oh-my-opencode-slim/docs/configuration.md

Configuration Reference

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

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Config Files

File	Purpose
~/.config/opencode/opencode.json	OpenCode core settings (plugin registration, providers)
~/.config/opencode/oh-my-opencode-slim.json	Plugin settings — agents, tmux, 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.

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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.

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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" },
    },
  },

  "tmux": {
    "enabled": true,  // Enable pane monitoring
    "layout": "main-vertical",
  },
}

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Full Option Reference

Option	Type	Default	Description
preset	string	—	Active preset name (e.g. "openai", "best")
presets	object	—	Named preset configurations
presets.<name>.<agent>.model	string	—	Model ID in provider/model format
presets.<name>.<agent>.temperature	number	—	Temperature (0–2)
presets.<name>.<agent>.variant	string	—	Reasoning effort: "low", "medium", "high"
presets.<name>.<agent>.skills	string[]	—	Skills the agent can use ("*", "!item", explicit list)
presets.<name>.<agent>.mcps	string[]	—	MCPs the agent can use ("*", "!item", explicit list)
tmux.enabled	boolean	false	Enable tmux pane spawning
tmux.layout	string	"main-vertical"	Layout: main-vertical, main-horizontal, tiled, even-horizontal, even-vertical
tmux.main_pane_size	number	60	Main pane size as percentage (20–80)
disabled_mcps	string[]	[]	MCP server IDs to disable globally
fallback.enabled	boolean	false	Enable model failover on timeout/error
fallback.timeoutMs	number	15000	Time before aborting and trying next model
fallback.retryDelayMs	number	500	Delay between retry attempts
fallback.chains.<agent>	string[]	—	Ordered fallback model IDs for an agent
fallback.retry_on_empty	boolean	true	Treat silent empty provider responses (0 tokens) as failures and retry. Set false to accept empty responses
council.master.model	string	—	Required if using council. Council master model
council.master.variant	string	—	Council master variant
council.master.prompt	string	—	Optional synthesis guidance for the master
council.presets	object	—	Required if using council. Named councillor presets
council.presets.<name>.<councillor>.model	string	—	Councillor model
council.presets.<name>.<councillor>.variant	string	—	Councillor variant
council.presets.<name>.<councillor>.prompt	string	—	Optional role guidance for the councillor
council.presets.<name>.master.model	string	—	Override global master model for this preset
council.presets.<name>.master.variant	string	—	Override global master variant for this preset
council.presets.<name>.master.prompt	string	—	Override global master prompt for this preset
council.default_preset	string	"default"	Default preset when none is specified
council.master_timeout	number	300000	Master synthesis timeout (ms)
council.councillors_timeout	number	180000	Per-councillor timeout (ms)
council.master_fallback	string[]	—	Fallback models for the council master
council.councillor_retries	number	3	Max retries per councillor and master on empty provider response (0–5)