Minibridge

Minibridge serves as a backend-to-frontend bridge, streamlining and securing

communication between Agents and MCP servers. It safely exposes [MCP

servers](https://modelcontextprotocol.io) to the internet and can optionally

integrate with generic policing services — known as Policers — for agent

authentication, content analysis, and transformation. Policers can be

implemented remotely via HTTP or locally using [OPA

Rego](https://www.openpolicyagent.org/docs/latest/policy-reference/) policies.

Minibridge can help ensure the integrity of MCP servers through

SBOM (Software Bill of Materials) generation and real-time validation.

Additionally, Minibridge supports OTEL and can

report/rettach spans from classical OTEL headers, as well as directly from the

MCP call, as inserted by certain tool like [Open

Inference](https://arize-ai.github.io/openinference).

• Minibridge Frontend: The Client connects to the Frontend part of Minibridge.
• Minibridge Backend: The Frontend connects to the Backend which wraps the MCP server.
• Minibridge Policer: The Policer runs in the Backend and can optionally take decision on the input and output based on some policies (locally with Rego or remotely using HTTPs)

> [!TIP]

> Conveniently, Minibridge can be started in an "all-in-one" (AIO) mode to act as a single process.

Why using Minibridge ?

Minibridge covers the following:

• Secure Transport: Use TLS with optionally, client certificate validation
• Integrity: Ensure the MCP server can not mutate tools, templates, etc. during the execution
• User Authentication: Transport the user information to the Policer
• Monitoring: Expose prometheus metrics
• Telemetry: Report traces and spans using Opentelemetry

Installation

Minibridge can be installed from various places:

Homebrew

On macOS, you can use Homebrew

brew tap acuvity/tap
brew install minibridge

AUR

On Arch based Linux distributions, you can run:

yay -S minibridge

Alternatively, to get the latest version from the main branch:

yay -S minibridge-git

Go

If you have the Go toolchain install:

go install go.acuvity.ai/minibridge@latest

Alternatively, to get the latest version from the main branch:

go install go.acuvity.ai/minibridge@main

Manually

You can easily grab a binary version for your platform from the [release

page](https://github.com/acuvity/minibridge/releases/tag/v0.6.2).

Features comparisons

✅ _Included_ | ⚠️ _Partial/Basic Support_ | 👤 _Custom User Implementation_ | ❌ _Not Supported_

Example: Configuring Minibridge in your MCP Client

Suppose your client configuration originally specifies an MCP server like this:

{
  "mcpServers": {
    "fetch": {
      "command": "uvx",
      "args": ["mcp-server-fetch"]
    }
  }
}

To route requests through Minibridge (enabling SBOM checks, policy enforcement, etc.), update the entry:

{
  "mcpServers": {
    "fetch": {
      "command": "minibridge",
      "args": ["aio", "--", "uvx", "mcp-server-fetch"]
    }
  }
}

• `minibridge aio`: Invokes Minibridge in “all-in-one” mode, wrapping the downstream tool.
• `uvx mcp-server-fetch`: The original MCP server command, now executed inside Minibridge.

> [!TIP]

> The location of the configuration files depends on your Client. For example, if you use Claude Desktop, configuration files are located:

>

> - macOS: `~/Library/Application Support/Claude/claude_desktop_config.json`

> - Windows: `%APPDATA%\Claude\claude_desktop_config.json`

>

> See the official MCP QuickStart for Claude Desktop Users documentation.

> [!IMPORTANT]

> Your client must be able to resolve the path of the binary.

> If you see an error like `MCP fetch: spawn minibridge ENOENT`, set the `command` parameter above to the full path of minibridge (`which minibridge` will give you the full path).

Documentation

Check out the complete documentation from the wiki pages.

Contribute

We are excited to welcome contributions from everyone! 🎉 Whether you're fixing bugs, enhancing features, improving documentation, or proposing entirely new ideas, your involvement helps strengthen the project and benefits the entire community.

You do not need to sign a Contributor License Agreement (CLA) — just open a pull request and let's collaborate!

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