Conciseness

The body is lean (~65 lines), assumes Claude's competence, and pads nothing — but the opening line repeats the frontmatter description verbatim, "Keep...the approved active task as the source of truth" appears twice (Core rules and again after path selection), and the closing fallback partially restates the opening one. These are minor trims, matching anchor 4 rather than 5's "every token earns its place".

Actionability

Concrete, executable instructions for a router skill: exactly which files to read and in what order ("Read spec-loop-plan-task/SKILL.md and the files it requires"), an explicit two-way path choice, and concrete routing rules for out-of-scope work. Per the code-vs-instruction note, the absence of code is not penalized; the minor gap is that key mechanics (the "Implementation notes" check, the meaning of `review`) are named but defined only in referenced files, holding it at anchor 4 rather than 5.

Workflow Clarity

The sequence is coherent: precondition check with explicit fallback (no approved task → return to plan skill), ordered reading, explicit path selection, then the pre-completion "Implementation notes" check. Checkpoints are present but the gating check's content lives in a referenced file, and Core rules precede the Read/path-selection ordering a reader would follow — clear sequence with minor gaps, i.e. anchor 4, not 5's explicit in-body validation steps.

Progressive Disclosure

The structure is exactly what progressive disclosure wants: a lean SKILL.md that points to one-level-deep detail files, each reference clearly signaled with its stated purpose ("defines the route rules, when canonical task sections may change..." / "defines the active path mechanics..."). Scored against the actual bundle, however, none of the referenced files (implementation-flow-guidance.md, chat-only-path-guidance.md, task-file-path-guidance.md) exist in the skill directory, so navigation cannot be verified — good structure with a real gap, anchor 4 rather than 5.

Specificity

The description lists several specific governance areas — "implementation-time routing, canonical task updates, and the final review checkpoint" — rather than vague filler, though "governs" frames duties abstractly and it stops short of saying what routing or updates concretely involve. It fits anchor 4 (several specific actions, minor gaps) better than 3 (only 1-2 concrete actions) and falls short of 5's comprehensive action coverage.

Completeness

Both questions are explicitly answered: "when" via the concrete trigger "after execution approval for implementation work in an approved chat-only or task-file task", and "what" via the three named responsibilities. Anchor 4's weakness ("'when' could be more explicit or specific") does not apply here — the when-condition is maximally explicit — so it reaches anchor 5.

Trigger Term Quality

Relevant trigger phrases exist ("after execution approval", "implementation work", "review checkpoint") but the vocabulary is internal spec-loop jargon ("chat-only or task-file task", "canonical task updates") with no natural synonyms a user would say (e.g. "build it", "start coding", "go ahead"). This matches anchor 3 — some relevant keywords, missing common variations — rather than 4, since natural user phrasings are largely absent.

Distinctiveness Conflict Risk

The trigger carves a clear niche (post-approval implementation phase of a spec-loop), so it is unlikely to fire for unrelated skills. Minor overlap risk remains with sibling bundle skills (spec-loop-plan-task, spec-loop-clarify-task) whose state-based triggers could be confused at boundaries, matching anchor 4 rather than 5's "minimal conflict risk".