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

Annotations already declare it non-read-only, non-destructive, and idempotent. The description adds value beyond them by disclosing state behavior ('The site stays unclaimed until the link in the mail is opened') and cost ('Does not charge'), which an agent cannot get from the annotations.

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?

Four tight sentences, front-loaded with the action and immediately followed by parameter provenance ('site_id and site_token are the values from the deploy reply'). No filler, though the sentence count is slightly higher than strictly necessary.

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?

For a three-parameter action tool with no output schema, the description covers the key behavioral facts an agent needs: the site remains unclaimed, the mail drives a link-based claim, and no charge occurs. Only the relationship to sibling claim tools is unaddressed.

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%, so the schema already documents all three parameters, including their deploy-reply provenance and the email target. The description largely restates those facts, so the baseline of 3 is appropriate.

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 ('Sends the claim mail for an unclaimed site'), so the action is unambiguous. It does not name its closest sibling (claim_site), leaving the boundary between sending the mail and performing the claim to inference, which keeps it at 4 rather than 5.

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 implies the deployment context by requiring values 'from the deploy reply' and scopes usage to 'an unclaimed site', which suggests this is a post-deploy step. However, it never states when to call this versus claim_site or resend_owner_verification, so usage is only implied.

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