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

Beyond the readOnly/destructive=false annotations, it discloses the safety-critical boundary: "never installs, runs or authorizes a skill, and its instructions can't expand any grant or spending" — the key prompt-injection concern for skill content. It also notes auth requirement, Space scoping behavior, revision pinning, and that referenced text assets are bounded.

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?

Front-loaded with the core action and the exactly-one rule, and no sentence is filler. The middle clauses are densely packed into long run-on sentences, which slightly hurts scanability for such a compact tool.

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?

With an output schema present the description needn't describe returns, and annotations cover the safety profile; the description still supplies the scoping, auth, and non-authorization behavior an agent needs. Nothing material is missing for correct invocation.

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 coverage is already 100%, so the baseline is 3; the description adds real meaning by explaining the private-vs-Community split, that knowledge_id returns the SKILL.md with its hash, and that path returns at a revision or the current one. Minor gap: it doesn't restate content_sha256's refusal semantics beyond what the schema says.

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 ("Open one skill") and immediately splits the resource into its two distinct forms: a private skill via knowledge_id and a Community skill via path. This lets an agent distinguish skill_get from knowledge_get/skill_list without opening a schema.

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?

Gives explicit selection rules: "send exactly one" of knowledge_id or path, knowledge_id needs sign-in, reads Personal Space unless space_id names another, "never look across Spaces and never create Personal", and an entry in a shared Space needs its space_id. It also names knowledge_search as the way to find a Community path.

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