Update httpx2 and datamodel-code-generator (#3645)

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Marcelo Trylesinski <marcelotryle@gmail.com>

Author: dependabot[bot]

pyproject.toml

@@ -111,7 +111,7 @@ docs = [
 # of the default groups so no other environment installs the client (or the
 # legacy httpx it depends on). See i18n/README.md.
 translate = ["anthropic>=0.121.0"]
-codegen = ["datamodel-code-generator==0.57.0"]
+codegen = ["datamodel-code-generator==0.81.0"]
 
 [build-system]
 requires = ["hatchling", "uv-dynamic-versioning"]

scripts/gen_surface_types.py

@@ -195,6 +195,7 @@ def run_codegen(schema_path: Path, output_path: Path) -> None:
             "--snake-case-field", "--remove-special-field-name-prefix",
             "--use-annotated", "--use-field-description", "--use-schema-description",
             "--enum-field-as-literal", "all",
+            "--default-values", '{"ElicitRequestFormParams.mode": "form"}',
             "--use-union-operator", "--use-double-quotes",
             "--use-type-alias", "--skip-root-model",
             "--extra-fields", "ignore",
@@ -252,6 +253,9 @@ def build(entry: dict[str, str]) -> str:
         source = raw.read_text(encoding="utf-8")
 
     source = re.sub(r"\A# generated by datamodel-codegen:\n#[^\n]*\n", "", source)
+    # Explicit __annotations__ hides declared fields under Python 3.14's deferred annotations.
+    source = source.replace('    __annotations__ = {\n        "__pydantic_extra__": Dict[str, Any],\n    }\n', "")
+    source = source.replace(", Dict,", ",")
     # Keep named aliases only for recursive types; other aliases remain ordinary Python types and unions.
     for node in reversed(ast.parse(source).body):
         if not (

tests/types/test_methods.py

@@ -960,6 +960,19 @@ def test_serialize_server_result_preserves_open_type_extras():
     assert sieved["tools"][0]["_meta"] == nested_meta
 
 
+@pytest.mark.parametrize("input_schema", [{}, {"type": "array"}])
+def test_serialize_server_result_rejects_invalid_tool_input_schema(input_schema: dict[str, Any]) -> None:
+    """The 2026 spec requires a tool's input schema to declare `type="object"`, even though it allows extra keys."""
+    result = {
+        "tools": [{"name": "echo", "inputSchema": input_schema}],
+        "resultType": "complete",
+        "ttlMs": 0,
+        "cacheScope": "private",
+    }
+    with pytest.raises(pydantic.ValidationError):
+        methods.serialize_server_result("tools/list", "2026-07-28", result)
+
+
 def test_serialize_server_result_drops_top_level_server_info_on_discover_but_keeps_the_meta_stamp():
     """Server identity moved from the discover body to result `_meta` (spec PR #3002):
     the sieve drops the removed body key and preserves the `_meta` stamp."""