Retrospective

<purpose> Knowledge capture at task completion. The Sionic AI insight: "Failed Attempts" tables get read more than any other documentation section. Success paths are nice. Failure paths save real time. This skill ensures both get documented before context is lost. </purpose>

When To Activate

<triggers> After completing significant work:

•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 </triggers>

Instructions

Step 1: Capture Failed Attempts First

Document what DIDN'T work before it fades from memory:

markdown

## 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

markdown

## 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

markdown

## 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

markdown

# 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

markdown

# 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

markdown

# 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