Names the domain (Codex custom agents) and two actions (create and update), but doesn't list more granular capabilities like configuring specific TOML fields, validating agent configs, or managing agent properties.

Describes what it does (create and update custom agents via TOML files) but has no explicit 'Use when...' clause or equivalent trigger guidance, which per the rubric caps completeness at 2, and the 'what' is also fairly thin, placing this at 1.

Includes relevant terms like 'Codex', 'custom agents', and 'TOML files', but misses natural variations users might say such as 'agent configuration', 'agent setup', '.toml', or 'define an agent'.

The combination of 'Codex custom agents' and 'TOML files' is a very specific niche that is unlikely to conflict with other skills. The domain is narrow and clearly defined.

Generally efficient but has some redundancy—the 'Role file contract' section partially restates information already covered in 'Non-Negotiable Inputs', and the `nickname_candidates` requirements could be more tightly integrated. Some sections like the default policy are lean and well-scoped.

Provides fully executable shell commands with concrete flags and values, a ready-to-run JSON example call, specific file paths, and clear validation steps (tomlq). The commands section is copy-paste ready with both minimal and extended examples.

The workflow is clearly sequenced (collect inputs → resolve path → write file → validate → return example), includes a validation step (step 4: validate TOML parse and required keys), and the guardrails section provides error recovery guidance for common failure modes like unknown agent_type.

Content is well-organized into logical sections (overview, inputs, contract, defaults, workflow, commands, guardrails, references) with clear one-level-deep references to external docs and templates. The skill stays at an appropriate overview level without becoming monolithic.