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

The description adds meaningful behavioral context beyond the annotations: it states that the tool 'Answers unrated rather than guessing when the evidence is thin', disclosing how it handles uncertainty. The readOnlyHint and openWorldHint annotations already cover the read-only and open-world aspects, and the description does not contradict them.

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 front-loaded: the first sentence states what the tool returns, the second explains its uncertainty behavior and scope. Every clause earns its place, with no wasted or redundant phrasing.

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 simple single-parameter read-only tool, the description covers the core purpose, the input semantics, the behavioral stance on uncertain evidence, and the applicable endpoint scope. Since there is no output schema, the description still provides enough about the returned verification aspects for an agent to select and invoke the tool confidently.

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 has 0% description coverage and only exposes the parameter name 'id_or_url', but the description compensates by clarifying that the value is an x402 endpoint or its URL. This gives the agent the domain-specific meaning needed to populate the argument correctly, though it does not elaborate on format nuances beyond the schema's length constraints.

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 states a specific verb ('Return') and a specific resource ('what has been verified about an x402 endpoint or its url'), and enumerates the concrete attributes returned: whether it answers, what it charges, and whether the price has moved. It also sets itself apart from typical capability-listing tools by focusing on verification status rather than capabilities, and the 'Works for endpoints Teppi does not operate' clause further scopes the 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 gives clear usage context by saying it works for endpoints Teppi does not operate, which helps an agent choose this tool for non-Teppi x402 endpoints. However, it does not explicitly name sibling alternatives or state when not to use this tool, so the routing guidance is present but not fully explicit.

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