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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It clearly states the tool does not write files, that the returned path in the reply is where installation should happen, and that installed skills become available without restarting. It doesn't mention permissions or error behavior, but the core behavioral constraints are disclosed beyond what any schema/annotation provides.

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 description is three sentences and front-loaded with the main action and resource, followed by the critical constraint that the tool cannot write files. Every sentence earns its place. A small amount of redundancy exists with the schema for the slug mention, but the sentence referencing list_skills is useful usage guidance, so no significant waste.

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 single-parameter read-like tool with no output schema, the description covers what the tool does, what the caller must do with the result, the path detail, the side effect of installation, and the source for the parameter value. No critical information an agent needs to call it correctly is missing.

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%: the slug parameter is fully described as 'The skill's slug, as returned by list_skills.' The description adds that slugs come from list_skills, which matches the schema. Since the schema already documents all parameter semantics, the baseline of 3 is appropriate; no additional parameter-level detail is needed.

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?

The description states a specific verb and resource ('Fetch one of this workspace's skills as a SKILL.md file'), and clarifies it returns file contents rather than installing anything. It also distinguishes itself from list_skills by explaining the relationship, so an agent can differentiate this getter from the sibling list tool without opening schemas.

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?

The description explicitly explains when to use this tool: to fetch a skill as an installable SKILL.md file, and it gives the follow-up action (write the file yourself, since the tool cannot write files). It also names list_skills as the source for available slugs, providing the alternative and prerequisite in one sentence.

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