wwebjs-mcp

client_getContactById

Retrieve a specific WhatsApp contact by its ID within a session, providing direct access to contact details for use in automation workflows.

Instructions

[Client] Get the contact

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": "client_getContactById"
  }
}

Input Schema

Name	Required	Description	Default
`contactId`	No	The whatsapp user's ID
`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

D1.7/5.0

Behavior1/5

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 disclosing behavior. It says nothing about read-only nature, session requirements, error handling (e.g., not-found behavior), or any side effects. The description is a bare phrase with zero behavioral context.

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

Conciseness2/5

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

The description is extremely short, but this is under-specification rather than helpful conciseness. It fails to include any substantive information beyond the tool name, so the brevity does not serve the agent's needs.

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

Completeness1/5

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

With no output schema, no annotations, and a one-phrase description, the tool is severely incomplete. It does not explain return values, error conditions, or how the contact is identified, leaving the agent without critical execution context.

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?

Schema coverage is 100%, with both contactId and sessionId having descriptions in the input schema. The baseline for high schema coverage is 3, and the description adds no additional parameter meaning. It does not clarify relationships or usage, but the schema already provides sufficient semantic grounding.

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

Purpose2/5

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

The description 'Get the contact' merely restates the tool name without specifying the resource scope or distinguishing it from sibling contact tools like client_getContacts, client_getContactDeviceCount, or contact_getAbout. It lacks the specificity of a clear verb+resource definition, making it minimally useful for selecting this tool over others.

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

Usage Guidelines1/5

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

There is no guidance on when to use this tool versus alternatives. It does not mention conditions like needing a contactId, whether this is for a single contact vs. a list, or any exclusions. The agent is left without context to choose this over other contact-related tools.

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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