LINE

Tip: After npm install -g agent-messenger, agent-line is available directly. For one-off execution without a global install you can use npm exec --package agent-messenger agent-line ..., pnpm dlx --package agent-messenger agent-line ..., yarn dlx agent-messenger agent-line ..., or bunx --package agent-messenger agent-line ....

Key Concepts

Before diving in, a few things about LINE's architecture:

Term	Description
MID	LINE's unique identifier for users, chats, and rooms. Prefixed with `u` (user), `c` (group chat), or `r` (room).
QR code login	The primary authentication method. Scan a QR code with the LINE mobile app to authorize the CLI.
ANDROIDSECONDARY	The default device type. Registers as a secondary Android device so your phone and desktop sessions stay active.
E2EE (Letter Sealing)	LINE's end-to-end encryption. The CLI attempts E2EE first and falls back to plaintext if keys aren't available.
Device types	Controls which device slot the CLI occupies. Secondary devices coexist with your other sessions.
PIN verification	During login, LINE may display a PIN that you confirm on your phone to authorize the new device.

Quick Start

# 1. Login (QR code — opens in browser, scan with LINE app)
agent-line auth login

# 2. List chat rooms
agent-line chat list

# 3. Send a message
agent-line message send <chat-id> "Hello from agent-line!"

# 4. List messages in a chat
agent-line message list <chat-id>

Authentication

LINE offers three authentication methods. QR code login is recommended because it doesn't require your email or password.

Registers the CLI as a secondary device using the ANDROIDSECONDARY slot by default. Your phone and desktop sessions keep running.

# Interactive — opens QR code in browser + prints to terminal
agent-line auth login

On login:

The CLI generates a QR code URL and opens it in your browser
The QR code also prints in the terminal as a fallback
Scan the QR code with the LINE mobile app
LINE may display a PIN to confirm on your phone
Login completes automatically after confirmation

Uses email and password credentials. LINE may still require PIN verification on your phone.

# Interactive — prompts for email and password
agent-line auth login --email user@example.com --password mypass

Directly authenticates with an existing auth token. Useful when you already have a valid token from another source.

agent-line auth login --token <auth-token>

Device Types

LINE allows multiple simultaneous sessions depending on the device type:

Device	Default?	Side Effect
ANDROIDSECONDARY	Yes	Secondary device, coexists with all sessions
IOSIPAD	No	Secondary device, coexists with all sessions
DESKTOPMAC	No	Replaces existing macOS desktop session
DESKTOPWIN	No	Replaces existing Windows desktop session

# Default: ANDROIDSECONDARY (safe for most users)
agent-line auth login

# Use iPad slot instead
agent-line auth login --device IOSIPAD

# Replace desktop session (kicks LINE desktop)
agent-line auth login --device DESKTOPMAC

Non-Interactive Mode (AI Agents)

When running outside a TTY (no interactive terminal), the CLI returns a next_action JSON response instead of displaying the QR code:

{
  "next_action": "run_interactive",
  "message": "QR code login requires an interactive terminal. Run agent-line auth login in a terminal with TTY support."
}

For non-interactive environments, use --email/--password or --token to authenticate without a QR code.

Auth Management

# Check auth status
agent-line auth status

# List all stored accounts
agent-line auth list

# Switch active account
agent-line auth use <account-id>

# Remove stored credentials
agent-line auth logout
agent-line auth logout <account-id>

Commands

Whoami Command

# Show current authenticated user
agent-line whoami
agent-line whoami --pretty

Output includes:

mid — your LINE user ID
display_name — your display name
status_message — your status message
picture_url — profile picture URL

Friend Commands

# List all friends
agent-line friend list
agent-line friend list --pretty

Output includes:

mid — friend's LINE user ID
display_name — friend's display name
status_message — friend's status message
picture_url — friend's profile picture URL

Chat Commands

# List conversations (DMs and groups)
agent-line chat list
agent-line chat list --pretty

# Limit number of chats returned
agent-line chat list -n 20

Output includes:

chat_id — MID of the chat (u/c/r prefix)
type — chat type (user, group, room, square)
display_name — chat or contact name
member_count — number of members (groups only)

Message Commands

# List messages in a chat room
agent-line message list <chat-id>
agent-line message list <chat-id> -n 50
agent-line message list <chat-id> --pretty

# Send a text message
agent-line message send <chat-id> "Hello world"
agent-line message send <chat-id> "Hello world" --pretty

Each message includes:

message_id — unique message identifier
chat_id — which chat the message belongs to
author_id — sender's MID
text — message text content (null for non-text messages)
content_type — message type (NONE = text, IMAGE, VIDEO, etc.)
sent_at — ISO 8601 timestamp

Fetching More Messages

Use the -n flag to control how many messages to fetch in a single request:

# Get latest 20 messages (default)
agent-line message list c7a8b9c0d1e2f3a4b5c6d7e8

# Get 50 messages
agent-line message list c7a8b9c0d1e2f3a4b5c6d7e8 -n 50

# Get 200 messages
agent-line message list c7a8b9c0d1e2f3a4b5c6d7e8 -n 200

Global Options

Option	Description
`--pretty`	Human-readable output instead of JSON

Storage

Credentials stored in ~/.config/agent-messenger/line-credentials.json (0600 permissions)
E2EE key storage in ~/.config/agent-messenger/line-storage/

Limitations

No file upload or download
No channel/chat room creation or management
No reactions or emoji
No message editing or deletion
No search across chats
Plain text messages only (no photos, videos, or rich content)
Chat IDs are MID strings, not human-readable — use chat list to discover them

Troubleshooting

`agent-line: command not found`

agent-line is NOT the npm package name. The npm package is agent-messenger.

# If installed globally
agent-line chat list --pretty

# If not installed, use --package
npx -y --package agent-messenger agent-line chat list --pretty

NEVER run npx agent-line without --package agent-messenger. It will fail or install a wrong package.

No credentials found

If auth status shows no account:

Run agent-line auth login to authenticate via QR code
Or use agent-line auth login --email ... --password ... for email login
Verify it worked with agent-line auth status

QR code not displaying

If the QR code doesn't open in your browser:

Check the terminal output for the ASCII QR code fallback
The QR URL is also printed — you can open it manually
Make sure you're running in an interactive terminal (TTY)

E2EE errors

The CLI tries E2EE (Letter Sealing) first and falls back automatically. If you see E2EE-related warnings, messages are still sent successfully without encryption.

PIN verification timeout

If the PIN expires before you confirm on your phone:

Run agent-line auth login again — a new QR code and PIN will be generated
Confirm the PIN on your phone within the time limit
The CLI automatically completes login after confirmation

SDK Usage

For programmatic access, import LineClient directly:

import { LineClient } from 'agent-messenger/line'

const client = await new LineClient().login()
try {
  const profile = await client.getProfile()
  console.log(profile.display_name)

  const chats = await client.getChats()
  const firstChat = chats[0]
  if (!firstChat) throw new Error('No chats available')

  await client.sendMessage(firstChat.chat_id, 'Hello from SDK!')
} finally {
  client.close()
}

AI Agent Integration

See skills/agent-line/ for:

Complete skill documentation
Common patterns for AI agent workflows

LINE

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