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 does this well by revealing that the call is pay-per-call ($0.05 USDC on Base via x402), requires a payment-signature header, and returns an error with payment terms if absent. This is meaningful business-critical context beyond a simple 'generates content' statement.

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 sentences, each earning its place: the function, the routing rule, and the payment requirement. The core purpose is front-loaded, and there is no fluff or repetition of schema content.

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 that there is no output schema and no annotations, the description covers the essential behavioral, commercial, and routing context well. It could be slightly more explicit about the query parameter being effectively required despite the schema listing no required parameters, but overall an agent has enough to invoke it correctly.

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 baseline is 3 even though the description adds no parameter-specific detail. The description reinforces the purpose of the query/context parameters at a high level, but it does not go beyond the schema’s own parameter descriptions.

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 ('Write') and a concrete resource ('3-email follow-up sequence') including its components (subjects, timing, body) and the exact target condition (prospects who did not reply). It also distinguishes itself from generate-cold-email by explicitly stating that first-touch emails belong to that sibling.

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 gives explicit routing guidance: use generate-cold-email for the first-touch email, and this tool for follow-ups after no reply. This tells the agent when to select this tool versus a closely related sibling without leaving it to inference.

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