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

Beyond the annotations, the description reveals important non-obvious behavior: watchlists appear in the owner's web app, the call is free, and watchlists count against a workspace allowance. It also explains the over-limit behavior. This is rich contextual detail that helps an agent anticipate side effects.

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 well-structured and front-loaded with the core purpose and return value. It includes a minor redundancy between 'Free to call' and 'Cost: free', but overall every sentence contributes useful workflow, allowance, or behavior information.

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 the tool's moderate complexity, the description covers creation, return value, downstream integration with two sibling tools, web-app visibility, and quota implications. There is no output schema, but the key return value (watchlistId) is stated. The description is sufficient for correct invocation.

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?

The input schema already documents both parameters completely (name and notes) with descriptions, so schema coverage is 100%. The description does not add much parameter-level detail, but it doesn't need to because the schema carries the load.

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 that this tool creates an empty watchlist, a named set of creators, and returns a watchlistId. It is easily distinguished from siblings like add_watchlist_profiles, delete_watchlist, and list_watchlists by focusing on the creation action.

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 an explicit usage workflow: create the watchlist, populate it with add_watchlist_profiles, and then pass the id to search_outliers. It does not explicitly mention when not to use it versus alternatives, but the workflow context is clear and practical.

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