oh-my-opencode-slim/docs/preset-switching.md

Preset Switching

Switch agent model presets at runtime using the /preset TUI slash command.

Controls

/preset opens a three-level preset manager in the TUI — pure TUI, like the built-in /models, so it triggers no LLM turn.

Level	What you do
1. Preset list	Apply / Edit / Delete an existing preset, or create a new one
2. Agent arrangement	Add / remove / edit the agents in a preset, then Save (or Save & Apply)
3. Edit agent	Pick model → variant (thinking strength) → temperature → options (JSON)

/preset is a TUI-only slash command (like /models). Invoke it via autocomplete selection or a keybind. Typing /preset + Enter does not open the manager (same design as /models).

How It Works

1. Define named presets in oh-my-opencode-slim.jsonc under the presets field, or create them interactively from the manager
2. The manager writes preset changes to the user config file
3. Apply persists the preset name to the config file only — the sidebar is NOT refreshed mid-session (the agent registry is unchanged until reload; showing new models against running agents would be misleading)
4. Reload OpenCode (or start a new conversation) for the new preset to take effect on the agent registry
5. The current session is not reloaded — this is deliberate. Hot-swapping the agent tree mid-conversation could truncate context (a new model may have a smaller window), drift prior assistant turns under a changed system prompt, leave running subagents referencing stale agent definitions, or shift tool/skill availability. A future path to true in-session switching without reset requires upgrading @opencode-ai/plugin (tracked in #799).

Level 3 — model and variant selection

The model picker lists every model from all connected providers (fetched from the server's provider registry). If the chosen model exposes variants (e.g. thinking, high, low), a variant picker follows — this is the "thinking strength" selector. Temperature is a numeric prompt (0–2 or blank). Options is a raw JSON prompt for provider-specific settings (e.g. {"thinking":{"type":"enabled","budgetTokens":10000}}).

Example Configuration

{
  "presets": {
    "cheap": {
      "orchestrator": { "model": "anthropic/claude-3.5-haiku" },
      "explorer": { "model": "openai/gpt-5.6-luna" },
      "oracle": { "model": "anthropic/claude-sonnet-4-6" }
    },
    "powerful": {
      "orchestrator": { "model": "openai/gpt-5.6" },
      "oracle": { "model": "anthropic/claude-opus-4-6" },
      "librarian": { "model": "anthropic/claude-sonnet-4-6" }
    },
    "thinking": {
      "oracle": {
        "model": "anthropic/claude-sonnet-4-6",
        "variant": "thinking",
        "options": { "thinking": { "type": "enabled", "budgetTokens": 10000 } }
      }
    }
  }
}

Supported Fields

The following fields are applied when the preset is loaded on restart:

Field	Description
model	Model ID in provider/model format. Array form (fallback chains) is resolved to the first entry
temperature	Inference temperature (0-2)
variant	Model variant (e.g. "thinking")
options	Provider-specific options (e.g. thinking budget)

Fields not applied at runtime (require restart): prompt, skills, mcps, displayName.

Startup Preset vs Runtime Switching

There are two ways to activate a preset:

Method	How	Persists?
Config file	Set "preset": "cheap" in oh-my-opencode-slim.jsonc	Yes, across restarts
/preset TUI command	Select a preset from the picker during a session	Yes — writes to config file

The /preset TUI command writes the selected preset name to the config file, so the switch persists across restarts. Reload OpenCode for the new preset to take effect on the agent registry. The current session continues uninterrupted with its existing models.

See Configuration for the full preset option reference.