WhatsApp MCP Server

send_text_message

Send text messages or template-based communications through WhatsApp Business API to specified recipients using phone numbers.

Instructions

Send a text message or template message via WhatsApp Business API

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>"
    },
    "name": "send_text_message"
  }
}

Input Schema

Name	Required	Description	Default
`to`	Yes	Recipient phone number with country code
`message`	No	Text message to send (optional if template_name is provided)
`template_name`	No	Template name to use (optional if message is provided)
`language_code`	No	Language code for template	en_US
`phone_number_id`	No	WhatsApp Business phone number ID (optional, uses env var if not provided)

Schema Changelog

Changes observed during successful MCP inspections.

First observedv1.0.0Jan 12, 2026

TDQS

C2.9/5.0

Behavior2/5

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

With no annotations provided, the description carries full burden for behavioral disclosure. It states this is a 'send' operation (implying mutation) but doesn't mention authentication requirements, rate limits, error conditions, or what happens on success/failure. For a messaging tool with zero annotation coverage, this leaves significant behavioral gaps.

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, efficient sentence that directly states the tool's function without unnecessary words. It's appropriately sized and front-loaded, with every word earning its place in conveying the core purpose.

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?

For a messaging tool with 5 parameters, no annotations, and no output schema, the description is insufficient. It doesn't explain what happens after sending (success indicators, message IDs, error responses), doesn't mention authentication or rate limiting, and provides no guidance on tool selection among 10 sibling messaging tools.

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 description coverage is 100%, so the schema already documents all 5 parameters thoroughly. The description adds no additional parameter semantics beyond what's in the schema (like explaining the relationship between message and template_name). Baseline 3 is appropriate when schema does the heavy lifting.

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

Purpose4/5

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

The description clearly states the action ('send') and resource ('text message or template message via WhatsApp Business API'), making the purpose immediately understandable. However, it doesn't explicitly differentiate from sibling tools like send_template_message or send_button_message, which would require more specific scope definition to earn a 5.

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 like send_template_message or send_button_message. There's no mention of prerequisites, use cases, or exclusions, leaving the agent with minimal context for tool selection among the messaging siblings.

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

Deploy Server