wwebjs-mcp

contact_getCountryCode

Retrieves the country code from a WhatsApp contact ID. Provide the session ID and contact ID to get the numeric country code prefix.

Instructions

[Contact] Get the country code. Returns the contact's country code, (1541859685@c.us) => (1).

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "sessionId": "<sessionId>"
    },
    "name": "contact_getCountryCode"
  }
}

Input Schema

Name	Required	Description	Default
`contactId`	No	Unique WhatsApp ID for the contact
`sessionId`	Yes	Unique identifier for the session (alphanumeric and - allowed)

Schema Changelog

Changes observed during successful MCP inspections.

First observedv1.0.0Aug 2, 2026

TDQS

A3.5/5.0

Behavior3/5

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It discloses the core behavior (returns the country code) and even gives an example, but does not mention potential errors, whether the operation is read-only, or any edge cases like invalid contact IDs. For a simple getter, this is adequate but not thorough.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is extremely concise, using one sentence and an example to convey the purpose and behavior. It is front-loaded with the verb 'Get' and includes only essential information, with no wasted words.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness3/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

The tool is low complexity with a full input schema, but there is no output schema or annotations. The description is complete enough for a trivial getter, yet it omits return type information (string vs. number) and error handling. Given the simplicity, this is acceptable but leaves some gaps for an agent relying solely on this text.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The input schema already provides 100% coverage with clear descriptions for both parameters. The description adds no extra meaning to the parameters beyond what the schema states, but it does reinforce that contactId is tied to the contact's country code. This meets the baseline for schema coverage.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool's function: 'Get the country code' for a contact, with a concrete example mapping a phone number to a country code. It distinguishes itself from sibling tools like client_getCountryCode by prefixing '[Contact]' and specifying it operates on a contact, making the purpose unambiguous.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines2/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description provides no guidance on when to use this tool versus alternatives such as client_getCountryCode or other contact-related tools. It implies usage for retrieving a contact's country code but does not state exclusions or prerequisites, leaving the agent without clear selection criteria.

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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