OpenCode Integration

OpenCode is an open-source AI coding agent for your terminal, IDE, or desktop. OffRail is a built-in provider in OpenCode, so setup takes under a minute — no config files or npm adapters required. You get access to 200+ models from 40+ providers, all tracked in one dashboard.

Prerequisites

• OpenCode installed — visit the OpenCode download page for your platform
• An OffRail API key

Setup

opencode

Why Use OffRail with OpenCode

• 200+ models — GPT-5, Claude, Gemini, Llama, and more from 40+ providers
• One API key — Stop juggling credentials for every provider
• Cost tracking — See what each coding agent costs in your dashboard
• Response caching — Repeated requests hit cache automatically
• Volume discounts — The more you use, the more you save

Adding Custom Models

The built-in provider gives you access to all standard OffRail models. If you want to add custom model aliases or configure models not yet listed in the built-in provider, you can create a config.json in your OpenCode configuration directory:

macOS/Linux: ~/.config/opencode/config.json

Windows: C:\Users\YourUsername\.config\opencode\config.json

{
	"provider": {
		"offrail": {
			"models": {
				"deepseek-v3": {
					"name": "DeepSeek V3"
				}
			}
		}
	}
}

Since OffRail is a built-in provider, you only need to specify what you're adding — OpenCode merges your config with the built-in provider definition, so npm, name, and baseURL don't need to be repeated.

After updating config.json, restart OpenCode to see the new models.

Pinning a Model to a Specific Provider

OpenCode's built-in model list only shows canonical model IDs (e.g. claude-sonnet-5), which OffRail routes to the best available provider automatically. If you want a model to always run on one specific provider — for example to guarantee a fixed price, a compliance boundary, or consistent behavior — use OffRail's provider/model syntax as the model ID.

Add the pinned variants you want as custom models, and they show up in OpenCode's model picker alongside the built-in list:

{
	"provider": {
		"offrail": {
			"models": {
				"anthropic/claude-sonnet-5": {
					"name": "Claude Sonnet 5 (Anthropic direct)"
				},
				"aws-bedrock/claude-sonnet-5": {
					"name": "Claude Sonnet 5 (AWS Bedrock)"
				}
			}
		}
	}
}

You can also pin one as your default model, or per-agent:

{
	"model": "offrail/anthropic/claude-sonnet-5"
}

For providers with multiple regions, append a region suffix to pin both provider and region, e.g. aws-bedrock/claude-sonnet-5:us. See the routing docs for the full syntax, and each model's available providers on the models page.

Disabling Fallback

By default, OffRail automatically fails over to alternative providers if your chosen provider is experiencing downtime — even for provider-pinned model IDs. To make the pin strict, pass the X-No-Fallback header. Requests will then be sent only to the provider you specified, with no automatic fallback.

{
	"provider": {
		"offrail": {
			"options": {
				"headers": {
					"X-No-Fallback": "true"
				}
			}
		}
	}
}

Switching Models

Select a different model directly in the OpenCode interface, or update the model field in your configuration:

{
	"model": "offrail/gpt-5-mini"
}

Troubleshooting

Connection timeout

Check that you have an active internet connection and that your API key is valid from the dashboard.

Custom models not showing up

After editing config.json, restart OpenCode completely for changes to take effect.

404 Not Found errors with custom config

If you are using a custom config.json, verify your baseURL is set to https://api.offrail.ai/v1 (note the /v1 at the end).

Configuration Tips

• Global configuration: Use ~/.config/opencode/config.json to apply settings across all projects
• Project-specific: Place opencode.json in your project root to override global settings for that project
• Model selection: You can specify different models for different types of tasks using OpenCode's agent configuration