WAHA MCP Server

Instructions

Implementation Reference

• src/index.ts:2135-2162 (handler)

  The main MCP tool handler function that processes the tool call, validates input, parses the participants JSON string from input, calls the underlying WAHAClient method, and returns a formatted response with the result.

  private async handleAddGroupParticipants(args: any) {
    const groupId = args.groupId;
    const participantsStr = args.participants;
  
    if (!groupId) {
      throw new Error("groupId is required");
    }
  
    if (!participantsStr) {
      throw new Error("participants is required");
    }
  
    const participants = JSON.parse(participantsStr);
  
    const result = await this.wahaClient.addGroupParticipants({
      groupId,
      participants,
    });
  
    return {
      content: [
        {
          type: "text",
          text: `Successfully added ${participants.length} participant(s) to group ${groupId}.\n${JSON.stringify(result, null, 2)}`,
        },
      ],
    };
  }

• src/index.ts:698-715 (registration)

  Tool registration in the list of available tools returned by ListToolsRequestSchema. Includes name, description, and input schema definition.

  {
    name: "waha_add_group_participants",
    description: "Add member(s) to a group. Requires admin privileges.",
    inputSchema: {
      type: "object",
      properties: {
        groupId: {
          type: "string",
          description: "Group ID (format: number@g.us)",
        },
        participants: {
          type: "string",
          description: "JSON array of participants to add (format: [{'id': 'number@c.us'}, ...])",
        },
      },
      required: ["groupId", "participants"],
    },
  },

• src/index.ts:701-714 (schema)

  Input schema definition for the tool, specifying required groupId and participants as JSON string.

  inputSchema: {
    type: "object",
    properties: {
      groupId: {
        type: "string",
        description: "Group ID (format: number@g.us)",
      },
      participants: {
        type: "string",
        description: "JSON array of participants to add (format: [{'id': 'number@c.us'}, ...])",
      },
    },
    required: ["groupId", "participants"],
  },

• src/client/waha-client.ts:981-1003 (helper)

  Underlying WAHA API client method that makes the HTTP POST request to the WAHA server endpoint /api/{session}/groups/{groupId}/participants/add to add participants to the group.

  async addGroupParticipants(params: {
    groupId: string;
    participants: Array<{ id: string }>;
  }): Promise<any> {
    const { groupId, participants } = params;
  
    if (!groupId) {
      throw new WAHAError("groupId is required");
    }
  
    if (!participants || participants.length === 0) {
      throw new WAHAError("participants array is required");
    }
  
    const endpoint = `/api/${this.session}/groups/${encodeURIComponent(groupId)}/participants/add`;
  
    const body = { participants };
  
    return this.request<any>(endpoint, {
      method: "POST",
      body: JSON.stringify(body),
    });
  }