APIWeaver + LibreChat: Complete MCP Integration

APIWeaver is a MCP server that An MCP server that dynamically creates MCP servers from web API configurations. This allows you to easily integrate any REST API, GraphQL endpoint, or web service into an MCP-compatible tool that can be used by AI assistants like Claude..

When integrated with LibreChat, you can:

• Register and configure APIs at runtime without server restart
• Support for REST APIs, GraphQL endpoints, and web services
• Multiple authentication methods for different API requirements

This guide provides step-by-step instructions to set up APIWeaver in LibreChat, including configuration, examples, and troubleshooting.

What You'll Achieve

After completing this setup:

• APIWeaver will be fully integrated and operational
• You can use APIWeaver tools directly in LibreChat
• All APIWeaver capabilities will be available for your workflows
• Access to 6 different tools

Prerequisites

Before starting, ensure you have:

• LibreChat installed and configured
• Compatible operating system (Docker (Recommended), Kubernetes, Local Installation, Cloud Platforms)

Installation

Step 1: Install APIWeaver

Configuration

Step 2: Configure LibreChat

1. Open LibreChat settings
2. Navigate to MCP server configuration
3. Add APIWeaver server with appropriate settings
4. Save and restart if needed

Examples

Once configured, you can use APIWeaver in LibreChat:

Register REST API with Authentication

Add a REST API with Bearer token authentication

Ask LibreChat: "Register the JSONPlaceholder API (https://jsonplaceholder.typicode.com) with GET and POST methods"

Expected Result: API registered successfully with auto-generated tools for posts, users, and comments endpoints

GraphQL Endpoint Integration

Connect to a GraphQL API for data querying

Ask LibreChat: "Register the GitHub GraphQL API with authentication and create tools for repository queries"

Expected Result: GraphQL endpoint configured with query tools for repositories, issues, and user data

API Testing and Validation

Test API connectivity before integration

Ask LibreChat: "Test connection to the Stripe API with my API key before registering it"

Expected Result: Connection test successful with API schema validation and endpoint verification

Multi-API Workflow

Integrate multiple APIs for complex workflows

Ask LibreChat: "Register both Twitter API and SendGrid API to create a workflow for social media monitoring and email alerts"

Expected Result: Both APIs registered with tools for tweet monitoring, email sending, and automated workflow execution

Testing Your Setup

1. Launch LibreChat
2. Verify APIWeaver is available in the tools list
3. Test basic APIWeaver functionality

Troubleshooting

Common Issues

API Registration Failed

Symptoms: Registration errors, Invalid API configuration, Connection timeouts

Cause: Incorrect API URL, authentication issues, or network problems

Solution:

• Verify API endpoint URL is accessible
• Check authentication credentials are valid
• Test API manually with curl or Postman first
• Ensure network connectivity and firewall settings

Authentication Not Working

Symptoms: 401 Unauthorized, 403 Forbidden, Auth token invalid

Cause: Incorrect authentication method or invalid credentials

Solution:

• Verify authentication method matches API requirements
• Check API key/token is not expired
• Confirm header format and parameter names
• Test authentication with API documentation examples

Transport Mode Not Connecting

Symptoms: Connection refused, Transport errors, Client not recognizing server

Cause: Incorrect transport configuration or port conflicts

Solution:

• Use streamable-http for modern clients
• Check port is not in use: netstat -an | grep :8000
• Verify host/port settings match client configuration
• Try different transport modes (stdio/http/sse)

Python Dependencies Missing

Symptoms: Import errors, Module not found, Package installation failures

Cause: Missing Python packages or virtual environment issues

Solution:

• Install requirements: pip install -r requirements.txt
• Create virtual environment: python -m venv apiweaver-env
• Activate environment before installation
• Upgrade pip: python -m pip install --upgrade pip

API Schema Generation Failed

Symptoms: Tool generation errors, Schema parsing failures, Endpoint mapping issues

Cause: Unsupported API format or incomplete API documentation

Solution:

• Provide OpenAPI/Swagger specification if available
• Start with simple GET endpoints first
• Manually configure complex APIs step by step
• Check API documentation for required parameters

MCP Server Not Connecting

Symptoms: Status shows "Disconnected" or "Error", Server not appearing in list, Connection timeout

Cause: Invalid configuration, missing dependencies, or server startup failure

Solution:

• Check librechat.yaml syntax is valid YAML
• Verify npx and Node.js are available (for stdio/command-based servers)
• Check server command and args are correct
• Review LibreChat logs for error messages: docker logs librechat
• Increase timeout value if server takes longer to initialize
• Ensure required ports are not blocked (for HTTP-based servers)

OAuth Authentication Failing

Symptoms: Status shows "OAuth Required", Redirect loop during auth, Token refresh errors

Cause: OAuth credentials not configured or redirect URLs incorrect

Solution:

• Verify OAuth clientId and clientSecret in librechat.yaml
• Check redirect URL is correctly set in OAuth provider settings
• Ensure authorizationUrl and tokenUrl are accessible
• Complete OAuth flow by clicking "Initialize" in MCP Settings panel
• Check browser console for OAuth-related errors

User Credentials Not Working

Symptoms: Prompts for credentials not appearing, Variables not substituted, Authentication errors

Cause: User credential variables incorrectly formatted or not entered

Solution:

• Use correct format: {{USER_VARIABLE_NAME}} in librechat.yaml
• Enter credentials through MCP Settings panel in UI
• Verify variable names match between config and UI
• Check credentials are saved per-user (not shared globally)

Tools Not Appearing in Chat

Symptoms: No tool dropdown available, MCP tools missing from interface, Server connected but tools unavailable

Cause: MCP server not properly integrated with chat endpoint or agent

Solution:

• Verify you are using an endpoint that supports MCP (not all models do)
• Check if Agent Builder is enabled and MCP tools are assigned to agent
• Restart chat session after adding new MCP servers
• Verify MCP server actually provides tools (some servers are resource-only)
• Check server logs to confirm tools are being discovered

Docker Deployment Problems

Symptoms: Container fails to start, Database connection errors, Port conflicts

Cause: Docker configuration issues or missing environment variables

Solution:

• Verify .env file is properly configured with all required variables
• Check MongoDB connection string is correct
• Ensure ports 3080 (frontend) and 3081 (backend) are available
• Run docker compose logs to view detailed error messages
• Verify Docker and Docker Compose versions meet minimum requirements

Performance Issues with MCP

Symptoms: Slow tool execution, Timeout errors, UI freezing during tool calls

Cause: Server timeout too short, inefficient MCP server, or network latency

Solution:

• Increase timeout values in librechat.yaml (both init and operation timeouts)
• Use HTTP transport instead of stdio for remote servers
• Monitor MCP server performance independently
• Consider caching for frequently accessed resources
• Use Streamable HTTP transport for production environments

APIWeaver not appearing in LibreChat

Symptoms: Server not listed, Tools not available

Cause: Configuration or installation issue

Solution:

• Verify configuration syntax
• Check APIWeaver installation
• Restart LibreChat
• Check logs for error messages

Next Steps

Now that APIWeaver is integrated with LibreChat:

• Explore all APIWeaver capabilities through LibreChat
• Check out other MCP servers that work with LibreChat
• Join the MCP community for tips and support
• Consider contributing to APIWeaver development

Need Help?

• Search for APIWeaver documentation
• Check the LibreChat MCP guide
• Join the MCP community discussions