Debugging MCP Server Connection Issues: A Complete Troubleshooting Guide for Wordle MCP (Python)

Debugging MCP server connection issues for the Wordle MCP (Python) involves verifying container runtime status, checking FastMCP initialization logs, validating network connectivity to the New York Times Wordle API, and ensuring the requests dependency is correctly installed in the environment.

The cr2007/mcp-wordle-python repository implements a lightweight FastMCP-based server that exposes the get_wordle_solution tool for fetching Wordle answers. When debugging MCP server connection issues, you must trace failures across the container runtime, dependency resolution, and external API boundaries.

Understanding the Wordle MCP Server Architecture

Core Components and Entry Points

The server architecture centers on the FastMCP runtime, which handles tool registration, client communication, and lifecycle management. The entry point is defined in [fastmcp.json](https://github.com/cr2007/mcp-wordle-python/blob/master/fastmcp.json):

{
    "entrypoint": "src/mcp_wordle/main.py",
    "environment": {
        "dependencies": ["requests"]
    }
}

Key implementation details in [src/mcp_wordle/main.py](https://github.com/cr2007/mcp-wordle-python/blob/master/src/mcp_wordle/main.py):

• Line 1: Imports FastMCP from the fastmcp package
• Line 13: Instantiates mcp = FastMCP("WordleMCP")
• Lines 30-68: Defines get_wordle_solution wrapped with @mcp.tool() decorator

Deployment Options

The server supports two primary runtime environments:

• Docker: Pre-built image ghcr.io/cr2007/mcp-wordle-python:latest provides isolated runtime with dependencies pre-installed
• uvx: One-line command uvx --from git+https://github.com/cr2007/mcp-wordle-python mcp-wordle runs via the uv package manager

Common MCP Server Connection Failure Points

Container Startup and Runtime Failures

Connection issues often originate before the MCP protocol even initializes. Docker daemon failures prevent the container from starting, while image pull errors occur when GitHub Container Registry is unreachable. If the container exits immediately upon startup, it typically indicates a missing dependency or entry point misconfiguration.

Network and API Connectivity Issues

The get_wordle_solution tool makes HTTP requests to https://www.nytimes.com/svc/wordle/v2/<date>.json with a 300-second timeout (requests.get(..., timeout=300)). The API imposes strict date validation:

• Minimum date: 2021-05-19 (Wordle launch)
• Maximum date: 23 days in the future from current date

Out-of-range dates return a structured error JSON rather than the solution data.

Dependency and Import Errors

The fastmcp.json declares requests as a required dependency. If the runtime environment lacks this package, the server raises an ImportError during initialization before registering any tools. This manifests as a connection failure in the MCP client because the server process terminates prematurely.

Step-by-Step Debugging MCP Server Connection Issues

Follow this systematic approach to isolate and resolve connection failures:

1. Verify the server process is active

   • Docker: Run docker ps and confirm the container ghcr.io/cr2007/mcp-wordle-python appears in the list
   • uvx: Confirm the terminal displays FastMCP startup logs without immediate exit

2. Inspect initialization logs

   • Docker: Execute docker logs <container-id> to check for ImportError or FastMCP registration messages
   • Look for the line indicating get_wordle_solution tool registration

3. Validate network connectivity

   • Test outbound connectivity from the container: docker exec -it <container-id> ping www.nytimes.com
   • Verify the host can reach the Wordle API endpoint

4. Test tool invocation with valid parameters

   • Use a date within the allowed window (e.g., 2024-02-01)
   • Check for timeout errors indicating network latency exceeding 300 seconds

5. Verify dependency installation

   • Confirm requests is importable: docker exec <container-id> python -c "import requests"
   • Check fastmcp.json dependency declarations match installed packages

Practical Debugging Examples

Verifying Docker Deployment

When the MCP client reports connection failures immediately after configuration, verify the container runtime:

# Pull the latest image

docker pull ghcr.io/cr2007/mcp-wordle-python:latest

# Run with interactive flags to observe startup

docker run --rm -i --init -e DOCKER_CONTAINER=true ghcr.io/cr2007/mcp-wordle-python:latest

# In a separate terminal, check container status

docker ps --filter "ancestor=ghcr.io/cr2007/mcp-wordle-python"

# If the container exited, inspect logs

docker logs $(docker ps -lq)

If logs show ModuleNotFoundError: No module named 'requests', the dependency installation failed despite the fastmcp.json declaration.

Debugging uvx Execution

For environments using uvx without Docker:

# Verify uv installation first

uv --version

# Execute with verbose output to catch repository cloning errors

uvx --from git+https://github.com/cr2007/mcp-wordle-python mcp-wordle

Successful initialization displays the FastMCP server identifier WordleMCP and confirms tool registration. If the process exits silently, check ~/.cache/uv/ for corrupted package metadata.

Testing Tool Logic Directly

Bypass the MCP transport layer to isolate API versus protocol issues:

# Direct import from source

from src.mcp_wordle.main import get_wordle_data

# Test valid date within API window

valid_response = get_wordle_data("2024-02-01")
print(f"Solution: {valid_response.get('solution')}")

# Test boundary condition (should error)

error_response = get_wordle_data("1999-01-01")
print(f"Error status: {error_response.get('status')}")

This approach confirms whether the requests timeout (300 seconds) or the NYT API date validation is causing the connection failure.

Summary

• Debugging MCP server connection issues requires checking three layers: container/runtime status, dependency resolution, and external API connectivity.
• The Wordle MCP server entry point is src/mcp_wordle/main.py, which registers get_wordle_solution via the FastMCP instance defined in fastmcp.json.
• Common failures include Docker daemon errors, missing requests dependencies, and Wordle API date validation errors (valid range: 2021-05-19 to 23 days future).
• Use docker logs to inspect FastMCP initialization and docker exec to verify network connectivity to www.nytimes.com before the 300-second timeout threshold.

Frequently Asked Questions

How do I verify the Wordle MCP server is running correctly?

Check active processes using docker ps to confirm the container ghcr.io/cr2007/mcp-wordle-python appears in the list, or observe the terminal output for FastMCP initialization logs when using uvx. Successful startup shows the server identifier WordleMCP and confirms tool registration without ImportError messages.

What causes "connection failed" errors when connecting to the Wordle MCP server?

Connection failures typically indicate the Docker daemon is not running, the container exited immediately due to missing requests dependencies declared in fastmcp.json, or the uvx environment cannot resolve the Git repository. Inspect docker logs for startup errors or verify uv installation with uv --version to isolate the runtime layer.

How do I debug date validation errors in the get_wordle_solution tool?

The Wordle API accepts dates from 2021-05-19 up to 23 days in the future. When debugging, test with a valid date like 2024-02-01 first. If you receive a JSON response containing status: "error" and an errors array, verify the input date falls within the allowed window and check the 300-second timeout hasn't expired due to network latency.

Can I run the Wordle MCP server without Docker?

Yes, you can run the server using uvx without installing Docker. Execute uvx --from git+https://github.com/cr2007/mcp-wordle-python mcp-wordle after installing the uv package manager. This method still requires network connectivity to fetch dependencies and communicate with the New York Times Wordle API endpoint at https://www.nytimes.com/svc/wordle/v2/.

{
  "mcpServers": {
    "instagit": {
      "command": "npx",
      "args": ["-y", "instagit@latest"]
    }
  }
}