Conciseness

The body is dense and project-specific with no padding: every line carries Vibe-specific conventions, and the few rationales ('Pytest displays docstrings instead of node IDs when present, which hurts', 'flake on loaded CI runners') are single clauses that earn their place. No section explains concepts Claude already knows, matching the lean anchor-5 example.

Actionability

Guidance is fully concrete and executable: exact paths and naming ('tests/stubs/', 'Fake*'), specific tools and marks (respx, '@pytest.mark.asyncio'), named fixtures ('config_dir', 'tmp_working_directory'), and copy-paste-ready commands ('uv run ruff format .', 'uv run pytest tests/app_server/backend_contract', 'uv run pyright'). This is actionable instruction-only guidance at the anchor-5 level.

Workflow Clarity

The refactor workflow is a clear numbered 1-5 sequence, and the Verification section sequences explicit validation commands with conditional checkpoints (run 'uv run pyright' when signatures/models/protocols change; run the backend contract suite after adapter or fixture changes). It is not 4 because validation is explicit and condition-gated rather than having minor gaps.

Progressive Disclosure

Sections are well-organized (principle, boundaries table, fakes-vs-mocks, workflow, test shape, avoid, verification) with no nested references. It is not 5 because the ~80-line body inlines several area-specific conventions (Windows CI requirements, per-area boundary details) that could live in reference files, and the only external pointer ('see vibe/cli-rust/AGENTS.md') is buried in a table cell rather than clearly signaled.

Specificity

The description lists multiple specific concrete actions — 'adding behavior coverage', 'testing ports/adapters', 'replacing brittle mocks', 'creating fakes', 'adding characterization tests' — giving comprehensive coverage of the test-writing task space. It is not 4 because the gaps are negligible; it is not below 5 since every listed action is concrete rather than generic.

Completeness

It explicitly answers both 'what' ('Write or refactor Mistral Vibe tests with proper decoupling') and 'when' via a concrete 'Use when...' clause enumerating triggers and target directories. This matches the anchor-5 example structure exactly, so neither 4 nor below fits.

Trigger Term Quality

Good keyword coverage with natural developer phrases ('brittle mocks', 'fakes', 'characterization tests', 'behavior coverage', 'refactors') plus many module names (config, sessions, hooks, MCP). It is not 5 because common variations like 'unit tests', 'test doubles', or 'flaky tests' are missing; it is above 3 because the natural-term coverage is broad, not partial.

Distinctiveness Conflict Risk

Scoping to 'Mistral Vibe tests' and specific test areas under tests/ creates a clear niche with distinct triggers, minimizing conflict with generic testing skills. It is not 4 because the project-specific scoping leaves only minimal overlap risk.