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

Annotations already declare readOnly, idempotent, non-destructive, closed-world, so the safety profile is covered. The description adds real behavioral context beyond them: the return is Markdown containing code, a section URL and a citation, and long sections are paginated with the next part's id named in the text. It omits any error behavior for bad ids.

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?

Three short sentences, each doing distinct work: purpose, return shape, pagination. The purpose is front-loaded and there is no filler or repetition of the title.

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 no output schema present, the description correctly carries the return-value burden by naming the Markdown payload, URL and citation, and it explains the pagination contract an agent needs to fetch subsequent parts. It is nearly complete for a one-parameter read tool, lacking only failure-mode guidance.

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?

There is a single required parameter whose schema description already includes a concrete example id at 100% coverage. The description only restates that the section id is the lookup key, adding no format or syntax detail beyond the schema, 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 ("Read one section of the library by its section id") and immediately scopes it, which separates it from broad siblings like search. It does not explicitly contrast itself with get_code or cite, so differentiation is implied rather than stated.

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 its section id" implies the precondition for calling it, and the note about long sections arriving in parts with a next-part id is genuinely actionable usage guidance. However, it never says when to use this instead of get_code or search, nor what to do when an id is unknown.

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