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

With no annotations, the description carries the full burden and does so well: it discloses the payment model (0.01 USDC, settles over x402 before any result), the testnet status (no real funds), the untrusted-content safety caveat for sources/evidence, and the shape of the result. These are exactly the behavioral facts an agent could not infer from the schema.

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?

Front-loaded with cost and purpose, then payment behavior and the security note. The enumeration of return fields (verified, confidence, sources, conflicts, evidence, summary) is somewhat redundant given an output schema exists, but everything else 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?

For a paid verification tool with a full schema and an output schema, the description covers purpose, cost, payment flow, testnet caveat and content-safety handling, leaving no material gap an agent would need before calling it.

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 company, claim, payment_id (reuse semantics) and max_sources are already documented in the schema. The description adds no syntax, format or constraint detail beyond that, so the baseline of 3 applies.

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+resource (verifies a company/data-point claim), the mechanism (x402-paid, multi-source), and the exact cost. There are no siblings to disambiguate from, and an agent can tell immediately what the tool returns.

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?

Usage is implied clearly by 'check whether a company/data-point claim holds', but there is no explicit when-not guidance or statement of prerequisites before calling. The description does note that an existing payment_id can be reused, which is a useful operational hint.

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