# Phase `wc` — a word-count CLI

**Mission.** Build a small, dependency-free `wc` clone in Python: a script `wc.py` in the work repo
that counts lines, words, and characters, plus a `pytest` suite. This is the single source of truth
for the phase — the Builder builds to the Definition of Done below; the Adversary cold-verifies it.

This task is deliberately tiny and fully local (no network, no services) so the example exercises the
loop-pair *protocol* — claim → cold-verify → PASS/FAIL handshake — not infrastructure.

## Definition of Done

Each Dn is an independent gate. The Builder claims it (`claim(Dn): …`); the Adversary records a fresh
PASS in `machine-docs/REVIEW-wc.md` after re-running the check from its own clone.

- **D1 — default output.** `python wc.py FILE` prints exactly `<lines> <words> <chars> <FILE>`
  (counts whitespace-separated words, `\n`-terminated lines, and bytes for `chars`), matching GNU
  `wc` on ASCII input.
- **D2 — flags.** `-l`, `-w`, `-c` restrict the output to that single count (e.g. `wc.py -l FILE`
  prints `<lines> <FILE>`). Flags may combine; output order is lines, words, chars.
- **D3 — stdin.** With no FILE argument, `wc.py` reads stdin and prints the counts with no filename.
- **D4 — tests green.** A `test_wc.py` runs under `pytest -q` with **0 failures**, covering: an empty
  file (`0 0 0`), a multi-line fixture, the no-trailing-newline case, and each flag.

## How the Adversary verifies (cold)

From a fresh clone of the work repo:

```bash
pytest -q                                  # D4: must be all-green
printf 'a b c\nd e\n' > /tmp/f.txt
python wc.py /tmp/f.txt                     # D1: expect "2 5 10 /tmp/f.txt"
python wc.py -l /tmp/f.txt                  # D2: expect "2 /tmp/f.txt"
printf 'a b c\nd e\n' | python wc.py        # D3: expect "2 5 10"
```

Expected outputs are above — the Builder must restate them (and the exact commands, plus the commit
sha) in `machine-docs/STATUS-wc.md` so the Adversary can re-run without reading the Builder's
reasoning. Any mismatch is a FAIL with repro steps in `machine-docs/REVIEW-wc.md`.

## Out of scope (defer to a later phase or DEFERRED.md)

Multibyte/`-m` char counting, `--files0-from`, multiple-file totals, locale handling. JSON output is
the next phase (`plans/json.md`).