OpenCode + RelayPlane
OpenCode is a terminal AI coding tool. RelayPlane is a local LLM proxy. They are complementary — point OpenCode at RelayPlane with one env var and get multi-model routing, rate limit management, cost tracking, and automatic fallbacks.
TL;DR
Add RelayPlane to OpenCode when you want:
- Automatic failover when Anthropic rate limits you mid-session
- Per-request cost visibility across every OpenCode session
- Complexity routing that sends simple tasks to cheaper models
- Multi-provider access without changing how OpenCode works
OpenCode alone is enough when:
- You only need coding assistance and do not track LLM spend
- You have a flat-rate subscription and cost per call does not matter
- You want zero additional local processes
Zero-code integration: one env var
OpenCode respects ANTHROPIC_BASE_URL. That is the only change needed.
Every LLM call OpenCode makes now routes through RelayPlane. Cost, model, and token count are logged to local SQLite. No code changes to OpenCode. No cloud account for RelayPlane.
Feature Comparison
| Feature | RelayPlane | Without RelayPlane |
|---|---|---|
| Multi-model routing RelayPlane sits between OpenCode and your model providers, letting you route requests across Anthropic, OpenAI, Gemini, and 8 other providers from a single endpoint. | Route between Anthropic, OpenAI, Gemini | Single provider per session |
| Rate limit management RelayPlane auto-fails over on 429 errors, so OpenCode sessions keep running even when a single provider is rate limited. | ||
| Per-session cost tracking Every LLM call OpenCode makes is logged to local SQLite with the exact model, token count, and dollar cost. No data leaves your machine. | SQLite, no cloud | No visibility |
| Context window routing RelayPlane routes by complexity: simple tasks go to cheaper models like Haiku, large context requests go to Opus. OpenCode sends every request to whichever model you configured. | ||
| Local install RelayPlane installs as a global npm package — no Python environment, no Docker, no repo to clone. | npm install -g @relayplane/proxy | N/A |
| Fallback models When a model is overloaded or returns an error, RelayPlane automatically falls back to a configured backup. Without it, OpenCode surfaces hard errors directly. | ||
| Works with OpenCode OpenCode respects ANTHROPIC_BASE_URL. Set it to http://localhost:4100 and every LLM call routes through RelayPlane automatically — zero code changes. | One env var | N/A |
OpenCode + RelayPlane: the full picture
What is OpenCode?
OpenCode is an open source terminal-based AI coding tool (MIT license) with over 200,000 weekly npm downloads. It supports any Anthropic-compatible endpoint via environment variable, which means any OpenCode user can point it at RelayPlane with a single export. OpenCode handles the coding interface; RelayPlane handles what happens at the LLM layer.
Why add a proxy to OpenCode?
OpenCode users hit the same problems as any heavy API consumer: rate limits during long sessions, no visibility into what each session costs, and hard failures when a single model is overloaded. RelayPlane adds auto-failover on 429s, per-request cost logging to local SQLite, and complexity-based routing — all without modifying how OpenCode works.
How the integration works
OpenCode reads ANTHROPIC_BASE_URL from the environment. Set it to http://localhost:4100 (where RelayPlane runs) and every Anthropic API call OpenCode makes routes through RelayPlane first. RelayPlane passes the request to the real provider, logs the response metadata, and returns the result unchanged. The integration is fully transparent to OpenCode.
What you get with RelayPlane
Multi-provider routing across Anthropic, OpenAI, Gemini, Mistral, and Ollama. Per-request cost tracking in local SQLite with a dashboard at localhost:4100. Automatic fallback when a model is rate limited or overloaded. Complexity-based routing that sends simple tasks to cheaper models automatically. All of it runs locally with no cloud account required.
OpenCode generates the requests. RelayPlane governs them.
OpenCode is one of the fastest growing AI coding tools with over 200,000 weekly npm downloads. It is open source (MIT), runs entirely in the terminal, and supports any Anthropic-compatible endpoint. That last point is what makes the RelayPlane integration trivial: there is no plugin, no fork, and no patch — just an env var.
RelayPlane is MIT licensed and runs entirely on your machine. It exposes a local endpoint that is fully compatible with the Anthropic API. When OpenCode connects to it, requests are forwarded to the real providers, cost metadata is written to local SQLite, and results are returned unchanged. The entire stack — OpenCode, RelayPlane, provider API — stays under your control.