hermes-agent/website/docs/developer-guide/gateway-internals.md

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7	Gateway Internals	How the messaging gateway boots, authorizes users, routes sessions, and delivers messages

Gateway Internals

The messaging gateway is the long-running process that connects Hermes to 14+ external messaging platforms through a unified architecture.

Key Files

File	Purpose
gateway/run.py	GatewayRunner — main loop, slash commands, message dispatch (~7,200 lines)
gateway/session.py	SessionStore — conversation persistence and session key construction
gateway/delivery.py	Outbound message delivery to target platforms/channels
gateway/pairing.py	DM pairing flow for user authorization
gateway/channel_directory.py	Maps chat IDs to human-readable names for cron delivery
gateway/hooks.py	Hook discovery, loading, and lifecycle event dispatch
gateway/mirror.py	Cross-session message mirroring for send_message
gateway/status.py	Token lock management for profile-scoped gateway instances
gateway/builtin_hooks/	Always-registered hooks (e.g., BOOT.md system prompt hook)
gateway/platforms/	Platform adapters (one per messaging platform)

Architecture Overview

┌─────────────────────────────────────────────────┐
│                 GatewayRunner                     │
│                                                   │
│  ┌──────────┐  ┌──────────┐  ┌──────────┐       │
│  │ Telegram  │  │ Discord  │  │  Slack   │  ...  │
│  │ Adapter   │  │ Adapter  │  │ Adapter  │       │
│  └─────┬─────┘  └─────┬────┘  └─────┬────┘       │
│        │              │              │             │
│        └──────────────┼──────────────┘             │
│                       ▼                            │
│              _handle_message()                     │
│                       │                            │
│          ┌────────────┼────────────┐               │
│          ▼            ▼            ▼               │
│   Slash command   AIAgent      Queue/BG            │
│    dispatch       creation     sessions            │
│                       │                            │
│                       ▼                            │
│              SessionStore                          │
│           (SQLite persistence)                     │
└─────────────────────────────────────────────────┘

Message Flow

When a message arrives from any platform:

1. Platform adapter receives raw event, normalizes it into a MessageEvent
2. Base adapter checks active session guard:
   • If agent is running for this session → queue message, set interrupt event
   • If /approve, /deny, /stop → bypass guard (dispatched inline)
3. GatewayRunner._handle_message() receives the event:
   • Resolve session key via _session_key_for_source() (format: agent:main:{platform}:{chat_type}:{chat_id})
   • Check authorization (see Authorization below)
   • Check if it's a slash command → dispatch to command handler
   • Check if agent is already running → intercept commands like /stop, /status
   • Otherwise → create AIAgent instance and run conversation
4. Response is sent back through the platform adapter

Session Key Format

Session keys encode the full routing context:

agent:main:{platform}:{chat_type}:{chat_id}

For example: agent:main:telegram:private:123456789

Thread-aware platforms (Telegram forum topics, Discord threads, Slack threads) may include thread IDs in the chat_id portion. Never construct session keys manually — always use build_session_key() from gateway/session.py.

Two-Level Message Guard

When an agent is actively running, incoming messages pass through two sequential guards:

1. Level 1 — Base adapter (gateway/platforms/base.py): Checks _active_sessions. If the session is active, queues the message in _pending_messages and sets an interrupt event. This catches messages before they reach the gateway runner.

2. Level 2 — Gateway runner (gateway/run.py): Checks _running_agents. Intercepts specific commands (/stop, /new, /queue, /status, /approve, /deny) and routes them appropriately. Everything else triggers running_agent.interrupt().

Commands that must reach the runner while the agent is blocked (like /approve) are dispatched inline via await self._message_handler(event) — they bypass the background task system to avoid race conditions.

Authorization

The gateway uses a multi-layer authorization check, evaluated in order:

1. Gateway-wide allow-all (GATEWAY_ALLOW_ALL_USERS) — if set, all users are authorized
2. Platform allowlist (e.g., TELEGRAM_ALLOWED_USERS) — comma-separated user IDs
3. DM pairing — authenticated users can pair new users via a pairing code
4. Admin escalation — some commands require admin status beyond basic authorization

DM Pairing Flow

Admin: /pair
Gateway: "Pairing code: ABC123. Share with the user."
New user: ABC123
Gateway: "Paired! You're now authorized."

Pairing state is persisted in gateway/pairing.py and survives restarts.

Slash Command Dispatch

All slash commands in the gateway flow through the same resolution pipeline:

1. resolve_command() from hermes_cli/commands.py maps input to canonical name (handles aliases, prefix matching)
2. The canonical name is checked against GATEWAY_KNOWN_COMMANDS
3. Handler in _handle_message() dispatches based on canonical name
4. Some commands are gated on config (gateway_config_gate on CommandDef)

Running-Agent Guard

Commands that must NOT execute while the agent is processing are rejected early:

if _quick_key in self._running_agents:
    if canonical == "model":
        return "⏳ Agent is running — wait for it to finish or /stop first."

