yoi/work-items/open/20260531-010005-plugin-extension-surface/artifacts/feature-registry-split-decision.md

Decision: split feature registry and Hook hardening from Plugin architecture

The Plugin architecture ticket remains the broad architecture surface for Tools, Hooks, runtime kinds, capability model, trust model, discovery/enablement, and MCP/WASM/declarative runtime mapping.

Two implementation-oriented prerequisite tickets are split out:

• plugin-feature-contribution-registry: define and implement the Pod-layer feature contribution registry so built-in and future external capabilities register through existing Tool / Hook / Notify paths instead of ad hoc Pod code paths.
• hook-public-surface-hardening: audit and harden pod::hook before exposing it as a feature/plugin contribution boundary, especially removing public access to raw internal action types that can inject model-visible Item values.

This preserves the desired detachable shape: feature state remains in the feature/extension module, while Pod interaction happens through existing durable host surfaces. WorkItem management should be implemented as a built-in feature contribution once the registry boundary is in place, rather than as a special Pod context-injection path.