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

Annotations only declare readOnlyHint and openWorldHint; the description adds substantial context beyond that — the call is paid, it returns a payment quote instead of data, and completing the read requires a second HTTP step with x402 settlement. It also flags a prerequisite health check, which is exactly the kind of operational disclosure an agent needs before invoking.

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?

Four short sentences, front-loaded with the identity check, then the return shape, then the non-data caveat, then the follow-up flow. No filler and no repetition of schema or annotation content.

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?

No output schema exists, and the description compensates by enumerating the return payload (price, network, asset, pay-to, exact URL) and clarifying it is not token data. It also completes the two-phase x402 workflow, so an agent can act correctly from the description alone.

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 baseline is 3, but the description adds a real constraint the schema does not encode: the two parameters are mutually exclusive ('Pass token or symbol, not both'), which matters given 0 required parameters.

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 ('whether a Keeta token ... is the official one') and immediately clarifies the tool is a paid quote rather than a data fetch ('It does not return data'). This distinguishes it from data-returning siblings like get_token and search_tokens.

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?

Gives explicit operational guidance: 'Pass token or symbol, not both', 'check get_x402_health first', and the follow-up action ('GET the returned URL over HTTP and pay with x402'). It lacks an explicit when-not clause versus data-reading siblings such as get_token, so 4 rather than 5.

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