register_sender_domain

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

Discloses that DNS records are returned and that emails will come from the custom domain after verification. However, lacks detail on side effects, potential failures, or required permissions. With no annotations, the description partially covers behavioral traits.

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?

Concise two-sentence description with no extraneous information. Every sentence adds value: first sentence defines the action, second explains output and benefit.

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?

Explains return value (DNS records) and next step (verification). Could mention failure modes or that domain must be owned, but overall adequate for a registration tool with no output schema.

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%, so baseline is 3. The description does not add additional meaning beyond the schema, such as domain format or uniqueness constraints.

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?

Clearly states the tool registers a custom email sending domain and returns DNS records. Distinguishes from siblings like remove_sender_domain, check_domain_status, and add_custom_domain by focusing on email sending.

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?

No explicit when-to-use or when-not-to-use guidance. Does not mention prerequisites like domain ownership or alternatives. The description only states what it does, not the context.

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