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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint, and destructiveHint=false, covering the safety profile. The description adds value by specifying the return structure (single profile object under data) and the types of signals it surfaces (country, verification details, username-change history), which goes beyond the annotations without contradicting them.

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 sentences with no wasted words. The purpose is front-loaded, followed by usage context and a clear alternative. Efficient and well-structured.

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 single-parameter read-only tool with a defined output schema (even if not shown here) and comprehensive annotations, the description covers everything needed: what it does, when to use it, what it returns, and how it differs from the sibling. Nothing essential is missing.

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% (the userName parameter is described as 'The screen name of the user'). The description adds a minor clarification with '@handle' implying format, but this is a small enhancement over the schema. Since the schema already covers the parameter adequately, a baseline of 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?

The description clearly states the tool retrieves the extended 'About this account' panel for an X user by handle, and explicitly distinguishes it from the standard profile tool get_twitter_user_info. This provides a specific verb, resource, and scope that uniquely identifies this tool among its many Twitter siblings.

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 gives explicit guidance: use for provenance and trust checks, and names the alternative (get_twitter_user_info) for standard profile data. It clearly states when to use this tool versus when not to, leaving no ambiguity for an agent.

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