diff --git a/agents/impl_generator.py b/agents/impl_generator.py
index fa293d9..33ce9f5 100644
--- a/agents/impl_generator.py
+++ b/agents/impl_generator.py
@@ -15,7 +15,6 @@ class GenerationAttempt:
 @dataclasses.dataclass(frozen=True)
 class ImplGenerationRequest:
     interface_str: str
-    test_str: str
     prior_attempts: list[GenerationAttempt] = dataclasses.field(default_factory=list)
 
 
@@ -30,7 +29,7 @@ def __init__(self, model_str: str = ''):
                 'The implementation should be fast, memory-efficient, and as simple as possible while meeting all requirements.')
         )
 
-    def _make_initial_prompt(self, python_interface: str, test_str: str) -> str:
+    def _make_initial_prompt(self, python_interface: str, test_code: str) -> str:
         example_impl = textwrap.dedent('''
             from my_interface import MyInterface
 
@@ -50,13 +49,13 @@ def foo(self) -> str:
             'The code you will generate is *not* an abstract class, and does *not* have any `@abstractmethod` annotations. '
             'The interface itself already exists in the same directory, so do not add it here. '
             'The test suite that should pass looks like this:\n\n'
-            f'{utils.wrap_code_in_markdown(test_str)}'
+            f'{utils.wrap_code_in_markdown(test_code)}'
             'An example implementation might look something like this:\n\n'
             f'{utils.wrap_code_in_markdown(example_impl)}'
         )
 
     def _make_improvement_prompt(
-            self, python_interface: str, test_str: str, prior_attempts: list[GenerationAttempt] = []
+            self, python_interface: str, test_code: str, prior_attempts: list[GenerationAttempt] = []
     ) -> str:
         # This variable is currently unused, but kept for possible future use
         _ = textwrap.dedent('''
@@ -79,7 +78,7 @@ def foo(self) -> str:
             'Your instructions were to make sure the name of the class ends with "Impl", and it inherits from the interface. '
             'You can assume the interface exists the same directory as the implementation being generated. '
             'The test suite that was run looks like this:\n\n'
-            f'{utils.wrap_code_in_markdown(test_str)}'
+            f'{utils.wrap_code_in_markdown(test_code)}'
             'When the tests were run, the following output indicates some problems:'
             f'```\n{prior_attempts[-1].errors}\n```\n\n'
             'Please generate a new implementation according to the same instructions, '
diff --git a/demo.py b/demo.py
index 977a3d1..617e2d6 100644
--- a/demo.py
+++ b/demo.py
@@ -177,7 +177,9 @@ def main(example_name: str):
         return
 
     test_str = test_gen.str_to_file(request, test_path)
-    impl_str = impl_gen.str_to_file(impl_generator.ImplGenerationRequest(example.code, test_str), impl_path)
+    with open(test_path, 'r') as test_file:
+        test_code = test_file.read()
+    impl_str = impl_gen.str_to_file(impl_generator.ImplGenerationRequest(example.code, prior_attempts=[]), impl_path)
     tests_pass, test_output = run_tests(project_dir)
 
     if not tests_pass:
@@ -194,7 +196,7 @@ def main(example_name: str):
         while not tests_pass and num_impl_rounds > 0:
             print('Tests did not pass, trying another round of impl generation.')
             impl_attempts.append(impl_generator.GenerationAttempt(impl_str, test_output))
-            impl_request = impl_generator.ImplGenerationRequest(example.code, test_str, impl_attempts)
+            impl_request = impl_generator.ImplGenerationRequest(example.code, impl_attempts)
             impl_str = impl_gen.str_to_file(impl_request, impl_path)
             tests_pass, test_output = run_tests(project_dir)
             num_impl_rounds -= 1
diff --git a/start.py b/start.py
index 01bf85a..2e7de09 100644
--- a/start.py
+++ b/start.py
@@ -83,27 +83,27 @@ def test_iteration_loop(self, iface_path: str) -> None:
 
         test_path = iface_path.replace('.py', '_test.py')
         request = test_generator.TestGenerationRequest(interface_str=iface_str)
-        test_str = self._test_gen.str_to_file(request, test_path)
+        test_code = self._test_gen.str_to_file(request, test_path)
         if compilation_error := try_compile_file(test_path):
-            attempt = test_generator.GenerationAttempt(code=test_str, errors=compilation_error)
+            attempt = test_generator.GenerationAttempt(code=test_code, errors=compilation_error)
             request = test_generator.TestGenerationRequest(interface_str=iface_str, prior_attempts=[attempt])
-            test_str = self._test_gen.str_to_file(request, test_path)
+            test_code = self._test_gen.str_to_file(request, test_path)
 
     def impl_iteration_loop(self, iface_path: str, test_path: str) -> None:
         """Iterates on impl creation, returning the finished file."""
         with open(iface_path, 'r') as iface_file:
             iface_str = iface_file.read()
         with open(test_path, 'r') as test_file:
-            test_str = test_file.read()
+            test_code = test_file.read()
 
         impl_path = iface_path.replace('.py', '_impl.py')
-        request = impl_generator.ImplGenerationRequest(iface_str, test_str)
+        request = impl_generator.ImplGenerationRequest(iface_str, prior_attempts=[])
         impl_str = self._impl_gen.str_to_file(request, impl_path)
         tests_pass, test_output = run_tests(self._working_dir)
         attempts = []
         while not tests_pass:
             attempts.append(impl_generator.GenerationAttempt(code=impl_str, errors=test_output))
-            request = impl_generator.ImplGenerationRequest(iface_str, test_str, attempts)
+            request = impl_generator.ImplGenerationRequest(iface_str, attempts)
             impl_str = self._impl_gen.str_to_file(request, impl_path)
             tests_pass, test_output = run_tests(self._working_dir)