Bug Description

Hermes can deliver duplicate agent-facing background-process notifications for the same process when notify_on_complete and watch_patterns are both involved.

The duplicate path is not specific to one adapter or one command. It can affect any background process where completion delivery and watch-pattern delivery both produce synthetic [SYSTEM: ...] events for the same process session.

Steps to Reproduce

1. Start a Hermes background process with notify_on_complete enabled.
2. Configure one or more watch_patterns that can match the process output.
3. Let the process produce matching output and then exit.
4. Observe the gateway delivering an agent-facing completion notification.
5. A later watch notification for the same process can still be injected, interrupting the agent even though the completion notification was already delivered.

Expected Behavior

• Once the gateway successfully injects a completion notification into the agent thread, that process completion should be treated as consumed.
• Later watch-pattern notifications for the same completed process should not interrupt the agent.
• Existing wait, poll, and read_log completion-consumption behavior should remain unchanged.
• Watch patterns should still fire for active processes before the completion has been consumed.

Actual Behavior

• wait, poll, and read_log already suppress redundant completion delivery by tracking _completion_consumed.
• Gateway-injected notify_on_complete messages were not marking the completion as consumed.
• A watcher path could therefore still inject a related watch notification for the same process after the agent had already received the completion notification.
• In practice this can show up as repeated synthetic system notifications or follow-up messages indicating the notification was already handled.

Affected Component

• Gateway notification delivery
• Background process registry / tools
• Gateway adapters that receive synthetic process events

Messaging Platform

Gateway-related; not specific to Telegram, Discord, Slack, or WhatsApp.

Debug Report

Not available. This was identified from the background-process notification flow and covered with targeted regression tests in #15277.

Operating System

N/A; runtime behavior is platform-independent.

Python Version

N/A.

Hermes Version

Current main before #15277.

Root Cause Analysis

ProcessRegistry tracks _completion_consumed so wait, poll, and read_log can avoid delivering the same completion more than once. However, successful gateway injection of an agent-facing completion notification did not update that consumed state.

Because the process was still considered unconsumed by the registry, _inject_watch_notification could later deliver a watch-pattern event for the same completed process.

Proposed Fix

Implemented in #15277:

• Add ProcessRegistry.mark_completion_consumed(session_id).
• Call it after successful gateway injection of a notify_on_complete synthetic event.
• Skip watch notification injection when the process completion is already consumed.
• Add regression coverage for gateway completion injection, watch suppression, and direct registry marking.

Validation

The PR validates the fix with:

uv run --extra dev pytest tests/tools/test_notify_on_complete.py tests/gateway/test_internal_event_bypass_pairing.py tests/tools/test_watch_patterns.py
python3.11 -m py_compile gateway/run.py tools/process_registry.py

PR

Fix: #15277