diff --git a/internal/scaffold/fullsend-repo/skills/code-implementation/SKILL.md b/internal/scaffold/fullsend-repo/skills/code-implementation/SKILL.md
index 4215a4985..6413f7be5 100644
--- a/internal/scaffold/fullsend-repo/skills/code-implementation/SKILL.md
+++ b/internal/scaffold/fullsend-repo/skills/code-implementation/SKILL.md
@@ -307,6 +307,10 @@ Before writing code, form a concrete plan:
    changed behavior needs updated tests.
 7. **Assess risk** — will this change affect other callers? Does it change a
    public interface? Could it break downstream consumers?
+8. **Verify API contracts per code path** — if the fix removes or empties
+   a parameter sent to an external API, check the API documentation or
+   test each code path that uses the function. Different operations
+   (e.g., approve vs request-changes) often have different required fields.
 
 When requirements are ambiguous, distinguish between "vague but actionable"
 (you can make a reasonable conservative interpretation) and "genuinely
diff --git a/internal/scaffold/scaffold_test.go b/internal/scaffold/scaffold_test.go
index 394f43b74..dd5ad7359 100644
--- a/internal/scaffold/scaffold_test.go
+++ b/internal/scaffold/scaffold_test.go
@@ -369,6 +369,14 @@ func TestCodeAgentContent(t *testing.T) {
 	assert.Contains(t, s, "code-implementation")
 }
 
+func TestCodeImplementationSkillAPIContractGuidance(t *testing.T) {
+	content, err := FullsendRepoFile("skills/code-implementation/SKILL.md")
+	require.NoError(t, err)
+	s := string(content)
+	assert.Contains(t, s, "Verify API contracts per code path")
+	assert.Contains(t, s, "removes or empties")
+}
+
 func TestCodeWorkflowContent(t *testing.T) {
 	content, err := FullsendRepoFile(".github/workflows/code.yml")
 	require.NoError(t, err)