twitter_user_mentions

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

Annotations already declare readOnlyHint, idempotentHint, and openWorldHint. The description adds the auth requirement (X_BEARER_TOKEN) and the exact return structure, which are valuable behavioral details. No contradiction with annotations.

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 description is compact: one line for purpose, one for return format, one for auth. Every sentence adds value and it is front-loaded with the core purpose. No fluff or redundancy.

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?

Even without an output schema, the description provides the return structure and auth condition, making it self-contained. It could be more complete by explicitly mentioning pagination or contrast with user tweets, but for a retrieval tool this is quite comprehensive.

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%: all five parameters have clear descriptions (e.g., 'Numeric user id. Required — part of the URL path.'). The description's 'mentioning an account' adds slight context for the id parameter, but the schema already carries the parameter semantics, resulting in the baseline score of 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?

The description 'Recent posts mentioning an account' uses a specific verb+resource and clearly states the return type. It distinguishes from sibling tools like twitter_user_tweets (posts by the user) and twitter_search_recent (general search). The inclusion of the return format reinforces the purpose.

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?

The description implies usage: when you need posts that mention a specific account. It provides context (recent posts, mentions) but does not explicitly name alternative tools or state when not to use it, so it falls short of a 5.

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