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

With no annotations, the description carries the burden. It reveals two key behaviors: it prepares but does not execute, and it returns the exact request and price. This is valuable, but it omits other behavioral aspects like payment authentication, idempotency, or error conditions. Still, the disclosure is honest and material.

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 sentences with no fluff. The core purpose and the critical non-execution constraint are front-loaded, and the rest is concise. It earns its place.

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?

The description covers the immediate action and result, and an output schema exists, so return format is handled. However, it does not explain how to obtain a valid slug, what 'inputs' should contain, or any prerequisites for a paid invocation (e.g., authentication). These gaps make the tool hard to use correctly without external knowledge.

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% and the description provides no explanation of 'slug' or 'inputs'. It doesn't clarify how to obtain a slug or what structure 'inputs' should take. The description adds no semantic value beyond the parameter names themselves, leaving the agent to guess.

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 clearly states the tool's purpose: 'Prepare a paid invocation of one live Agent Shop service' and clarifies it returns the x402 HTTP request and price without executing. This distinguishes it from sibling tools like get_service (view details) and list_services (enumerate), though it doesn't name them explicitly.

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?

The description implies usage: it's for preparing an invocation, not executing it. It explicitly notes what it does NOT do ('does not execute the service or bypass payment'), which hints at a boundary, but it lacks explicit guidance on when to choose this over siblings or any prerequisites (e.g., need a slug from a prior search).

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