kestrel-channel-whatsapp 0.2.1

WhatsApp channel for Kestrel agents — isolated-venv feature (WhatsApp-Web via neonize + Twilio).

kestrel-channel-whatsapp

WhatsApp messaging channel for Kestrel agents. It runs as an isolated-venv feature: the transport (neonize, which needs protobuf 7 — incompatible with the host's gRPC/Google-AI stack) runs in a per-agent venv and process, and the host talks to it over the SDK's stdio JSON-RPC isolated-feature contract.

It's a single package. The base install is the lightweight host-side marker (SDK only). The transport (neonize/twilio/segno) is the [service] extra, which the host loader installs into a per-agent isolated venv — so the heavy, protobuf-7 deps never touch the host venv:

host venv:           pip install kestrel-channel-whatsapp            # marker, SDK-only
per-agent venv:      pip install "kestrel-channel-whatsapp[service]"  # + transport (done by the loader)

How it integrates

The service advertises a whatsapp channel capability at initialize. The host (kestrel-sovereign ≥ 0.31, the isolated-runtime channel bridge from #1825) registers a forwarding ChannelAdapter into ChannelFeature.registry, so the agent uses the generic channels tools unchanged:

Direction	Path
Outbound	channels_send(channel="whatsapp", to, message) → host proxy → service whatsapp_send tool → provider
Inbound	provider → service emits a channel.inbound event → host proxy → ChannelFeature.handle_inbound → channel.message cognition signal → agent replies via channels_send

Service tools: whatsapp_send, whatsapp_status, whatsapp_link (QR pairing for the web provider).

Providers

Provider	Outbound	Inbound	Notes
web (default)	✅	✅	neonize (whatsmeow) — links as a companion device. Scan the whatsapp_link QR in WhatsApp → Linked Devices. Needs system libmagic.
twilio	✅	❌	Outbound-only in the isolated runtime — Twilio inbound needs a public HTTP webhook, which the stdio service does not host. whatsapp_status reports inbound_supported: false.

A freshly queued message is reported as PENDING, not delivered — the agent will not claim delivery it cannot confirm.

Install

The host installs the [service] extra into a per-agent venv automatically when the feature is enabled. To develop locally:

uv pip install -e /path/to/kestrel-channel-whatsapp            # host-side marker
uv pip install -e "/path/to/kestrel-channel-whatsapp[service]" # + transport, to test the service

Add WhatsAppFeature to the agent's features list in multi_agent.toml, then restart the host. The feature appears in the agent's features UI with a config form.

Configuration

Set via the features UI / persisted config (forwarded to the service through the initialize handshake), or via environment variables (UI/persisted config wins; env is a fallback):

Config key	Env var	Notes
provider	KESTREL_WHATSAPP_PROVIDER	web (default) or twilio
session_db	KESTREL_WHATSAPP_SESSION_DB	web: neonize companion-session SQLite path
allowed_senders	—	E.164 allowlist; empty = allow all
account_sid	TWILIO_ACCOUNT_SID	twilio only
auth_token	TWILIO_AUTH_TOKEN	twilio only (secret)
from_number	TWILIO_WHATSAPP_FROM	twilio sender, E.164. Defaults to the sandbox [phone]

Linking the web provider

1. Enable the feature with provider="web" and restart the host.
2. Call whatsapp_link (or !whatsapp link) — it returns a pairing QR.
3. On your phone: WhatsApp → Settings → Linked Devices → Link a Device → scan.
4. Once linked, whatsapp_status reports connected: true; the agent receives inbound messages as channel.message signals and replies via channels_send.