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

Goes well past the readOnlyHint/openWorldHint annotations: discloses the browser-minted signed request mechanism, that no account or login is needed, that the signer is a shared warm-browser worker making calls slower than the plain feed read, and that a missing signer worker surfaces as an upstream 503. That is exactly the failure and latency context an agent needs before retrying or escalating.

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 core action and scope lead, followed by return shape and then the operational caveats. Four sentences all carry information, though the return-field enumeration ('text and optional highlight flags/search type, plus upstream search/word request ids') is the most expendable given an output schema exists.

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 single-parameter, read-only lookup with an output schema and annotations, nothing material is missing: scope, auth model, latency expectation, and the 503 failure mode are all covered. An agent can call it and interpret failure correctly without further inference.

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 description coverage is 100% and the single parameter is documented as 'Partially typed search keyword', so the schema already carries the semantics. The description's phrase 'partially typed keyword' reinforces prefix behavior but adds no format, length, or encoding detail beyond the schema — baseline 3.

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 ('Fetch anonymous Rednote search suggestions for a partially typed keyword') and scopes it precisely with 'Only suggestions are returned: Rednote search results and profiles require login and are not exposed.' That explicitly separates it from rednote_explore/rednote_note and the xiaohongshu siblings, so an agent can pick correctly without opening schemas.

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?

It clearly frames the input as a 'partially typed keyword' (autocomplete use) and states what it cannot do (search results, profiles). It also flags the cost tradeoff versus 'the plain feed read', which implies when a cheaper alternative is preferable, though it never names that alternative tool explicitly.

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