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

With no annotations provided, the description carries the behavioral burden. It discloses that the call is paid ($0.05/call), read-only, and safe to retry. This is valuable operational context beyond the schema, though it does not mention potential errors, rate limits, or exact response structure.

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 two sentences with no fluff. The primary action and output are front-loaded, followed by the use case and important operational caveats (cost, read-only, retry safety). Every sentence earns its place.

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 tool is simple and the description covers what the tool returns, how to use the result, and key operational behavior. Since there is no output schema, the description could be more explicit about whether the result includes similarity scores alongside phrases, but overall it provides enough for an agent to select and invoke the tool effectively.

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 baseline is 3. The description adds context about the tool's output but does not add meaning beyond what the schema already provides for the parameters. The 'n' parameter is only described as 'Bank size,' which is adequate but not enriched.

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 the verb and resource: 'Returns the ranked phrase bank for one category.' It also specifies the phrase length range (1 to 4 words) and ordering ('ordered by similarity to the category'), which makes the tool's purpose unambiguous and distinct from siblings like topic_scorer_find or topic_scorer_score.

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 use case: 'Use it to seed a brief.' Additionally, the category parameter documentation points to topic_scorer_find for looking up a category, giving the agent a clear path to a sibling tool. It does not explicitly state when not to use this tool, so it stops short of a 5.

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