generate_dmarc

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

Annotations already declare readOnlyHint and destructiveHint:false, and the description reinforces this with 'Nothing is looked up or stored.' It further discloses the return of warnings about common mistakes that break mail, providing transparency beyond annotations. No contradictions found.

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 every sentence contributes: purpose, policy risks, key recommendations, return details, and a note on side effects. It is front-loaded with the essential purpose. Slightly dense but no filler; might be slightly overlong for rapid scanning, but structure is logical.

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?

Despite no output schema, the description clearly states the return values (record, host, warnings) and explains key pitfalls. All 9 parameters are documented in schema, and the description adds the critical risk context and rollout strategy, making it complete for a generation tool with both safety and usability considerations.

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% with descriptions for all 9 parameters, yet the description adds substantial semantic value beyond the schema by explaining policy meanings (none vs quarantine vs reject), the necessity of rua, the effect of percentage, and alignment pitfalls. This exceeds the baseline for full schema coverage.

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 opens with 'Build a DMARC record — the _dmarc TXT record' which clearly specifies the verb (build) and resource (DMARC TXT record). It distinguishes itself from sibling checking tools like check_dmarc by focusing on generation and policy guidance, making its purpose unambiguous.

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 practical guidance: 'Always publish a rua address', 'Use percentage to apply an enforcing policy', and explains the progression from p=none to p=quarantine/reject. However, it does not explicitly contrast with alternative tools (e.g., when to use check_dmarc instead), only implicitly through purpose, so it lacks explicit exclusion criteria.

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