Extending with Drop-in Plugins

The defining rule of the codebase: **new capabilities are drop-in files, never core
edits.** A new integration, ability, event source, communication channel, data connector,
secrets vault, encryption method, payment processor, or scheduler provider is added as
its own new file in the matching folder — carrying a small self-describing header — and
the app auto-discovers it. You never register it in a central list.

Why it matters: the core stays small and stable, and editions can ship a tested subset
of capabilities just by including or excluding files.

The how-to and the contract live in these pages:

• Core vs Plugins: Structure Philosophy — the principle and where the seams are.
• Adding a Plugin — the step-by-step.
• The FEATURE Header — the self-describing header every capability declares.
• Agent Abilities (drop-in) — abilities specifically, as drop-in files.
• Ability-Bundled Skills — shipping a skill alongside an ability.
• The Feature Catalog and Discovery — how the app finds and lists it all.
• Editions and the Production Path / Edition Gating and Packaging — shipping a

subset.