LINE

Run Mibyan as a LINE bot via the official LINE Messaging API. The adapter lives as a bundled platform plugin under plugins/platforms/line/ — no core edits, just enable it like any other platform. LINE is the dominant messaging app in Japan, Taiwan, and Thailand. If your users live there, this is how they reach you.

Run mibyan gateway setup and pick LINE for a guided walk-through.

How the bot responds

Context	Behavior
1:1 chat (`U` IDs)	Responds to every message
Group chat (`C` IDs)	Responds when the group is on the allowlist
Multi-user room (`R` IDs)	Responds when the room is on the allowlist

Inbound text, images, audio, video, files, stickers, and locations are all handled. Outbound text uses the free reply token first (single-use, ~60s window) and falls back to the metered Push API when the token has expired.

Step 1: Create a LINE Messaging API channel

Go to the LINE Developers Console.
Create a Provider, then under it a Messaging API channel.
From the channel’s Basic settings tab, copy the Channel secret.
From the Messaging API tab, scroll to Channel access token (long-lived) and click Issue. Copy the token.
In the Messaging API tab, also disable Auto-reply messages and Greeting messages so they don’t fight your bot’s replies.

Step 2: Expose the webhook port

LINE delivers webhooks over public HTTPS. The default port is 8646 — override with LINE_PORT if needed.

# Cloudflare Tunnel (recommended for production — fixed hostname)
cloudflared tunnel --url http://localhost:8646

# ngrok (good for dev)
ngrok http 8646

# devtunnel
devtunnel create mibyan-line --allow-anonymous
devtunnel port create mibyan-line -p 8646 --protocol https
devtunnel host mibyan-line

Copy the https://... URL — you’ll set it as the webhook URL below. Leave the tunnel running while testing. For production, set up a fixed Cloudflare named tunnel so the webhook URL doesn’t change on restart.

Step 3: Configure Mibyan

Add to ~/.mibyan/.env:

LINE_CHANNEL_ACCESS_TOKEN=YOUR_LONG_LIVED_TOKEN
LINE_CHANNEL_SECRET=YOUR_CHANNEL_SECRET

# Allowlist — at least one of these (or LINE_ALLOW_ALL_USERS=true for dev)
LINE_ALLOWED_USERS=U1234567890abcdef...           # comma-separated U-prefixed IDs
LINE_ALLOWED_GROUPS=C1234567890abcdef...          # optional group IDs
LINE_ALLOWED_ROOMS=R1234567890abcdef...           # optional room IDs

# Required for image / audio / video sends — the public HTTPS base URL
# the tunnel resolves to.  Without it, send_image/voice/video will refuse.
LINE_PUBLIC_URL=https://my-tunnel.example.com

Then in ~/.mibyan/config.yaml:

gateway:
  platforms:
    line:
      enabled: true

That’s enough — the bundled-plugin scan in gateway/config.py automatically picks up plugins/platforms/line/. No Platform.LINE enum edit, no _create_adapter registration.

Step 4: Set the webhook URL

Back in the LINE console:

Open your channel → Messaging API tab.
Under Webhook settings → Webhook URL, paste https://<your-tunnel>/line/webhook (note the /line/webhook path — the adapter listens there).
Click Verify. LINE pings the URL; you should see a 200.
Toggle Use webhook to On.

Step 5: Run the gateway

mibyan gateway

The agent log shows:

LINE: webhook listening on * (all interfaces, IPv4+IPv6):8646/line/webhook (public: https://my-tunnel.example.com)

Add the bot as a friend from the LINE app (scan the QR in the channel’s Messaging API tab) and send it a message.

Slow LLM responses

LINE’s reply token is single-use and expires roughly 60 seconds after the inbound event. Slow LLMs can’t reply in time, which would normally force a paid Push API call. When the LLM is still running past LINE_SLOW_RESPONSE_THRESHOLD seconds (default 45), the adapter consumes the original reply token to send a Template Buttons bubble:

🤔 Still thinking. Tap below to fetch the answer when it’s ready. [ Get answer ]

The user taps Get answer when convenient — that postback delivers a fresh reply token, which the adapter uses to send the cached answer (still free). State machine: PENDING → READY → DELIVERED, plus ERROR for cancelled runs (the orphan PENDING resolves to “Run was interrupted before completion.” after /stop so the persistent button doesn’t loop). To disable the postback button and always Push-fallback instead:

LINE_SLOW_RESPONSE_THRESHOLD=0

For the postback flow to fire reliably, suppress chatter that would consume the reply token before the threshold:

# ~/.mibyan/config.yaml
display:
  interim_assistant_messages: false
  platforms:
    line:
      tool_progress: off

Cron / notification delivery

LINE_HOME_CHANNEL=Uxxxxxxxxxxxxxxxxxxxx     # default delivery target

Cron jobs with deliver: line route to LINE_HOME_CHANNEL. The adapter ships a standalone Push-only sender so cron jobs work even when cron runs in a separate process from the gateway.

