handbooks/README.md

# Handbooks

Instance-agnostic reference material for coding agents — the verbose, citable kind that belongs in
a retrieval store, not in a skill.

## What goes here

- Public standards, style guides, and conventions that apply regardless of which box or project is
  running — general git operations, language style guides, CERT/MISRA-style rulebooks.
- Long-form and specific. A handbook can be as detailed as it needs to be; nothing here is loaded
  into a model's context wholesale, so length carries no per-turn tax.

## What does not go here

- **Anything specific to one machine or one project.** A local Gitea's branch-naming rule, this
  box's PR checklist — that's instance-bound and belongs in that project's own KB corpus instead
  (the `engineering` corpus, for
  [halogen](https://git.novoyuuparosk.org/mikkeli/halogen-workstation-roadmap)).
- **Short, prescriptive procedures achievable within a context window or two.** That's a skill, not
  a handbook — it gets loaded, not retrieved. See `skills/` in the halogen-workstation-roadmap repo
  for the sibling convention.
- **The retrieval store itself.** This repo holds the source-of-truth markdown a human has vouched
  for. The chunked, embedded index built from it is derived and rebuildable state — it lives beside
  whichever KB is consuming it, never committed here.

## Format

One markdown file per topic at the repo root. Each file should stand as a single admittable
document — the same shape a human vouches for at KB admission time.

Each file opens with a small flat YAML frontmatter block — `title` and `collections` only, no nested
structure, so it stays greppable without a YAML dependency (same reasoning `index.py` itself gives
for hand-parsing `corpora.yaml`):

```yaml
---
title: Git operations
collections: [handbooks, dev-practice]
---
```

`title` and `collections` are the two ingest-time values that are actually about the document, so
they live with it instead of being retyped by hand at admission time — that's what let `--collection
dev-practice` and an actual admission of `handbooks` drift apart on 2026-08-22, silently, until it was
noticed by inspection rather than by anything catching it.

`version` is deliberately **not** a frontmatter field — a file can't contain the hash of the commit
that writes it, the same self-reference problem any `__COMMIT__` build stamp runs into. It stays a
value computed at admission time, same as before, just scoped to the file rather than the whole repo.

## Ingesting a handbook

Markdown needs no conversion and no extraction verifier — admit it straight from this repo, reading
`title`/`collections` from the frontmatter instead of retyping them:

```bash
F=~/dev/handbooks/git-operations.md
TITLE=$(sed -n '/^---$/,/^---$/{/^title:/s/^title:[[:space:]]*//p}' "$F")
COLLECTIONS=$(sed -n '/^---$/,/^---$/{/^collections:/s/^collections:[[:space:]]*//p}' "$F" \
  | tr -d '[]' | tr ',' '\n' | sed 's/^ *//;s/ *$//')
VERSION=$(git -C ~/dev/handbooks log -1 --format=%h -- "$F")

index.py admit "$F" --corpus engineering --vouch mikkeli \
  --title "$TITLE" --version "$VERSION" \
  $(for c in $COLLECTIONS; do printf -- '--collection %s ' "$c"; done)
```

⚠ **`--version` is the last commit that touched *this file*, not the repo's `HEAD`.** A whole-repo
`HEAD` pin would bump every handbook's recorded version on any unrelated edit, even one that never
touched this document — the per-file form is what actually answers "which revision does this chunk
reflect."

⚠ **Re-admitting replaces a document outright, with no version history kept.** The `--version` pin is
the only record of which revision a chunk reflects, which is also why editing a file here does not by
itself update the corpus — re-admission is deliberate, a fresh claim about a specific version of a
document, not something that should happen automatically on every commit.

## Status

Started 2026-08-21. First handbook, `git-operations.md`, composed 2026-08-21 – 2026-08-22: branching,
committing, merging vs. rebasing, reverting and undoing, remotes and collaboration, tags and releases.
Confirmed ingestible 2026-08-22 — 30 chunks, heading paths intact, retrieved correctly.

Second handbook, `failure-handling.md`, composed 2026-08-22: input contract discipline, failure-
propagation discipline. Environment/verification parity was scoped out of it deliberately — a
different axis (how confidence is established, not how code behaves), queued as a handbook of its
own rather than folded in.

Frontmatter (`title`, `collections`) added to both 2026-08-22, after `--collection dev-practice` in
this file's own recipe was found to have drifted from `handbooks`, the value actually used at
admission — the two ingest-time values that describe the document now live with it instead of being
retyped by hand.