Conciseness

Dense, high-signal content with zero explanation of concepts Claude already knows, and no filler hedging. Minor over-explanation remains: the "Why this shape" philosophy section and repeated restatements of the Verifier-dispatch rule (Critical rule 5, Flow→Verify, Sub-agents, Example 2) could be trimmed. Not level 5 because some rhetorical padding ("Freeze the obligations. Free the plan.") and rule repetition is trimmable; not level 3 because there is no genuinely unnecessary explanation.

Actionability

Fully executable guidance: a copy-paste script table ("python3 <skill-dir>/scripts/validate_plan.py <feature>"), a concrete artifact tree (.specs/features/<feature>/plan.md, checks.md, verification.md), three worked examples with numbered actions and results, and cause/solution troubleshooting. All named scripts and reference files exist in the bundle.

Workflow Clarity

Clear four-phase sequence (PLAN → CHECKS → BUILD → VERIFY diagram) with explicit validation checkpoints before each phase (validate_plan.py before presenting, validate_checks.py before building, check_commit.py before each commit, validate_verification.py before declaring done), a feedback loop for error recovery ("Read the script stderr, fix the artifact it named, and re-run the same command"), and a documented degraded path. Matches the level-5 anchor: clear sequence, explicit validation, error-recovery loops.

Progressive Disclosure

The body is an overview holding the pinned cross-phase rules, with each phase's full process one level deep in clearly signaled, verified-existing references (references/plan.md, checks.md, build.md, verify.md, memory.md — all present; reference files link only to siblings and one external URL, no deeper nesting). Scripts and fixtures live in scripts/. Content is appropriately split and easy to navigate.

Specificity

The description enumerates the full pipeline concretely: "one human-reviewed plan with EARS criteria, path, entities, interface and one-way doors, then proof-backed checks, then build, then an independent Verifier" — multiple specific actions with comprehensive coverage. It uses third-person voice throughout, so no person-voice penalty applies.

Completeness

Explicitly answers both what ("Spec-driven feature work that freezes obligations instead of the plan: ...") and when ("Use when the user says ...") with concrete trigger phrases, plus negative triggers ("Do NOT use for standalone design documents..."). This matches the level-5 anchor exactly; level 4 would require a less explicit 'when'.

Trigger Term Quality

Six explicit triggers ("tlc-spec-lean", "plan feature", "specify feature", "write the checks", "build this plan", "verify work") are phrases a user would naturally say. Not level 5: a few natural synonyms are missing (e.g. "write the spec", "spec out", "review my work"); not level 3 because coverage is genuinely good rather than partial.

Distinctiveness Conflict Risk

Clear niche (spec-driven feature workflow with independent Verifier), a unique skill-name trigger, and explicit exclusion of adjacent use cases ("standalone design documents unattached to a feature, architecture decomposition analysis, or work that already has a task list"). Minimal conflict risk.