Environment variable reference

Variable	Required	Default	Description
`LINE_CHANNEL_ACCESS_TOKEN`	yes	—	Long-lived channel access token
`LINE_CHANNEL_SECRET`	yes	—	Channel secret (HMAC-SHA256 webhook verification)
`LINE_HOST`	no	unset (dual-stack: all interfaces, IPv4+IPv6)	Webhook bind host
`LINE_PORT`	no	`8646`	Webhook bind port
`LINE_PUBLIC_URL`	for media	—	Public HTTPS base URL; required for image/voice/video sends
`LINE_ALLOWED_USERS`	one of	—	Comma-separated user IDs (U-prefixed)
`LINE_ALLOWED_GROUPS`	one of	—	Comma-separated group IDs (C-prefixed)
`LINE_ALLOWED_ROOMS`	one of	—	Comma-separated room IDs (R-prefixed)
`LINE_ALLOW_ALL_USERS`	dev only	`false`	Skip allowlist entirely
`LINE_HOME_CHANNEL`	no	—	Default cron / notification delivery target
`LINE_SLOW_RESPONSE_THRESHOLD`	no	`45`	Seconds before the postback button fires (`0` = disabled)
`LINE_PENDING_TEXT`	no	”🤔 Still thinking…”	Bubble text shown alongside the postback button
`LINE_BUTTON_LABEL`	no	”Get answer”	Button label
`LINE_DELIVERED_TEXT`	no	”Already replied ✅“	Reply when an already-delivered button is tapped again
`LINE_INTERRUPTED_TEXT`	no	”Run was interrupted before completion.”	Reply when a `/stop` orphan button is tapped
`LINE_EXPIRED_TEXT`	no	”That request has expired — send your message again.”	Reply when a button whose cached answer is gone is tapped

Troubleshooting

“invalid signature” on webhook verify. The Channel secret was copied wrong, or your tunnel rewrote the request body. Verify with curl -i https://<tunnel>/line/webhook/health first — that should return {"status":"ok","platform":"line"}. Bot receives nothing in groups. Check LINE_ALLOWED_GROUPS includes the C... group ID. To find a group ID, send a test message and grep ~/.mibyan/logs/gateway.log for LINE: rejecting unauthorized source — the rejected source dict has the IDs. send_image fails with “LINE_PUBLIC_URL must be set”. LINE’s Messaging API does not accept binary uploads — images, audio, and video must be reachable HTTPS URLs. Set LINE_PUBLIC_URL to the tunnel’s public hostname and the adapter will serve files from /line/media/<token>/<filename> automatically. Postback button never appears. Either the LLM responded faster than LINE_SLOW_RESPONSE_THRESHOLD, or another bubble (tool-progress, streaming) consumed the reply token first. See the suppression block under “Slow LLM responses”. “already in use by another profile”. The same channel access token is bound to another running Mibyan profile. Stop the other gateway or use a separate channel.

Limitations

Bubble and length caps. Each LINE text bubble is capped at 5000 characters. Longer responses are smart-chunked at ~4500 characters across up to 5 bubbles per Reply/Push call, splitting on natural boundaries where possible.
No native message editing. LINE has no edit-message API — streaming responses always send fresh bubbles, never edit prior ones.
No Markdown rendering. Bold (**), italics (*), code fences, and headings render as literal characters. The adapter strips them before sending; URLs are preserved ([label](https://github.com/NousResearch/hermes-agent/tree/main/website/docs/user-guide/messaging/url) becomes label (url)).
Loading indicator is DM-only. LINE rejects the chat/loading API for groups and rooms, so the typing indicator only shows in 1:1 chats.

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How the bot responds

Step 1: Create a LINE Messaging API channel

Step 2: Expose the webhook port

Step 3: Configure Mibyan

Step 4: Set the webhook URL

Step 5: Run the gateway

Slow LLM responses

Cron / notification delivery

Environment variable reference

Troubleshooting

Limitations

​How the bot responds

​Step 1: Create a LINE Messaging API channel

​Step 2: Expose the webhook port

​Step 3: Configure Mibyan

​Step 4: Set the webhook URL

​Step 5: Run the gateway

​Slow LLM responses

​Cron / notification delivery

​Environment variable reference

​Troubleshooting

​Limitations

How the bot responds

Step 1: Create a LINE Messaging API channel

Step 2: Expose the webhook port

Step 3: Configure Mibyan

Step 4: Set the webhook URL

Step 5: Run the gateway

Slow LLM responses

Cron / notification delivery

Environment variable reference

Troubleshooting

Limitations