Files
hermes-agent/website/docs/user-guide/features/plugins.md
Teknium 72250b5f62 feat: config-gated /verbose command for messaging gateway (#3262)
* feat: config-gated /verbose command for messaging gateway

Add gateway_config_gate field to CommandDef, allowing cli_only commands
to be conditionally available in the gateway based on a config value.

- CommandDef gains gateway_config_gate: str | None — a config dotpath
  that, when truthy, overrides cli_only for gateway surfaces
- /verbose uses gateway_config_gate='display.tool_progress_command'
- Default is off (cli_only behavior preserved)
- When enabled, /verbose cycles tool_progress mode (off/new/all/verbose)
  in the gateway, saving to config.yaml — same cycle as the CLI
- Gateway helpers (help, telegram menus, slack mapping) dynamically
  check config to include/exclude config-gated commands
- GATEWAY_KNOWN_COMMANDS always includes config-gated commands so
  the gateway recognizes them and can respond appropriately
- Handles YAML 1.1 bool coercion (bare 'off' parses as False)
- 8 new tests for the config gate mechanism + gateway handler

* docs: document gateway_config_gate and /verbose messaging support

- AGENTS.md: add gateway_config_gate to CommandDef fields
- slash-commands.md: note /verbose can be enabled for messaging, update Notes
- configuration.md: add tool_progress_command to display section + usage note
- cli.md: cross-link to config docs for messaging enablement
- messaging/index.md: show tool_progress_command in config snippet
- plugins.md: add gateway_config_gate to register_command parameter table
2026-03-26 14:41:04 -07:00

3.7 KiB

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Plugins

Hermes has a plugin system for adding custom tools, hooks, slash commands, and integrations without modifying core code.

Build a Hermes Plugin — step-by-step guide with a complete working example.

Quick overview

Drop a directory into ~/.hermes/plugins/ with a plugin.yaml and Python code:

~/.hermes/plugins/my-plugin/
├── plugin.yaml      # manifest
├── __init__.py      # register() — wires schemas to handlers
├── schemas.py       # tool schemas (what the LLM sees)
└── tools.py         # tool handlers (what runs when called)

Start Hermes — your tools appear alongside built-in tools. The model can call them immediately.

Project-local plugins under ./.hermes/plugins/ are disabled by default. Enable them only for trusted repositories by setting HERMES_ENABLE_PROJECT_PLUGINS=true before starting Hermes.

What plugins can do

Capability How
Add tools ctx.register_tool(name, schema, handler)
Add hooks ctx.register_hook("post_tool_call", callback)
Add slash commands ctx.register_command("mycommand", handler)
Ship data files Path(__file__).parent / "data" / "file.yaml"
Bundle skills Copy skill.md to ~/.hermes/skills/ at load time
Gate on env vars requires_env: [API_KEY] in plugin.yaml
Distribute via pip [project.entry-points."hermes_agent.plugins"]

Plugin discovery

Source Path Use case
User ~/.hermes/plugins/ Personal plugins
Project .hermes/plugins/ Project-specific plugins (requires HERMES_ENABLE_PROJECT_PLUGINS=true)
pip hermes_agent.plugins entry_points Distributed packages

Available hooks

Plugins can register callbacks for these lifecycle events. See the Event Hooks page for full details, callback signatures, and examples.

Hook Fires when
pre_tool_call Before any tool executes
post_tool_call After any tool returns
pre_llm_call Before LLM API request (planned)
post_llm_call After LLM API response (planned)
on_session_start Session begins (planned)
on_session_end Session ends (planned)

Slash commands

Plugins can register slash commands that work in both CLI and messaging platforms:

def register(ctx):
    ctx.register_command(
        name="greet",
        handler=lambda args: f"Hello, {args or 'world'}!",
        description="Greet someone",
        args_hint="[name]",
        aliases=("hi",),
    )

The handler receives the argument string (everything after /greet) and returns a string to display. Registered commands automatically appear in /help, tab autocomplete, Telegram bot menu, and Slack subcommand mapping.

Parameter Description
name Command name without slash
handler Callable that takes args: str and returns `str
description Shown in /help
args_hint Usage hint, e.g. "[name]"
aliases Tuple of alternative names
cli_only Only available in CLI
gateway_only Only available in messaging platforms
gateway_config_gate Config dotpath (e.g. "display.my_option"). When set on a cli_only command, the command becomes available in the gateway if the config value is truthy.

Managing plugins

/plugins              # list loaded plugins in a session
hermes config set display.show_cost true  # show cost in status bar

See the full guide for handler contracts, schema format, hook behavior, error handling, and common mistakes.