Use default Mock AI provider

Author: johnsamuelwrites

multilingualprogramming/__main__.py

@@ -42,6 +42,7 @@
 from multilingualprogramming.exceptions import UnsupportedLanguageError
 from multilingualprogramming.lexer.lexer import Lexer
 from multilingualprogramming.parser.parser import Parser
+from multilingualprogramming.runtime.ai_runtime import AIRuntime, MockProvider
 from multilingualprogramming.source_extensions import (
     find_package_init,
     has_source_extension,
@@ -86,6 +87,14 @@ def _read_source_file(path: str) -> str:
         sys.exit(1)
 
 
+def _ensure_default_ai_provider() -> None:
+    """Register the CLI's default mock provider when none is active."""
+    try:
+        AIRuntime.get_provider()
+    except RuntimeError:
+        AIRuntime.register(MockProvider())
+
+
 def _parse_program_from_file(path: str, lang: str | None):
     source = _read_source_file(path)
     lexer = Lexer(source, language=lang)
@@ -98,6 +107,7 @@ def _parse_program_from_file(path: str, lang: str | None):
 def cmd_run(args):
     """Execute a multilingual source file."""
     source = _read_source_file(args.file)
+    _ensure_default_ai_provider()
 
     # Determine package context so that relative imports work.
     # Walk up from the file's directory while package initializer files exist;

tests/language_completeness_cli_test.py

@@ -30,6 +30,7 @@
 from multilingualprogramming.keyword.language_pack_validator import (
     LanguagePackValidator,
 )
+from multilingualprogramming.runtime.ai_runtime import AIRuntime, MockProvider
 
 
 def _parse(source, lang="en"):
@@ -420,6 +421,54 @@ def test_cmd_run_show_backend_writes_report_to_stderr(self):
         self.assertEqual(stdout.getvalue(), "hello\n")
         self.assertIn("[backend] python (python-codegen-exec)", stderr.getvalue())
 
+    def test_cmd_run_registers_default_mock_provider_for_ai_programs(self):
+        with tempfile.NamedTemporaryFile(
+            "w", suffix=".multi", delete=False, encoding="utf-8"
+        ) as tmp:
+            tmp.write(
+                'fn main() uses ai:\n'
+                '    print(prompt @claude-sonnet: "hello")\n'
+                'main()\n'
+            )
+            tmp_path = tmp.name
+
+        args = Namespace(file=tmp_path, lang="en", show_backend=False)
+        stdout = io.StringIO()
+        try:
+            AIRuntime.reset()
+            with patch("sys.stdout", stdout):
+                cmd_run(args)
+        finally:
+            AIRuntime.reset()
+            Path(tmp_path).unlink(missing_ok=True)
+
+        self.assertIn("mock response to:", stdout.getvalue())
+
+    def test_cmd_run_preserves_existing_registered_provider(self):
+        with tempfile.NamedTemporaryFile(
+            "w", suffix=".multi", delete=False, encoding="utf-8"
+        ) as tmp:
+            tmp.write(
+                'fn main() uses ai:\n'
+                '    print(prompt @claude-sonnet: "hello")\n'
+                'main()\n'
+            )
+            tmp_path = tmp.name
+
+        args = Namespace(file=tmp_path, lang="en", show_backend=False)
+        stdout = io.StringIO()
+        provider = MockProvider().add_response("custom provider response")
+        try:
+            AIRuntime.reset()
+            AIRuntime.register(provider)
+            with patch("sys.stdout", stdout):
+                cmd_run(args)
+        finally:
+            AIRuntime.reset()
+            Path(tmp_path).unlink(missing_ok=True)
+
+        self.assertEqual(stdout.getvalue().strip(), "custom provider response")
+
 
 # ---------------------------------------------------------------
 # WS7: REPL improvements