---
name: skill-training
description: Improve skills from real corrections and develop expertise in new domains. Use for repeated mistakes, learning how to learn, transferring procedures across tools, and verifying that learned behavior persists. Separate source reading from tested competence.
---

# skill-training

For developing expertise in a new domain or improving the learning process itself,
read [learning-transfer.md](references/learning-transfer.md). It separates source
coverage, procedural change, held-out performance, cross-domain transfer and retention.

A skill that is never updated from real runs decays: the world moves and the
file does not. The correction the user just made is the training data, and it
is gone the moment this session closes.

## When this fires

The user edited the output before using it. Or rejected it. Or said "not like
that." Or fixed the same thing twice. That is the signal, and it is easy to
miss because the work still got done.

## The loop

1. **Name the delta.** What did the output say, what did the user change it
   to, and what is the difference in one sentence. Not the diff. The rule
   behind the diff.
2. **Ask which kind it is.** Three answers, and the user picks:
   - **Persist.** Always do it this way from now on.
   - **One-off.** This case was special, change nothing.
   - **Always ask.** Put a question in the skill at this point.
   Guessing here is how a skill acquires rules nobody wanted.
   If the user has already explicitly said to persist the lesson, use that answer;
   do not ask them to repeat it.
3. **Edit the skill file**, not the output. Fixing the artifact solves today.
   Fixing the file solves the next twenty.
4. **Append a dated changelog line** to the skill saying what changed and
   what prompted it. A rule whose reason is lost gets removed by whoever
   finds it unconvincing.
5. **Verify the edit landed.** Read the file back and confirm the new text is
   there. A stale string match fails silently, and a change you reported but
   never applied is worse than no change, because it stops both of you from
   ever looking at that spot again.

## Anchor the rule to its incident

A constraint carrying only a rationale gets raised by the next person who
disagrees with the rationale. A constraint carrying what actually happened
does not. Write the observation, not the reasoning.

## Where the lesson goes

Not everything belongs in the skill.

- **A reusable judgment** goes in the skill, or in a rule under
  `~/.claude/rules/` when it spans skills.
- **A repeatable mechanical failure** becomes a test next to the code. A
  paragraph does not fail CI.
- **A fact about the user, a project or a person** goes in the second brain,
  not in the skill. Skills hold instructions. Files hold facts.

If a correction produces none of those, it was a typo. Fix it and move on.

## Keep the skill short

Every training pass wants to add a line. Length is what stops a skill being
obeyed, so a pass that adds should also look for what the addition makes
redundant.

Training note, 2026-09-23: domain learning must improve and test the reusable learning
method too. Added a transfer protocol and explicit absolute-readiness requirements;
the protocol itself remains subject to comparative evaluation.

Training note, 2026-09-23: repeated corrections produced notes while the requested
workflow stayed unfinished. Apply the behavioral correction to the active work
before reporting it learned. Answer status questions briefly and continue authorized
work; a saved lesson is not completion. If a hook claims no durable change after a
verified edit, inspect its accounting instead of generating duplicate notes.