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

Beyond the readOnlyHint and idempotentHint annotations, the description adds crucial behavioral detail: the connector never pays, does not sign or settle, does not receive the private image, and requires human payment execution. It also lists concrete error conditions, giving the agent a clear and truthful side-effect profile.

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 short sentences with no filler: the core action, the crucial payment limitation, and the error contract. The most decision-relevant constraint ('never pays') appears in the first sentence and is reinforced by the title.

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 one-integer-parameter read-only tool with no output schema, the description covers purpose, side effects, payment authorization boundary, and expected errors. The only notable gap is not describing the shape or content of the returned payment requirement, which would be helpful without an output schema.

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 0%, so the description must compensate for the 'level' parameter. It adds minimal meaning by saying 'for one level', but it does not explain what a level denotes or why the valid range is 1-107; the schema still carries most of the parameter meaning.

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?

Description states a specific action ('Read the x402 payment requirement') and resource ('one level'), and explicitly delimits what it does not do: pay, sign, settle, or receive the private image. This clearly differentiates it from payment-executing tools and from siblings by framing it as a read-only preparation step.

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?

Clearly communicates the core usage context: use this to inspect payment requirements without executing payment, and a human must authorize and execute payment separately. It does not name sibling alternatives explicitly, but the exclusion is strong enough to prevent the agent from attempting payment through this connector.

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