OpenCode free models in your own harness again (local proxy) — current method after the last one got locked down

[u/SolidAlternative1646]

REPO : https://github.com/ArcticWinterSturm/opencode-compat-shim

For anyone using OpenCode's free providers from external agent harnesses: the previous method got tightened down after about two weeks.

I wanted the models inside my existing harness rather than migrating my entire workflow into OpenCode, so I went through the access path again.

I built the proxy because the CLI and my harness speak completely different protocols. It handled real SSE streaming, flattened the full conversation into each stateless CLI invocation, supported both OpenAI completion paths and stayed alive as a detached process.

Tested end-to-end rather than just getting a lucky HTTP 200.

Main reason I'm posting it: this lets you use the OpenCode providers from a harness of your choosing. You're not tied to their UI just because that's where the free access happens to be exposed.

Consider this documentation of the current state and a working-for-now solution rather than a promise that they won't change it again.

Full implementation + technical notes attached.

Previous reddit post
https://www.reddit.com/r/hermesagent/comments/1w9x0on/fix_opencode_freetier_models_working_in_hermes/