add_custom_domain

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

With no annotations, the description carries the full burden. It discloses that the tool returns DNS instructions for human configuration, implying the actual DNS setup is not automated. However, it does not mention side effects, permission requirements, or whether the operation is reversible. This is adequate but not rich.

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?

Description is two sentences with no wasted words. It front-loads the purpose and outcome, making it efficient for an agent to parse.

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 simplicity of the tool (3 required params, no nested objects, no output schema), the description covers the key aspects: what it does and what the human will receive. It is complete enough for safe invocation, though it omits any mention of idempotency or failure scenarios.

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 each parameter having a clear description (e.g., domain, subdomain_name, project_id). The tool description does not add new meaning beyond what the schema already provides, so baseline 3 applies.

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?

Description clearly states the action (register) and resource (custom domain). It mentions returning DNS instructions, which distinguishes it from read-only domain checks. However, it does not explicitly differentiate from sibling tools like remove_custom_domain or check_domain_status, so it misses the highest level of clarity.

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?

Description implies use when registering a custom domain but provides no explicit guidance on when to use this tool versus alternatives, nor does it mention prerequisites or exclusions. The usage context is only implied.

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