Teams MCP

send_channel_message

Send messages to Microsoft Teams channels with text, markdown formatting, mentions, attachments, and importance levels for team communication.

Instructions

Send a message to a specific channel in a Microsoft Team. Supports text and markdown formatting, mentions, and importance levels.

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": {
      "teamId": "<teamId>",
      "channelId": "<channelId>",
      "message": "<message>"
    },
    "name": "send_channel_message"
  }
}

Input Schema

Name	Required	Description
`teamId`	Yes	Team ID
`channelId`	Yes	Channel ID
`message`	Yes	Message content
`importance`	No	Message importance
`format`	No	Message format (text or markdown)
`mentions`	No	Array of @mentions to include in the message
`imageUrl`	No	URL of an image to attach to the message
`imageData`	No	Base64 encoded image data to attach
`imageContentType`	No	MIME type of the image (e.g., 'image/jpeg', 'image/png')
`imageFileName`	No	Name for the attached image file

Schema Changelog

Changes observed during successful MCP inspections.

First observedAug 18, 2025

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 mentions 'Supports text and markdown formatting, mentions, and importance levels' which describes capabilities but not behaviors. Critical behavioral aspects are missing: whether this is a mutating operation (implied but not stated), permission requirements, rate limits, error conditions, or what happens on success (e.g., returns message ID?). For a message-sending tool with 10 parameters, this is inadequate.

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

Conciseness4/5

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

The description is a single, efficient sentence that communicates the core purpose upfront. It wastes no words on redundancy or unnecessary elaboration. However, it could be more structured by separating purpose from capabilities for even clearer scanning.

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 complex mutation tool with 10 parameters, no annotations, and no output schema, the description is insufficient. It doesn't address critical context: mutation nature, authentication requirements, error handling, return values, or usage boundaries. The agent lacks enough information to use this tool confidently beyond basic parameter filling.

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 parameters thoroughly. The description adds minimal value beyond the schema - it mentions 'text and markdown formatting' (covered by the 'format' enum), 'mentions' (covered by the 'mentions' array), and 'importance levels' (covered by the 'importance' enum). No additional semantic context is provided about parameter interactions or usage patterns.

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 a message') and target ('to a specific channel in a Microsoft Team'), which is specific and actionable. It distinguishes from siblings like 'send_chat_message' by specifying 'channel' rather than 'chat', but doesn't explicitly contrast them. The mention of supported features (formatting, mentions, importance) adds useful detail about capabilities.

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_chat_message' or 'reply_to_channel_message'. It mentions supported features but doesn't specify prerequisites, constraints, or typical use cases. The agent must infer usage from the tool name and parameter names alone.

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