check_bimi

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

No annotations provided, so the description carries full burden. It explicitly says 'Read-only', 'No auth, no destructive actions; only fetches the public logo + certificate.' This fully discloses safety and non-destructive nature.

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 moderately long but each sentence adds value: purpose, detailed checks, usage advice. It is well-structured and front-loaded with the main action. Could be slightly tighter, but not wasteful.

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?

For a single-parameter tool with no output schema, the description fully covers input, process, and outputs (parsed tags, compliance, etc.). No gaps remain.

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 100% (one parameter 'domain' with description). The description adds meaning by explaining what actions are performed on the domain (validate BIMI TXT, fetch logo, etc.), which goes beyond the schema's simple type definition.

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 is a 'Read-only BIMI readiness check' and specifies exact validations: BIMI TXT record, logo, certificate. It returns parsed BIMI tags, logo compliance, certificate validity, and vendor readiness. This differentiates it from sibling tools like check_dmarc or check_spf.

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?

Explicitly states 'Use before paying for a VMC/CMC and before publishing the DNS record.' This gives clear context. However, it does not explicitly mention when not to use or specify alternatives, though the list of sibling tools implies distinct purposes.

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