Configuration Reference

Complete reference for all configuration files and options in oh-my-opencode-slim.

Config Files

File	Purpose
`~/.config/opencode/opencode.json`	OpenCode core settings (plugin registration, providers)
`~/.config/opencode/oh-my-opencode-slim.json`	Plugin settings — agents, multiplexer, MCPs, council
`~/.config/opencode/oh-my-opencode-slim.jsonc`	Same, but with JSONC (comments + trailing commas). Takes precedence over `.json` if both exist
`.opencode/oh-my-opencode-slim.json`	Project-local overrides (optional, checked first)

💡 JSONC recommended: Use the .jsonc extension to add comments and trailing commas. If both .jsonc and .json exist, .jsonc takes precedence.

Prompt Overriding

Customize agent prompts without modifying source code. Create markdown files in ~/.config/opencode/oh-my-opencode-slim/:

File	Effect
`{agent}.md`	Replaces the agent's default prompt entirely
`{agent}_append.md`	Appends custom instructions to the default prompt

When a preset is active, the plugin checks ~/.config/opencode/oh-my-opencode-slim/{preset}/ first, then falls back to the root directory.

Example directory structure:

~/.config/opencode/oh-my-opencode-slim/
  ├── best/
  │   ├── orchestrator.md        # Preset-specific override (used when preset=best)
  │   └── explorer_append.md
  ├── orchestrator.md            # Fallback override
  ├── orchestrator_append.md
  ├── explorer.md
  └── ...

Both {agent}.md and {agent}_append.md can coexist — the full replacement takes effect first, then the append. If neither exists, the built-in default prompt is used.

JSONC Format

All config files support JSONC (JSON with Comments):

Single-line comments (//)
Multi-line comments (/* */)
Trailing commas in arrays and objects

Example:

{
  // Active preset
  "preset": "openai",

  /* Agent model mappings */
  "presets": {
    "openai": {
      "oracle": { "model": "openai/gpt-5.4" },
      "explorer": { "model": "openai/gpt-5.4-mini" },
    },
  },

  "multiplexer": {
    "type": "tmux",
    "layout": "main-vertical",
  },
}

Full Option Reference

Option	Type	Default	Description
`preset`	string	—	Active preset name (e.g. `"openai"`, `"best"`)

Runtime Preset Switching

Startup Toast

Set showStartupToast to false if you want to disable the startup toast that appears when the plugin activates.

{
  "showStartupToast": false
}

Agent Display Names

Use displayName to give an agent a user-facing alias while keeping the internal agent name unchanged.

{
  "agents": {
    "oracle": {
      "displayName": "advisor"
    },
    "explorer": {
      "displayName": "researcher"
    }
  }
}

With this config, users can refer to @advisor and @researcher, while the plugin still routes them to oracle and explorer internally.

Notes:

displayName works in both top-level agents overrides and inside presets
@ prefixes and surrounding whitespace are normalized automatically
Display names must be unique
Display names cannot conflict with internal agent names like oracle or explorer

Custom Agents

Unknown keys under agents are treated as custom subagents. A custom agent needs its own model, a normal prompt, and optionally an orchestratorPrompt that teaches the orchestrator exactly when to delegate to it.

{
  "agents": {
    "janitor": {
      "model": "github-copilot/gpt-5.4",
      "prompt": "You are Janitor. Audit codebase entropy, dead code, docs drift, naming inconsistencies, and unnecessary complexity. Prefer analysis and plans over direct edits.",
      "orchestratorPrompt": "@janitor\n- Role: Maintenance specialist for codebase cleanup and entropy reduction\n- **Delegate when:** after large refactors • cleanup/technical-debt review • dead code or docs drift is suspected\n- **Don't delegate when:** feature implementation • urgent debugging • UI/UX work"
    }
  }
}