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

Beyond the annotations, the description discloses critical behavior: known_bad is true only under a specific combination of conditions, and it is null, never false, for unknown creators. This 'absence is not innocence' framing adds important interpretive context that annotations cannot convey.

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 compact and every sentence earns its place: the first defines the tool's batch capability and output, the second gives the direct sibling alternative, and the third clarifies the nuanced known_bad flag. It is front-loaded with the most important operational facts.

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?

The description covers the major invocation context: batch scope, output row fields, sibling routing, and the interpretation of known_bad. With no output schema present, the row-field list helps, though some domain terms such as 'apparent-versus-true operator collapse' remain unexplained and would benefit from a brief definition or example.

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%, so the schema already documents both parameters and the maxItems limit. The description adds context about the batch-oriented purpose and the known_bad decision logic, but not additional parameter-level syntax or format details.

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 uses a specific verb and resource: 'Screen up to 200 creator addresses in ONE call'. It clearly states the output shape, compact rows with named fields, and explicitly differentiates this from the sibling groundtruth_screen_creator by saying to use this instead of looping over that tool.

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 explicitly says 'Use this instead of calling groundtruth_screen_creator in a loop.' This directly communicates when to choose this batch tool over the sibling single-creator tool, giving the agent a clear routing decision.

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