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

Annotations already declare read-only, idempotent, open-world, non-destructive behavior, so the safety profile is covered. The description adds value beyond that by disclosing the commercial model: ¥0.1 per call, billed only on success, with automatic refund on failure or empty result. It does not say what an empty-but-successful response looks like or whether lookups by an invalid handle count as failures.

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 in a deliberate order: what it does, what it returns, when to use it, with cost/refund as a closing note. Every sentence carries distinct information and nothing is repeated from the schema or annotations.

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, the return-field list is essential and present, and the pricing/refund note covers the main operational risk of calling it. The one gap is identifier selection between the two optional lookup parameters, which the agent must infer from the schema alone.

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%, so both lookup keys (rest_id and the @handle) and the alternate auth token are already documented in the schema. The description adds no guidance on choosing rest_id versus screen_name, nor on precedence if both are supplied, so it does not exceed the baseline.

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?

"获取推特用户信息" names a specific verb and resource, and the following sentence enumerates exactly what comes back (nickname, follower count, like count, bio, verification status). It is clear enough on its own, but it never contrasts itself with tw_user_posts, which an agent must distinguish when it wants a user's tweets rather than the profile.

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 gives concrete usage contexts (influencer screening, account profiling, grouping by follower tier), which tells the agent what kind of task this call serves. It stops short of exclusions or naming an alternative tool for post retrieval, so the routing guidance is contextual rather than complete.

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