SemaphoreUI MCP Server

A Model Context Protocol (MCP) server that connects AI assistants to SemaphoreUI - enabling natural language control of Ansible automation.

Quick Start

Prerequisites

• Docker (or Podman)
• A running SemaphoreUI instance with an API token
• Claude Desktop or Claude Code (or another MCP client)
• Node.js (for Claude Desktop only - required for mcp-remote)

1. Get a SemaphoreUI API Token

1. Login to your SemaphoreUI instance
2. Go to User Settings
3. Generate a new API token

2. Run the MCP Server

docker run -d --name semaphore-mcp \
  --network host \
  -e SEMAPHORE_URL=http://localhost:3000 \
  -e SEMAPHORE_API_TOKEN=your-token-here \
  -e MCP_PORT=8500 \
  ghcr.io/cloin/semaphore-mcp:latest

Note: SEMAPHORE_URL is where the MCP server connects to SemaphoreUI. MCP_PORT is where the MCP server listens for client connections (Claude Desktop/Code). Use this port in your client configuration below.

3a. Configure Claude Desktop

Claude Desktop requires the mcp-remote proxy to connect to HTTP-based MCP servers. This requires Node.js to be installed (npx comes with npm).

Edit your config file:

• macOS: ~/Library/Application Support/Claude/claude_desktop_config.json
• Windows: %APPDATA%\Claude\claude_desktop_config.json
• Linux: ~/.config/claude-desktop/claude_desktop_config.json

{
  "mcpServers": {
    "semaphore": {
      "command": "npx",
      "args": ["mcp-remote", "http://127.0.0.1:8500/mcp"]
    }
  }
}

3b. Configure Claude Code

Claude Code supports remote MCP servers directly:

claude mcp add --transport http semaphore http://127.0.0.1:8500/mcp

Verify it's configured:

claude mcp list

4. Test It

Restart Claude Desktop and try:

"List all projects in SemaphoreUI"

Docker Networking

The MCP server container needs to reach your SemaphoreUI instance.

SemaphoreUI on the same host:

Use --network host so the container can access localhost:

docker run -d --name semaphore-mcp \
  --network host \
  -e SEMAPHORE_URL=http://localhost:3000 \
  -e SEMAPHORE_API_TOKEN=your-token \
  -e MCP_PORT=8500 \
  ghcr.io/cloin/semaphore-mcp:latest

SemaphoreUI on a different host:

Use the IP or hostname directly (no --network host needed):

docker run -d --name semaphore-mcp \
  -e SEMAPHORE_URL=http://192.168.1.100:3000 \
  -e SEMAPHORE_API_TOKEN=your-token \
  -p 8500:8000 \
  ghcr.io/cloin/semaphore-mcp:latest

For more details, see Docker's networking documentation.

Configuration

Variable	Required	Default	Description
SEMAPHORE_URL	Yes	-	URL to your SemaphoreUI instance
SEMAPHORE_API_TOKEN	Yes	-	API token from SemaphoreUI
MCP_TRANSPORT	No	http	Transport mode: http or stdio
MCP_HOST	No	0.0.0.0	Host to bind to
MCP_PORT	No	8000	Port to listen on

What You Can Do

Once connected, you can interact with SemaphoreUI through natural conversation:

Run automation:

"Run the database backup playbook on production"

Monitor tasks:

"Show me all failed tasks from the last hour and analyze the errors"

Manage infrastructure:

"Create a new staging environment with APP_ENV=staging"

Troubleshoot:

"Get the output from task 42 and tell me why it failed"

Available Tools

Projects: list_projects, get_project, create_project, update_project, delete_project

Templates: list_templates, get_template, create_template, update_template, delete_template

Tasks: list_tasks, get_task, run_task, stop_task, get_task_raw_output, filter_tasks, bulk_stop_tasks

Analysis: analyze_task_failure, bulk_analyze_failures, get_latest_failed_task

Environments: list_environments, get_environment, create_environment, update_environment, delete_environment

Inventory: list_inventory, get_inventory, create_inventory, update_inventory, delete_inventory

Repositories: list_repositories, get_repository, create_repository, update_repository, delete_repository

Access keys: list_access_keys, create_access_key, delete_access_key

Troubleshooting

Container won't start or exits immediately:

docker logs semaphore-mcp

Can't connect to SemaphoreUI from container:

• If SemaphoreUI is on localhost, use --network host
• Check that the URL is reachable from inside the container
• Verify the API token is correct

Claude Desktop not seeing the MCP server:

• Ensure the container is running: docker ps
• Check the port is accessible: curl http://127.0.0.1:8500/mcp
• Restart Claude Desktop after config changes

Enable debug logging:

docker run -d --name semaphore-mcp \
  --network host \
  -e SEMAPHORE_URL=http://localhost:3000 \
  -e SEMAPHORE_API_TOKEN=your-token \
  -e MCP_PORT=8500 \
  -e MCP_LOG_LEVEL=DEBUG \
  ghcr.io/cloin/semaphore-mcp:latest

Development

For local development and contributing, see DEVELOPMENT.md.

For testing documentation (unit tests, E2E tests, CI/CD), see TESTING.md.

Resources

• SemaphoreUI Documentation
• SemaphoreUI API Reference
• Model Context Protocol
• GitHub Issues

License

This project is licensed under the GNU Affero General Public License v3.0 - see the LICENSE file for details.

Note: Versions prior to 1.0.0 were released under the MIT License.