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

Annotations already cover the safety profile (readOnly, idempotent, closed-world, non-destructive), so the bar is lower. The description still adds useful behavior: results are ranked by relevance, capped by 'limit', and each hit carries summary/tags/next-slug fields. It does not discuss empty-result or no-match behavior, keeping it just short of a 5.

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, zero filler, with the core action and return shape front-loaded and the caveat about the manual's size placed last. Every sentence carries information the agent can act on.

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?

An output schema exists, so return values need not be spelled out, and the annotations cover the safety hints; the description nonetheless adds the small-manual caveat and relevance ranking. Nothing needed to call or route this tool 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 coverage is 100%: both 'query' and 'limit' are described in-schema, including the 1-20 range and default of 5. The description only references 'limit' and 'your own words' without adding format or syntax detail, so the baseline 3 is appropriate.

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 ('Search the manual') and immediately scopes what comes back (ranked topics with slug, title, summary, tags, next slugs). It even distinguishes itself from a sibling by noting that 'about' lists every topic, so an agent can tell the two apart 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?

Explicitly tells the agent when NOT to use it: 'The manual is small: about lists every topic, and you may not need a search at all.' This names the alternative tool and the condition under which it wins, which is exactly the routing guidance a search tool needs among nine siblings.

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