Verify if up to 50 international phone numbers have WhatsApp accounts without messaging them. Check contact availability before outreach or importing lists.
Vérifie si des numéros ont un compte WhatsApp, sans rien leur envoyer.
| Name | Required | Description | Default |
|---|---|---|---|
| phones | Yes | Numéros internationaux (`+33612345678` ou `33612345678`), 50 au plus. | |
| account | No |
| Name | Required | Description | Default |
|---|---|---|---|
| results | Yes |
Changes observed during successful MCP inspections.
v0.1.1Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint and openWorldHint, so the safety profile is covered. The description does add non-obvious context — the checked numbers are not notified — but says nothing about rate limiting, error behavior for invalid numbers, or what happens when the account parameter is omitted.
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?
A single tight sentence with the core action and the key constraint front-loaded. Nothing is wasted, though it is arguably too brief for a tool with an undocumented parameter.
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?
The presence of an output schema means return values need not be described. However, for a two-parameter tool with an unexplained account parameter and no usage routing, the description leaves meaningful gaps an agent would have to guess at.
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 only 50%: the phones parameter is fully documented in the schema (format, max 50), but the account parameter has no description anywhere, and the description offers no hint about its role. With a mutation-relevant scope selector left entirely unexplained, the description fails to compensate for the gap.
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: checks whether phone numbers have a WhatsApp account. The added 'sans rien leur envoyer' sharpens the scope (a lookup, not a message) and implicitly separates it from the send_* siblings. It does not name any sibling explicitly, so it falls 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?
No statement of when to reach for this tool versus alternatives such as search_contacts or send_message. The implied use case (validate numbers before messaging them) must be inferred from 'sans rien leur envoyer', with no prerequisites or exclusions spelled out.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.