opencode is an open-source AI coding agent from Anomaly. It runs as a terminal TUI first, with a desktop app, IDE extensions, and GitHub and GitLab integration around the same core. The agent is free; you connect whatever model provider you already pay for.
models and pricing
opencode has no fixed model. You bring API keys for any provider, with Claude, GPT, and Gemini named on its homepage. The optional opencode Console adds pay-per-token access to a curated list of 60+ models, but nothing requires it. opencode states that it does not store your code or context data.
what it’s good at
A plan mode proposes changes before any file is touched, and edits can be
undone and redone. /init analyzes a project and writes an AGENTS.md so
later sessions start informed. The same agent is reachable from the
terminal, a desktop app, an IDE, or a CI integration.
opencode in crystl
opencode runs in a crystl shard with its own model selection, activity visibility, and real approval cards for its tool calls, delivered through a plugin crystl injects into the session. Crystl treats its compatibility as partial because the card only opens on opencode’s own permission event, and a missed answer falls back to opencode’s native prompt.
The profile describes what crystl has tested; it never supplies a command, hook script, or launch setting. Those remain local to the Crystl installation.