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

Annotations already declare readOnlyHint and non-destructive, but the description adds genuinely important context: it never charges and never sends a request, which disambiguates the otherwise alarming 'paid request' framing. Saying it uses a working example body over HTTP also shapes expectations about output. No auth or rate-limit detail, but the key behavioral risk is addressed.

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?

One sentence, front-loaded with the safety-critical caveat ('Free and read-only; never charges or sends a request') before the return description. No wasted words.

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?

With no output schema, the description carries the burden of describing the return value, and it does so: payment steps, curl, JavaScript, example body. Minor gap around error behavior for an unrecognized utility id, but everything needed to call it correctly is present.

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% and the single `utility` parameter is fully documented with examples in the schema. The description only refers to 'the chosen utility' without adding accepted-format guidance beyond what the schema already provides, so baseline 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: it returns x402 payment steps plus curl and JavaScript snippets for a chosen utility. The 'ready-to-run / working example body' framing makes the output concrete. It doesn't explicitly differentiate itself from get_utility_details or search_utilities, but the deliverable (runnable code) is distinctive enough to be recognizable.

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 — call this when you need executable code for a paid utility rather than metadata. There is no explicit statement of when to prefer this over get_utility_details or how to follow up after obtaining the snippet, so the agent must infer the routing.

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