diff --git a/CHANGELOG.md b/CHANGELOG.md
index 414fe53f8..5becaa0a4 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,7 +7,7 @@
 - Fixed a validation bypass in `PlanGenerationGraph._validate()` (issue #10480):
   the artificial ``or len(all_code) > 10`` condition that caused any code longer
   than 10 characters to auto-pass LLM validation has been removed.  LLM verdicts
-  are now solely responsible for determine pass/fail status, enabling the retry
+  are now solely responsible for determining pass/fail status, enabling the retry
   logic and broken-code rejection to operate correctly.
 
 - Hardened the TDD bug-fix quality gate for issue #629: PR parsing now
diff --git a/features/steps/validation_bypass_issue_10480_steps.py b/features/steps/validation_bypass_issue_10480_steps.py
index c3565bd60..0eb4ee09a 100644
--- a/features/steps/validation_bypass_issue_10480_steps.py
+++ b/features/steps/validation_bypass_issue_10480_steps.py
@@ -40,10 +40,10 @@ def make_fake_llm(responses: list[str]) -> FakeListLLM:
 # ---------------------------------------------------------------------------
 # Background steps
 # ---------------------------------------------------------------------------
-@given("the plan generation coverage module is imported")
-def step_coverage_module_imported(context):
-    """Ensure the plan_generation module is importable."""
-    assert PlanGenerationGraph is not None
+# Note: "the plan generation coverage module is imported" is defined in
+# features/steps/plan_generation_coverage_boost_steps.py and reused here
+# (behave discovers steps globally across features/steps/). Defining it
+# again would raise AmbiguousStep.
 
 
 @given("the validation bypass test helper is ready")
@@ -168,7 +168,7 @@ def step_validation_message_contains_feedback(context):
     )
 
 
-@then("and no artificial length threshold bypassed the rejection")
+@then("no artificial length threshold bypassed the rejection")
 def step_no_length_threshold_bypass(context):
     """Confirm that code length did not override a FAIL verdict.
 
@@ -185,7 +185,7 @@ def step_no_length_threshold_bypass(context):
     )
 
 
-@then("and the validation message should preserve the full LLM feedback")
+@then("the validation message should preserve the full LLM feedback")
 def step_validation_preserves_feedback(context):
     """Full message must contain the original LLM response."""
     assert context.validation_result is not None
@@ -196,7 +196,7 @@ def step_validation_preserves_feedback(context):
     )
 
 
-@then("and the code-length condition must NOT override the FAIL verdict")
+@then("the code-length condition must NOT override the FAIL verdict")
 def step_code_length_not_override(context):
     """Definitive regression test: code length > 10 did not cause auto-pass.
 
diff --git a/features/validation_bypass_issue_10480.feature b/features/validation_bypass_issue_10480.feature
index c953220cf..c653ca03d 100644
--- a/features/validation_bypass_issue_10480.feature
+++ b/features/validation_bypass_issue_10480.feature
@@ -7,30 +7,35 @@ Feature: Validation bypass fix (issue #10480)
     Given the plan generation coverage module is imported
     And the validation bypass test helper is ready
 
+  @tdd_bug_10480
   Scenario: LLM returns FAIL for short code and validation correctly rejects it
     Given an LLM mock that responds with "FAIL: syntax error"
     When a PlanGenerationGraph _validate is called with short generated code
     Then the validation result status should be "FAIL"
     And the validation message should contain the LLM feedback
 
+  @tdd_bug_10480
   Scenario: LLM returns FAIL for long code and validation correctly rejects it
     Given an LLM mock that responds with "FAIL: unsafe pattern detected"
     When a PlanGenerationGraph _validate is called with longer generated code
     Then the validation result status should be "FAIL"
     And no artificial length threshold bypassed the rejection
 
+  @tdd_bug_10480
   Scenario: LLM returns PASS and validation correctly accepts it
     Given an LLM mock that responds with "PASS"
     When a PlanGenerationGraph _validate is called with any generated code
     Then the validation result status should be "PASS"
     And the validation message should contain the LLM feedback
 
+  @tdd_bug_10480
   Scenario: LLM returns FAIL with additional details and validation correctly rejects
     Given an LLM mock that responds with "FAIL: missing error handling in auth module"
     When a PlanGenerationGraph _validate is called with generated code
     Then the validation result status should be "FAIL"
     And the validation message should preserve the full LLM feedback
 
+  @tdd_bug_10480
   Scenario: Validation ignores code length and does not auto-pass long code
     Given an LLM mock that responds with "FAIL: security vulnerability"
     When a PlanGenerationGraph _validate is called with code longer than 10 characters