Lean, imperative body that assumes Claude's competence — it never explains what threat modeling, trust boundaries, or assets are. Minor asset-list redundancy between steps 2 and 3 keeps it from being flawless, but every section earns its place.

Concrete, specific instructional guidance throughout: a defined 8-step process, a literal output filename pattern (`<repo-or-dir-name>-threat-model.md`), qualitative low/medium/high scales, and a verbatim output contract in the referenced prompt template — actionable without needing code.

Clear numbered sequence with explicit validation checkpoints: step 6 pauses for user feedback before finalizing, and step 8 is a pre-finalization quality-check checklist with feedback/retry semantics for error recovery.

The body is an overview pointing to two real, one-level-deep reference files (`references/prompt-template.md`, `references/security-controls-and-assets.md`), clearly signaled in a References section with a 'Only load the reference files you need' directive — easy navigation, no deep nesting.

Lists multiple concrete actions — 'enumerates trust boundaries, assets, attacker capabilities, abuse paths, and mitigations, and writes a concise Markdown threat model' — matching the level-3 anchor of multiple specific concrete actions.

Explicitly answers both what (enumerates boundaries/assets/abuse paths/mitigations, writes a Markdown threat model) and when ('Use when the user asks to threat model a codebase or path...'), with an explicit 'Do NOT use for...' exclusion clause.

Natural user phrasing is well covered: 'threat model a codebase or path', 'enumerate threats or abuse paths', 'AppSec threat modeling' — terms a user would actually say.

Clear niche with distinct triggers; it explicitly differentiates from sibling skills ('Do NOT use for... security best practices (use security-best-practices)... code review... non-security design work'), making wrong-skill conflict unlikely.