Authentication

Grok supports several authentication methods, including interactive browser login, enterprise single sign-on (SSO), and headless CI/CD runners.

Browser Login (Default)

On first launch, Grok opens your browser to authenticate with grok.com:

grok

Grok stores credentials in ~/.grok/auth.json and reuses them across sessions. Grok refreshes access tokens automatically in the background. When a token can't be refreshed, Grok prompts you to sign in again. Credentials without a server-provided expiry fall back to a 30-day lifetime.

Re-authenticate

To switch accounts or resolve an authentication problem, run:

grok login

Running grok login starts the sign-in flow again, replacing your cached session. By default, it opens your browser and signs in through xAI OAuth at auth.x.ai. Pass a flag to select a different flow:

To sign out, run grok logout. It takes no flags and clears your cached credentials.

API Key

For CI/CD, automation, or environments without browser access, use an API key from console.x.ai:

export XAI_API_KEY="xai-..."
grok

Grok uses the API key as a fallback when no session token is active. If you have already signed in interactively, the stored session token takes precedence. To fall back to the API key, run grok logout or delete ~/.grok/auth.json.

OIDC (Customer SSO)

Authenticate developers through your own Identity Provider (IdP) -- such as Okta, Azure AD, or Auth0 -- instead of grok.com.

1. Register a public client in your IdP

• Grant type: Authorization Code with PKCE (Proof Key for Code Exchange)
• Redirect URI: http://127.0.0.1/callback -- a loopback address. Grok binds a random port at sign-in time, and most IdPs treat the loopback redirect as port-agnostic per RFC 8252.
• No client secret. PKCE replaces it.

2. Configure the CLI

Via config file:

# ~/.grok/config.toml
[grok_com_config.oidc]
issuer = "https://acme.okta.com"
client_id = "0oa1b2c3d4e5f6g7h8i9"

Or via environment variables:

export GROK_OIDC_ISSUER="https://acme.okta.com"
export GROK_OIDC_CLIENT_ID="0oa1b2c3d4e5f6g7h8i9"

You can also override the API endpoint to point at your own proxy:

export GROK_CLI_CHAT_PROXY_BASE_URL="https://grok-proxy.acme.com/v1"

3. Run grok

The CLI discovers endpoints via {issuer}/.well-known/openid-configuration, opens the IdP login page, and stores tokens in ~/.grok/auth.json. Tokens auto-refresh silently via the stored refresh_token.

Optional fields

External Auth Provider

When browser-based login isn't possible -- for example, on sandboxed VMs, CI runners, or air-gapped networks -- delegate authentication to an external binary or script.

How It Works

+--------------+     sh -c     +------------------------+
|     Grok     |-------------->|  your auth binary      |
|              |               |                        |
|  reads       |<-- stdout ----|  prints token          |
|  auth.json   |               |                        |
|              |   (stderr)    |  prints status/URLs    |--> surfaced to user
+--------------+               +------------------------+

1. Grok runs your command via sh -c "<command>"
2. Your binary runs whatever auth flow it needs (SSO, device code, certificate exchange)
3. stderr carries human-readable output, such as login URLs and status messages. Grok reads stderr and surfaces it to the user; in the TUI, it turns the first https:// URL into a clickable sign-in link.
4. stdout is captured by Grok and saved as the access token
5. Exit 0 = success; exit non-zero = Grok falls back to interactive login

The stdout / stderr Contract

Do not print anything to stdout except the token. No progress messages, no debug output. Grok reads stdout, trims surrounding whitespace, and parses the result as a token.

stdout Token Format

Bare string -- just the raw token:

eyJhbGciOiJSUzI1NiIs...

JSON -- with optional refresh token and expiry:

{"access_token": "eyJhbGciOi...", "refresh_token": "ref-tok", "expires_in": 3600}

Use JSON if your tokens expire and you want Grok to automatically re-run the binary before expiry.

