Conciseness

The body is dense with tool-specific guidance (NVM resolution sequence, installer placement policy, OPSX workflow) and avoids explaining concepts Claude already knows, but the NVM section restates its own code twice — 'Do not conclude that OpenSpec is unavailable merely because it is absent from the initial PATH' repeats what the resolution sequence already demonstrates — and the symlink path explanation appears in two sections. Not level 5 because every token does not earn its place; not level 3 because the padding is isolated to a few sentences rather than whole sections.

Actionability

Provides copy-paste bash for NVM resolution, installer invocation, and CLI state/validation commands ('openspec list', 'openspec validate --all'), plus a fallback ('perform the same workflow directly in files under openspec/changes/<change>/') for tools without slash commands. Not level 5 because several workflow steps remain directive rather than executable ('Explore unclear requirements before creating artifacts', 'Review and refine proposal.md, delta specs, design.md, and tasks.md') with no examples of well-formed artifacts.

Workflow Clarity

The Default Workflow is a clear six-step sequence (explore, propose, review, apply tasks one at a time, verify against proposal/specs/design/tasks, sync and archive) with explicit validation mandated in Artifact Standards ('Run OpenSpec validation and the repository's canonical validation before claiming completion'). Not level 5 because there is no error-recovery feedback loop (nothing says what to do when validation fails or a task check reveals a defect); not level 3 because checkpoints are explicit rather than implicit.

Progressive Disclosure

The single bundle file (scripts/install-openspec) is appropriately externalized and the ~107-line body is organized into clear, well-scoped sections with no content that clearly belongs in a separate file. Not level 5 because the installer is referenced via the shared '~/.agents/skills/openspec/scripts/install-openspec' path rather than a clearly signaled relative bundle path, and the machine-specific NVM detail could live in a reference file.

Specificity

The description names the domain ('Spec-driven development with OpenSpec') and one or two actions ('structured planning'), which matches the anchor for a named domain with 1-2 concrete actions. Not level 4 because it never lists several specific actions the skill performs (proposing changes, generating delta specs, applying task lists, archiving) — 'change proposals' and 'delta specs' appear only as trigger nouns; not level 2 because it is tied to a specific tool and methodology rather than generic language.

Completeness

Both questions are answered explicitly: 'what' via 'Spec-driven development with OpenSpec' and 'when' via a fully enumerated 'Use when the user mentions...' clause with concrete trigger phrases. Not level 4 because the 'when' is already maximally explicit and specific, so the level-4 anchor ('when could be more explicit or specific') does not fit.

Trigger Term Quality

Coverage is comprehensive with synonyms and abbreviations: 'OpenSpec', 'OPSX', 'spec-driven development', 'SDD', plus artifact-level terms ('change proposals', 'delta specs', '/opsx commands') and intent phrases ('structured planning for features, migrations, refactors, or bug fixes'). Not level 4 because no natural term a user would say for this skill is missing — the product name, its alias, the methodology, and its abbreviation are all present.

Distinctiveness Conflict Risk

The tool-specific triggers (OpenSpec, OPSX, SDD, delta specs) carve out a clear niche with minimal conflict risk. Not level 5 because the intent clause 'or wants structured planning for features, migrations, refactors, or bug fixes' is broad enough to fire on generic planning requests that overlap with general planning or spec-writing skills; not level 3 because the primary triggers are unambiguously tied to one tool.