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Overview

Forge exposes a REST API for the web UI and an MCP server for AI agent integration. This guide helps troubleshoot API connection and communication issues.

Connection Errors

Cannot Connect to Backend

Problem: Frontend shows “Failed to connect to API” or network errors Symptoms:
  • Tasks don’t load
  • Empty project list
  • Console errors: net::ERR_CONNECTION_REFUSED
Solutions:

CORS Errors

Problem: Access to fetch has been blocked by CORS policy Cause: Backend and frontend on different origins Solution:

Timeout Errors

Problem: Requests timeout with no response Solutions:

Authentication Errors

Unauthorized (401)

Problem: API returns 401 Unauthorized Cause: Missing or invalid auth token (GitHub OAuth) Solution:

Forbidden (403)

Problem: API returns 403 Forbidden Cause: Insufficient permissions for requested resource Solution:

Request Errors

Bad Request (400)

Problem: API returns 400 Bad Request Causes:

Not Found (404)

Problem: API returns 404 Not Found Solutions:

Internal Server Error (500)

Problem: API returns 500 Internal Server Error Solution:

MCP Server Errors

MCP Server Not Responding

Problem: AI agent can’t connect to Forge via MCP Symptoms:
  • MCP tools not available in AI agent
  • Connection timeoutErrors in AI agent logs
Solutions:
Claude Code (.claude/mcp.json):
Cursor (settings.json):

MCP Tools Not Available

Problem: list_tasks, create_task, etc. not showing up in AI agent Solution:
1

Verify MCP Server Started

2

Check Tool Mode

3

Restart AI Agent


MCP Tool Execution Failed

Problem: MCP tool returns error when executed Common Errors:

SSE (Server-Sent Events) Issues

Real-time Logs Not Streaming

Problem: Task execution logs don’t appear in real-time Causes & Solutions:

Database Errors

SQLite Errors

Problem: API returns database-related errors

Performance Issues

Slow API Responses

Problem: API requests take very long to respond Solutions:

Rate Limiting

Problem: AI executor APIs return rate limit errors Solution:

Debugging API Issues

Enable Debug Logging

Test API Directly

Inspect Network Traffic


Next Steps

Common Issues

General troubleshooting guide

Git Worktree Errors

Worktree-specific issues

API Reference

Complete API documentation

MCP Tools

MCP integration reference