proxy-doctor

Diagnose proxy misconfigurations that break AI coding tools.

When your browser works fine but Cursor / VS Code / Windsurf AI features don't — proxy-doctor tells you exactly why and how to fix it.

The Problem

AI coding tools (Cursor, VS Code with Copilot, Windsurf) rely on long-lived streaming connections (SSE/HTTP2) that break when:

Your system proxy points to a localhost port where nothing is listening
A VPN/proxy app was closed but its settings linger in macOS system preferences
Your editor inherited stale proxy environment variables from launchctl
The proxy is running but buffers streaming responses, breaking AI completions

The result: "browser works, AI editor doesn't" — the most common and frustrating developer experience.

What It Checks

proxy-doctor inspects 5 layers of your macOS proxy configuration:

Layer	What	How
1. System Proxy	Web/HTTPS/SOCKS proxy across all network services	`networksetup`
2. Residual Values	Disabled proxies with stale localhost addresses	Parse disabled-but-set entries
3. Port Health	Whether referenced proxy ports are actually listening	`socket.connect()`
4. Editor Config	`settings.json`, `argv.json`, recent error logs	File read + pattern match
5. GUI Environment	`http_proxy`/`https_proxy` in GUI app context	`launchctl getenv`

Quick Start

CLI

# Install
pip install proxy-doctor

# Run diagnosis (JSON output — default, optimized for AI agents)
proxy-doctor check

# Run diagnosis (human-readable output)
proxy-doctor check --human

# Show recommended fixes
proxy-doctor fix

# Check a different editor
proxy-doctor check --editor vscode

As an MCP Tool (for AI agents)

proxy-doctor ships as an MCP server that AI agents can call directly:

# Install with MCP support
pip install proxy-doctor[mcp]

# Run MCP server
python -m proxy_doctor.mcp_server

Add to your MCP configuration (e.g., Cursor ~/.cursor/mcp.json):

{
  "mcpServers": {
    "proxy-doctor": {
      "command": "python3",
      "args": ["-m", "proxy_doctor.mcp_server"]
    }
  }
}

Note: "command" must point to the Python where proxy-doctor[mcp] is installed. If python3 doesn't work, use the full path (run which python3 or python3 -c "import sys; print(sys.executable)" to find it).

Your AI agent can then call:

diagnose_proxy(editor="cursor") — full 5-layer diagnosis with evidence
list_fixes(editor="cursor") — recommended fixes with executable commands
supported_editors() — list available editors

For AI Agents: Quick Install

One-liner (paste this to your AI agent):

Install proxy-doctor (pip install proxy-doctor[mcp]) and add it to your MCP config with command python -m proxy_doctor.mcp_server. Then use the diagnose_proxy tool to check proxy health.

If you are an AI agent setting up proxy-doctor for your user:

# 1. Install
pip install proxy-doctor[mcp]

# 2. Find the Python path
python3 -c "import sys; print(sys.executable)"

# 3. Add to ~/.cursor/mcp.json (use the path from step 2)
# {
#   "mcpServers": {
#     "proxy-doctor": {
#       "command": "<python-path-from-step-2>",
#       "args": ["-m", "proxy_doctor.mcp_server"]
#     }
#   }
# }

# 4. If MCP is not available, use CLI directly (zero dependencies):
proxy-doctor check          # JSON output
proxy-doctor check --human  # human-readable
proxy-doctor fix            # show fixes (read-only)
proxy-doctor fix --apply    # apply fixes (asks for confirmation)

Daemon Mode (v0.2+)

Run proxy-doctor as a persistent background service with automatic health monitoring:

# Start daemon (installs as macOS launchd service)
proxy-doctor daemon start

# Check daemon status
proxy-doctor daemon status

# Stop daemon
proxy-doctor daemon stop

# Check for updates
proxy-doctor update

The daemon runs every 5 minutes, compares results with the previous check, and sends a macOS notification when status changes (e.g. healthy → unhealthy).

