send_claim_codeStep 2 (mail route): a 6-digit code to an address at the claimed domain. local is the part before the @ (e.g. jane or admin). Not for a mailbox provider's domain (gmail.com, tuta.com …): DNS, the meta tag or the file prove those. verify_claim checks the code.
| Name | Required | Description | Default |
|---|---|---|---|
| local | Yes | the part before @, e.g. jane or admin | |
| claim_id | Yes | The claim's id, from claim_domain or whoami |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=false, openWorldHint=true, idempotentHint=false and destructiveHint=false, so the external side effect and non-idempotency are covered. The description adds that a code is emitted and later checked by verify_claim, but says nothing about resend behavior, code expiry, rate limits, or what happens if the address isn't valid for the claim.
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 short sentences, front-loaded with the route/step context and then the exclusion, with no filler. The telegraphic fragments ('Step 2 (mail route): a 6-digit code…') cost a little readability but not efficiency.
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 two-parameter tool with fully documented schema, no output schema, and annotations covering the safety profile, the description supplies what matters: the route, the exclusion set, and the follow-up verification step. Nothing an agent needs to invoke it 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%, so both parameters are already documented, and the description's 'local is the part before the @ (e.g. jane or admin)' merely restates the schema wording. It adds only the indirect hint that the domain comes from the claim rather than the caller, so baseline 3 is right.
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 identifies a specific resource (a 6-digit claim code) and its delivery channel/scoping (mailed to an address at the claimed domain), and places it as 'Step 2 (mail route)' in a workflow. The precise verb is only implied by the tool name and 'mail route', and the counterpart step-1 tool is not named, so it falls just short of a 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 gives a concrete exclusion ('Not for a mailbox provider's domain (gmail.com, tuta.com …)') and redirects those cases to the DNS, meta-tag or file routes, and it points to verify_claim as the check. It still doesn't state positively when the mail route is the right choice versus the other proof methods for a self-hosted domain.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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