Get User Videos

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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint, so safety is covered; the description goes further by disclosing the auth requirement (TweetAPI API key), the cost model (one request per call, usually 1 unit, cost estimate returned per result), and the one-page pagination contract. Those are the operational details an agent needs and none of them are present in the structured fields. The only redundancy is restating 'Read-only', which does not contradict the 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?

Four compact sentences, front-loaded with what is fetched, then sibling routing, then operational facts, then pagination. Every sentence advances the agent's decision except the brief 'Read-only', which duplicates an annotation but costs almost nothing. No filler or restated title.

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 an output schema present, the description correctly avoids describing return shapes and instead covers what the schema cannot: auth, cost, page size, and the exact continuation field. All three parameters are documented and the username prerequisite is called out, so an agent has everything needed to call this correctly on the first try.

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% and the parameter descriptions are already strong (cursor semantics, numeric userId with a username-lookup fallback, full vs compact trade-off). The description still adds value by tying cursor to the concrete return path 'completeness.nextCursor', making the loop explicit rather than implied. It adds little on userId or responseFormat, so it is slightly above the high-coverage baseline rather than a full rewrite.

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 states a specific verb and resource ('Fetch one page of a user's posts that contain videos') and anchors it to a familiar analogy ('as on the Videos tab of their profile'). It also names the sibling it is not ('Photos are a separate feed: use tweetapi_user_photos'), so an agent can separate it from tweetapi_user_photos and tweetapi_user_tweets without opening any schema.

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 an explicit alternative and the condition that selects it ('Photos are a separate feed: use tweetapi_user_photos'), plus the prerequisite path for username inputs ('call tweetapi_user_by_username first'), which is repeated in the schema. The pagination continuation rule ('call again with cursor set to this result's completeness.nextCursor') tells the agent exactly how to iterate, leaving nothing to inference.

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