Fix nullable blocker in strict coding result schema

scripts/codex_von_worker.py

@@ -44,7 +44,7 @@
         "deploy_commit": {"type": "string"},
         "blocker": retry_policy.BLOCKER_SCHEMA,
     },
-    "required": ["status", "summary", "evidence", "question", "deploy_commit"],
+    "required": ["status", "summary", "evidence", "question", "deploy_commit", "blocker"],
     "additionalProperties": False,
 }
 
@@ -442,7 +442,8 @@ def check_task(config, api, task_id):
 
 
 def validate_result(value):
-    fields = set(RESULT_SCHEMA["required"])
+    # Strict output requires every property; retained old results may omit blocker.
+    fields = set(RESULT_SCHEMA["required"]) - {"blocker"}
     if not isinstance(value, dict) or set(value) - {"blocker"} not in (
         fields,
         fields - {"deploy_commit"},

scripts/codex_von_worker_prompt.md

@@ -76,7 +76,7 @@ include `blocker`: key (stable dependency name), kind (dependency or transient),
 owner, recovery, scope_json (JSON object of relevant revision/profile/scope),
 required_observations_json (JSON object of exact observations that demonstrate
 repair), and probe_key (null unless an applicable operator probe is supplied).
-Use null or omit blocker otherwise. Report observed facts, not an inferred ready
+Use null for blocker otherwise. Report observed facts, not an inferred ready
 flag; authentication/profile prerequisites must include their actual observations.
 The controller adds the task/actor/organisation and failed-attempt binding.
 Do not classify code you can safely repair as a controller dependency. Continue

tests/backend/test_codex_von_worker.py

@@ -18,6 +18,32 @@
 spec.loader.exec_module(worker)
 
 
+def test_result_schema_meets_strict_provider_contract_and_preserves_old_results():
+    # The provider rejects an object before execution if any declared property
+    # is absent from required, even when the property's value permits null.
+    def check_objects(schema):
+        if "properties" in schema:
+            assert set(schema["required"]) == set(schema["properties"])
+            assert schema["additionalProperties"] is False
+            for child in schema["properties"].values():
+                check_objects(child)
+
+    check_objects(worker.RESULT_SCHEMA)
+    legacy = {
+        "status": "completed",
+        "summary": "Done",
+        "evidence": "Verified",
+        "question": "",
+        "deploy_commit": "",
+    }
+    assert worker.validate_result(legacy) == legacy
+    current = dict(legacy, blocker=None)
+    assert worker.validate_result(current) == current
+    assert "null" in worker.RESULT_SCHEMA["properties"]["blocker"]["type"]
+    older = {key: value for key, value in legacy.items() if key != "deploy_commit"}
+    assert worker.validate_result(older) == older
+
+
 @pytest.fixture(autouse=True)
 def isolated_archive_boundary(monkeypatch):
     # Existing controller tests isolate publication; canonical archive capture