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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the description's extra disclosure is what matters. It adds that the tool issues terms 'exactly as the paid endpoint' does, that settlement happens over a separate HTTP endpoint, and that no MCP client holds a wallet for signing. These are useful behavioral traits beyond the annotations, though it doesn't mention potential rate limits or error conditions, which are minor for a read-only tool.

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 sentences, each earning its place: the first states function and output, the second gives a concrete use case, the third clarifies boundaries and a key limitation. It is front-loaded with the core purpose and contains zero fluff or repetition.

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, read-only tool with no output schema, the description is remarkably complete. It covers what is returned, when to use it, what it doesn't do, and the settlement URL in the response. It doesn't define 'x402' or list error conditions, but those are optional for a tool this simple. A 4 reflects the high coverage without penalizing for non-essential omissions.

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 coverage is 100%, so the parameter description already exists. The description's mention of 'service's report' slightly clarifies that serviceId refers to the service owning the report, but it doesn't add meaning beyond what the schema provides. Baseline 3 applies because the schema carries the parameter semantics fully.

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 ('read') and resource ('live x402 payment terms for a service's report'), enumerates exactly what is returned (price, one offer per settlement rail), and notes it matches the paid endpoint. This clearly distinguishes it from sibling tools like edge_get_free_sample or edge_get_service – an agent knows its function without opening the schema.

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 when-to-use: 'Use this to check a report's cost against your own spend policy before committing.' It also provides a clear when-not-to-use: settlement is not done through this tool and requires the plain HTTP endpoint named in the response. This covers both usage context and an alternative pathway, exceeding the baseline.

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