Conciseness

The body assumes Claude's competence — no concept explanations, just procedure — but it is noticeably repetitive: the glob-artifact rules appear in step 2, again as step 4's dense five-item subprocedure, again in Guardrails ("never write to a glob `resolvedOutputPath`… Do not advance the build frontier"), and again in Output. This fits anchor 3 ("mostly efficient but… could be tightened") better than anchor 4: the repetition goes beyond minor over-explanation.

Actionability

Fully executable guidance: concrete commands (`openspec status --change "<name>" --json`, `openspec instructions "<artifact-id>" --change "<name>" --json`, `openspec list --json`, `openspec store list --json`), the exact JSON fields to read (`root`, `existingOutputPaths`, `lastModified`, `isPlanningComplete`), copy-ready announce strings ("Using change: <name>"), and fail-if-exists create semantics. Not below 5: for an instruction-only skill this is copy-paste-ready procedural guidance covering the common cases.

Workflow Clarity

Six clearly sequenced steps with explicit validation checkpoints and feedback loops: a root check before any write, non-zero-exit-as-data guidance ("read the JSON instead of retrying"), user confirmation before every write, refresh-and-recheck immediately before creating a glob file, and stop-and-reconcile behavior when a check fails. This matches the anchor-5 example of a sequence with explicit validation and error-recovery loops.

Progressive Disclosure

No bundle files exist (no references/, scripts/, or assets/), and the body needs none — it is organized into well-labeled sections (Store selection, Project check, Input, Steps, Output, Guardrails) with cross-skill pointers rather than nested file references. Not 5: the five-item glob-artifact subprocedure inside step 4 inlines dense conditional detail that could be lifted into its own subsection or a reference file, which is a minor organization gap matching anchor 4.

Specificity

The description lists several concrete, domain-anchored actions ("revising its existing planning artifacts and keeping them coherent", "fold new decisions into it", "reconcile its artifacts after an edit") plus an explicit boundary ("Never edits code"). It sits between anchors 4 and 5: the actions are overlapping variations of one core operation rather than a comprehensive set of distinct capabilities, so anchor 4 ("several specific actions; minor gaps") is the closest fit, not 5's comprehensive coverage.

Completeness

It explicitly answers both questions: what ("Update an OpenSpec change by revising its existing planning artifacts and keeping them coherent with one another… Never edits code") and when ("Use when the user wants to revise a change's plan, fold new decisions into it, or reconcile its artifacts after an edit. Also use when the user says 'openspec update change' or 'opsx update'"). This matches the anchor-5 pattern of concrete what + explicit trigger phrases; anchor 4 would require the when to be less explicit or specific.

Trigger Term Quality

It includes literal phrases a user would naturally say — "openspec update change", "opsx update", "revise a change's plan", "reconcile its artifacts" — giving good keyword coverage. Not 5 because a few natural synonyms are absent (e.g., "edit the plan", "update the spec", "make the plan consistent"); not 3 because the terms present are specific and varied rather than generic.

Distinctiveness Conflict Risk

The niche is clear (updating an OpenSpec change's planning artifacts) and the description actively defuses the one real collision — the `openspec update` CLI command — with explicit routing ("If the user means the openspec update CLI command… run that command instead"). Third-person voice is used throughout, so no voice penalty applies; conflict risk with sibling OpenSpec skills is minimal.