@oxel40/opencode-model-groups

Switch a whole team of opencode agents between named model/variant presets — from one config file and a /modelgroup picker in the TUI.

Define a group once:

// ~/.config/opencode/model-groups.json
{
  "groups": {
    "default": {},
    "hierarchical": {
      "orchestrator": { "model": "github-copilot/claude-opus-5", "variant": "medium" },
      "implementer": { "model": "github-copilot/claude-opus-5", "variant": "low" },
      "verifier": { "model": "github-copilot/gpt-5.6-luna", "variant": "medium" }
    }
  }
}

Point your agents at it with a group:<alias> placeholder instead of a real model string:

// opencode.json
{
  "agent": {
    "orchestrator": { "model": "group:orchestrator" },
    "implementer": { "model": "group:implementer" }
  }
}

Then flip the whole team between presets with the /modelgroup command (bound in the TUI), without editing opencode.json at all. Any agent whose alias is missing from the active group falls back to opencode's own default model.

Install

// opencode.json — rewrites `group:*` model placeholders on config load
{
  "plugin": ["@oxel40/opencode-model-groups"]
}

// tui.json — adds the `/modelgroup` picker command
{
  "plugin": ["@oxel40/opencode-model-groups/tui"]
}

Both entries are needed: the server half resolves the placeholders, the TUI half lets you switch the active group interactively. opencode installs npm plugins automatically via Bun at startup.

How it works

• ~/.config/opencode/model-groups.json holds every named group. Missing file → the plugin is a no-op.
• The currently active group name is plugin-owned state, written by /modelgroup to opencode's state dir — not part of opencode.json.
• On every config load, group:<alias> in an agent's model (or in the top-level model/small_model) is replaced with that alias's entry from the active group. An alias absent from the group is dropped (falls back to opencode's default); a malformed entry (missing model) is dropped and logged as an error.
• Switching groups via /modelgroup disposes the running instance so the next request re-resolves config with the new group.

License

MIT