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

Annotations already declare the tool safe and non-destructive. The description adds behavioral context beyond annotations, including "Uses metered access" and the return shape of "ranked services, example endpoints, and a next step." No contradiction with annotations was found.

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 three focused, front-loaded sentences with no filler. Each sentence earns its place: what it does, what to supply, what it returns, metered access caveat, and sibling alternative.

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?

For a single-parameter discovery tool with an output schema and good annotations, the description is complete. It covers the trigger condition, input style, output contents, cost/access trait, and the key alternative sibling tool.

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 schema already covers the single capability parameter at 100%, so the baseline is 3. The description adds value by specifying the expected concise format and giving contrasting examples such as "sms" and "manage DNS," which goes beyond the schema's examples.

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: "Find third-party APIs for a capability when the provider is unknown." It clearly distinguishes itself from the sibling factreason_integration_brief by explicitly stating when that sibling should be used instead.

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 states the exact condition for use (provider unknown), gives an example capability format, and explicitly names the alternative: "When the provider is already known, call factreason_integration_brief instead." This is clear when-to-use vs. when-not-to-use guidance.

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