dossier_cors

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

With no annotations provided, the description carries the full burden. It discloses that the tool performs a single OPTIONS request via fetch with a 5-second timeout, returns a CheckResult with status and reason on failure. It also explains defaults when origin/method are omitted. However, it does not mention potential side effects (none expected) or error handling beyond the generic reason field.

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?

The description is concise: two sentences, no redundant wording. It front-loads the core action ('Send a CORS preflight...') and then provides usage guidance and behavioral details 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 the tool's simplicity (3 parameters, no nested objects, no output schema), the description adequately covers purpose, parameters, behavior, and output format. It also mentions the specific HTTP method and timeout, leaving no major unknowns.

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 input schema already has 100% description coverage. The description adds value by specifying that domain must be a public FQDN and rejecting IPs, ports, etc., and by explaining the defaults for origin and method. This provides clarity beyond the schema's basic 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 clearly states it sends a CORS preflight OPTIONS request and returns access-control-* headers, using specific verbs ('Send', 'verify', 'check'). It distinguishes itself from sibling tools like dossier_dns or dossier_tls by focusing exclusively on CORS policy verification.

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 explicitly indicates when to use the tool: 'verify CORS policy' or 'check whether a domain allows cross-origin requests'. It also explains how to customize the preflight by providing origin and method, or omitting them for defaults. While it doesn't list explicit alternatives, the sibling tools are clearly in different domains (DNS, headers, etc.), so the context is sufficiently clear.

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