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

Annotations already mark this as non-read-only, open-world, non-idempotent, and non-destructive. The description adds important behavioral context beyond annotations: paid per call in USDC via x402, price shown by service_details, and no charge for invalid input or failed upstream sources.

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?

Two compact sentences with no wasted text. The core action is front-loaded, and the billing caveat follows immediately.

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 two-parameter execution tool with no output schema, the description covers the key call behavior, return type, and billing/failure semantics. It omits deeper output-shape detail, but that is largely inherent because the returned JSON depends on the selected service.

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 100%, so both parameters are already documented in the schema. The description adds no parameter-level syntax or shape details beyond saying the service runs 'with its parameters'; it only points to service_details for pricing.

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 and resource: run a Vextorium service with parameters and get the JSON result. It is clearly an execution tool, but it does not explicitly distinguish itself from search_services or service_details beyond referencing service_details for pricing.

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 after finding a service and checking details, since price is shown by service_details. However, it does not explicitly say when to use this tool versus search_services or service_details, nor does it state prerequisites beyond the payment model.

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