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

With no annotations, the description carries the full burden, and it delivers the key traits: the call is free, the service is paid, and payment is x402 with USDC on Base. It does not spell out auth requirements or that the tool is read-only, but for a zero-parameter info endpoint that omits little of practical consequence.

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?

Three short sentences, front-loaded with the cost profile ('Free.') and the routing instruction ('Call this first'). Every clause adds information; there is no filler or restatement of the name.

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?

There is no output schema, but the description enumerates the returned content (products, prices, payment instructions), which compensates. For a simple, parameterless info tool with no annotations this is close to complete; only auth/rate-limit behavior is unaddressed.

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 tool takes zero parameters, so there is no syntax to document and the baseline of 4 applies. The description correctly spends no words on inputs.

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 ('Describes this paid website-audit service') and enumerates exactly what it returns: the three products, their prices, and the x402 payment procedure. An agent cannot confuse this informational tool with the audit siblings (audit_site, deep_audit, scan_site), whose names imply performing an audit rather than describing the service.

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?

It gives an explicit trigger: 'Call this first if you do not know how to pay', which implies the negative case (skip it when you already know how to pay). It does not name the sibling tools or state conditions for choosing among the audits, but the routing guidance for this tool itself is clear.

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