smart-mcp-proxy/mcpproxy-go v0.58.0 on GitHub

This release introduces enhanced preflight capabilities for smarter tool availability checking and improves agent authentication security.

New Features

In-band preflight for tool descriptions — Added describe_tool check mode that allows agents to verify tool availability and fetch descriptions before invocation, implementing MCP spec 099. This enables more intelligent tool selection with upfront availability validation.
Required-tools preflight validation — New deterministic availability check that verifies whether specific tools are accessible, with detailed reason taxonomy explaining why tools might be unavailable (e.g., permissions, resource limits, configuration issues). Implements spec 098.
Preflight telemetry counters — Added baseline metrics tracking preflight usage patterns, including filter-diagnostics engagement rates and availability blocks, enabling better visibility into how agents discover and validate tools.

Bug Fixes

Fixed stale agent-token security issue — Resolved a critical authentication bug where expired agent tokens with stale ProfilePin references would incorrectly resolve to deny-all scope instead of properly rejecting the authentication attempt. This ensures more secure and predictable authorization behavior.

Applies to both Personal and Teams editions unless otherwise noted.

Download Installers

Platform	Download	Notes
macOS (Apple Silicon)	Download DMG	Signed & Notarized - Recommended for M1/M2/M3/M4
macOS (Intel)	Download DMG	Signed & Notarized
Windows (64-bit)	Download Setup	Setup wizard
Windows (ARM64)	Download Setup	For ARM Windows devices
Linux Debian/Ubuntu (AMD64)	Download .deb	`sudo apt install ./mcpproxy_*.deb`
Linux Debian/Ubuntu (ARM64)	Download .deb	For ARM64 (Raspberry Pi etc.)
Linux Fedora/RHEL (AMD64)	Download .rpm	`sudo dnf install ./mcpproxy-*.rpm`
Linux Fedora/RHEL (ARM64)	Download .rpm	For ARM64
Linux (AMD64) — tarball	Download tar.gz	Binary only
Linux (ARM64) — tarball	Download tar.gz	Binary only

Homebrew (macOS/Linux):

brew install smart-mcp-proxy/mcpproxy/mcpproxy

Other download options (auto-update URLs, archives)

Auto-update URLs (always points to latest):

Binary archives (this version):

Installation Instructions

Windows

Download the installer for your architecture
Run mcpproxy-setup-*.exe
Follow the installation wizard (requires Administrator privileges)
Launch "MCPProxy" from Start Menu

macOS

Download the signed DMG for your Mac
Double-click the DMG to mount it
Double-click the PKG installer inside
Follow the installation wizard
Launch mcpproxy.app from Applications folder

Linux / Manual Installation

Download the appropriate archive
Extract: tar -xzf mcpproxy-*.tar.gz
Make executable: chmod +x mcpproxy
Run: ./mcpproxy serve

Platform Support & Usage

Platform Support

macOS: Full system tray support with menu and icons
Windows: Full system tray support with menu and icons
Linux: Headless mode only (CLI)

Usage

GUI (Recommended):

Launch mcpproxy.app from Applications (auto-starts core server)
Manages server via system tray menu

CLI:

mcpproxy serve                           # Start server
mcpproxy serve --listen 127.0.0.1:8081  # Custom port
export MCPPROXY_API_KEY=your-secret-key  # Set API key