# AGENTS.md — `iftypeset` working rules

These instructions apply to the entire `iftypeset/` tree.

## Non‑negotiables (copyright + scope)

- Do **not** OCR/transcribe Chicago/Bringhurst into the repo. Rules are **paraphrases only** with **pointer refs** (e.g., `CMOS18 §6.2 p377 (scan p10)`).
- OCR is allowed only **ephemerally** (stdout or temp files deleted) to locate pointers.
- Prefer deterministic, measurable rules. If it can’t be automated, mark it as manual via `tags: ["manual_checklist=true"]` and ensure it lands in the checklist output.

## “Don’t lose work” operating practice

- Trust the filesystem, not the chat transcript.
- Use `./scripts/audit.sh` to capture current state.
- Use `./scripts/ci.sh` as the fastest sanity check.
- After meaningful changes, create a restore point: `./scripts/checkpoint.sh "short note"`.
- Checkpoints are recorded in `docs/CHECKPOINTS.md`.

## Session ID hygiene (required)

Codex CLI shows a `session_id` via `/status` (look for the `Session:` line). To prevent two terminals from sharing/overwriting one session state:

- Run `/status` at session start and copy the `Session:` value.
- When claiming a task in `docs/13-task-board.md`, include it in `owner` (example: `codex-cli (gpt-5.2) [sid: 019b…]`).
- Also include it in your row in `/root/docs/SESSION_STATE.md` (either in `who` or `notes`).
- If you ever see two live terminals with the same `session_id`, stop one and start a fresh session (new `session_id`).

Fallback (if `/status` is unavailable):

```bash
day_dir=/root/.codex/sessions/$(date -u +%Y/%m/%d)
latest=$(ls -1t "$day_dir"/rollout-*.jsonl | head -n 1)
python3 - <<'PY' "$latest"
import json,sys
print(json.loads(open(sys.argv[1]).readline())["payload"]["id"])
PY
```

If multiple sessions are active, run this immediately after starting your session so “latest” corresponds to your own launch.

## When adding rules

- Follow `spec/schema/rule.schema.json` strictly; run `PYTHONPATH=src python3 -m iftypeset.cli validate-spec --spec spec --build-indexes`.
- Keep `rule_text` short and paraphrased; never paste long passages.
- Prefer adding new batches (e.g., `v1_links_004.ndjson`) over editing old IDs; deprecate instead of mutating IDs.

## When changing code

- Keep dependencies minimal (currently `requirements.txt` is intentionally small).
- Update `app/CLI_SPEC.md` and `STATUS.md` when behavior or counts change.
- Ensure `./scripts/ci.sh` passes before handing off.

## Typography baseline (house default)

- Default body font size is `12pt` for reader-facing PDFs; do not go below `12pt` unless the profile description explicitly justifies it (e.g., slide decks, constrained one-page CVs).
- Prefer fixing density with margins/spacing/layout before shrinking type.