src/ix/genai/ollama_client.py

@@ -168,9 +168,7 @@ class OllamaClient:
             "model": request_kwargs.get("model"),
             "messages": messages,
             "stream": False,
-            "format": _sanitise_schema_for_ollama(
+            "format": response_schema.model_json_schema(),
-                response_schema.model_json_schema()
-            ),
         }
 
         options: dict[str, Any] = {}
@@ -202,52 +200,4 @@ class OllamaClient:
         return out
 
 
-def _sanitise_schema_for_ollama(schema: Any) -> Any:
-    """Strip null branches from ``anyOf`` unions.
-
-    Ollama 0.11.8's llama.cpp structured-output implementation segfaults on
-    Pydantic v2's standard Optional pattern::
-
-        {"anyOf": [{"type": "string"}, {"type": "null"}]}
-
-    We collapse any ``anyOf`` that includes a ``{"type": "null"}`` entry to
-    its non-null branch — single branch becomes that branch inline; multiple
-    branches keep the union without null. This only narrows what the LLM is
-    *told* it may emit; Pydantic still validates the real response and can
-    accept ``None`` at parse time if the field is ``Optional``.
-
-    Walk is recursive and structure-preserving. Other ``anyOf`` shapes (e.g.
-    polymorphic unions without null) are left alone.
-    """
-    if isinstance(schema, dict):
-        cleaned: dict[str, Any] = {}
-        for key, value in schema.items():
-            if key == "anyOf" and isinstance(value, list):
-                non_null = [
-                    _sanitise_schema_for_ollama(branch)
-                    for branch in value
-                    if not (isinstance(branch, dict) and branch.get("type") == "null")
-                ]
-                if len(non_null) == 1:
-                    # Inline the single remaining branch; merge its keys into the
-                    # parent so siblings like ``default``/``title`` are preserved.
-                    only = non_null[0]
-                    if isinstance(only, dict):
-                        for ok, ov in only.items():
-                            cleaned.setdefault(ok, ov)
-                    else:
-                        cleaned[key] = non_null
-                elif len(non_null) == 0:
-                    # Pathological: nothing left. Fall back to a permissive type.
-                    cleaned["type"] = "string"
-                else:
-                    cleaned[key] = non_null
-            else:
-                cleaned[key] = _sanitise_schema_for_ollama(value)
-        return cleaned
-    if isinstance(schema, list):
-        return [_sanitise_schema_for_ollama(item) for item in schema]
-    return schema
-
-
 __all__ = ["OllamaClient"]

tests/unit/test_ollama_client.py

@@ -79,13 +79,7 @@ class TestInvokeHappyPath:
         body_json = json.loads(body)
         assert body_json["model"] == "gpt-oss:20b"
         assert body_json["stream"] is False
-        # Format is the pydantic schema with Optional `anyOf [T, null]`
+        assert body_json["format"] == _Schema.model_json_schema()
-        # patterns collapsed to just T — Ollama 0.11.8 segfaults on the
-        # anyOf+null shape, so we sanitise before sending.
-        fmt = body_json["format"]
-        assert fmt["properties"]["bank_name"] == {"title": "Bank Name", "type": "string"}
-        assert fmt["properties"]["account_number"]["type"] == "string"
-        assert "anyOf" not in fmt["properties"]["account_number"]
         assert body_json["options"]["temperature"] == 0.2
         assert "reasoning_effort" not in body_json
         assert body_json["messages"] == [