fix(extensions): warn on alias hook canonicalization; fix pluralization (#2017)

- Emit a compatibility warning when a hook ref is silently lifted from
  alias form (ext.cmd) to canonical (speckit.ext.cmd), so extension
  authors are notified to update their manifest in both rename and
  alias-canonicalization cases
- Pluralize removal confirmation: '1 command' vs 'N commands from AI agent'
- Update hook canonicalization test to assert the new warning is emitted
- Fix test assertions to match correct singular/plural strings

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: iamaeroplane

src/specify_cli/__init__.py

@@ -3139,7 +3139,8 @@ def extension_remove(
     # Confirm removal
     if not force:
         console.print("\n[yellow]⚠  This will remove:[/yellow]")
-        console.print(f"   • {cmd_count} commands from AI agent")
+        cmd_label = "command" if cmd_count == 1 else "commands"
+        console.print(f"   • {cmd_count} {cmd_label} from AI agent")
         if skill_count:
             console.print(f"   • {skill_count} agent skill(s)")
         console.print(f"   • Extension directory: .specify/extensions/{extension_id}/")

src/specify_cli/extensions.py

@@ -295,6 +295,14 @@ def _validate(self):
                         f"updated to '{final_ref}'. "
                         f"The extension author should update the manifest."
                     )
+                else:
+                    # Alias-form ref was canonicalized (e.g. 'ext.cmd' → 'speckit.ext.cmd').
+                    self.warnings.append(
+                        f"Hook '{hook_name}' referenced alias '{command_ref}'; "
+                        f"updated to canonical command '{final_ref}'. "
+                        f"The extension author should update the manifest to reference "
+                        f"the canonical command name directly."
+                    )
 
     @staticmethod
     def _try_correct_command_name(name: str, ext_id: str) -> Optional[str]:

tests/test_extensions.py

@@ -393,6 +393,10 @@ def test_hook_alias_ref_canonicalized_to_speckit_form(self, temp_dir, valid_mani
 
         # Hook ref should be lifted to canonical form for skill-mode invocation.
         assert manifest.hooks["after_tasks"]["command"] == "speckit.test-ext.greet"
+        # A compatibility warning should be emitted so the author knows to update.
+        assert len(manifest.warnings) == 1
+        assert "test-ext.greet" in manifest.warnings[0]
+        assert "speckit.test-ext.greet" in manifest.warnings[0]
 
     def test_hook_non_dict_value_raises(self, temp_dir, valid_manifest_data):
         """A non-mapping hooks value raises ValidationError."""
@@ -3144,8 +3148,8 @@ def test_remove_confirmation_counts_primary_command_only(self, extension_dir, pr
             result = runner.invoke(app, ["extension", "remove", "test-ext"], input="n\n")
 
         plain = strip_ansi(result.output)
-        # The fixture has 1 command and 0 aliases → "1 commands from AI agent"
-        assert "1 commands from AI agent" in plain
+        # The fixture has 1 command and 0 aliases → "1 command from AI agent"
+        assert "1 command from AI agent" in plain
 
     def test_remove_confirmation_counts_aliases(self, temp_dir, project_dir):
         """Removal confirmation shows primary + alias count, not just primary."""
@@ -3198,9 +3202,9 @@ def test_remove_confirmation_counts_aliases(self, temp_dir, project_dir):
             result = runner.invoke(app, ["extension", "remove", "ext-with-alias"], input="n\n")
 
         plain = strip_ansi(result.output)
-        # 1 primary + 1 alias = "2 commands from AI agent" (not "1")
+        # 1 primary + 1 alias = "2 commands from AI agent" (not "1 command")
         assert "2 commands from AI agent" in plain
-        assert "1 commands from AI agent" not in plain
+        assert "1 command from AI agent" not in plain
 
 
 class TestExtensionUpdateCLI: