Signal

Same tools, same access model. No bot API, so the plumbing is different.

Signal runs as a provider next to Telegram and Discord, or on its own. There is no bot API: hotline talks to a locally running signal-cli daemon, linked to your Signal account as a secondary device.

signal-cli is a third-party client, not an official Signal product. This is the part an official hosted product structurally can't ship, and the reason hotline covers Signal at all.

Setup

Install signal-cli. On macOS: brew install signal-cli. On Linux, download a release from github.com/AsamK/signal-cli/releases (it is not in apt) and put signal-cli on your PATH. Java 17+ required.
Link it to your account as a secondary device:
```
signal-cli link -n hotline
```
It prints a sgnl://linkdevice?... URI. Render it as a QR code (qrencode -t ansiutf8 'sgnl://...') and scan it from your phone under Settings → Linked Devices. Registration stays on your phone; hotline never touches it.
Run the daemon and keep it running (tmux, or a systemd user service with ExecStart=signal-cli -a +15551234567 daemon --http 127.0.0.1:8080):
```
signal-cli -a +15551234567 daemon --http 127.0.0.1:8080
```

Point hotline at it in the shared .env:

# ~/.claude/channels/tele-go/.env
SIGNAL_ACCOUNT=+15551234567           # the linked account, E.164
SIGNAL_DAEMON_URL=http://127.0.0.1:8080   # optional, this is the default
SIGNAL_ACCOUNT_WORK=…                 # signal:work, if you run named instances

Enable the provider and run:
```
HOTLINE_PROVIDERS=telegram,discord,signal hotline
```
In a Claude Code setup, HOTLINE_PROVIDERS belongs in the env block of your .mcp.json; see Multiple providers.
Message the account from another Signal account. Unknown senders get a pairing code; approve it from your terminal:
```
hotline pair <code> --provider signal
```

--provider signal points pair/deny/status at the Signal state (<stateDir>/signal/); named instances use --provider signal:work with state under <stateDir>/signal/instances/work/.

Behavior notes

Senders are identified by phone number (E.164); the allowlist holds numbers. DM chat_ids are the peer's number, group chat_ids are group:<id>. Add those to groups in the Signal access.json.
Signal has no inline buttons. Buttons render as numbered text options, and replying with the number sends the chosen label back to Claude. Same round trip, typed instead of tapped.
The permission relay is text-only: prompts arrive as a message, answer with yes <code> or no <code>.
Reactions and edits are native (signal-cli sendReaction and send --edit-timestamp). Bubbles are paced with Signal's typing indicator. Messages split at 2000 chars, where Signal clients switch to long-text attachments.
Message ids are Signal timestamps (Signal's message identity); inbound ids carry the author as <timestamp>:<number> so reactions target correctly.
Inbound images are fetched from the daemon into the inbox; other attachments surface an id for download_attachment (50MB cap both ways).
The daemon's HTTP endpoint has no authentication. Keep it on 127.0.0.1.

next: Discord →