hermes-bus-plugin 0.4.2

Hermes bus integration plugin — auto-start, auto-register, message injection, bus tools

hermes-bus-plugin

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Hermes Agent plugin for message bus integration — lifecycle management, external message injection, bus tools.

A thin integration layer between Hermes Agent and the hermes-bus / hermes-notify packages.

Install

# Via Hermes plugin manager
hermes plugins install hermes-bus-plugin

# Or copy to ~/.hermes/hermes-agent/plugins/
cp -r hermes-bus-plugin ~/.hermes/hermes-agent/plugins/
hermes plugins enable hermes-bus-plugin

Session Naming

Each CLI window registers a unique bus endpoint on startup. The default endpoint is hermes-bus (first session), with hermes-bus-2, hermes-bus-3, etc. for additional sessions. To give your session a stable name that survives reconnection:

/title my-agent-name

The plugin uses the title set by /title as the bus endpoint name.

Action	When	Description
Start bus daemon	Plugin load	Ensures hermes-bus is running
Register listener	Plugin load	Opens a bus endpoint for incoming messages
Print notifications	On bus message	print: true → terminal (only when context is NOT true)
Inject context + push	On bus message	context: true → inject into LLM context + push to Agent via pending_input (overrides print, token-heavy — use sparingly)
Execute command	On bus message	command → async subprocess (audio, scripts, etc.) — runs inside Hermes process, no external daemon needed

Provided Tools

bus_send — send a message through the bus to any endpoint:

bus_send(target="notifier", type="progress", text="50% done")

bus_status — check bus health and connected endpoints:

bus_status()

bus_info — show current session's bus connection details:

bus_info()

Route Rules

Messages arriving at the bus are matched against ~/.hermes/bus-rules.yaml rules. Each rule can trigger three independent actions:

Field	Behavior	Default
print	Print to terminal	false
print_format	Template or script for terminal output	{text}
context	Inject into LLM context + push to Agent	false
context_format	Template or script for context/push text	{text}
command	Execute shell command (audio, script, etc.)	none

Priority Logic

context and print are mutually exclusive:

• context: true → inject context + push to Agent (print is ignored). ⚠️ Token-heavy — each push triggers an Agent turn.
• print: true → terminal output only (only when context is NOT true)
• command → always executed if defined, independent of context/print

Format Templates

print_format and context_format support these placeholders:

Placeholder	Description
{from}	Sender endpoint name
{text}	Message body text
{type}	Message type
{ts}	Unix timestamp (raw)
{ts:%Y-%m-%d %H:%M:%S}	strftime formatted
{color:cyan}	ANSI foreground color (black/red/green/yellow/blue/magenta/cyan/white)
{color:bold_green}	Bold color variant
{bold}	Bold text
{reset}	Reset all styles

Script Support

If print_format or context_format starts with ~ or / and points to an executable file, the script is run with FROM, TYPE, TEXT as environment variables and its stdout is used as the rendered output (supports ANSI colors).

#!/bin/bash
# format-notify.sh — example format script
GREEN="\033[1;32m"
YELLOW="\033[1;33m"
RESET="\033[0m"

case "$TYPE" in
  task_done)  echo -e "${GREEN}✔ ${FROM}${RESET} — ${TEXT}" ;;
  task_error) echo -e "${YELLOW}✖ ${FROM} failed${RESET}\n   ${TEXT}" ;;
  *)          echo -e "${FROM}: ${TEXT}" ;;
esac

# bus-rules.yaml
- match_type: task_done
  print: true
  print_format: "~/scripts/format-notify.sh"

Example Rules

callbacks:
  # Notification only (no context)
  - match_type: ack
    print: true
    print_format: "{color:cyan}📬 {from}{reset}  {text}  [{ts:%H:%M}]"
    context: false

  # Silent context injection
  - match_type: progress
    print: false
    context: true

  # Context + terminal + audio
  - match_type: task_done
    print: true
    print_format: "{color:bold_green}✔ {from}{reset} → {text}  {color:cyan}[{ts:%H:%M:%S}]{reset}"
    context: true
    command: "afplay ~/sounds/done.mp3"

Requirements

• hermes-bus (pip)
• hermes-notify (pip)

Both are auto-detected — the plugin degrades gracefully if they're missing.

Architecture

External process ──→ hermes-bus ──→ hermes-bus-plugin ──→ LLM context
                        (socket)        ├─ pre_llm_call hook
                                        └─ async subprocess (command: audio/script)

Hermes session ──→ bus_send tool ──→ hermes-bus ──→ target endpoint

command execution (audio playback, shell scripts) runs inside the Hermes process via subprocess.Popen. No external daemon (bus-notifier) needed — one less process to manage, no point-to-point routing issues, no silent failures.