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

With no annotations, the description carries the full burden and does so well: free, no arguments, no sign-in, per-call x402 payment, exact price schedule with currency amounts and exchange rate, and callback events. An agent knows the cost model, auth model, and side-effect profile before calling.

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?

Front-loaded with the purpose and the three things it returns, then details. The enumerated price tiers are verbose but load-bearing for an agent planning spend, so they earn their place despite the length.

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, so the description must describe return contents, and it does: service summary, payment flow, price terms, callback events, agent rules. Nothing needed to call this correctly 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?

Zero parameters, so baseline is 4. The description confirms 'Free and needs no arguments,' which aligns with the empty schema and removes any ambiguity about invocation.

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 and resource ('Describe Verifi') and enumerates exactly what the call returns: service summary, payment mechanics, live price terms, callback events, agent rules. It also distinguishes itself from verify_claim by naming it as the authoritative source for the actual payment requirement.

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?

'Call it once to plan' and 'Describe Verifi before using it' give clear when-to-use context, and the pointer to verify_claim as authoritative for payment requirements establishes the relationship to an alternative. No explicit when-not guidance, but the purpose is effectively prerequisite discovery.

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