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

Annotations already cover safety (readOnlyHint=true) and idempotency. The description adds the list of returned fields but no additional behavioral traits like rate limits, auth needs, or handling of private accounts. With strong annotations, the extra value is minimal.

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 one concise sentence followed by a list of fields. Every phrase is necessary, no wasted words, and the action 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?

An output schema exists, so return values are covered. The description lists the main fields returned. It is complete for the tool's purpose, though it could mention error handling (e.g., user not found) or field availability for private accounts, but that's not essential given the schema.

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?

Both parameters have clear schema descriptions (100% coverage). The description adds a small clarification (username without @), which marginally helps but does not significantly enhance meaning beyond the schema.

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 it retrieves a user's Twitter profile by username, listing specific returned fields (display name, bio, counts, etc.). It is distinct from sibling tools like twitter.users.followers or twitter.tweets.search.

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 explains what the tool does but lacks explicit guidance on when to use it versus alternatives. No when-not-to-use or sibling differentiation is provided, leaving usage context implied.

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