Get List Details

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

Annotations already declare readOnly, idempotent, openWorld and non-destructive, so 'Read-only' is redundant, but the description adds genuinely new behavior: a TweetAPI API key is required, one request is made per call, it usually costs 1 unit, and results carry a cost estimate. That cost and auth context is not derivable from any structured field.

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?

Three sentences, front-loaded with the resource and payload, then alternatives, then cost/auth caveats. Slightly padded by the redundant 'Read-only' and repeated cost phrasing ('usually costing 1 unit' plus 'cost estimate'), but nothing is wasted overall.

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 need no prose explanation, yet the description still previews the shape usefully. For a single-parameter read tool, auth, cost, request count and sibling routing are all covered, leaving nothing an agent needs 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 coverage is 100% and the schema already documents the listId as 'Numeric list ID, or a list link such as https://x.com/i/lists/1234567890'. The description's 'by List ID or List link' restates that without adding format or edge-case detail, so the baseline 3 applies.

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 ('Fetch one X List's details') and enumerates what comes back: name, description, owner, member and follower counts, visibility. It also names the three sibling list tools it is not, so an agent can separate it from tweetapi_list_members, tweetapi_list_tweets and tweetapi_list_followers without reading 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?

Routes the agent explicitly: use this for details, tweetapi_list_tweets for posts, tweetapi_list_members for accounts in the list, tweetapi_list_followers for followers. Each alternative is paired with the condition that selects it, which is exactly what the crowded list_* sibling set requires.

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