buy_verification_credits

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

No annotations are provided, so the description carries the full burden. It discloses that this is a purchase transaction requiring on-chain payment with USDC and returns payment instructions, but lacks details on costs, rate limits, or error handling. The description adds some behavioral context but is incomplete for a financial transaction tool.

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 that are front-loaded with the core action and usage context, with no wasted words. Every sentence adds value by explaining the tool's purpose and behavioral outcome efficiently.

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 no annotations and no output schema, the description covers the purpose and usage well but lacks details on costs, transaction confirmation, or error cases. For a financial tool with on-chain interactions, this leaves gaps in behavioral transparency, though it's adequate for basic understanding.

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 the schema fully documents the 'count' parameter. The description doesn't add parameter details beyond the schema, but it contextually explains that credits are for verification beyond the free tier, which helps interpret the parameter's purpose. With 1 parameter and high schema coverage, baseline 3 is appropriate, but the added context justifies a 4.

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 specific action ('Buy x402 verification credits with USDC on-chain'), identifies the resource ('verification credits'), and distinguishes it from siblings by focusing on credit purchasing for paywall owners, unlike tools like 'create_paywall' or 'get_usage'.

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?

Explicitly states when to use this tool: for paywall owners needing credits beyond the free tier (1,000/month) without Stripe billing. It also implies when not to use it (if within free tier or with Stripe), though it doesn't name specific alternatives.

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