hermes - 💡(How to fix) Fix feat: Extension point for registering custom Slack Block Kit action handlers

Summary

Currently, there is no non-invasive way to register custom Slack Block Kit action handlers (button clicks, menu selections, etc.) in the Slack platform adapter (gateway/platforms/slack.py). Any feature that needs to respond to interactive component actions — such as approval flows, archive confirmations, or custom workflows — requires directly modifying the core adapter code.

Problem

The existing action handler registrations are hardcoded inside SlackAdapter.connect():

# gateway/platforms/slack.py, lines ~666-682
for _action_id in ("hermes_approve_once", ...):
    self._app.action(_action_id)(self._handle_approval_action)

for _action_id in ("hermes_confirm_once", ...):
    self._app.action(_action_id)(self._handle_slash_confirm_action)

To add a new action handler (e.g., for a custom approval workflow), users must:

1. Add self._app.action(action_id)(handler) in the connect() method
2. Add the handler method to SlackAdapter

This is an invasive modification that will conflict on every git pull upgrade.

Existing Extension Points (insufficient)

Proposed Solution

Add an extension mechanism for Slack interactive component handlers. Possible approaches:

Option A: Expose the Bolt App via lifecycle hook

Extend the gateway:startup hook context to include a reference to active platform adapters, allowing plugins/hooks to call adapter.app.action(...) after connection.

Option B: Dedicated action handler registry

Create a lightweight registry (similar to platform_registry.py) specifically for Slack action handlers:

from gateway.slack_actions import slack_action_registry

slack_action_registry.register(
    action_ids=["approve_tdai_archive", "discard_tdai_archive"],
    handler=handle_archive_action,
)

Option C: Plugin hook in SlackAdapter.connect()

Add a _post_connect_hook() method that plugins can override to register additional actions after the Bolt app is initialized.

Use Case

We built a custom "archive approval" workflow that sends Block Kit cards with approve/discard buttons. Responding to these button clicks requires listening for approve_tdai_archive and discard_tdai_archive action IDs. Without an extension point, we had to patch slack.py directly — which will break on upgrades.

Environment

• Hermes Agent: latest (main branch)
• Platform: macOS 26.5
• Python: 3.11 (venv)