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

Annotations already establish read-only, non-destructive, closed-world behavior. The description adds useful behavioral detail by disclosing the returned payload: full text with everything under it, URL, and revision. It does not explain invalid-id behavior, but the return scope is substantive for a read-only fetch.

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 a single dense sentence with no filler and front-loads the resource being fetched. Its grammar is slightly telegraphic, but every clause carries relevant information about input source, scope, and return fields.

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 simple one-parameter fetch tool with no output schema, the description supplies the important return fields and input source. It leaves gaps around error handling and sibling-tool distinction, but is otherwise sufficient to invoke the tool correctly.

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?

With one parameter at 0% schema description coverage, the description compensates by explaining that `id` comes from a prior search result and identifies a chapter or section. It does not specify the id format beyond what the schema type provides, but the critical origin and meaning are stated.

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 resource and scope: one chapter or section of the guide, selected by an id, returning full text, URL, and revision. This distinguishes it from search by noting the id comes from search results, but it does not clearly differentiate it from the `read` sibling.

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 phrase 'by the `id` search returned' implies this tool is used after a search call. However, there is no explicit guidance on when to choose `fetch` versus `read` or `index`, and no when-not-to-use conditions.

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