Use when: making a mistake, breaking build/tests, realizing wrong approach, misunderstanding requirements, using wrong patterns, forgetting conventions, receiving correction from user, unexpected behavior, or any error situation
SkillScore36Maintained
Automatic
◆Knowledge Management pack
Last verified 8/22/2026
What it changes
Passed 4 of 11 test cases with the skill, and 2 of 11 without it.
Without skill14%
With skill36%
Checks it passed that the model alone missed
Creates the file at .claude/errors.md
Targets .claude/errors.md for the entry
Includes a header section titled Project Errors
and 6 more in the full report
6 fixed2 passed either way13 still failing1 broke
Pass-rate lift
+23 pp
Tokens
-29%
Agent turns
0%
Response time
-45%
Model gemini-3.6-flashMeasured 8/22/2026v18 of 22 cases passed with skill · 11 comparable
Tokens, turns and time describe resource use, not a dollar price.
See it in action
One of 6 test cases the skill fixed. Same model, same prompt, with and without the skill.
1 of 6
Prompt
I want you to refactor the database connection pool in db.ts. Before you start making changes, what project file should you inspect to avoid past mistakes?
What was checked, without and with the skill
Checked
Without skill
With skill
Identifies .claude/errors.md as the file to inspect before acting
Missed
Passed
case-17 · gemini-3.6-flash · 8/22/2026 · answers are capped and redacted
What's inside
The instructions your model reads when the skill loads.
SKILL.md51 linessingle file
Error Memory
Document errors to avoid repeating them.
Trigger
Invoke when:
Build/tests fail after your action
User corrects you
You realize a wrong approach
You forget a project convention
Unexpected behavior occurs
Process
Identify error type
tech : build, tests, syntax, runtime
ctx : conventions, patterns, project stack
comp : misunderstood requirements
Analyze root cause (not symptom)
Formulate fix as reusable rule
Append line to .claude/errors.md:
| MM-DD | type | Short error | Root cause | Rule to follow |
Create file if missing with this template:
# Project Errors
> Past Claude mistakes on this project. Check before acting.
| Date | Type | Error | Cause | Fix |
|------|------|-------|-------|-----|
## Legend
- **tech** : Technical (build, tests, syntax)