whatsapp-mcp-server

whatsapp_send_audio

Send an audio message to a WhatsApp phone number using a publicly accessible audio URL. Requires recipient number and audio URL.

Instructions

Send an audio message to a WhatsApp phone number. Provide a publicly accessible audio URL.

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": {
      "to": "<to>",
      "audio_url": "<audio_url>"
    },
    "name": "whatsapp_send_audio"
  }
}

Input Schema

Name	Required	Description
`to`	Yes	Phone number in E.164 format, e.g. +15551234567
`audio_url`	Yes	Publicly accessible URL of the audio file
`reply_to_message_id`	No	Message ID to reply to

Schema Changelog

Changes observed during successful MCP inspections.

First observedv1.1.0Jun 26, 2026

TDQS

B3.4/5.0

Behavior2/5

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

No annotations are provided, so the description carries the full burden. It only states that the tool sends an audio message, with no disclosure about file formats, size limits, rate limits, or whether it is destructive. This is insufficient for an agent to understand behavioral consequences.

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?

Extremely concise: two short sentences that front-load the action. No superfluous text.

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

Completeness2/5

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

Given the tool involves sending audio with 3 parameters and no output schema or annotations, the description is bare-bones. It omits critical context such as supported audio formats, file size limits, group chat support, and prerequisites (e.g., WhatsApp Business account).

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%, so the description does not need to explain parameters in detail. It adds some value by emphasizing the 'publicly accessible' requirement for audio_url, but does not add significant meaning beyond the schema.

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?

Clearly states the action ('send'), resource ('audio message'), and a key requirement (publicly accessible audio URL). Differentiates from sibling tools like whatsapp_send_text and whatsapp_send_image by specifying 'audio'.

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

Usage Guidelines3/5

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

Implies usage context by mentioning the need for a publicly accessible audio URL, but does not explicitly state when to prefer this tool over alternatives (e.g., whatsapp_upload_media) or when not to use it.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Deploy Server