OAuth Authentication

Many MCPs require authentication to access their services. SLOP MCP provides seamless OAuth support with automatic reconnection.

Supported MCPs

OAuth works with any MCP that implements the MCP OAuth specification, including:

• Figma - Design file access
• Linear - Issue tracking
• Dart - Project management
• Notion - Workspace access
• Slack - Channel messaging
• GitHub (OAuth apps) - Repository access

Quick Start

Login

slop-mcp mcp auth login figma

This will:

1. Open your default browser
2. Redirect to the MCP's OAuth consent page
3. After you authorize, capture the token
4. Automatically reconnect the MCP with new credentials

Check Status

slop-mcp mcp auth status figma

Output:

Figma authentication status:
  Authenticated: Yes
  Expires: 2024-01-15T10:30:00Z
  Has refresh token: Yes

Logout

slop-mcp mcp auth logout figma

Using in Claude Code

With the SLOP MCP plugin, authentication is available via the auth_mcp tool:

User: I need to access my Figma designs

Claude: Let me authenticate with Figma.

> auth_mcp action="login" name="figma"

Opening browser for OAuth authentication...
Successfully authenticated with figma - connection re-established with new credentials

Now I can access your Figma files. What would you like to do?

Auto-Reconnection

New in v0.3.0: After successful authentication, SLOP MCP automatically:

1. Stores the OAuth token securely
2. Disconnects the existing MCP connection
3. Reconnects with the new credentials
4. Re-indexes available tools

No manual reconnection needed!

Before v0.3.0:
1. auth login figma
2. (manually) mcp remove figma
3. (manually) mcp add figma ...
4. Now it works

After v0.3.0:
1. auth login figma
2. It just works ✓

Token Storage

OAuth tokens are stored securely in your system's credential store:

Platform	Storage Location
macOS	Keychain
Linux	Secret Service (libsecret)
Windows	Credential Manager

Fallback: ~/.config/slop-mcp/tokens.json (encrypted)

Token Refresh

SLOP MCP automatically refreshes tokens when they expire:

1. Before making an MCP call, check token expiry
2. If expired and refresh token exists, refresh automatically
3. If refresh fails, prompt for re-authentication

You don't need to manage token lifecycle manually.

Configuration for OAuth MCPs

OAuth MCPs must use HTTP transport (streamable or SSE):

mcp "figma" {
    transport "streamable"
    url "https://mcp.figma.com/mcp"
}

mcp "linear" {
    transport "sse"
    url "https://mcp.linear.app/sse"
}

warning

OAuth does not work with stdio transport MCPs. The MCP must expose an HTTP endpoint.

Troubleshooting

"OAuth flow failed"

1. Check your internet connection
2. Verify the MCP URL is correct
3. Ensure the MCP supports OAuth

# Verify MCP is reachable
curl https://mcp.figma.com/.well-known/oauth-authorization-server

"Token expired" errors

Force a refresh:

slop-mcp mcp auth login figma --force

Browser doesn't open

Set your browser manually:

export BROWSER=/usr/bin/firefox
slop-mcp mcp auth login figma

Or use the URL directly:

slop-mcp mcp auth login figma --no-browser
# Prints URL to copy/paste

"Connection failed after auth"

Check that the MCP is properly configured:

slop-mcp mcp list
# Should show: figma (streamable) - connected

If disconnected, try:

slop-mcp mcp remove figma
slop-mcp mcp add figma -t streamable https://mcp.figma.com/mcp
slop-mcp mcp auth login figma

Security Best Practices

1. Don't share tokens - Tokens are personal credentials
2. Use MCP-specific scopes - Only authorize needed permissions
3. Rotate periodically - Logout and re-login monthly
4. Audit access - Check MCP provider's connected apps page

API Reference

auth_mcp Tool

{
  "action": "login" | "logout" | "status" | "list",
  "name": "mcp-name"  // Required for login/logout/status
}

CLI Commands

# Authenticate
slop-mcp mcp auth login <name>
slop-mcp mcp auth login <name> --force
slop-mcp mcp auth login <name> --no-browser

# Check status
slop-mcp mcp auth status <name>

# Remove token
slop-mcp mcp auth logout <name>

# List all authenticated MCPs
slop-mcp mcp auth list