diff --git a/server/migrations/20260417100050_enhance_kol_constraints.down.sql b/server/migrations/20260417100050_enhance_kol_constraints.down.sql
new file mode 100644
index 0000000..959ec06
--- /dev/null
+++ b/server/migrations/20260417100050_enhance_kol_constraints.down.sql
@@ -0,0 +1,7 @@
+DROP INDEX IF EXISTS idx_kol_package_tenant;
+
+ALTER TABLE kol_prompts
+    DROP CONSTRAINT IF EXISTS chk_kol_prompts_active_has_published_revision;
+
+ALTER TABLE kol_usage_logs
+    DROP CONSTRAINT IF EXISTS fk_kol_usage_logs_prompt_revision;
diff --git a/server/migrations/20260417100050_enhance_kol_constraints.up.sql b/server/migrations/20260417100050_enhance_kol_constraints.up.sql
new file mode 100644
index 0000000..23fb1ab
--- /dev/null
+++ b/server/migrations/20260417100050_enhance_kol_constraints.up.sql
@@ -0,0 +1,18 @@
+-- Enhance KOL core tables with integrity constraints and missing index.
+-- Follow-up to 20260417100000 addressing review findings:
+--   1. Composite FK for usage-log audit replay (prompt_id, prompt_revision_no)
+--   2. CHECK: active prompts must have a published revision
+--   3. Tenant-leading index on kol_packages for list paths
+
+ALTER TABLE kol_usage_logs
+    ADD CONSTRAINT fk_kol_usage_logs_prompt_revision
+    FOREIGN KEY (prompt_id, prompt_revision_no)
+    REFERENCES kol_prompt_revisions(prompt_id, revision_no);
+
+ALTER TABLE kol_prompts
+    ADD CONSTRAINT chk_kol_prompts_active_has_published_revision
+    CHECK (status <> 'active' OR published_revision_no IS NOT NULL);
+
+CREATE INDEX idx_kol_package_tenant
+    ON kol_packages(tenant_id, created_at DESC)
+    WHERE deleted_at IS NULL;