Bypass commands (/stop, /new, /approve, /deny, /queue, /status) have special handling.

Config Sources

The gateway reads configuration from multiple sources:

Source	What it provides
~/.hermes/.env	API keys, bot tokens, platform credentials
~/.hermes/config.yaml	Model settings, tool configuration, display options
Environment variables	Override any of the above

Unlike the CLI (which uses load_cli_config() with hardcoded defaults), the gateway reads config.yaml directly via YAML loader. This means config keys that exist in the CLI's defaults dict but not in the user's config file may behave differently between CLI and gateway.

Platform Adapters

Each messaging platform has an adapter in gateway/platforms/:

gateway/platforms/
├── base.py              # BaseAdapter — shared logic for all platforms
├── telegram.py          # Telegram Bot API (long polling or webhook)
├── discord.py           # Discord bot via discord.py
├── slack.py             # Slack Socket Mode
├── whatsapp.py          # WhatsApp Business Cloud API
├── signal.py            # Signal via signal-cli REST API
├── matrix.py            # Matrix via matrix-nio (optional E2EE)
├── mattermost.py        # Mattermost WebSocket API
├── email_adapter.py     # Email via IMAP/SMTP
├── sms.py               # SMS via Twilio
├── dingtalk.py          # DingTalk WebSocket
├── feishu.py            # Feishu/Lark WebSocket or webhook
├── wecom.py             # WeCom (WeChat Work) callback
└── homeassistant.py     # Home Assistant conversation integration

Adapters implement a common interface:

• connect() / disconnect() — lifecycle management
• send_message() — outbound message delivery
• on_message() — inbound message normalization → MessageEvent

Token Locks

Adapters that connect with unique credentials call acquire_scoped_lock() in connect() and release_scoped_lock() in disconnect(). This prevents two profiles from using the same bot token simultaneously.

Delivery Path

Outgoing deliveries (gateway/delivery.py) handle:

• Direct reply — send response back to the originating chat
• Home channel delivery — route cron job outputs and background results to a configured home channel
• Explicit target delivery — send_message tool specifying telegram:-1001234567890
• Cross-platform delivery — deliver to a different platform than the originating message

Cron job deliveries are NOT mirrored into gateway session history — they live in their own cron session only. This is a deliberate design choice to avoid message alternation violations.

Hooks

Gateway hooks are Python modules that respond to lifecycle events:

Gateway Hook Events

Event	When fired
gateway:startup	Gateway process starts
session:start	New conversation session begins
session:end	Session completes or times out
session:reset	User resets session with /new
agent:start	Agent begins processing a message
agent:step	Agent completes one tool-calling iteration
agent:end	Agent finishes and returns response
command:*	Any slash command is executed

Hooks are discovered from gateway/builtin_hooks/ (always active) and ~/.hermes/hooks/ (user-installed). Each hook is a directory with a HOOK.yaml manifest and handler.py.

Memory Provider Integration

When a memory provider plugin (e.g., Honcho) is enabled:

1. Gateway creates an AIAgent per message with the session ID
2. The MemoryManager initializes the provider with the session context
3. Provider tools (e.g., honcho_profile, viking_search) are routed through:

AIAgent._invoke_tool()
  → self._memory_manager.handle_tool_call(name, args)
    → provider.handle_tool_call(name, args)

4. On session end/reset, on_session_end() fires for cleanup and final data flush

Memory Flush Lifecycle

When a session is reset, resumed, or expires:

1. Built-in memories are flushed to disk
2. Memory provider's on_session_end() hook fires
3. A temporary AIAgent runs a memory-only conversation turn
4. Context is then discarded or archived

Background Maintenance

The gateway runs periodic maintenance alongside message handling:

• Cron ticking — checks job schedules and fires due jobs
• Session expiry — cleans up abandoned sessions after timeout
• Memory flush — proactively flushes memory before session expiry
• Cache refresh — refreshes model lists and provider status

Process Management

The gateway runs as a long-lived process, managed via:

• hermes gateway start / hermes gateway stop — manual control
• systemctl (Linux) or launchctl (macOS) — service management
• PID file at ~/.hermes/gateway.pid — profile-scoped process tracking

Profile-scoped vs global: start_gateway() uses profile-scoped PID files. hermes gateway stop stops only the current profile's gateway. hermes gateway stop --all uses global ps aux scanning to kill all gateway processes (used during updates).

Related Docs

• Session Storage
• Cron Internals
• ACP Internals
• Agent Loop Internals
• Messaging Gateway (User Guide)