- Wait until the next session (context will be lost)
ALWAYS
- Document failures FIRST while memory is fresh
- Include time estimates (helps calibrate future estimates)
- Extract the key insight (the "aha" moment)
- Offer to create skills from significant patterns
- Be honest about what took longer than expected
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