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

Annotations already declare readOnlyHint, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds genuine behavioral value beyond that: it masks cookie values in the output (a data-handling trait) and notes free-mode pricing and limits. It does not describe return structure or pagination, but with annotations carrying safety this is solid added context.

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?

Compact and front-loaded, leading with the core action and scope. The semicolon-separated pricing/limit clauses are slightly choppy but each earns its place by clarifying cost and constraints.

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 no explanation, and annotations cover the safety profile. The description covers purpose, free-mode cost, value masking, and limits — enough for an agent to call this read-only audit 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 coverage is 67% and the description's only parameter-relevant statement is 'up to 50 Set-Cookie headers', which merely restates the schema's maxItems:50. The legacy requestId/maxPriceMicroUsd fields are already documented in the schema as ignored in free mode. Baseline 3 fits since the schema does most of the work.

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 ('Check') and a precise resource ('Set-Cookie headers') with the attributes audited ('security attributes and prefix rules'). This differentiates it from siblings like security_header_audit and security_csp_audit by scope, though it doesn't explicitly name those alternatives.

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 no when-to-use guidance, no prerequisites, and no routing against the many sibling security audits (csp, header, jwt, secret_scan). It only states constraints ('existing source and input limits apply') and pricing, not usage context.

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