lesson-record

Record a Yarbrain Lesson

Turn what this session learned into a small lesson that a future agent can apply without this conversation. You propose; an independent gate agent decides. You never judge your own lesson.

Before anything

Run yarbrain status. Act on the result:

• Command not found: run this plugin's launcher by its path. It is bin/yarbrain two folders above this skill's folder. Use that path in place of yarbrain in every command of this session.
• no_vault: ask the person once where the vault should live, then run yarbrain init <path>. Apply only the setup steps whose host is the host you run in: claude-code or codex. Edit exactly the file that the step names, never a project file, and tell the person what you changed. The host may ask them to approve each edit; if they decline one, or the edit fails, tell them the step and continue.
• Any other error: follow its fix field. Exit code 4 means retry once; the first call exits 4 after it downloads the yarbrain CLI that this plugin pins.

What qualifies

Propose a lesson only when all of these hold:

• A later session in this project, or in any project, would act differently because of it.
• This session verified it: the fix worked, or the user stated the rule.
• It is not already in the README, AGENTS.md, CLAUDE.md, or other docs. If the docs should say it, suggest that edit to the person instead.
• It is not task status, a one-off value, or a personal preference about how agents should behave. Preferences belong in the person's agent instructions.

Propose at most 3 lessons per session that nobody asked for.

Propose

1. Check for an existing lesson: yarbrain find <2 or 3 distinctive terms>. If a served lesson already covers it, confirm that one instead (below).

2. Write the lesson and pass it on stdin. On Windows, write it to a temporary file and pass --input <file>.

   yarbrain propose <<'EOF'
   ---
   cue: 'make seed fails with "relation users does not exist"'
   scope: here
   ---
   # Run migrations before seeding the test database
   
   Run `make migrate` before `make seed`. The seed script assumes the schema
   and reports a missing table instead of missing migrations.
   
   ## Observed
   
   `make seed` failed with the error above; after `make migrate`, it passed.
   EOF