dossier_dmarc

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

Despite no annotations, the description discloses key behavioral traits: queries via Cloudflare DoH with 5s timeout, parses tag=value pairs, and specifies return format (CheckResult with success/error). This is fairly transparent for a read-only tool.

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 focused sentences: purpose, usage context, technical details. No redundant words; front-loaded with the core function. 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?

The tool is simple (one param, no output schema). The description covers what, how, and return format. Could mention potential errors or rate limits, but the 5s timeout and error reason in response partially mitigate. Complete enough for effective use.

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 schema description already covers the one parameter well (public FQDN, restrictions). The description adds minor value by reiterating the constraint but does not significantly expand beyond schema. With 100% schema coverage, baseline 3 is appropriate.

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 uses a specific verb ('Retrieve and parse') and distinctly identifies the resource (DMARC policy from _dmarc.<domain> TXT record). It also distinguishes from sibling tools by explicitly mentioning pairing with dossier_spf and dossier_dkim.

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?

Provides explicit use cases: 'audit email authentication policy, verify p and rua settings, confirm alignment mode.' Suggests pairing with sibling tools for complete coverage, guiding the agent on when to use this tool versus alternatives.

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