Open-source app for OpenCode

OpenCode reaches its own interface through its own attach flow, with no multiplexer in the picture and nothing to enable first — the session Happier started is the session opencode reattaches to, and the app keeps taking messages while a terminal is sitting on it.

The other half of the story is credentials: OpenCode brings a provider layer of its own, so Codex, OpenAI, Claude-subscription and Anthropic profiles you connected once are all selectable at session start, and a pool assembled for a different agent turns out to be useful here. The Claude subscription entry accepts both shapes the release brokers — a browser login and a setup token — while the Anthropic one stays an API key, and which of them you are running under is chosen when the session starts rather than inherited from whatever that computer was last signed into.

Forking is where the release gives this one room. An OpenCode conversation can be forked whole, and it can be forked from a particular message — the difference between “try that again differently” and “go back to before the third tool call, then try that again differently”. Skills and slash commands you keep in .opencode/skills and .opencode/commands, or under ~/.config/opencode, are read as prompt assets and travel with the session, so what you taught the CLI at your desk is still there when the session is being answered from a phone.

OpenCode is SST’s terminal coding agent, and it brings its own provider layer: you point it at a model you already have access to and it drives that model against your repository. happier opencode runs the same binary with the same opencode auth credentials, in the same directory.

Happier supplies the devices. A session you started in a terminal in one room is readable and answerable from a phone in another, and the transcript is encrypted on your computer before it goes anywhere.

The iOS and Android apps, the desktop app for macOS, Windows and Linux, and app.happier.dev are all clients onto the OpenCode process running on your computer — not read-only mirrors. Answer a permission request, send the next instruction, browse the repository, read the diff. The transcript is end-to-end encrypted before it leaves your computer, so the server carrying it holds ciphertext.

Happier installs on the computer that already holds your repository, and happier opencode starts OpenCode there as an ordinary subprocess, in the directory you point it at, signed in the way you signed it in. There is no gateway between the agent and SST, and no copy of your source anywhere else.

Happier looks for opencode on your PATH first and runs the copy you installed. If there is not one, it can install opencode-ai into ~/.happier/tools/providers/opencode/ — its own directory, not your global npm prefix. A copy you manage yourself is never replaced or upgraded behind your back.

SST’s own install and sign-in guide is at opencode.ai/docs. Happier does not mirror it, because a copy of someone else’s install instructions is a copy that goes stale.

Configuration reference for the Happier side — OpenCode in the Happier docs.

OpenCode is one of the agents Happier can point at a credential you connected once instead of at whatever that computer is logged into. It accepts a Codex subscription, an OpenAI API key, a Claude subscription or an Anthropic API key.

Connected services are keyed by the credential, not by the agent, so the same Codex subscription is selectable for every agent that can take it, on every computer you have connected — which is also what makes a pool of your own accounts useful across more than one of them. The credential is encrypted and decrypted on your own devices; the docs page carries the per-profile rules, because which kinds of profile each agent accepts is exactly the sort of detail that moves between releases.

OpenCode is one of 13 command-line coding agents Happier runs, and they share one session list, one permission inbox, one set of keyboard shortcuts and one MCP configuration.

You define an MCP server once and OpenCode receives it as native MCP inventory, next to whatever MCP servers it already had of its own.

That matters most on the days you are running more than one: sessions from different vendors side by side, and a notification tap opening the session that raised the request rather than the app’s front door. The full list is here.

Typing happier opencode in a terminal starts the session right where you are standing, and the same session is in the app at the same time. What you read in that shell is Happier’s own display of the session — the transcript, the permission prompts, the tool output — rather than OpenCode’s interface. Nobody has to give up the terminal to get a phone client.

happier attach <session-id> opens OpenCode’s own TUI on that same session through OpenCode’s attach flow. Both ends stay writable, with no multiplexer involved and nothing to switch on first — type in the TUI and it appears in the app, send from the app and it appears in the TUI.

The attach guide lists the cases instead of promising all of them.

One command on the computer that holds your code, then happier opencode in the repository you want to work in.

Walkthroughs are in the guides. All of it is MIT-licensed, and the relay is one you can run yourself.