Create Domain Claim

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

With no annotations, the description carries the full burden and does well. It discloses key side effects: domain is recreated, brand-new DKIM keys are generated, previous DNS records become invalid, and a TXT record is returned that must be displayed and added to DNS. It also details the follow-up workflow. It doesn't cover failure modes or auth requirements, but the core behavioral impact is well communicated.

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 four sentences, each earning its place: purpose, side effects, required action, and workflow. It is front-loaded with the core purpose and uses concise, imperative language. No filler or redundancy.

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 tool that initiates a multi-step workflow, the description gives a complete flow: returns a TXT record, user must add it, then verify-domain-claim, then poll get-domain-claim until status is 'completed'. It also explains the DKIM key reset, which is crucial context. It doesn't elaborate on failure cases or output structure, but the essential workflow is well covered given the schema handles parameter details.

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 description coverage is 100%, with all six parameters having meaningful descriptions. The tool description adds no extra parameter-level detail beyond the schema, so the baseline of 3 is appropriate. It doesn't need to compensate for schema gaps.

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 the tool's specific purpose: 'Start a claim for a domain another Resend account has already verified.' This distinguishes it from create-domain (for new domains) and aligns with the claim workflow. The verb 'start' plus the resource 'domain claim' is explicit and 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?

The description provides clear usage context: use when a domain is already verified by another Resend account. It also gives explicit next steps: 'use verify-domain-claim, then poll get-domain-claim'. It doesn't explicitly say 'use instead of create-domain', but the scenario is clear enough to guide selection.

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