feat(webhooks): stamp the emitting profile on outbound webhook payloads

Under a multiplexed gateway every profile's outbound webhooks share one
delivery worker, so receivers could not tell which profile fired an
event. Add a top-level `profile` field to the payload, resolved at fire
time from the bound Hermes home via get_active_profile_name() ("default"
outside profiles). Documents the field in the wire-format section.

Reported by @vszgdcn8cj-ctrl.

Fixes #92674

agent/outbound_webhooks.py

@@ -445,8 +445,13 @@ def _serialize_payload(
         cwd = str(Path.cwd())
     except OSError:
         cwd = ""
+    # Resolved at fire time from the bound home so a multiplexed gateway's
+    # receivers can tell which profile emitted the event (#92674).
+    from hermes_cli.profiles import get_active_profile_name
+
     payload = {
         "hook_event_name": event,
+        "profile": get_active_profile_name(),
         "tool_name": kwargs.get("tool_name"),
         "tool_input": kwargs.get("args") if isinstance(kwargs.get("args"), dict) else None,
         "session_id": kwargs.get("session_id") or kwargs.get("parent_session_id") or "",

tests/agent/test_outbound_webhooks.py

@@ -301,6 +301,23 @@ class TestPayload:
         assert payload["delivery_id"] == "did_1234"
         assert payload["timestamp"].endswith("Z")
 
+    def test_profile_field_reflects_bound_profile_home(self, tmp_path, monkeypatch):
+        """Receivers behind a multiplexed gateway need to know which profile
+        fired (#92674): ``profile`` follows the bound home at fire time."""
+        from hermes_constants import reset_hermes_home_override, set_hermes_home_override
+
+        monkeypatch.setenv("HERMES_HOME", str(tmp_path))
+        profile_home = tmp_path / "profiles" / "b"
+        profile_home.mkdir(parents=True)
+        token = set_hermes_home_override(profile_home)
+        try:
+            body = outbound_webhooks._serialize_payload("on_session_end", {}, "did_1")
+        finally:
+            reset_hermes_home_override(token)
+        assert json.loads(body)["profile"] == "b"
+        body = outbound_webhooks._serialize_payload("on_session_end", {}, "did_2")
+        assert json.loads(body)["profile"] == "default"
+
     def test_unserialisable_values_stringified(self):
         body = outbound_webhooks._serialize_payload(
             "on_session_end", {"weird": object()}, "did_1"

website/docs/user-guide/features/hooks.md

@@ -1876,11 +1876,12 @@ Secrets: prefer `secret_env` (the name of an environment variable, typically set
 
 ### Wire format
 
-Each firing POSTs a JSON body with the same top-level shape as shell hooks' stdin, plus delivery metadata:
+Each firing POSTs a JSON body with the same top-level shape as shell hooks' stdin, plus delivery metadata. `profile` names the Hermes profile that emitted the event (`"default"` outside profiles), so receivers behind a multiplexed gateway can tell profiles apart:
 
 ```json
 {
   "hook_event_name": "on_session_end",
+  "profile": "default",
   "tool_name": null,
   "tool_input": null,
   "session_id": "sess_abc123",