# Phase `json` — machine-readable output

**Mission.** Extend the `wc.py` from the previous phase with a `--json` mode, without regressing any
`wc`-phase behaviour. Single source of truth for this phase.

(The phase config gives the Builder `claude-opus-4-8` for this phase — an example of a per-phase
model override; the Adversary stays on the default model.)

## Definition of Done

- **D1 — json output.** `python wc.py --json FILE` prints a single JSON object:
  `{"lines": N, "words": N, "chars": N, "file": "FILE"}` (valid JSON, parseable by `json.loads`).
  With stdin (no FILE), `"file"` is `null`.
- **D2 — composes with flags.** `--json` honours `-l/-w/-c`: only the requested counts appear as keys
  (plus `file`). E.g. `wc.py --json -l FILE` → `{"lines": N, "file": "FILE"}`.
- **D3 — no regression.** Every `wc`-phase gate (D1–D4 there) still passes unchanged.
- **D4 — tests green.** `test_wc.py` is extended for the JSON cases and `pytest -q` is all-green.

## How the Adversary verifies (cold)

```bash
pytest -q                                              # D4 + D3 regression
printf 'a b c\nd e\n' > /tmp/f.txt
python wc.py --json /tmp/f.txt | python -c 'import sys,json; d=json.load(sys.stdin); \
  assert d=={"lines":2,"words":5,"chars":10,"file":"/tmp/f.txt"}, d; print("ok")'   # D1
python wc.py --json -l /tmp/f.txt                      # D2: expect {"lines": 2, "file": "/tmp/f.txt"}
```

The Builder restates the exact commands, expected JSON, and commit sha in
`machine-docs/STATUS-json.md`. When every DoD item has a fresh PASS in `machine-docs/REVIEW-json.md`
and there is no `## VETO`, the Builder writes `## DONE` to `STATUS-json.md` — this is the last phase,
so the watchdog then fires the one-shot `reporter` (see `agents.toml` `[loop].on_complete`).