Summary

A plugin installed from an enterprise-managed marketplace is reported as managed, desired, installed, and enabled, but its native plugin hooks do not run when a session materializes.

Reproduction

1. Create a local Git-backed plugin marketplace containing a plugin with:

   • a normal skill, so plugin discovery is observable;
   • hooks/hooks.json with a SessionStart command that writes its JSON stdin to a file.

2. Return these managed settings from /copilot_internal/managed_settings:

   {
     "extraKnownMarketplaces": {
       "managed-marketplace": {
         "source": {
           "source": "git",
           "url": "file:///path/to/marketplace"
         },
         "autoUpdate": false
       }
     },
     "enabledPlugins": {
       "managed-hook-plugin@managed-marketplace": true
     }
   }

3. Create a session with enableManagedSettings: true.

4. Install managed-hook-plugin@managed-marketplace through session.rpc.plugins.install.

5. Disconnect, create a second session, and send one prompt so the session materializes.

session.rpc.plugins.list() reports:

{
  "name": "managed-hook-plugin",
  "marketplace": "managed-marketplace",
  "enabled": true,
  "managed": true,
  "managedDesiredEnabled": true,
  "installed": true
}

Expected

The managed plugin's SessionStart command runs once.

Actual

The session completes normally, but the hook command is never invoked.

Regression range

• @github/copilot-sdk 1.0.13 / Copilot CLI 1.0.83: a runtime-installed plugin's SessionStart hook runs.
• VS Code 1.139's SDK canary / Copilot CLI 1.0.85: the same runtime-installed plugin and hook are discovered, but the hook does not run.
• @github/copilot-sdk 1.0.15-unstable.35663726336.gcb2a8cc / runtime 1.0.87-unstable.r35651157977.g1aacd25: still reproduces.

SDK-supplied session callbacks can bridge this when allowManagedHooksOnly is absent. With allowManagedHooksOnly: true, SDK callbacks are correctly suppressed, so the runtime must execute the native managed-plugin hook while retaining its managed provenance.