authprobe

AuthProbe is an MCP server used to diagnose OAuth-related issues in MCP flows. It runs as an MCP server and exposes a diagnostic workflow that traces the MCP discovery/init, PRM, issuer metadata, and protected-resource checks, helping you pinpoint exactly where an RFC or MCP violation occurs during an MCP scan. The server can operate in standard MCP mode or bridge stdio-based MCP commands to a local HTTP endpoint for testing. The core capabilities include executing a scan against an MCP URL, producing actionable diagnostics, and optionally providing RFC-based explanations or verbose trace output to aid debugging. You can also leverage an interactive bridge mode to test existing HTTP-based checks against stdio servers and integrate with other tooling.

To use AuthProbe as an MCP server, configure it with the mcpServers entry and run the server, typically via: mcpServers.authprobe -> command: "authprobe", args: ["mcp", "--transport", "stdio"]. Then point your MCP client tests at the server (e.g., through a local bridge or a container) to perform automated scans or to capture protocol diagnostics. The toolset supports standard scan commands, explanation mode for RFC compliance gaps, and detailed traces to help triage failures across OAuth discovery, metadata, and protected resources.

Prerequisites

• Go toolchain installed (for building from source or using the Go install option)
• Internet access to fetch modules (or use the prebuilt binaries or Docker image)
• Optional: Docker if you want to run via container

Installation options Option A: Install using Go toolchain (recommended for dev and CI)

1. Install the latest AuthProbe binary into your Go workspace: go install github.com/authprobe/authprobe/cmd/authprobe@latest
2. Run the MCP server via the MCP bridge: mcpServers.authprobe command: "authprobe", args: ["mcp", "--transport", "stdio"]

Option B: Install via the official install script (latest release)

1. Run the installer script (no sudo required; installs into ~/.local/bin): curl -fsSL https://raw.githubusercontent.com/authprobe/authprobe/main/scripts/install.sh | sh
2. Run the MCP server as above: ~/.local/bin/authprobe mcp --transport stdio

Option C: Run using Docker

1. Pull the latest image: docker pull ghcr.io/authprobe/authprobe:latest
2. Run the MCP server: docker run --rm ghcr.io/authprobe/authprobe:latest mcp --transport stdio

Option D: Clone and build from source

1. Clone the repo: git clone https://github.com/authprobe/authprobe.git && cd authprobe
2. Run a scan against an MCP URL (example): go run cmd/authprobe/main.go scan https://mcp.example.com/mcp

Check version (if installed): authprobe --version authprobe 0.4.0 (commit ...)

Environment variables and configuration tips:

• OPENAI_API_KEY can be set to enable optional LLM-based explanations of failures (used with --explain and related flags).
• ANTHROPIC_API_KEY can be set to use Anthropic for explanations if preferred.
• When using the stdio bridge mode, ensure the command provided (e.g., npx -y @modelcontextprotocol/server-everything) is accessible in the environment and that transport stdio is configured correctly.
• The MCP server supports standard OAuth discovery and protected-resource metadata checks; enabling verbose tracing (--explain --trace-failure) can generate large logs—use selectively in CI or local debugging.
• If you encounter network/timeouts, verify that MCP URLs are reachable from the environment running the AuthProbe server and that any required headers or content types conform to the MCP spec.
• Docker users: you can pass additional command-line arguments to the container as needed, but ensure you expose any necessary ports or bridges if integrating with local tooling.