From lesson-learned
Analyzes git history of recent code changes to extract grounded software engineering lessons from diffs, commits, and principles catalog.
npx claudepluginhub softaworks/agent-toolkit --plugin lesson-learnedThis skill uses the workspace's default tool permissions.
Extract specific, grounded software engineering lessons from actual code changes. Not a lecture -- a mirror. Show the user what their code already demonstrates.
Reviews recent git diffs and commits with brutal honesty before PRs, spotting 2am logic flaws, copy-paste artifacts, debug leftovers, hacks, and poor naming.
Generates concise structured PR descriptions from git commit history by grouping changes, ignoring noise, and minimally inspecting diffs. Use for clean consistent PRs with low token usage.
Summarizes recent codebase activity over a time period (default 2 weeks): features landed, fixes, refactors, focus/neglected areas, and contributor patterns. Uses git log or timewarp tools for quick catch-up.
Share bugs, ideas, or general feedback.
Extract specific, grounded software engineering lessons from actual code changes. Not a lecture -- a mirror. Show the user what their code already demonstrates.
Load the principles reference first.
references/se-principles.md to have the principle catalog availablereferences/anti-patterns.md if you suspect the changes include areas for improvementDo not proceed until you've loaded at least se-principles.md.
Ask the user or infer from context what to analyze.
| Scope | Git Commands | When to Use |
|---|---|---|
| Feature branch | git log main..HEAD --oneline + git diff main...HEAD | User is on a non-main branch (default) |
| Last N commits | git log --oneline -N + git diff HEAD~N..HEAD | User specifies a range, or on main (default N=5) |
| Specific commit | git show <sha> | User references a specific commit |
| Working changes | git diff + git diff --cached | User says "what about these changes?" before committing |
Default behavior:
git log with the determined scope to get the commit list and messagesgit diff for the full diff of the scopegit diff --stat first, then selectively read the top 3-5 most-changed filesIdentify the dominant pattern -- the single most instructive thing about these changes.
Look for:
Map findings to specific principles from references/se-principles.md. Be specific -- quote actual code, reference actual file names and line changes.
Use this template:
## Lesson: [Principle Name]
**What happened in the code:**
[2-3 sentences describing the specific change, referencing files and commits]
**The principle at work:**
[1-2 sentences explaining the SE principle]
**Why it matters:**
[1-2 sentences on the practical consequence -- what would go wrong without this, or what goes right because of it]
**Takeaway for next time:**
[One concrete, actionable sentence the user can apply to future work]
If there is a second lesson worth noting (maximum 2 additional):
---
### Also worth noting: [Principle Name]
**In the code:** [1 sentence]
**The principle:** [1 sentence]
**Takeaway:** [1 sentence]
| Avoid | Why | Instead |
|---|---|---|
| Listing every principle that vaguely applies | Overwhelming and generic | Pick the 1-2 most relevant |
| Analyzing files that were not changed | Scope creep | Stick to the diff |
| Ignoring commit messages | They contain intent that diffs miss | Read them as primary context |
| Abstract advice disconnected from the code | Not actionable | Always reference specific files/lines |
| Negative-only feedback | Demoralizing | Lead with what works, then suggest improvements |
| More than 3 lessons | Dilutes the insight | One well-grounded lesson beats seven vague ones |