Kyle Carberry 0f86c4237e feat: add workspace MCP tool discovery and proxying for chat (#23680)
Coder's chat (chatd) can now discover and use MCP servers configured in
a workspace's `.mcp.json` file. This brings project-specific tooling
(GitHub, databases, docs servers, etc.) into the chat without any manual
configuration.

## How it works

The workspace agent reads `.mcp.json` from the workspace directory (same
format Claude Code uses), connects to the declared MCP servers —
spawning child processes for stdio servers and connecting over the
network for HTTP/SSE — and caches their tool lists. Two new agent HTTP
endpoints expose this:

- `GET /api/v0/mcp/tools` returns the cached tool list (supports
`?refresh=true`)
- `POST /api/v0/mcp/call-tool` proxies calls to the correct server

On each chat turn, chatd calls `ListMCPTools` through the existing
`AgentConn` tailnet connection, wraps each tool as a
`fantasy.AgentTool`, and adds them to the LLM's tool set alongside
built-in and admin-configured MCP tools. Tool names are prefixed with
the server name (`github__create_issue`) to avoid collisions.

Failed server connections are logged and skipped — they never block the
agent or break the chat. Child stdio processes are terminated on agent
shutdown.
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Coder enables organizations to set up development environments in their public or private cloud infrastructure. Cloud development environments are defined with Terraform, connected through a secure high-speed Wireguard® tunnel, and automatically shut down when not used to save on costs. Coder gives engineering teams the flexibility to use the cloud for workloads most beneficial to them.

  • Define cloud development environments in Terraform
    • EC2 VMs, Kubernetes Pods, Docker Containers, etc.
  • Automatically shutdown idle resources to save on costs
  • Onboard developers in seconds instead of days

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Quickstart

The most convenient way to try Coder is to install it on your local machine and experiment with provisioning cloud development environments using Docker (works on Linux, macOS, and Windows).

# First, install Coder
curl -L https://coder.com/install.sh | sh

# Start the Coder server (caches data in ~/.cache/coder)
coder server

# Navigate to http://localhost:3000 to create your initial user,
# create a Docker template and provision a workspace

Install

The easiest way to install Coder is to use our install script for Linux and macOS. For Windows, use the latest ..._installer.exe file from GitHub Releases.

curl -L https://coder.com/install.sh | sh

You can run the install script with --dry-run to see the commands that will be used to install without executing them. Run the install script with --help for additional flags.

See install for additional methods.

Once installed, you can start a production deployment with a single command:

# Automatically sets up an external access URL on *.try.coder.app
coder server

# Requires a PostgreSQL instance (version 13 or higher) and external access URL
coder server --postgres-url <url> --access-url <url>

Use coder --help to get a list of flags and environment variables. Use our install guides for a complete walkthrough.

Documentation

Browse our docs here or visit a specific section below:

  • Templates: Templates are written in Terraform and describe the infrastructure for workspaces
  • Workspaces: Workspaces contain the IDEs, dependencies, and configuration information needed for software development
  • IDEs: Connect your existing editor to a workspace
  • Administration: Learn how to operate Coder
  • Premium: Learn about our paid features built for large teams

Support

Feel free to open an issue if you have questions, run into bugs, or have a feature request.

Join our Discord to provide feedback on in-progress features and chat with the community using Coder!

Integrations

We are always working on new integrations. Please feel free to open an issue and ask for an integration. Contributions are welcome in any official or community repositories.

Official

Community

Contributing

We are always happy to see new contributors to Coder. If you are new to the Coder codebase, we have a guide on how to get started. We'd love to see your contributions!

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Apply here if you're interested in joining our team.

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