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

With no annotations, the description carries the full transparency burden and does so thoroughly. It discloses the return envelope, the x402 PaymentRequired behavior with exact payment details, the fact that nothing executes or charges until payment verifies, and the nuance that a zero-result scan is a billable run rather than an error.

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?

The description is compact, organized by WHEN / NOT for / Returns, and every sentence provides distinct decision-relevant information. The key usage trigger is front-loaded, keeping the reader from having to parse dense prose.

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?

Given the absence of annotations and output schema, the description fully covers what is needed to invoke and interpret the tool: return format, payment flow, error semantics, and interaction with the get_capability sibling. It also signals that an unpaid call is not a real failure.

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?

The input schema already covers both parameters with 100% description coverage: 'id' as capability id and 'input' as an object conforming to the capability's input_schema. The tool description adds little parameter-level meaning, so the baseline of 3 is appropriate.

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 clear action ('invoke a listed skill') and the specific condition for using it (user wants matching names now and is ready to pay). Explicitly distinguishes itself from other operations by naming what it is NOT for, such as quotes, news, or unsupported chart patterns.

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?

Provides both positive and negative usage conditions. It names when to invoke, when not to invoke, and even routes the agent to read get_capability ta-primitives before refusing a named indicator. This is explicit contextual guidance beyond mere tool selection.

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