Reject CTO generated cache residue

tools/validate_cto_child.py

@@ -5,10 +5,17 @@ from __future__ import annotations
 
 import json
 import re
+import sys
 from pathlib import Path
 
 
 ROOT = Path(__file__).resolve().parents[1]
+sys.dont_write_bytecode = True
+
+GENERATED_ARTIFACT_DIRS = [
+    "tools/__pycache__",
+    ".pytest_cache",
+]
 
 REQUIRED_FILES = [
     "AGENTS.md",
@@ -180,6 +187,7 @@ REQUIRED_LEGACY_INGEST_PHRASES = [
     "Source Clusters Assessed By Intention",
     "Do not activate Case as default backend.",
     "Do not mutate target repositories.",
+    "Generated Cache Custody",
 ]
 
 REQUIRED_ARCHITECTURE_CLOSEOUT_PRD_PHRASES = [
@@ -1903,6 +1911,15 @@ def workboard_status(text: str, issue_id: str) -> str | None:
     return match.group(1).strip() if match else None
 
 
+def validate_no_generated_artifact_residue(checked: list[str]) -> list[str]:
+    errors: list[str] = []
+    for relpath in GENERATED_ARTIFACT_DIRS:
+        checked.append(f"generated_artifact_absent:{relpath}")
+        if (ROOT / relpath).exists():
+            errors.append(f"generated_artifact_residue:{relpath}")
+    return errors
+
+
 def main() -> int:
     checked: list[str] = []
     errors: list[str] = []
@@ -1945,6 +1962,8 @@ def main() -> int:
             if phrase not in text:
                 errors.append(f"missing_legacy_ingest_phrase:{phrase}")
 
+    errors.extend(validate_no_generated_artifact_residue(checked))
+
     brief = ROOT / ".sot/03-PROTOCOLS/CTO-CASE-BACKEND-BRIEF.md"
     if brief.is_file():
         text = brief.read_text(encoding="utf-8")