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

Annotations only declare the broad hints (readOnlyHint=false, idempotentHint=false, destructiveHint=false). The description adds substantial context the annotations cannot: the check reaches out to DNS, is rate-limited behind a certificate budget, expects minute-scale polling, and defines the 48-hour hard-failure window that maps to domain_failed.

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?

Front-loaded with the action, then the prerequisites and timing constraints; every sentence carries operational information. It is dense and slightly run-on, but there is no filler to cut.

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 no output schema, the description does describe the result semantics (answers the check, yields domain_failed on permanent failure) and the full remediation loop, which is what an agent needs. The remaining gap is the unaddressed idempotency_key and the exact success/failure response shape.

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 0% across three parameters, so the description must carry the load, and it largely does not. hostname and project_id are only obliquely implied by 'one of the project's domains', and idempotency_key — important given idempotentHint=false — is never mentioned.

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?

States a specific verb and resource ('run the ownership check for one of the project's domains now') and even describes the answering behavior. It is clearly separable from siblings such as list_domains, attach_domain, and delete_domain.

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?

Explicitly says when to call it ('after the DNS record is published'), how to call it ('poll in minutes rather than in seconds' due to the certificate budget), and what to do on permanent failure (delete_domain, fix the record, attach_domain again). Alternative tools are named with the condition that selects them.

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