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

Annotations already declare readOnlyHint=true, openWorldHint=false, and idempotentHint=true, so safety is covered. The description adds genuinely new operational context: cost ($0.001 per call), no account requirement, and the fact that the result is a typed verdict rather than generated prose. Only auth/rate-limit specifics are missing.

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 tight sentences with the core capability front-loaded and secondary facts (engine, pricing, sample endpoint) trailing. No sentence is wasted, though 'Powered by Jev (TypeSafe System One)' is branding that adds little for an agent.

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 two-parameter, read-only tool with an output schema, the description supplies cost, account posture, and output nature without needing to restate return values. The one real gap is the absence of any comparison to the closely-related fact_check sibling.

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 both parameters ('claim' and 'source') are already fully documented in the schema. The description adds no syntax, format, or constraint detail beyond that, which is the expected baseline when the schema does the heavy lifting.

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 both resources: checking 'whether a source supports, contradicts, or gives insufficient information about a claim.' The phrase 'typed verdict with a real probability, not generated text' clarifies the output nature. However, it does not distinguish itself from the sibling fact_check tool, leaving sibling differentiation to inference.

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?

No explicit when-to-use or when-not-to-use guidance, and the obvious alternative (fact_check) is never named or contrasted. 'Try GET /verify/sample' is a discoverability pointer, not usage guidance, so an agent still cannot tell when this is preferable to its siblings.

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