wwebjs-mcp

groupChat_setPicture

Set the group profile picture for a WhatsApp chat. Provide the chat ID and base64-encoded image data to update the group's photo.

Instructions

[Group Chat] Set the group picture

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": "groupChat_setPicture"
  }
}

Input Schema

Name	Required	Description
`chatId`	No	Unique WhatsApp id for the given chat group
`sessionId`	Yes	Unique identifier for the session (alphanumeric and - allowed)
`pictureData`	No	Base64-encoded data of the file
`pictureMimeType`	No	MIME type of the attachment

Schema Changelog

Changes observed during successful MCP inspections.

First observedv1.0.0Aug 2, 2026

TDQS

B3.1/5.0

Behavior1/5

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

The description merely restates the tool name ('Set the group picture') and provides no additional behavioral context. With no annotations, the description carries the full burden of disclosure, but it omits any side effects, requirements, or post-conditions (e.g., whether the picture becomes immediately visible, if there are size limits, or whether admin rights are needed).

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 a single, front-loaded sentence that is clear and free of unnecessary words. It efficiently conveys the core purpose without padding.

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 simple and the schema fully documents parameters, so the description is minimally viable. However, it lacks any usage context or behavioral details (e.g., whether this is a mutating operation with side effects, or how it differs from sibling tools), which limits its completeness for an agent deciding when to invoke it.

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 descriptions for all four parameters (100% coverage), so the baseline is 3. The description adds no additional parameter semantics beyond what the schema already states, such as the format of pictureData or the meaning of chatId.

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 action: 'Set the group picture' with a resource qualifier '[Group Chat]'. It distinguishes from siblings like groupChat_deletePicture and other setter tools (channel_setProfilePicture, client_setProfilePicture) by specifying the group chat context and the set operation.

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?

No guidance is provided on when to use this tool versus alternatives or any prerequisites. The description does not mention when to prefer this over groupChat_deletePicture or other group settings tools, nor any conditions like admin permissions or media requirements.

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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