The open source AI coding agent.

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This is a personal fork of anomalyco/opencode. It is not affiliated with the OpenCode team. Changes vs upstream are documented in FORK.md.

TUI changes in this fork:

• Configurable sidebar sections — hide MCP list, LSP list, and file-diff via tui.json
• Aggregated subagent (Task tool) token + cost totals in the Context sidebar widget
• Collapsible system context block inline in the session thread

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Building from source

# Install dependencies
bun install

# Run directly without building (dev mode)
bun run dev

Installing the binary

Build a native binary for your platform and symlink it onto your PATH:

# Build (run from packages/opencode)
bun run build --single

# Symlink the output binary — update the filename to match your platform/arch
ln -sf "$(pwd)/dist/opencode-darwin-arm64" ~/.local/bin/opencode

# Verify
opencode --version

After pulling upstream changes, re-run bun run build --single to rebuild. The symlink points directly to the binary, so no re-linking needed.

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Configuration

Two config files, both in ~/.config/opencode/:

File	Purpose
opencode.json	Main config — model, providers, permissions, agents, MCP, plugins
tui.jsonc	TUI display settings only (theme, keybinds, sidebar, etc.)

They are intentionally separate — upstream explicitly deprecated putting TUI keys inside opencode.json and migrates them out automatically. opencode.json is server/agent config; tui.jsonc is display/client config.

A project-level opencode.json at the repo root is merged on top of the global one and takes precedence.

Main config (~/.config/opencode/opencode.json)

{
  "$schema": "https://opencode.ai/config.json",

  // Default model
  "model": "anthropic/claude-sonnet-4-5",

  // Override the system prompt for a specific agent
  "agent": {
    "build": {
      "prompt": "You are a focused coding agent. Be concise and direct."
    }
  }
}

The agent.prompt field replaces the built-in "You are OpenCode..." system prompt entirely for that agent. If omitted, the default prompt is chosen based on the model family (Anthropic, GPT, Gemini, etc.).

TUI config (~/.config/opencode/tui.jsonc)

{
  "$schema": "https://opencode.ai/tui.json",
  "sidebar": {
    "show_file_diff": false,        // hide Modified Files
    "show_mcp": false,              // hide MCP list
    "show_lsp": false,              // hide LSP list
    "show_subagent_costs": true,    // aggregate subagent token/cost in Context widget
    "show_system_context": true     // collapsible system context block in thread
  }
}

AGENTS.md

Instruction files are loaded separately from the JSON config. OpenCode looks for AGENTS.md (or CLAUDE.md) walking up from the current directory to the repo root, plus ~/.config/opencode/AGENTS.md as a global fallback. These are appended to the system prompt, not a replacement for it.

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Syncing with upstream

# Add upstream remote once
git remote add upstream git@github.com:anomalyco/opencode.git

# Pull upstream changes onto dev branch
git fetch upstream
git merge upstream/dev

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Agents

OpenCode includes two built-in agents you can switch between with the Tab key.

• build - Default, full-access agent for development work
• plan - Read-only agent for analysis and code exploration

Learn more about agents.

Documentation

For more info on how to configure OpenCode, head over to our docs.