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

Annotations already declare readOnlyHint and openWorldHint, so safety is covered. The description adds real behavioral context beyond that: this is a single-shot suggestion lookup with no page_token/pagination, which prevents a common misuse. It does not describe result volume or ordering, but the output schema exists to cover returns.

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 compact sentence with the positive purpose front-loaded and the exclusion/pagination caveats after it. Nothing is wasted and there is no redundant framing.

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 one-parameter read-only suggestion lookup with full schema coverage, existing annotations, and an output schema, the definition supplies everything needed to call it correctly: what it returns, what it must not be confused with, and the no-pagination rule.

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 keyword parameter's own description already spells out the exclusions (no video/profile links, aweme_id, sec_user_id, page_token). The description's param guidance is essentially a restatement rather than new meaning, so baseline 3 applies for a single well-documented parameter.

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+resource: returns autocomplete/suggestion words from Douyin's regular search input box. It also separates itself from the content-search siblings by declaring it is not for searching videos, users, or products (douyin_search_videos/users/products), so an agent can pick it out 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?

Gives a clear negative boundary ('not for searching works, users, or products') that maps onto the three search_* siblings, plus a hard constraint not to pass page_token. It stops short of explicitly naming those sibling tools or describing the positive trigger case (keyword autocomplete for the regular search box), so routing still needs a small inference.

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