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

With no annotations, the description carries the full burden and does disclose the significant non-obvious behavior: $0.01 USDC per call, x402 payment requirements returned, and the agent's wallet executing the payment. It omits auth scope and rate-limit behavior, but the paid-call flow is the key surprise an agent must know.

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, front-loaded lines: purpose with output shape first, then cost, then a concrete invocation example. Every sentence earns its place with no filler.

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?

An output schema exists so return values need not be detailed, and the description still summarizes the score/grade result. The payment flow is covered; only auth context and failure modes are 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?

Schema description coverage is 0%, but the description compensates with an explicit call example headers(domain="acme.com") that shows the expected format (bare domain, no scheme). With only one self-explanatory parameter this is nearly sufficient, though the required/optional nature is left to the schema.

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 (audit) and resource (HTTP security headers: HSTS, CSP, X-Frame-Options), plus the concrete output shape (0-100 score, A-F grade). This clearly separates it from siblings like ssl_check, dns, and tech_stack without opening any schema.

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?

There is no guidance on when to reach for this tool versus ssl_check or other siblings, and no preconditions stated beyond the payment note. The example implies a single-domain use case but the description never routes the agent between alternatives.

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