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

Annotations already declare readOnly, idempotent, non-destructive, closed-world, so safety is covered. The description adds genuinely new behavioral context: the body is Markdown, 'see_also' chains to further slugs, and 'sha256' lets the caller verify the content read. It stops short of mentioning error behavior for a bad slug.

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?

A single dense sentence front-loads the operation and key, then uses two short clauses for the return contract. No filler and nothing that could be cut without losing meaning.

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?

One required parameter, full schema coverage, an output schema in place, and annotations covering the safety profile. The description supplements the output schema with the chaining hint (see_also) and verification hint (sha256), leaving nothing an agent needs to invoke it 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?

Schema coverage is 100% and the single parameter is already documented with an example, so the baseline is 3. The description adds provenance meaning ('from about or search_library') that the schema does not convey, telling the agent where a valid slug comes from.

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 ('Read one topic of the manual in full') plus the lookup key ('by its slug'), which cleanly separates it from sibling search_library and about. An agent can identify the operation without opening the 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?

Names the source of the required slug ('from about or search_library'), which implicitly tells the agent this tool is the follow-up step after those two. It does not state when-not to use it or what to do if the slug is unknown, so it stops short of full routing guidance.

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