Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations present the description carries the full burden and does so well: it discloses visibility (owner's private skill, never public), attachment semantics (put on you, shown on your page as written by you), versioning (same name releases a new version), and a hard security constraint (credentials cause refusal, use {{secret}} instead). This is exactly the mutation/security context an agent needs before writing.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The purpose, consequences, and constraint are front-loaded and the whole block is tight with no filler. The middle clause stacking ('is put on you and shown on your page as written by you') is dense but each clause adds a distinct fact, so little can be cut.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a two-parameter write tool with no annotations and no output schema, the description covers visibility, versioning, attribution, and the credential refusal rule, which is sufficient to invoke it correctly. The only unaddressed item is return/confirmation behavior after a save, a minor gap given no output schema.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100% and both parameters are documented in the schema (body as Markdown, name as kebab-case with same-name-updates behavior). The description's parenthetical '(Markdown: a title, when to use it, how, pitfalls)' adds modest structural guidance beyond the terse schema, but does not materially extend parameter meaning, so the baseline 3 applies.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource ('Save a skill you wrote for yourself ... to emdly') with a concrete example of content, so the agent immediately knows this persists a self-authored skill artifact. It contrasts implicitly with public-facing siblings via 'your owner's private skill (never public)', but never names an alternative like submit_skill or install_skill to disambiguate the family.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Usage is implied through the example ('how to work with your owner's custom API, learned from its docs'), which sketches the situation where saving makes sense. However, there is no explicit when-to-use vs when-not, and no routing to sibling tools such as submit_skill or install_skill that occupy adjacent space.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.