dossier_dkim

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

Without annotations, the description fully discloses behavior: parallel Cloudflare DoH TXT queries per selector, 5 s timeout, and the output structure (CheckResult). It does not explicitly declare read-only status, but the nature of probing implies non-destructiveness. The description adds valuable behavioral context beyond what annotations would provide.

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 at three sentences, each serving a distinct purpose: action/query pattern, usage guidelines, technical details/output. No redundant information; every sentence earns its place.

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 lack of output schema, the description adequately explains the return value (CheckResult with fields). It covers domain validation, default selectors, parallel query behavior, and timeout. For a tool with 2 parameters, this is complete; however, it could mention potential errors (e.g., domain not resolvable) more explicitly.

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%, but the description adds significant meaning: explaining that selectors are optional with a default set, and adding domain validation rules ('Must be resolvable on the public internet; IPs, ports, etc. rejected'). It also lists the default selectors, which is not in 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?

The description clearly specifies the action ('Probe a domain's DKIM public keys'), the resource (domain), and the method (querying <selector>._domainkey.<domain>). It distinguishes from siblings like dossier_spf and dossier_dmarc, and explicitly states the use case ('verify signing configuration or discover active selectors').

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 provides clear guidance on when to supply selectors vs omit, and explains the default selectors. It also includes prerequisites (domain must be a public FQDN). However, it does not explicitly state when not to use this tool or mention alternatives among siblings.

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