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

Annotations only cover readOnly/openWorld, so the description earns credit by disclosing that results are relevance-sorted, that not every item is guaranteed to contain the keyword, and that recall is not guaranteed. It does not, however, describe pagination end conditions or response volume.

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?

One dense but front-loaded sentence built from semicolon-separated clauses: capability first, caveats next, alternatives last. Every clause carries information, though the run-on length slightly hurts scannability.

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 two-parameter search tool with an output schema and safety annotations, the description supplies scope, result caveats, and sibling routing. The main residual gap is pagination behavior, which the schema partially covers but the description leaves implicit.

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 both parameters already carry detailed descriptions (including page_token scoping and exact-token reuse rules). The description adds no parameter 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 (搜索小红书视频标签结果), fixes the note_type to video, and explicitly distinguishes itself from xhs_search_notes and xhs_search_images. An agent can identify the tool without opening any 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?

Gives explicit routing: use xhs_search_notes(note_type="video") when sorting or publish-time filtering is needed, and xhs_search_images when images are needed, while stating this tool rejects those filter params. When-to-use and when-not-to-use are both covered.

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