confirme_courrielCan this email address receive mail? Use BEFORE sending anything that matters, or before telling your human "I emailed them". Syntax, MX servers, disposable domain, role address, verdict. No message is sent. Signed receipt included.
| Name | Required | Description | Default |
|---|---|---|---|
| cle | No | Optional: your Confirme key (cj_…) if this server URL does not already carry ?cle=. Get one free with confirme_sac. | |
| courriel | Yes |
Changes observed during successful MCP inspections.
Input schema / properties / cleAdded value: +{
+ "description": "Optional: your Confirme key (cj_…) if this server URL does not already carry ?cle=. Get one free with confirme_sac.",
+ "type": "string"
+}Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so the safety profile is covered. The description adds meaningful context beyond that: 'No message is sent' clarifies it is a passive probe rather than a send, and 'Signed receipt included' discloses what comes back. It does not discuss rate limits or timeout behavior, keeping it at a 4.
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 core question, then usage timing, then what is checked, then a reassurance clause. Every sentence earns its place and there is no redundancy or 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?
There is no output schema, so the description must convey return content, and it does list the concrete signals returned (syntax, MX servers, disposable domain, role address, verdict, signed receipt). This is nearly complete, though the format or structure of the 'verdict' is left unspecified.
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 50%: the optional 'cle' parameter is documented in the schema, while 'courriel' has none. The description implies the required input is the email address under test, but adds no format or syntax detail beyond what the JSON key already conveys. Baseline 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?
The opening question 'Can this email address receive mail?' names a specific resource (an email address) and operation (deliverability check), and the enumeration of checks (syntax, MX, disposable domain, role address, verdict) makes the purpose concrete. The email-address focus inherently distinguishes it from domain-oriented siblings like confirme_domaine.
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?
Explicit when-to-use guidance is given with strong framing: 'Use BEFORE sending anything that matters, or before telling your human "I emailed them".' This tells the agent the exact trigger conditions. It stops short of naming an alternative tool or an explicit when-not-to-use, so it is not a full 5.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Add one secure layer between your agents and this server.