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

Beyond the annotations (destructiveHint=true, idempotentHint=true), it discloses what actually gets destroyed: any existing — including working — domain stops serving until verify_custom_domain passes again, so the creator should be consulted. It also clarifies the entitlement requirement (Premium) and the critical non-behavior that it does not touch DNS or activate the domain, which is exactly what an agent needs to avoid misrepresenting the effect.

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 sentences, front-loaded with the core action, then the destructive warning, then the clarification of scope. Every sentence carries distinct, necessary information with no filler.

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?

With an output schema present, return values need not be explained; the description still covers the operation's effect, its prerequisite, and the required follow-up tool. Nothing an agent needs to call this correctly is missing.

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%, and the schema already supplies the example format (priya.in). The description adds no syntax or format detail beyond the schema, so the baseline of 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?

The description states a specific verb and resource: it records the desired domain and returns the DNS record to add. It is immediately distinguishable from siblings like verify_custom_domain (which checks) and remove_custom_domain (which removes).

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?

It gives clear context: this is a Premium operation, it warns to confirm with the creator if a domain is already active, and it routes the follow-up step to verify_custom_domain. It doesn't explicitly name get_custom_domain as the way to check current state, but the usage conditions are well covered.

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