Follow-up to the previous commit:
- Add _is_loopback_host() helper covering 127.0.0.1, localhost, ::1,
ip6-localhost, ip6-loopback (case-insensitive). Empty/None host is
treated as non-loopback since unset usually means public default bind.
- Fix mixed-indent comment in the safety rail (comment now aligned with
the if-block) and collapse the nested-if into one condition.
- Add TestInsecureNoAuthSafetyRail covering rejection on 0.0.0.0, a LAN
IP, and empty host; allowance on 127.0.0.1/localhost; plus unit-level
parametrized coverage of _is_loopback_host for spellings we can't bind
in the hermetic test env (::1, ip6-localhost, ip6-loopback).
- Pin test_connect_starts_server + test_webhook_deliver_only defaults
to 127.0.0.1 so they keep passing under the new rail.
- Document the behavior in website/docs/user-guide/messaging/webhooks.md.
External services can now push plain-text notifications to a user's chat
via the webhook adapter without invoking the agent. Set deliver_only=true
on a route and the rendered prompt template becomes the literal message
body — dispatched directly to the configured target (Telegram, Discord,
Slack, GitHub PR comment, etc.).
Reuses all existing webhook infrastructure: HMAC-SHA256 signature
validation, per-route rate limiting, idempotency cache, body-size limits,
template rendering with dot-notation, home-channel fallback. No new HTTP
server, no new auth scheme, no new port.
Use cases: Supabase/Firebase webhooks → user notifications, monitoring
alert forwarding, inter-agent pings, background job completion alerts.
Changes:
- gateway/platforms/webhook.py: new _direct_deliver() helper + early
dispatch branch in _handle_webhook when deliver_only=true. Startup
validation rejects deliver_only with deliver=log.
- hermes_cli/main.py + hermes_cli/webhook.go: --deliver-only flag on
subscribe; list/show output marks direct-delivery routes.
- website/docs/user-guide/messaging/webhooks.md: new Direct Delivery
Mode section with config example, CLI example, response codes.
- skills/devops/webhook-subscriptions/SKILL.md: document --deliver-only
with use cases (bumped to v1.1.0).
- tests/gateway/test_webhook_deliver_only.py: 14 new tests covering
agent bypass, template rendering, status codes, HMAC still enforced,
idempotency still applies, rate limit still applies, startup
validation, and direct-deliver dispatch.
Validation: 78 webhook tests pass (64 existing + 14 new). E2E verified
with real aiohttp server + real urllib POST — agent not invoked, target
adapter.send() called with rendered template, duplicate delivery_id
suppressed.
Closes the gap identified in PR #12117 (thanks to @H1an1 / Antenna team)
without adding a second HTTP ingress server.
