feat(channels): Signal messenger support via signal-cli daemon

[ibhagwan]

Implements Signal platform adapter using signal-cli daemon HTTP/JSON-RPC interface.

Features:

• Continuous SSE streaming with exponential backoff reconnection (2s→60s)
• Typing indicators sent every 8 seconds while processing messages
• Attachment upload/download with 100MB size validation
• DM pairing integration (reuses existing pairing system)
• Group message filtering (disabled by default for security)
• Allowlist checking for E.164 numbers and UUIDs
• Phone number redaction in all debug logs (+1555****4567)
• Health check monitor for stale SSE connections
• Enhanced session context: shows E164 + UUID for DMs, name + ID for groups

Signal support in send_message tool:

• Added 'signal' platform to platform_map
• Added attachments array parameter for sending files
• Added _send_signal() function using JSON-RPC
• Updated tool schema with Signal examples

Authorization fixes:

• Added SIGNAL_ALLOWED_USERS and SIGNAL_GROUP_ALLOWED_USERS support
• Fixed group allowlist checking in run.py _is_user_authorized()
• Signal users in group allowlist now correctly authorized

Phone redaction:

• Added _SIGNAL_PHONE_RE regex pattern for E164 numbers
• Added redact function matching signal.py _redact_phone() logic
• Applied to RedactingFormatter for all gateway logs

Session context improvements:

• Added user_id_alt field for Signal UUIDs and chat_id_alt for group IDs
• Updated description property to show E164 + UUID for DMs (e.g., 'DM with John Smith (+15551234567/uuid:abc...)')
• Updated description to show group name + ID (e.g., 'group: Supreme Leader (ID: abc123)')
• Updated build_source() in base adapter to accept new optional fields

Configuration (environment variables):

• SIGNAL_HTTP_URL, SIGNAL_ACCOUNT (required)
• SIGNAL_ALLOWED_USERS, SIGNAL_GROUP_ALLOWED_USERS
• SIGNAL_DM_POLICY (pairing|allowlist|open)
• SIGNAL_GROUP_POLICY (disabled|allowlist|open)
• SIGNAL_DEBUG for verbose logging

Files:

• gateway/platforms/signal.py: NEW - Complete adapter (934 lines)
• gateway/run.py: SignalAdapter factory, group allowlist, SIGNAL_DEBUG
• gateway/config.py: Platform.SIGNAL enum, env overrides
• gateway/session.py: Added user_id_alt and chat_id_alt fields, enhanced description
• gateway/platforms/base.py: Added user_id_alt and chat_id_alt params to build_source
• tools/send_message_tool.py: Signal platform + attachments support
• agent/redact.py: Signal phone number redaction
• hermes_cli/config.py, setup.py: Signal config metadata
• tests/gateway/test_signal.py: NEW - Unit tests
• tests/agent/test_redact.py: Added Signal redaction tests

[teknium1]

Thanks for this substantial contribution, @ibhagwan! This is a really well-built adapter — solid architecture, good security defaults (pairing for DMs, groups disabled), SSE reconnection with exponential backoff, and clean integration with the existing platform patterns. Great work.

We're going to hold off on merging for now since we want to be able to test a new platform adapter end-to-end before landing it, but we've done a thorough review and want to share our findings so you can address them in the meantime:

Bugs

1. Timestamp read from wrong dict (Medium)
Around line 529 in signal.py:

timestamp = envelope.get("timestamp", 0)

Should be envelope_data.get("timestamp", 0) — all other message fields are read from envelope_data (the inner dict extracted from envelope["envelope"]). As-is, timestamps always fall back to datetime.now().

2. Inconsistent HTTP library in send_message_tool.py (Medium)
_send_signal() uses aiohttp, but the Signal adapter itself uses httpx throughout. This introduces an unnecessary extra dependency and inconsistency. Should use httpx to match.

3. Account phone number logged without redaction (Low-Medium)
A few log lines expose the raw account phone number:

• Line ~422: f"[Signal] Config: http_url={self.http_url}, account={self.account}"
• Line ~520: SSE URL includes raw account in the URL string
• Line ~522: f"[Signal] SSE listener starting for account: {self.account}"
• Line ~1014: f"[Signal] Account: {self.account}"

Most other log lines correctly use self._redact_phone() — these were just missed.

4. __import__ hack in send_message_tool.py (Low)

"id": f"send_{int(__import__('time').time() * 1000)}",

Should just import time at the top of the file.

5. Wildcard allowlist check (Low)

if self.allowed_users == ["*"]:

This only matches if the list is exactly ["*"]. If someone configures SIGNAL_ALLOWED_USERS=*,+1234567890, the wildcard won't be detected. Should be "*" in self.allowed_users instead.

6. Async tests require pytest-asyncio (Low)
3 tests in test_signal.py use @pytest.mark.asyncio but pytest-asyncio isn't in test dependencies, so they fail. Either add it to pyproject.toml test deps or rewrite those tests as synchronous.

What we verified (for when we revisit)

Full diff reviewed — all 17 files, 1856 additions checked. Delegated deep-dive analysis that:

• Compared signal.py adapter against existing Telegram/WhatsApp/Discord adapters for pattern consistency
• Verified all shared file changes (run.py, session.py, config.py, base.py, send_message_tool.py, redact.py) are backward-compatible
• Checked security model: auth flow, allowlists, phone redaction, group policy defaults
• Ran test suite — 1666 passed, 3 async Signal tests failed (pytest-asyncio missing, not code bugs)
• Audited SessionSource additions (user_id_alt, chat_id_alt) — optional params with None defaults, safe
• Confirmed extract_images regex update for file:// URLs is correct and doesn't break http/https
• Verified get_connected_platforms() fix in config.py correctly handles Signal's non-token auth and also fixes WhatsApp case
• Checked pairing system integration — reuses existing pairing flow, returns existing pending code instead of rate-limiting

What looked great

• Follows BasePlatformAdapter correctly (connect/disconnect/send/send_typing/send_image/get_chat_info/build_source)
• SSE streaming with exponential backoff (2s→60s) + health monitoring + _force_reconnect() via response close
• Default security: DM policy=pairing, groups=disabled
• Attachment handling: 100MB size validation, magic-byte extension detection, base class cache utilities
• Phone redaction in agent/redact.py with _SIGNAL_PHONE_RE regex
• Config/CLI integration complete: setup wizard, status display, env overrides all wired
• Backward-compatible changes throughout shared files

Next steps

• Set up signal-cli test instance for end-to-end verification
• Contributor addresses the 6 issues above
• Re-review and merge

[teknium1]

Thanks for the excellent work @ibhagwan! Your Signal adapter implementation was the foundation for what we merged in commit 24f549a.

We rebuilt it on current main (the branch had diverged significantly in 4 shared files) and fixed the bugs identified during review:

• Timestamp reads from envelope_data (not outer wrapper)
• Uses httpx consistently (send_message tool was using aiohttp)
• SIGNAL_DEBUG scoped to signal logger only (not root)
• extract_images regex NOT modified (preserves group numbering for all platforms)
• pairing.py NOT modified (no cross-platform side effects)
• Authorization delegated to run.py (no dual-auth layer)
• Wildcard uses set membership, .zip for PK magic bytes

Your architecture design — SSE streaming + JSON-RPC + health monitoring — was solid and we kept it intact. You're credited as co-author in the commit.

Closing this PR since the work is merged. Thank you! 🎉

[ibhagwan]

Tysm, that's fantastic news @teknium1!