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

Goes well past the annotations: uniform 202 response whether or not the caller is eligible (enumeration resistance), 15-minute confirmation window, domain-control and original-scope checks, replacement does not extend the original 90-day expiry, single-use code with idempotent retry, and a security constraint about never placing the code in a URL. The idempotency claim is consistent with idempotentHint=true.

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?

Dense and front-loaded: the core action comes first, then the confirmation flow, then constraints, then safety rules. Telegraphic phrasing ('POST origin for a uniform 202 response') occasionally costs clarity, but no sentence is padding.

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 only two flat parameters, no output schema, and minimal annotations, this covers the security posture, timing, response code, and expiry semantics an agent needs to call it safely. Remaining gap is what a failed or ineligible attempt looks like beyond the uniform 202, and the unresolved meaning of 'origin'.

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%, so the description must carry parameter meaning and only partly does: recovery_code's role, single-use nature, and 15-minute lifetime are explained, and the URL warning implies it travels in the body. The 'origin' parameter is never defined — whether it is the site being verified, the requesting domain, or an endpoint — leaving the required argument ambiguous.

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?

Opens with a specific verb and resource: request an email-based ownership-credential replacement for an existing verified private contact. The two-phase nature (request, then confirm with recovery_code) is described but not signposted as a mode switch, and nothing distinguishes it from siblings start_ownership_proof / confirm_ownership_proof.

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?

Gives a clear operating context: only for existing verified private contacts, one request per grant, then the same origin plus recovery_code within 15 minutes to confirm. It also states the exclusion case — revoked/expired grants or changed domains need a fresh ownership proof — though it does not name the sibling tool that provides that proof.

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