OpenCode: Use Any AI Model as a Terminal Coding Agent (140K+ Stars)

What Is OpenCode?

OpenCode is the most popular open-source coding CLI on GitHub (140K+ stars). It’s a universal adapter — connect any AI model and use it as a full terminal coding agent. The tool is free; you only pay for API tokens.

The killer value: use Claude Opus 4.7 at ~$30-80/month instead of $200/month for Claude Code Max. Same model, same intelligence, fraction of the price.

I ran it for 30 days. Average daily cost: $2-4. Covered 80% of my coding tasks. Only switched to Claude Code for complex architecture work.

How Much Does OpenCode Save?

	Claude Code Max	OpenCode + API
Model	Claude Opus 4.7	Claude Opus 4.7
Monthly cost	$200/mo fixed	~$30-80/mo
Rate limits	Capped	Pay-per-token, no cap
Provider lock-in	Anthropic only	Switch anytime

For 2-4 hours of daily AI coding, that’s 60-85% savings for the same model.

How to Install OpenCode

# Option 1: Go
go install github.com/opencode-ai/opencode@latest

# Option 2: Homebrew
brew install opencode-ai/tap/opencode

# Option 3: Curl
curl -fsSL https://opencode.ai/install.sh | sh

Verify: opencode --version

How to Configure a Provider

Create ~/.config/opencode/config.json:

{
  "provider": "anthropic",
  "model": "claude-sonnet-4-20250514",
  "providers": {
    "anthropic": {
      "apiKey": "${ANTHROPIC_API_KEY}"
    }
  }
}

Set your key and launch:

export ANTHROPIC_API_KEY="sk-ant-..."
cd your-project
opencode

How to Switch Models

# Claude Opus for complex architecture
opencode --model claude-opus-4-20250514

# GPT-4o for general coding
opencode --provider openai --model gpt-4o

# Local model for private code
opencode --provider ollama --model deepseek-coder-v3

How to Use Local Models (Fully Offline)

# Install Ollama
curl -fsSL https://ollama.ai/install.sh | sh

# Pull a coding model
ollama pull deepseek-coder-v3

# Configure OpenCode
opencode --provider ollama --model deepseek-coder-v3

Zero data leaves your machine. Perfect for sensitive codebases.

Who Should Use OpenCode?

✅ Want Claude/GPT-level agents without $200/mo subscriptions ✅ Need to switch between models for different tasks ✅ Work with sensitive code that can’t leave your machine ✅ Want full control over AI tooling

❌ Want zero-config out-of-box experience (use Claude Code or Antigravity instead)

Troubleshooting

API key not found

echo $ANTHROPIC_API_KEY  # Check it's set
echo 'export ANTHROPIC_API_KEY="your-key"' >> ~/.bashrc && source ~/.bashrc

Slow responses

• Cloud providers: check internet connection
• Ollama: ensure service is running (ollama serve)
• Try a smaller model first to confirm setup works

High unexpected costs

• Check usage on provider’s dashboard
• Use --model flag for cheaper models on simple tasks
• Set spending limits in your provider account

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Related Articles

• 5 Best Free AI Coding CLI Tools in 2026
• Claude Code vs Antigravity vs Codex: Real Cost
• Claude Code Installation Guide

Links

• OpenCode GitHub (140K+ stars)
• Anthropic API Keys
• OpenAI API Keys
• Ollama (local models)