line

LINE channel for Claude Code

Connect a LINE Official Account to your Claude Code session via an MCP server. When a colleague messages your LINE OA, the bot forwards the message into your active Claude Code session and exposes tools to reply, fetch recent messages, and download attachments.

This is a port of Anthropic's official discord plugin to the LINE Messaging API. It is not a generic LINE bot framework — its purpose is to let you discuss code, designs, and decisions on LINE with your Claude Code instance acting as a participant.

⚠️ Different from hermes-plugin-line. That plugin adapts a LINE OA into the Hermes Agent gateway. This plugin plugs a LINE OA into the Claude Code CLI itself as a channel.

Prerequisites

• Bun — curl -fsSL https://bun.sh/install | bash
• cloudflared — brew install cloudflared (only if you want auto-tunneling; see Tunneling below)
• A LINE Official Account with the Messaging API enabled. Get one at LINE Developers Console.

Quick Setup

1. Create a LINE Messaging API channel

1. In the LINE Developers Console, create a Provider, then a Messaging API channel.
2. Basic settings → copy the Channel secret.
3. Messaging API → issue a Channel access token (long-lived). Copy it.
4. Messaging API → set Use webhook to Enabled.
5. Messaging API → Auto-reply messages = Disabled, Greeting messages = your call (the plugin doesn't override these). Otherwise the LINE platform will respond instead of forwarding to your bot.
6. To use the bot in groups: in the OA Manager (admin.line.biz), go to Settings → Response settings and enable "Allow bot to join groups and multi-person chats."

2. Install the plugin

These are Claude Code commands — run claude to start a session first.

This repo is its own marketplace (it ships a .claude-plugin/marketplace.json). Register it once, then install:

/plugin marketplace add liyoungc/claude-code-line-plugin
/plugin install line@claude-code-line-plugin

3. Save credentials

/line:configure <CHANNEL_ACCESS_TOKEN> <CHANNEL_SECRET>

Writes LINE_CHANNEL_ACCESS_TOKEN=... and LINE_CHANNEL_SECRET=... to ~/.claude/channels/line/.env. The file is chmod 600. You can also write that file by hand or set the variables in your shell environment — shell takes precedence.

4. Relaunch with the channel flag

The MCP server won't connect without this — exit your session and start a new one:

claude --channels plugin:line@claude-code-line-plugin

On startup the server will:

• Bind a local HTTP listener on 127.0.0.1:8765
• Spawn cloudflared tunnel --url to get a fresh https://….trycloudflare.com
• PUT https://api.line.me/v2/bot/channel/webhook/endpoint to register that URL with LINE — no manual webhook URL setup required

Watch the stderr output (the Claude Code MCP log) for:

line channel: webhook listener on http://127.0.0.1:8765/webhook
line channel: cloudflared tunnel up at https://abcd-1234.trycloudflare.com
line channel: webhook endpoint set to https://abcd-1234.trycloudflare.com/webhook

5. Pair

With Claude Code running from step 4, message your LINE OA — it replies with a 6-character pairing code. In your Claude Code session:

/line:access pair <code>

Your next LINE message reaches the assistant.

6. Lock it down

Pairing is for capturing LINE userIds. Once you and your colleagues are in:

/line:access policy allowlist

Tunneling

The plugin defaults to a cloudflared quick tunnel — fresh *.trycloudflare.com URL on every session, automatically registered with LINE. This is fine for occasional/personal use.

For a stable URL (e.g. your VPS reverse proxy), set:

LINE_WEBHOOK_URL=https://yourdomain.example.com/webhook
LINE_TUNNEL=off

The plugin will skip cloudflared and PUT your fixed URL to LINE.

Tools exposed to the assistant

Tool	Purpose
reply	Send a message via LINE Push API. Auto-chunks at 5000 chars. Optional quote_to for LINE Quote replies. files is parsed but image upload requires hosted URLs (not yet implemented).
fetch_messages	Read recent inbound messages from this session's in-process buffer. LINE has no history API, so this is best-effort.
download_attachment	Pull an inbound image/video/audio/file by message ID into ~/.claude/channels/line/inbox/.

Why no react / edit_message?

LINE doesn't support editing sent messages, and its reaction API is limited to specific message types and user contexts. The official discord plugin's react and edit_message don't have stable LINE equivalents.

Permission relay