Lessons Skill

Manages the self-improvement loop. Use this skill when:

• The user corrects a mistake or gives feedback that should change future behavior
• You want to review past lessons at the start of a session
• After completing a task, to capture any patterns worth preserving

Lesson file

All lessons live in .claude/lessons.local.md.

Workflow: Recording a Lesson

Step 1: Read the current lessons file

cat .claude/lessons.local.md

Step 2: Identify the lesson

From the user correction, extract:

• Mistake: What went wrong (be specific, not generic)
• Pattern: The concrete rule to apply going forward
• Trigger: The condition that should activate this rule

Step 3: Append the entry

Add a new entry at the bottom of .claude/lessons.local.md, above the closing comment:

## 2026-03-17 — [short title]

**Mistake**: [What went wrong]
**Pattern**: [Rule to apply going forward]
**Trigger**: [When to apply this rule]

Use absolute dates (YYYY-MM-DD), never relative ("today", "last week").

Step 4: Confirm

Report the new entry to the user briefly:

Lesson recorded: [short title]

Workflow: Reviewing Lessons

At the start of a session, or when asked:

1. Read .claude/lessons.local.md
2. Identify lessons relevant to the current task
3. Internalize them — do not re-state them all back to the user unless asked
4. Apply them silently

Workflow: Pruning Lessons

Lessons become stale when:

• They reference a pattern that's been fixed in the code
• They duplicate another lesson
• They're too generic to be actionable

When pruning, remove the entry entirely. Don't leave tombstones.

Rules

• Never invent a lesson that wasn't triggered by an actual correction
• Be specific: "always read the file before editing" is better than "be careful"
• One lesson per entry — don't bundle unrelated corrections together
• Update an existing lesson if a correction refines a known pattern rather than creating a duplicate