Configuration

Via config file:

# ~/.grok/config.toml
[auth]
auth_provider_command = "/usr/local/bin/my-auth-provider"
auth_provider_label = "Acme Corp"   # optional -- customizes the TUI login button
auth_token_ttl = 3600               # optional -- token lifetime in seconds

Or via environment variables:

export GROK_AUTH_PROVIDER_COMMAND="/usr/local/bin/my-auth-provider"
export GROK_AUTH_PROVIDER_LABEL="Acme Corp"
export GROK_AUTH_TOKEN_TTL=3600

Token Refresh

When Grok needs to refresh an expired token, it re-runs your binary with GROK_AUTH_EXPIRED=1 set in the environment. Your binary can use this to take a faster silent-refresh path:

#!/bin/sh
if [ "$GROK_AUTH_EXPIRED" = "1" ]; then
    echo "Refreshing token..." >&2
    TOKEN=$(my-company-auth --refresh --silent)
else
    echo "Authenticating via Acme Corp SSO..." >&2
    TOKEN=$(my-company-auth --login --interactive)
fi

if [ -z "$TOKEN" ]; then
    echo "Authentication failed" >&2
    exit 1
fi

echo "{\"access_token\": \"$TOKEN\", \"expires_in\": 3600}"

Environment Variables

Device Code Flow

For headless environments (SSH sessions, Docker containers, remote VMs) where no browser is available locally:

grok login --device-auth    # or: grok login --device-code

This prints a URL and code to the terminal. Open the URL on any device, enter the code, and complete authentication. Grok polls until the login is confirmed.

You can also implement the device-code flow through an External Auth Provider for full control.

Automatic Credential Refresh

Grok automatically refreshes expired credentials:

• Before expiry: If your auth provider returned expires_in (JSON output) or you set auth_token_ttl, Grok re-runs the auth binary ~5 minutes before expiry.
• On auth error: If the server returns 401 Unauthorized, Grok refreshes the credentials and retries the request.
• OIDC: If a refresh_token is available, Grok silently refreshes via your IdP without re-opening the browser.

Tune the refresh buffer:

# Refresh 5 minutes before expiry (default)
export GROK_AUTH_EARLY_INVALIDATION_SECS=300

# Disable the proactive buffer: refresh at expiry or on a 401 (set to 0)
export GROK_AUTH_EARLY_INVALIDATION_SECS=0

Hot Reload

Grok picks up changes to ~/.grok/auth.json automatically. If you update credentials externally (for example, with a script that writes new tokens), Grok uses the new credentials on the next API call without a restart.

Auth Precedence

Grok resolves credentials for each request in this order, highest to lowest:

1. Per-model api_key or env_key -- set under [model.<name>] in config.toml. Wins whenever present.
2. Active session token -- obtained through browser, OIDC/OAuth2, or external-provider login and stored in ~/.grok/auth.json.
3. XAI_API_KEY -- fallback when no session token is active.

When more than one login flow is configured, Grok populates the session token from the first available source, highest to lowest:

1. External auth provider (auth_provider_command)
2. Enterprise OIDC -- when OIDC is configured, through [grok_com_config.oidc] in config.toml or the GROK_OIDC_ISSUER and GROK_OIDC_CLIENT_ID environment variables
3. xAI OAuth2 browser login -- the default

During a session, the active method handles all mid-session refreshes.

Troubleshooting

Debug logging

Set RUST_LOG to control the verbosity of the file log and headless stderr output. (The TUI's on-screen tracing pane uses a fixed filter and ignores RUST_LOG.) In the TUI, file logging defaults to DEBUG; in headless mode (-p), RUST_LOG defaults to error.

In the TUI, set GROK_LOG_FILE to an absolute path to write logs to that file:

GROK_LOG_FILE=/tmp/grok.log RUST_LOG=debug grok
tail -f /tmp/grok.log

GROK_LOG_FILE is treated as a literal file path. A relative value such as 1 writes a file named 1 in the current directory.

In headless mode, logs go to stderr. Redirect them to a file:

RUST_LOG=debug grok -p "hello" 2> /tmp/grok.log

Common log messages

Common fixes

• "Authentication failed" -- Run grok logout to clear cached credentials, then grok login to sign in again.
• Token expires too quickly -- Set auth_token_ttl or return expires_in in your auth provider's JSON output.
• OIDC redirect fails -- Ensure your IdP allows loopback redirect URIs (http://127.0.0.1/callback).
• External auth provider not found -- Check that the auth_provider_command path is correct and the binary is executable.

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