Common OpenCode Errors and How to Fix Them: Complete Troubleshooting Guide

If you’re a developer working with OpenCode, the open-source AI coding agent, you’ve likely encountered frustrating errors that slow down your workflow. This comprehensive guide covers the most frequent OpenCode errors, their root causes, and practical solutions to get you back to coding efficiently.

Understanding OpenCode Error Patterns

OpenCode errors typically fall into several categories: terminal management issues, session synchronization failures, WebSocket connection problems, agent configuration errors, and build-related issues. Understanding these patterns helps you quickly identify and resolve problems as they arise.

Terminal Management Errors

Failed to Create Terminal

One of the most common errors occurs when attempting to create new terminal sessions. The error message “Failed to create terminal” appears when the backend PTY service cannot initialize a new terminal process.

Common Causes:

• System resource limitations (too many open terminals)
• Permission issues with the working directory
• Backend service not running or not responding
• Network connectivity issues between frontend and backend

Solutions:

1. Check if you’ve reached the maximum terminal session limit (OpenCode defaults to 20)
2. Verify that the OpenCode backend service is running
3. Ensure you have write permissions in your project directory
4. Check network connectivity to the OpenCode server
5. Review backend logs for more detailed error information

# Check running OpenCode processes
ps aux | grep opencode

# Verify backend health
curl http://localhost:PORT/health

Failed to Update Terminal

When terminal properties (title, size, etc.) fail to update, it typically indicates a synchronization issue between the frontend state and the backend PTY service.

Troubleshooting Steps:

• Verify that the terminal ID is valid and not already closed
• Check network connectivity
• Ensure the backend PTY service is responsive
• Clear browser cache and restart the OpenCode application

Failed to Clone Terminal

Terminal cloning failures occur when attempting to duplicate an existing terminal session. This error often stems from resource constraints or invalid terminal references.

Prevention:

• Don’t clone terminals that are in a closed or error state
• Ensure sufficient system resources before cloning
• Check that the source terminal is healthy

Session Synchronization Errors

Failed to Load Sessions

OpenCode manages multiple coding sessions across projects, and loading failures can significantly impact productivity. This error typically appears when switching between projects or after a restart.

Root Causes:

• Network connectivity issues
• Backend database or storage problems
• Corrupted session cache
• Authentication/authorization failures

Resolution Strategies:

1. Clear your local session cache
2. Check network connectivity to the OpenCode server
3. Verify your authentication token is valid
4. Restart the OpenCode backend service
5. Check server logs for detailed error information

# Clear session cache (location varies by OS)
# Linux/macOS: ~/.config/opencode/cache/
# Windows: %APPDATA%\opencode\cache\

# Restart backend
opencode server restart

Failed to Bootstrap Instance

When OpenCode fails to bootstrap a project instance, it cannot initialize the necessary services for that project. This is a critical error that prevents any coding work in that project.

Common Reasons:

• Invalid or missing project configuration
• Git repository issues (OpenCode relies heavily on VCS integration)
• Provider configuration problems (API keys for AI models)
• Network connectivity to external services

Fix Steps:

1. Verify your project has a valid configuration file
2. Check Git repository status and ensure it’s accessible
3. Validate your AI provider credentials (OpenAI, Anthropic, etc.)
4. Check network connectivity to required external services
5. Review project metadata files for corruption

WebSocket Connection Errors

WebSocket Connection Failures

WebSocket errors are particularly problematic as they prevent real-time features like session sharing and live collaboration. The error “WebSocket error” indicates the connection between client and server has been disrupted.

Primary Causes:

• Missing or incorrect API URL configuration
• Protocol mismatch (HTTP vs HTTPS, WS vs WSS)
• Firewall or proxy blocking WebSocket connections
• Server-side WebSocket implementation issues
• Network instability

Configuration Checklist:

# Ensure these environment variables are set
VITE_API_URL=https://your-opencode-server.com
API_URL=https://your-opencode-server.com

SSL/TLS Considerations: OpenCode forces secure WebSocket connections (WSS). If running locally:

• Use self-signed certificates for development
• Configure your browser to trust the certificate
• For production, use valid SSL certificates

Testing WebSocket Connectivity:

// Test WebSocket connection manually
const ws = new WebSocket('wss://your-server.com/share_poll?id=test');
ws.onopen = () => console.log('Connected');
ws.onerror = (e) => console.error('Error:', e);
ws.onclose = () => console.log('Closed');

Message Parsing Errors

When WebSocket messages arrive in unexpected formats, OpenCode logs “Error parsing WebSocket message.” This usually indicates version mismatches or corrupted data.

Solutions:

• Ensure client and server are running compatible versions
• Check network logs for message corruption
• Verify message format matches expected schema
• Update both client and server to latest versions

Agent Configuration Errors

Agent File Already Exists

When creating custom agents, you might encounter “Error: Agent file already exists.” This occurs when attempting to overwrite an existing agent configuration without explicit confirmation.

Best Practices:

• Always check if an agent file exists before creating
• Use descriptive, unique names for your agents
• Consider versioning agent configurations
• Review existing agents before creating new ones

# List existing agents
opencode agent list

# Check if specific agent exists
ls ~/.config/opencode/agent/
ls .opencode/agent/

Agent Generation Failures

When the LLM fails to generate an agent configuration, it often indicates issues with the model provider or insufficient context.

Troubleshooting:

1. Verify your AI provider API key is valid
2. Check that you have sufficient quota/credits
3. Provide more detailed descriptions for complex agents
4. Try different models (some are better at agent generation)
5. Review provider-specific documentation

Build and Development Errors

Build Errors in VS Code Extension

For developers working on the VS Code extension, build errors can occur during development or packaging.

