Growth Log Skill

The problem: Most people write "fixed a bug in X" as a learning log. That's a diary entry, not a learning artifact. A real growth log extracts the pattern so you recognize it next time.

This skill teaches: How to write learning entries that compound across sessions. Works with any note-taking system — Markdown files, Notion, Obsidian, plain text. Templates are generic; adapt to your setup.

When to Activate

• After completing a complex task (multi-file, new feature, architecture change)
• After a failure, mistake, or "that was harder than expected" moment
• When you want to review what you've learned over a period

When NOT to activate: Trivial changes (typo fixes, single-line tweaks, config value changes with no debugging). The threshold: did this task involve debugging, redoing, rollback, or a non-obvious decision? If yes → write an entry. If no → skip.

The Three Rules

Rule 1: Failures > Achievements

A failure is nutritionally denser than a success. One bug that took 2 hours to find teaches more than 3 features that worked first try.

Bad: "Successfully implemented the login flow." Good (web dev): "Login flow: session token wasn't persisting because the cookie SameSite defaulted to Lax in Chrome 128+. Pattern: always explicitly set SameSite=None; Secure when cross-origin. Signal to recognize: auth breaks after browser upgrade or when crossing origin boundaries." Good (data pipeline): "CSV import failed silently on empty rows because pandas.read_csv(dropna=False) keeps zero-width rows that len() counts as valid. Pattern: always df.dropna(how='all', inplace=True) before row-count validation."

Rule 2: The Bole Principle (伯乐原则)

Before writing a new entry, ask: "Is this fundamentally the same as something I already recorded?"

Same root cause, different symptom → merge, don't duplicate. New root cause → new entry.

How to check: Search existing entries for keywords from your root cause before writing. If you find a match, add your new symptom as an additional example under the existing entry rather than creating a duplicate.

Example: "Forgot to update the output index after creating a file" and "Forgot to update skill ratings after a task" — same root cause (no automatic capture trigger). Merge into one entry about "post-task capture gaps."

Rule 3: Must Be Transferable

Every entry must answer: "Next time I face a similar situation, what do I do differently?"

If you can't write that sentence, you haven't extracted the pattern yet.

How to extract a pattern from a concrete event:

1. State what happened in one sentence
2. Ask "why?" iteratively until you reach root cause (usually 3-5 whys)
3. Generalize: "What class of problem is this?" (not "Chrome 128 bug" but "browser default change breaking existing behavior")
4. Formulate as: "Next time I see [signal], I will [action]."
5. Name the signal: what specific observable tells you this pattern is active?

Entry Template

Scope: One entry per distinct root cause. Typical length: 4-8 sentences. If it takes >2 minutes to write, you're narrating events. If <30 seconds, you haven't gone deep enough.

## [Title: the pattern, not the event]

### Context
- What was I trying to do?
- What went wrong / what worked surprisingly well?

### Root Cause / Core Insight
- The underlying mechanism, not just the symptom

### The Pattern (transferable)
- Next time [similar situation], I will [specific action].
- Signal to recognize: [what observable tells me this pattern is active?]

### Related
- [entry-name](../path/to/related-entry.md)

Entry Types

All four types use the template above. The type determines which sections carry the most weight:

Type	When to Use	Emphasis	Example Title
Failure	Something broke, needed debugging, or required rework	Root Cause	"Config inheritance ≠ behavior inheritance across sessions"
Methodology	A repeatable process emerged from the work	Context / Pattern	"PPT → open-book exam study guide: three-layer structure"
Pattern Discovery	A reusable insight about tools, systems, or thinking	Pattern section	"PR description template: describe the gap, not the feature"
Capability Change	A measurable skill improvement	Context (before vs after)	"Git: from clone/push to independent PR with 12 commits"

Quality Checklist

Before finalizing a growth log entry:

• Does the title name the pattern, not the event?
• Is there a "Next time I will..." sentence?
• Is the "Signal to recognize" specific enough to trigger the pattern next time?
• Did I search existing entries for duplicates before writing? (Bole Principle)
• Is the root cause distinguished from the symptom?
• Are related memories cross-linked?
• Is the entry 4-8 sentences? Shorter = too shallow; longer = narrating events.

Anti-Patterns

• Avoid: "Fixed bug in payment module" (event, not pattern)
• Avoid: Copying the git commit message verbatim (commits describe what changed; logs extract why it matters)
• Avoid: Writing an entry for every commit (only when a pattern emerges)
• Avoid: Skipping the transferable sentence (without it, it's just a diary — this is non-negotiable)
• Avoid: Duplicating the same pattern under different titles (violates Bole Principle — search before writing)

Storage

Store entries wherever you keep notes. Common patterns:

• Markdown files in a growth-log/ directory (one file per day: YYYY-MM-DD.md)
• A dedicated section in Notion, Obsidian, or your note-taking app
• Plain text files with a consistent naming convention

Pick one convention and stick to it. Searchability matters more than format.

If You Use Delivery Gate

The delivery-gate Stop hook checks that learning files were modified today via filesystem timestamps. This skill teaches what to write — so the file that delivery-gate checks actually contains useful patterns, not empty timestamps.

Task completes → delivery-gate checks: was the learning file touched today?
  → Stale (no file modified): block — "what did you learn?"
  → Fresh (file touched): pass — this skill ensures the content is useful

Having enforcement without methodology → empty entries. Having methodology without enforcement → forgotten captures. Each is independently useful; together they close the loop.