diff --git a/data_prep/introspector.py b/data_prep/introspector.py
index c088f2ff5..6d7a04285 100755
--- a/data_prep/introspector.py
+++ b/data_prep/introspector.py
@@ -343,7 +343,8 @@ def query_introspector_public_classes(project: str) -> list[str]:
   return _get_data(resp, 'classes', [])
 
 
-def query_introspector_source_code(project: str, filepath: str,
+def query_introspector_source_code(project: str,
+                                   filepath: str,
                                    begin_line: int = 0,
                                    end_line: int = 10000) -> str:
   """Queries FuzzIntrospector API for source code of a
diff --git a/experiment/evaluator.py b/experiment/evaluator.py
index f07cf225a..5c1fb249b 100644
--- a/experiment/evaluator.py
+++ b/experiment/evaluator.py
@@ -284,6 +284,7 @@ def _fix_generated_fuzz_target(self, ai_binary: str,
                                  dual_logger: _Logger, language: str):
     """Fixes the generated fuzz target."""
     jvm_coverage_fix = False
+    error_desc, errors = '', []
     if build_result.succeeded:
       if language == 'jvm':
         jvm_coverage_fix = True
@@ -293,7 +294,6 @@ def _fix_generated_fuzz_target(self, ai_binary: str,
         else:
           dual_logger.log(f'Warning: Build succeed but no run_result in '
                           f'{generated_oss_fuzz_project}.')
-          error_desc, errors = '', []
     else:
       error_desc, errors = None, build_result.errors
 
@@ -402,7 +402,7 @@ def check_target(self, ai_binary, target_path: str) -> Result:
         # Gets line coverage (diff) details.
         coverage_summary = self._load_existing_coverage_summary()
 
-        if self.benchmark.language in ['python', 'jvm']:
+        if self.benchmark.language in ['python', 'jvm'] and run_result.coverage:
           # The Jacoco.xml coverage report used to generate summary.json on
           # OSS-Fuzz for JVM projects does not trace the source file location.
           # Thus the conversion may miss some classes because they are not
@@ -427,9 +427,10 @@ def check_target(self, ai_binary, target_path: str) -> Result:
           coverage_percent = 0.0
 
         existing_textcov = self.load_existing_textcov()
-        run_result.coverage.subtract_covered_lines(existing_textcov)
+        if run_result.coverage:
+          run_result.coverage.subtract_covered_lines(existing_textcov)
 
-        if total_lines:
+        if total_lines and run_result.coverage:
           coverage_diff = run_result.coverage.covered_lines / total_lines
         else:
           dual_logger.log(
@@ -441,7 +442,7 @@ def check_target(self, ai_binary, target_path: str) -> Result:
         # 1) Build success and run crashed (expected for exceptions)
         # 2) Build success, run success and coverage diff > 0
         gen_succ = build_result.succeeded and run_result
-        if gen_succ and run_result.succeeded:
+        if gen_succ and run_result and run_result.succeeded:
           gen_succ = gen_succ and (coverage_diff > 0)
       else:
         gen_succ = build_result.succeeded and run_result and run_result.succeeded
diff --git a/llm_toolkit/prompt_builder.py b/llm_toolkit/prompt_builder.py
index 3af1a41f5..a42aebb99 100644
--- a/llm_toolkit/prompt_builder.py
+++ b/llm_toolkit/prompt_builder.py
@@ -1073,11 +1073,11 @@ def __init__(self,
 
     # Load templates.
     if self.jvm_cov_fix:
-        self.template_file = self._find_template(
-            template_dir, 'jvm_requirement_coverage_fixing.txt')
+      self.template_file = self._find_template(
+          template_dir, 'jvm_requirement_coverage_fixing.txt')
     else:
-        self.template_file = self._find_template(
-            template_dir, 'jvm_requirement_error_fixing.txt')
+      self.template_file = self._find_template(
+          template_dir, 'jvm_requirement_error_fixing.txt')
 
   def _find_template(self, template_dir: str, template_name: str) -> str:
     """Finds template file based on |template_dir|."""
@@ -1105,6 +1105,8 @@ def build(self,
     with open(self.template_file, 'r') as f:
       prompt_text = f.read()
 
+    proj = self.benchmark.project
+
     # Format the repository
     target_repository = oss_fuzz_checkout.get_project_repository(
         self.benchmark.project)
@@ -1122,13 +1124,13 @@ def build(self,
       harnesses = introspector.query_introspector_for_harness_intrinsics(proj)
       for pair in harnesses:
         path = pair.get('source', '')
-        if source_path:
+        if path:
           source = introspector.query_introspector_source_code(proj, path)
           if source:
             source_list.append(source)
 
       prompt_text = prompt_text.replace('{EXISTING_HARNESS}',
-                                          '\n---\n'.join(source_list))
+                                        '\n---\n'.join(source_list))
 
       # Add all public candidates to prompt
       methods = introspector.query_introspector_jvm_all_public_candidates(proj)