Configuration

Data Layout

~/.arc/
├── config.json              # Profile registry and active profile
├── update-check.json        # Cached latest version from npm (4h TTL)
├── profiles/
│   └── <name>/              # Tool config dir for this profile
│       ├── .credentials.json    # OAuth tokens (Claude)
│       ├── oauth_creds.json     # OAuth tokens (Gemini)
│       ├── auth.json            # OAuth tokens (Codex)
│       ├── .api-key             # Plaintext API key fallback
│       ├── settings.json        # Tool settings
│       └── .arc-shared.json     # Shared layer sync manifest
├── shared/                  # Shared layer (synced across enabled profiles)
│   ├── settings.json            # Shared MCP servers (mcpServers key)
│   ├── commands/                # Shared command files
│   ├── CLAUDE.md                # Shared instructions
│   ├── memory/                  # Shared memory (linked via junction/symlink)
│   └── projects/                # Shared projects (linked via junction/symlink)
├── credentials/             # [experimental] Hot-swap snapshots
│   ├── swap-manifest.json
│   └── <name>/
├── memory/                  # Persistent memory store
├── tasks/
│   └── tasks.json           # Task store
├── sessions.json            # Session store
├── plugins/
│   └── installed.json       # Plugin registry
├── remote-agents.json       # Remote agent registry
├── skills/                  # Skill definitions
├── logs/
│   └── structured.jsonl     # Structured log
└── traces/                  # OpenTelemetry JSONL traces

config.json

The central configuration file. Contains the profile registry, active profile, and display settings.

{
  "version": 1,
  "activeProfile": "work",
  "profileOrder": ["work", "personal", "gemini-work"],
  "profiles": {
    "work": {
      "tool": "claude",
      "authType": "oauth",
      "configDir": "/home/user/.arc/profiles/work",
      "description": "Work Claude account",
      "createdAt": "2025-01-01T00:00:00.000Z",
      "useShared": true,
      "useSharedMemory": true,
      "launchArgs": ["--model", "sonnet"]
    },
    "gemini-work": {
      "tool": "gemini",
      "authType": "api-key",
      "configDir": "/home/user/.arc/profiles/gemini-work",
      "createdAt": "2025-01-01T00:00:00.000Z"
    },
    "personal": {
      "tool": "claude",
      "authType": "api-key",
      "configDir": "/home/user/.arc/profiles/personal",
      "apiKeyStorage": "keyring",
      "createdAt": "2025-01-01T00:00:00.000Z",
      "envOverrides": {
        "ANTHROPIC_BASE_URL": "https://api.example.com"
      }
    }
  }
}

Profile Fields

Field	Type	Description
tool	string?	Agent binary (claude, gemini, codex, ...). Defaults to "claude"
authType	string	One of oauth, api-key, bedrock, vertex, foundry
configDir	string	Absolute path to the profile's tool config directory
description	string?	Optional human-readable label
createdAt	string	ISO 8601 creation timestamp
inherits	string?	Name of a base profile to inherit from
apiKeyStorage	"keyring" | "file"?	Where API keys are stored. Defaults to keyring with file fallback
envOverrides	object?	Extra env vars injected on launch
useShared	boolean?	Whether this profile inherits from ~/.arc/shared/
useSharedMemory	boolean?	Whether memory/ is linked to shared/memory/
useSharedProjects	boolean?	Whether projects/ is linked to shared/projects/
launchArgs	string[]?	Default flags passed to the agent tool on every launch
enforcement	"off" | "log" | "advise" | "enforce"?	Hook enforcement mode for this profile. Defaults to "log". See Hooks & Supervision
hooks	object?	Per-hook config overrides ({ "hook-name": { enabled, timeout } }). See Hook Configuration

arc.json

Per-workspace configuration file. Place in the project root for automatic profile and adapter selection.

{
  "profile": "work",
  "adapter": "claude-code",
  "hooks": {
    "enforcement": "warn"
  },
  "telemetry": {
    "exporter": "otlp",
    "endpoint": "http://localhost:4318/v1/traces",
    "sampleRate": 1.0
  }
}

When arc launch runs inside a directory containing arc.json, the workspace config is applied on top of the resolved profile.

arc.json Fields

Field	Type	Description
profile	string?	Override active profile for this workspace
adapter	string?	Override adapter selection
hooks.enforcement	string?	Hook enforcement mode (off, log, warn, enforce)
telemetry.exporter	string?	Telemetry exporter (console, jsonl, otlp)
telemetry.endpoint	string?	OTLP collector endpoint
telemetry.sampleRate	number?	Trace sample rate (0.0 - 1.0)

Profile Config Directory

Each profile's configDir is a standard agent tool config directory. ARC sets CLAUDE_CONFIG_DIR (or the equivalent env var for other tools) before launching.

File	Written By	Purpose
.credentials.json	Claude Code	OAuth tokens
oauth_creds.json	Gemini CLI	OAuth tokens
auth.json	Codex CLI	OAuth tokens
settings.json	Agent tool / user	Tool settings (MCP servers, etc.)
.api-key	ARC	Plaintext API key fallback
.arc-shared.json	ARC	Shared layer sync manifest

API Key Storage

API keys are stored via @napi-rs/keyring:

• Service name: arc
• Account: <profile-name>

If the native keyring is unavailable (missing build tools, headless environment), ARC falls back to ~/.arc/profiles/<name>/.api-key.

Environment Variables

Variable	Purpose
ARC_DIR	Override the ARC data directory (default: ~/.arc)
ARC_PROFILE	Override the active profile for a single invocation
ARC_LOCAL_BIN_DIR	Override the local shim install directory (default: ~/.local/bin)
ARC_INSTALL_DIR	Override the bootstrap install root (default: ~/.arc-install)

Auth Environment Variables

These are set by ARC when launching a profile and cleared before each launch to prevent leakage:

Variable	Set When
CLAUDE_CONFIG_DIR	Always (Claude profiles)
CLAUDE_CODE_USE_BEDROCK	authType: "bedrock"
CLAUDE_CODE_USE_VERTEX	authType: "vertex"
CLAUDE_CODE_USE_FOUNDRY	authType: "foundry"
ANTHROPIC_API_KEY	authType: "api-key" (Claude)
GOOGLE_API_KEY	authType: "api-key" (Gemini)
AWS_ACCESS_KEY_ID	authType: "bedrock" (if in envOverrides)
AWS_SECRET_ACCESS_KEY	authType: "bedrock" (if in envOverrides)
AWS_REGION	authType: "bedrock" (if in envOverrides)