x402_payment_quote

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

With no annotations provided, the description carries full responsibility for behavioral disclosure. It clearly states the tool is offline, read-only, does not charge or call a facilitator, and returns an error object for missing services. This is unusually complete and directly addresses the key risks an agent needs to know 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?

The description is two sentences with zero filler. The purpose is front-loaded, followed by the most important behavioral caveats and a sibling exclusion. Every sentence 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?

For a one-parameter tool with a rich schema (100% coverage), an output schema, and clear behavioral caveats, this description is complete. It covers what the tool does, how it behaves (read-only, offline), error handling, and sibling differentiation. Nothing critical is missing.

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 schema already documents the 'service' parameter at 100% coverage, so the baseline is 3. The description adds value beyond the schema by stating that missing services return an error object, which tells the agent the service must be a known paywalled service name. It also reaffirms 'named service,' reinforcing the parameter's role.

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 opens with a specific verb-resource pair: 'Return an offline x402 payment quote for a named service.' It also explicitly distinguishes itself from siblings with 'Not create_agent or run_task,' so an agent can tell exactly what this tool does and what it does not.

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 names two sibling tools it is not ('Not create_agent or run_task') and states 'Read-only simulation,' which implies it should be used when a quote is needed without an actual charge or facilitator call. It does not provide a full when-to-use versus alternatives matrix, but the context is clear for a simple one-parameter tool.

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