feat(skills): writing-criteria, one source for runnable criteria (order 7c)

A brief success criterion and a plan's Verify, Regression, End-to-end and
Verification lines are each one command the criteria runner accepts, written
as the line's first backticked span; anything more is bash tests/<name>.sh,
and each must be able to go red (the runner reads the exit code only).

- skills/writing-criteria/SKILL.md (S1 form), with Runs:/Refused:/Never red:
  examples that a pin runs through the criteria runner
- brief-reviewer and plan-critic preload writing-criteria and
  reviewing-adversarially (S3 + S4); the copied runner rules leave them, the
  two templates and /trekplan, which names the skill where the plan is written
  and where its three reviewers start
- eval cases 3 fire / 2 quiet / 1 effect; tests/lib/skills-criteria-prose-pins
- review-630 @~1 pin follows the text into the skill; trekplan-stats line_ref
  re-measured

Baseline without the skill: 24 of 27 written checks refused by the runner,
and 0 of 3 reviewers saw that git status/git log can never go red. With it:
0 of 27 refused, 3 of 3 reviewers flagged both.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

commands/trekplan.md

@@ -444,9 +444,14 @@ unchanged since /trekbrief's review"), and continue to Phase 5. Exit 1
 pass, or a brief from another producer) or 2 (could not run): review it as
 below (operator decision 2026-10-08).
 
-Launch the **brief-reviewer** agent:
+Launch the **brief-reviewer** agent. It has `voyage:writing-criteria` and
+`voyage:reviewing-adversarially` preloaded through its `skills:` line; name
+both in the prompt anyway, so the rules hold even where preloading did not
+happen.
 Prompt: "Review this task brief for quality: {brief_path}. Check completeness,
 consistency, testability, scope clarity, and research-plan validity.
+Follow the writing-criteria skill (each success criterion is one command the
+criteria runner accepts, and it can go red) and the reviewing-adversarially skill.
 Read local files only inside the repo under exploration, plus paths this prompt gives you (the brief, the plan, and templates it names)."
 
 Handle the verdict:
@@ -709,7 +714,7 @@ Do NOT write this synthesis to disk. It is internal working context only.
 >
 > **Two step rules at every plan_version** (no version bump; a plan without
 > the field is unchanged): the optional `Regression:` field (K10) holds ONE
-> backticked command the criteria runner allows, with no pipe and no `&&` —
+> backticked command the criteria runner accepts (`voyage:writing-criteria`) —
 > usually `npm test`, the suite the step must not break. `Verify:` stays the
 > step's own test, the one that is red first; `Regression:` is what the
 > executor runs green before the checkpoint, so a step whose red test is a
@@ -824,24 +829,13 @@ Write the plan following the template structure. The plan MUST include:
      npm test
      node --test tests/lib/x.test.mjs
      ```
-   The command must also be one the criteria runner is allowed to run: a test
-   runner (`npm test`, `npm run <script>`, `node --test <file>`, `vitest`,
-   `jest`, `pytest`, `python -m pytest`, `uv run pytest`, `cargo test`,
-   `go test`, `make test`), `bash <script under tests/>` (also
-   `/bin/bash <script under tests/>`, to pin the system shell), or a read-only
-   `git` subcommand (`status`, `log`, `diff`, `show`, `ls-files` — not `git
-   grep`) — with no pipe, redirect or `&&`. It runs with no shell: its words
-   reach the runner as written, so a word with a quote, backslash, `$`,
-   brace, or a leading `~` or `@` is refused (a git revision such as `@~1`
-   is the one exception), a glob only reaches
-   `node --test` on Node 21 and later (which expands its own patterns), no
-   path climbs out with `..` or starts at `/` (git included), each runner
-   takes a short list of read-only options, and nothing may follow
-   `make test`. A trailing `# comment` is dropped, on a line of a shell fence and in a backticked command alike;
-   in a backticked command it may not hold a quote, `$`, backtick or backslash (the executor passes the
-   span on inside double quotes), and such a comment is refused, not dropped. Anything else is reported NOT
-   RUN, never executed and never failed. A check that needs more than that is
-   wrapped in a script under `tests/` and declared as `bash tests/<script>.sh`.
+   Each command is written by the `voyage:writing-criteria` skill (use it by
+   name before you write this section and the steps' `Verify:`, `Regression:`
+   and `End-to-end:` lines): one command the criteria runner accepts, in plain
+   words, a script under `tests/` (`bash tests/<script>.sh`) for anything
+   more, and a command that can go red. Anything the runner refuses is
+   reported NOT RUN, never executed and never failed, and an unrunnable plan
+   criterion stops `/trekexecute` Phase 7.
 9. **Estimated Scope** — File counts and complexity rating.
 
 ### Quality standards
@@ -962,11 +956,20 @@ Then launch two review agents **in parallel — emit both Agent tool calls in a
 single assistant message turn** (same pattern as Phase 5 exploration). They
 have zero data dependencies; serializing them wastes 30–60 seconds per run.
 
+Both reviewers are asked for `voyage:writing-criteria` and
+`voyage:reviewing-adversarially` by name. `plan-critic` has both preloaded;
+`scope-guardian` has `voyage:reviewing-adversarially` preloaded and gets the
+writing-criteria rule in one sentence in its prompt, for the brief's criteria
+it traces into `## Verification`.
+
 **plan-critic** — adversarial review of the plan.
 Prompt: "Review this implementation plan for the task: {task}.
 Plan file: {plan path}. Read it and find every problem — missing steps,
 wrong ordering, fragile assumptions, missing error handling, scope creep,
 underspecified steps. Rate each finding as blocker, major, or minor.
+Follow the writing-criteria skill (every check is one command the criteria
+runner accepts, and one that can never go red is a finding) and the
+reviewing-adversarially skill.
 End your response with the REQUIRED machine-readable `json` findings block
 (schema in `agents/plan-critic.md`) so the orchestrator can pipe it to the
 dedup helper. You have no Write tool — return the block inline, do not write a file.
@@ -980,7 +983,10 @@ Task: {task}. Brief file: {brief_path}. Plan file: {plan path}.
 Find scope creep (plan does more than the brief requires) and scope gaps
 (plan misses brief requirements). Check that referenced files and functions
 exist. Verify that every Success Criterion in the brief is covered by the
-plan's Verification section. End your response with the REQUIRED machine-readable
+plan's Verification section. Follow the writing-criteria skill for those
+criteria (each is one command the criteria runner accepts, and it can go red)
+and the reviewing-adversarially skill.
+End your response with the REQUIRED machine-readable
 `json` findings block (schema in `agents/scope-guardian.md`). You have no Write
 tool — return the block inline, do not write a file.
 Read local files only inside the repo under exploration, plus paths this prompt gives you (the brief, the plan, and templates it names)."