Our review
Captures significant errors encountered during development along with their root causes and prevention strategies.
Strengths
- Prevents repeating the same mistakes by building a reusable knowledge base
- Enables pattern matching for similar issues across projects
- Encourages thorough root cause analysis and structured documentation
- Seamlessly integrates into the development workflow with minimal overhead
Limitations
- Requires consistent discipline to maintain the reflexion log
- Only effective for significant issues, not quick fixes
- Quality heavily depends on the accuracy of the analysis provided
Use after resolving a complex or recurring problem that would benefit from future reference.
Do not use for trivial errors, typos, or issues that are already well-documented.
Security analysis
SafeThe skill only uses read-only tools (Read, Grep, Glob) and does not instruct any potentially harmful operations. It focuses on documenting errors and lessons learned.
No concerns found
Examples
Log a reflexion for the OAuth token refresh bug we just fixed. The root cause was that the error handler didn't distinguish between expired access token and expired refresh token.Create a reflexion entry about the N+1 query problem in the user listing endpoint. We fixed it by adding eager loading.Save a reflexion for the build failure caused by missing environment variable. The solution was to add a validation step in the CI pipeline.name: reflexion description: Capture significant errors, root causes, and prevention strategies for future reference argument-hint: [issue description] user-invocable: true allowed-tools:
- Read
- Grep
- Glob
/reflexion - Error Learning and Prevention
Capture significant issues encountered during development for future reference.
Purpose
Document errors and their resolutions to:
- Prevent repeating the same mistakes
- Build a knowledge base of solutions
- Enable pattern matching for similar issues
- Improve agent effectiveness over time
Inputs
$ARGUMENTS: Description of the issue (optional, can be inferred from context)${PROJECT_NAME}: Current project context${CLAUDE_SESSION_ID}: Session identifier for linking- Current conversation context (errors, debugging, resolutions)
Outputs
Reflexion record stored in Serena project memory under reflexion/ namespace.
High Signal/Noise Threshold
Only record issues that are:
- Significant: Required meaningful debugging effort
- Non-Obvious: The solution wasn't immediately clear
- Preventable: Could be avoided in future with the right knowledge
- Generalizable: Applies beyond this specific instance
Do NOT record:
- Simple typos or syntax errors
- Issues fixed in seconds
- One-off configuration problems
- Highly project-specific issues with no general lesson
Workflow
1. Identify the Issue
From context or $ARGUMENTS:
- What went wrong?
- What was the symptom?
- When did it manifest?
2. Analyze Root Cause
- Why did this happen?
- What assumption was incorrect?
- What information was missing?
- Was documentation unclear or absent?
3. Document Solution
- What fixed the issue?
- What was the key insight?
- How long did resolution take?
4. Define Prevention
- How can this be avoided in future?
- What should be checked first?
- Are there patterns to recognize?
- Should documentation be updated?
5. Store Reflexion
Create a reflexion record with the schema below.
Reflexion Schema
# reflexion/YYYY-MM-DD-short-description.md
---
date: YYYY-MM-DD
session_id: ${CLAUDE_SESSION_ID}
agent: [Which agent encountered this]
task: [What task was being performed]
severity: low | medium | high | critical
tags:
- [category]
- [technology]
---
## Known Issue
[Clear description of what went wrong]
## Symptoms
- [Observable symptom 1]
- [Observable symptom 2]
## Root Cause
[Why this happened - the underlying issue]
## Solution
1. [Step 1 of the fix]
2. [Step 2 of the fix]
3. [Verification step]
## Prevention
- [How to avoid this in future]
- [What to check first when seeing similar symptoms]
- [Patterns to recognize]
## Related
- [Link to relevant docs]
- [Similar past issues]
Example
---
date: 2026-01-24
session_id: abc123
agent: Developer
task: Implement OAuth authentication
severity: high
tags:
- authentication
- token-refresh
- error-handling
---
## Known Issue
Authentication fails silently when refresh token expires during long-running session.
## Symptoms
- Users logged out unexpectedly after ~1 hour
- No error messages displayed
- Network tab showed 401 responses being swallowed
## Root Cause
Token refresh endpoint returns 401 when refresh token is expired, but error handler was catching all 401s and returning a generic "unauthorized" without distinguishing between invalid token and expired refresh token.
## Solution
1. Added explicit check for refresh token expiry in 401 handler
2. Implemented token refresh retry logic with exponential backoff
3. Added user notification prompting re-authentication when refresh fails
## Prevention
- Always handle 401 responses explicitly in auth flows
- Distinguish between token types (access vs refresh) in error handling
- Add logging for token lifecycle events
- Consider health check endpoint for token validity before operations
Validation Checklist
- [ ] Issue is significant (worth recording)
- [ ] Root cause is identified (not just symptoms)
- [ ] Solution is actionable and specific
- [ ] Prevention strategies are generalizable
- [ ] Severity accurately reflects impact
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