OpenCode

OpenCode tutorial — Open-source terminal AI coding agent compatible with 75+ providers. Connect to EasyRouter via interactive menu or config file using the OpenAI-compatible API.

Project Introduction

OpenCode is an open-source terminal AI coding agent with both TUI and CLI modes. It's compatible with 75+ AI service providers and, via its built-in @ai-sdk/anthropic and @ai-sdk/openai-compatible adapters, can seamlessly connect to both Anthropic-protocol models and OpenAI-compatible models served by EasyRouter.

Website: https://opencode.ai
GitHub: https://github.com/opencode-ai/opencode

📦 Prerequisites

What you'll need

OpenCode installed
An EasyRouter endpoint (must end with /v1)
An EasyRouter API key (generated in the console)
A model ID exactly matching one exposed by your EasyRouter console (e.g. claude-sonnet-4-6, claude-haiku-4-5, deepseek-v4-pro, gpt-5.5)

Add EasyRouter directly from the OpenCode TUI:

Launch the OpenCode TUI
Type /connect
In the provider list, choose "Other" (custom endpoint)
Fill in:
- Base URL: https://easyrouter.io/v1
- API Key: your EasyRouter API key
After saving, type /models and switch to the newly added model

🔧 Option 2: Config file (recommended for regular use)

Good for pinning multiple models and reusing across projects.

1. Edit OpenCode config

File location:

Global: ~/.config/opencode/opencode.json
Per-project (takes precedence): opencode.json in your project root

{
  "$schema": "https://opencode.ai/config.json",
  "provider": {
    "easyrouter-anthropic": {
      "npm": "@ai-sdk/anthropic",
      "name": "EasyRouter (Anthropic)",
      "options": {
        "baseURL": "https://easyrouter.io/v1",
        "apiKey": "sk-123"
      },
      "models": {
        "claude-sonnet-4-6": {
          "name": "Claude Sonnet 4.6",
          "limit": { "context": 200000, "output": 8192 }
        },
        "haiku": {
          "id": "claude-haiku-4-5",
          "name": "Claude Haiku 4.5 (fast)",
          "limit": { "context": 200000, "output": 8192 }
        }
      }
    },
    "easyrouter": {
      "npm": "@ai-sdk/openai-compatible",
      "name": "EasyRouter",
      "options": {
        "baseURL": "https://easyrouter.io/v1",
        "apiKey": "sk-123"
      },
      "models": {
        "deepseek-v4-flash": {
          "name": "DeepSeek V4 Flash",
          "limit": { "context": 131072, "output": 16384 }
        },
        "deepseek-v4-pro": {
          "name": "DeepSeek V4 Pro",
          "limit": { "context": 131072, "output": 16384 }
        },
        "gpt-5.5": {
          "name": "GPT-5.5",
          "limit": { "context": 128000, "output": 32768 }
        },
        "gpt-5.4": {
          "name": "GPT-5.4",
          "limit": { "context": 128000, "output": 32768 }
        },
        "gpt-5.4-mini": {
          "name": "GPT-5.4 Mini",
          "limit": { "context": 128000, "output": 16384 }
        }
      }
    }
  },
  "model": "easyrouter-anthropic/claude-sonnet-4-6",
  "autoshare": false
}

Key fields

The example declares two providers:
- easyrouter-anthropic: npm must be @ai-sdk/anthropic — use this for Claude and other Anthropic-protocol models
- easyrouter: npm must be @ai-sdk/openai-compatible — use this for DeepSeek, GPT, and other OpenAI-compatible models
Both providers share the same baseURL: https://easyrouter.io/v1
apiKey is embedded directly in the config file — replace sk-123 with your real EasyRouter API key (the example value is a placeholder)
Model IDs under models must exactly match the model names exposed by your EasyRouter console. You can use a custom alias by adding an id field pointing to the real model (see haiku → claude-haiku-4-5 in the example)
The top-level model field sets the default model in the form <provider>/<model>
Per-project opencode.json takes precedence over the global config

2. Configure the API key

The example above already embeds the API key directly in opencode.json via options.apiKey. Just replace sk-123 with your real EasyRouter key — no extra step required.

Optional: manage keys via auth.json

If you'd rather not store the API key in opencode.json, remove the apiKey field from the config and edit ~/.local/share/opencode/auth.json instead:

{
  "easyrouter-anthropic": {
    "type": "api",
    "key": "sk-your-easyrouter-key"
  },
  "easyrouter": {
    "type": "api",
    "key": "sk-your-easyrouter-key"
  }
}

Or use the CLI:

opencode auth login

Pick easyrouter-anthropic and/or easyrouter when prompted and paste your API key.

✅ Step 3: Verify

Launch OpenCode and type /models. You should see entries like easyrouter-anthropic/claude-sonnet-4-6 and easyrouter/deepseek-v4-pro. Pick a model and send a test message — a normal response means you're set.

❓ Troubleshooting

Issue	Fix
EasyRouter models don't show in `/models`	Check that `provider.easyrouter-anthropic.models` or `provider.easyrouter.models` is populated
Model not found	Confirm the model ID matches your EasyRouter console exactly
Invalid API key	Verify `apiKey` in `opencode.json` or your `auth.json`; or re-run `opencode auth login`
Claude models return protocol errors	Make sure you're calling the `easyrouter-anthropic` provider (`@ai-sdk/anthropic`), not `easyrouter` (`@ai-sdk/openai-compatible`)
Config changes not picked up	Restart OpenCode; per-project config wins over global