Common Issues:

• Dependency version conflicts
• TypeScript compilation errors
• Missing required packages
• esbuild configuration problems

Resolution Steps:

1. Run npm install to ensure all dependencies are installed
2. Clear node_modules and reinstall: rm -rf node_modules && npm install
3. Check TypeScript configuration for errors
4. Review esbuild configuration in sdks/vscode/esbuild.js
5. Ensure you’re using compatible Node.js version

# Clean build
npm run clean
npm install
npm run build

GitHub Integration Errors

OpenCode integrates with GitHub for various operations, and failures can occur due to authentication, rate limiting, or permission issues.

Common Errors:

• “Failed to download image” - Image asset retrieval fails
• “Failed to check permissions” - GitHub API permission checks fail
• Rate limiting exceeded - Too many API requests

Solutions:

1. Verify GitHub personal access token is valid
2. Check token has required permissions (repo, read:org, etc.)
3. Respect GitHub API rate limits (60 requests/hour for unauthenticated)
4. Use authenticated requests for higher rate limits (5000 requests/hour)
5. Implement retry logic with exponential backoff

# Verify GitHub token
curl -H "Authorization: token YOUR_TOKEN" https://api.github.com/user

# Check rate limit status
curl -H "Authorization: token YOUR_TOKEN" https://api.github.com/rate_limit

Environment and Configuration Issues

Missing Environment Variables

Many OpenCode errors stem from incomplete or incorrect environment configuration.

Critical Variables:

• API_URL - Backend API endpoint
• DATABASE_URL - Database connection string
• AI provider keys (OPENAI_API_KEY, ANTHROPIC_API_KEY, etc.)
• GitHub tokens if using GitHub integration

Setup Guide:

# Create .env file in project root
cat > .env << EOF
API_URL=http://localhost:3000
DATABASE_URL=postgresql://user:password@localhost:5432/opencode
OPENAI_API_KEY=sk-...
GITHUB_TOKEN=ghp_...
EOF

# Load environment variables
source .env

# Verify variables are loaded
env | grep -E '(API_URL|DATABASE|OPENAI|GITHUB)'

Provider Configuration Problems

OpenCode supports multiple AI providers, and misconfiguration is a common source of errors.

Provider-Specific Issues:

OpenAI:

• Invalid API key format (must start with sk-)
• Insufficient credits
• Model not available in your tier

Anthropic:

• API key format (must start with sk-ant-)
• Rate limits (free tier: 50 requests/minute)
• Model access permissions

Google (Gemini):

• OAuth token expiration
• Project ID misconfiguration
• API not enabled in Google Cloud Console

Performance-Related Errors

Resource Exhaustion

OpenCode can be resource-intensive, especially when running multiple sessions or processing large codebases.

Symptoms:

• Slow response times
• Failed operations
• Memory errors
• CPU throttling

Optimization Strategies:

1. Limit concurrent terminal sessions
2. Archive old sessions
3. Increase system resources (RAM, CPU)
4. Use code indexing sparingly
5. Clear caches regularly

# Monitor resource usage
htop

# Check OpenCode memory usage
ps aux | grep opencode | awk '{print $6}' | awk '{sum+=$1} END {print sum/1024 " MB"}'

# Clear caches
rm -rf ~/.cache/opencode/*

Debugging and Logging

Enabling Debug Mode

OpenCode includes comprehensive debug logging that can help identify the root cause of errors.

How to Enable:

1. Set environment variable: DEBUG=opencode:*
2. Or pass debug flag: opencode --debug
3. For web interface, add ?debug=true to URL

Log Locations:

• Backend logs: /var/log/opencode/ or stdout
• Frontend logs: Browser console (F12)
• Extension logs: VS Code output panel

Analyzing Error Messages

When you encounter an error, follow this systematic approach:

1. Identify the Error Type: Is it a network, configuration, or logic error?
2. Check Recent Changes: Did anything change recently (updates, config)?
3. Review Logs: Look for stack traces and context
4. Reproduce Consistently: Can you reproduce the error reliably?
5. Search Documentation: Check OpenCode docs and GitHub issues
6. Minimal Reproduction: Create a minimal example if possible

Prevention Strategies

Regular Maintenance

Prevent errors before they occur with regular maintenance:

1. Keep Updated: Regularly update OpenCode to the latest version
2. Clean Up: Periodically clear caches and archives
3. Monitor Resources: Keep an eye on system resource usage
4. Backup Configuration: Backup your agent configurations and settings
5. Test Changes: Test significant changes in a safe environment first

Best Practices

Follow these best practices to minimize errors:

1. Use Version Control: Keep your project under Git
2. Validate Configurations: Test configurations before deploying
3. Monitor Logs: Regularly review error logs for patterns
4. Document Setup: Document your environment and configuration
5. Plan for Failures: Implement error handling and retry logic

Getting Help

When you can’t resolve an error yourself:

1. Search Existing Issues: Check GitHub issues for similar problems
2. Provide Context: When asking for help, include:
   • OpenCode version
   • Operating system and version
   • Error message and stack trace
   • Steps to reproduce
   • Configuration details (redact sensitive info)
3. Use Debug Logs: Include relevant debug logs
4. Be Specific: The more specific, the better the help you’ll receive

Conclusion

While OpenCode errors can be frustrating, most are resolvable with systematic troubleshooting and a good understanding of the system’s architecture. By familiarizing yourself with common error patterns and implementing preventive measures, you can minimize downtime and maintain a productive development workflow.

Remember that software development is iterative – errors are opportunities to learn and improve your understanding of the tools you use. With this guide, you’re now equipped to handle the most common OpenCode errors and get back to what matters: writing great code.

For the most up-to-date information and community support, visit the OpenCode GitHub repository and join the discussion in issues and pull requests.