Napkin is the durable runbook for this repo and this user. It is not session memory and not generalized reusable learning.
Session start
- Read
.sandbox/napkin.mdif it exists and apply it silently. - If it does not exist, do nothing unless the session uncovers something worth keeping.
- Do not treat curation as ritual. Clean it up only when you add to it or when noise is getting in the way.
What belongs
Add a note only if it is likely to matter again:
- repo-specific gotcha or toolchain trap
- recurring user preference
- non-obvious tactic that repeatedly saves time
- stable workflow guidance not already covered by the prompt,
AGENTS.md, or task docs
What stays out
Do not put these in napkin:
- session timelines, handoffs, or current task status
- long transcripts or postmortems
- generic rules already covered elsewhere
- one-off facts with no likely reuse
- notes without a concrete action
Note shape
Keep notes short, standalone, and actionable.
1. **[YYYY-MM-DD] Short rule**
Do instead: concrete repeatable action.
Use categories only if they help. Do not invent structure for its own sake.
If you create a new file, start with:
# Napkin Runbook
## Repo Guardrails
1. **[YYYY-MM-DD] Short rule**
Do instead: concrete repeatable action.
## User Directives
1. **[YYYY-MM-DD] Preference**
Do instead: exact behavior.
Curation
If you touch napkin, prune aggressively:
- merge duplicates
- delete stale, weak, or obvious notes
- delete notes that duplicate the prompt,
AGENTS.md, or task docs - prefer a few high-signal notes over broad coverage
- move task-specific material to the
journal - move broadly reusable lessons to the reusable-learning flow
Example
1. **[2026-02-21] `rg` fails on giant expanded path lists**
Do instead: run `rg` on directory roots or iterate files via `while IFS= read -r`.