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

Annotations already declare readOnlyHint and openWorldHint, covering safety and open-world behavior. The description adds that it returns user profiles and a pagination token, but the output schema already covers return format and the page_token parameter schema covers pagination mechanics; no additional auth or rate-limit context is provided. Added value beyond annotations is modest.

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?

Two tightly written sentences: the first states purpose and pagination support, the second routes to alternatives. No filler or repetition; information is front-loaded.

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?

Given a read-only search tool with annotations, full schema coverage, and an output schema, the description supplies purpose, pagination behavior, and explicit alternative selection guidance. Nothing material is missing for an agent to call it correctly.

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 both parameters are documented with examples and pagination instructions. The description mentions keyword search and page_token pagination but adds no semantic detail beyond what the schema already provides. Baseline 3 is appropriate.

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: search X/Twitter users by keyword. It also distinguishes itself from sibling detail tools by explicitly routing to them when user_id, username, or profile URL is already known.

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?

Explicitly states when to use this tool (discover accounts by name/keyword) and when not to use it (when user_id, username, or profile URL is known, use the corresponding user detail tool). The alternative selection condition is unambiguous.

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