Menu Bar (SwiftBar)

# If SwiftBar is installed
cp plugins/swiftbar/proxy-doctor.5m.sh ~/Library/Application\ Support/SwiftBar/Plugins/
chmod +x ~/Library/Application\ Support/SwiftBar/Plugins/proxy-doctor.5m.sh

Shows a green/red/orange indicator in your menu bar with one-click diagnosis.

Example Output

Unhealthy (Case A: dead proxy port)

{
  "status": "unhealthy",
  "diagnosis": {
    "case": "A",
    "root_cause": "Editor is configured to use proxy at 127.0.0.1:10903, but no process is listening on that port.",
    "confidence": "high",
    "source": "system proxy (Wi-Fi (http))",
    "browser_explanation": "Browser may use a different proxy path (e.g. browser-only mode) or fall back to a direct connection."
  },
  "fixes": [
    {
      "fix_id": "clear-system-http-wi-fi",
      "description": "Disable http proxy on Wi-Fi",
      "command": "networksetup -setwebproxystate \"Wi-Fi\" off",
      "risk": "low"
    }
  ]
}

Healthy

proxy-doctor v0.2.0
Editor: cursor | Platform: Darwin

Status: HEALTHY

No proxy contamination detected.

Supported Editors

Editor	Config Detection	Log Scanning	Status
Cursor	yes	yes	supported
VS Code	yes	yes	supported
Windsurf	yes	yes	supported
Claude Desktop	planned	—	future
Zed	planned	planned	future

How It Works

proxy-doctor identifies three failure patterns:

Case A — Dead proxy port (high confidence): Your system or editor points to 127.0.0.1:port but nothing is listening. This happens when a VPN/proxy app is closed but its settings remain.

Case B — Streaming broken (medium confidence): A proxy is running, but it buffers SSE/streaming connections that AI editors depend on. Common with browser-only proxy modes.

Case C — Path mismatch (medium confidence): Browser and editor use different proxy paths. Browser works via a dedicated proxy route; editor inherits a stale or incompatible one.

Platform Support

macOS: Full support (system proxy, launchctl, networksetup)
Linux: Partial (editor config + environment variables; no networksetup)
Windows: Not yet supported

Trust & Permissions

proxy-doctor follows a read-only by default design. No system changes are made unless you explicitly opt in.

Default Behavior (read-only)

Access	What	Why
Reads	System proxy settings, editor config files, launchctl env vars, local port status	Core diagnostic functionality
Writes	`~/.proxy-doctor/` only (cache, logs, update state)	Daemon state persistence
Network	`pypi.org` (version check only)	Auto-update feature
Does NOT	Modify proxy settings, change editor config, send telemetry, access credentials	By design

Opt-in Fix Application

proxy-doctor fix shows the recommended commands but does not execute them.

To apply fixes, use proxy-doctor fix --apply:

Each fix is shown with its command and risk level
You are prompted individually for each fix ([y/N])
Default is No — nothing runs unless you type y
You can abort at any time with Ctrl+C

This two-step model lets AI agents safely call list_fixes() via MCP to see what needs fixing, then present the commands to users for approval.

Feedback

Found a bug? Have a suggestion? Diagnosis didn't help?

GitHub Issues: https://github.com/Jiansen/proxy-doctor/issues/new
For AI agents: The JSON output includes a feedback.report_issue URL — include the full JSON when filing issues.

For AI agents providing feedback programmatically (zero dependencies):

# Create a GitHub issue via CLI (requires gh)
proxy-doctor check | gh issue create --repo Jiansen/proxy-doctor \
  --title "Diagnosis report: [describe issue]" --body-file -

# Or simply: copy the JSON output into a new issue at
# https://github.com/Jiansen/proxy-doctor/issues/new

Development

git clone https://github.com/Jiansen/proxy-doctor.git
cd proxy-doctor

# Install in development mode
pip install -e ".[dev,mcp]"

# Run tests
make test

# Run linter
make lint

If proxy-doctor helped you fix a proxy issue, consider giving it a star on GitHub — it helps others discover the tool.

License

MIT

Proxy Doctor

Quick Install