Mattermost HostBLOCK
A Mattermost integration that connects to Model Context Protocol (MCP) servers, leveraging a LangGraph-based Agent.
Overview
From the repository's own README, as read at the audited commit. Badges and raw HTML are left out.
A Mattermost integration that connects to Model Context Protocol (MCP) servers, leveraging a LangGraph-based AI agent to provide an intelligent interface for interacting with users and executing tools directly within Mattermost.
Demo
1. Github Agent in support channel - searches the existing issues and PRs and creates a new issue if not found
2. Search internet and post to a channel using Mattermost-MCP-server
Scroll below for full demo in YouTube
Features
- 🤖 Langgraph Agent Integration: Uses a LangGraph agent to understand user requests and orchestrate responses.
- 🔌 MCP Server Integration: Connects to multiple MCP servers defined in
mcp-servers.json. - 🛠️ Dynamic Tool Loading: Automatically discovers tools from connected MCP servers and makes them available to the AI agent. Converts MCP tools to langchain structured tools.
- 💬 Thread-Aware Conversations: Maintains conversational context within Mattermost threads for coherent interactions.
- 🔄 Intelligent Tool Use: The AI agent can decide when to use available tools (including chaining multiple calls) to fulfill user requests.
- 🔍 MCP Capability Discovery: Allows users to list available servers, tools, resources, and prompts via direct commands.
- #️⃣ Direct Command Interface: Interact directly with MCP servers using a command prefix (default:
#).
Overview
The integration works as follows:
- Mattermost Connection (`mattermost_client.py`): Connects to the Mattermost server via API and WebSocket to listen for messages in a specified channel.
- **MCP Connections (`mcp_clien
2d4fd778af51OBSERVED · 2026-10-08Connect
Built from this server's own package name, version and transport as found in its source — not copied from anyone's documentation, so it cannot drift against a page we do not control. Replace the environment placeholders with a token scoped to the least it needs.
claude mcp add mattermost-mcp-host --env AZURE_OPENAI_API_KEY=${AZURE_OPENAI_API_KEY} --env MATTERMOST_TOKEN=${MATTERMOST_TOKEN} -- uvx mattermost-mcp-host{
"mcpServers": {
"mattermost-mcp-host": {
"command": "uvx",
"args": [
"mattermost-mcp-host"
],
"env": {
"AZURE_OPENAI_API_KEY": "${AZURE_OPENAI_API_KEY}",
"MATTERMOST_TOKEN": "${MATTERMOST_TOKEN}"
}
}
}
}Exposed tools (10)
7 read · 3 write · 0 destructive.
| Tool | Risk | Description |
|---|---|---|
add-reaction | write | Add a reaction emoji to a post |
chat | read | Chat with Ollama model |
create-project-channel | write | Create a new channel for a project |
echo | read | Echo a message |
generate | read | Generate text using Ollama |
list_models | read | List all available models from Ollama |
pin-important-message | read | Pin an important message in a channel |
post-message | write | Post a message to a Mattermost channel |
reverse | read | Reverse a message |
search-posts | read | Search for posts with specific keywords |
Trust audit
BLOCKgrade D · trust 69/100 Do not install this without reading the findings. The audit found something that could harm you or your machine.
| Layer | What it checks | Result |
|---|---|---|
| L0 | Provenance & inventory | PASS |
| L1 | Static analysis of the code | FAIL |
| L2 | Instruction surface (what it tells the agent) | PASS |
| L3 | Class-specific surface | PASS |
| L4 | Behavioural (sandbox) | SKIPPED |
What the source does
- Filesystem
- none-observed
- Network
- declared (5 observation(s))
- Shell
- declared (1 observation(s))
- Dependencies
- pinned
- Secrets in source
- none-found
Findings (6)
result = eval(expression, {"__builtins__": {}}, {"abs": abs, "round": round, "max": max, "min": min})demo/demo-1.gif
demo/demo-2.gif
demo/demo-3.gif
- Save the access token in the .env file
# curl -LsSf https://astral.sh/uv/install.sh | sh
Gates applied: no_behavioural_pass.
2d4fd778af51full audit observations/trust-audit/mcp-server/jagan-shanmugam__mattermost-host.json · Report an issue / request a re-scanAudit history
Every audit this server has had. A grade with a past is a grade somebody is still checking.
| Date | Source | Verdict | Grade | Score | Change |
|---|---|---|---|---|---|
| 2026-10-08 | 2d4fd778af51 | BLOCK | D | 69 | first audit |
Questions
What is the Mattermost Host MCP server?
A Mattermost integration that connects to Model Context Protocol (MCP) servers, leveraging a LangGraph-based Agent.
What tools does Mattermost Host expose?
10 in total: 7 read-only, 3 that write, and 0 that can delete or overwrite. Every one is listed on this page with its risk.
Is Mattermost Host safe to connect to an agent?
No — not without reading the findings first. The audit graded it D (69/100) and found 1 critical or high issue in the source. Each one is listed on this page with the file and line it is on.
What credentials does Mattermost Host need?
It reads AZURE_OPENAI_API_KEY and MATTERMOST_TOKEN from the environment. Give it a token scoped to the least it needs — an agent that can be talked into calling a tool can be talked into calling it with your credentials.
How does Mattermost Host run?
It speaks stdio, so it runs as a local process your client starts. It is published on PyPI as mattermost-mcp-host.
How current is this page?
The grade is for one exact copy of the source (2d4fd778af51), read on 2026-10-08. The repository is watched and re-audited when it changes.