CLI and API polish

docs/internal-extension-framework.md

@@ -187,6 +187,18 @@ Extension registries are optimized for common lookup patterns:
 Kinds and capabilities are indexed at registration time, so large registries can
 avoid repeated full scans for basic discovery.
 
+The same registry is exposed on the CLI for practical discovery:
+
+```bash
+mkt extension list
+mkt extension inspect memory.context-package
+mkt extension commands
+```
+
+This makes the extension catalog part of the user-visible contract. When a
+capability gains a CLI command, the descriptor should declare that command so
+generated docs and audits can compare intent with the live surface.
+
 ### Execution Lifecycle
 
 `ExtensionExecutor` wraps a descriptor factory with deterministic lifecycle