"anyOf": [
                    {
                        "type": "array",
                        "items": {
                            "type": "string",
                            "contentMediaType": "application/octet-stream",
                        },
                    },
                    {"type": "null"},
                ],
                "title": "P",
            }
        },

    assert app.openapi()["components"]["schemas"][body_model_name] == {
        "properties": {
            "p": {
                "anyOf": [
                    {"type": "string", "contentMediaType": "application/octet-stream"},
                    {"type": "null"},
                ],
                "title": "P",
            }
        },
        "title": body_model_name,
        "type": "object",
    }

        "properties": {
            "p": {
                "type": "array",
                "items": {
                    "type": "string",
                    "contentMediaType": "application/octet-stream",
                },
                "title": "P",
            },
        },
        "required": ["p"],
        "title": body_model_name,
        "type": "object",
    }

    assert app.openapi()["components"]["schemas"][body_model_name] == {
        "properties": {
            "p": {
                "title": "P",
                "type": "string",
                "contentMediaType": "application/octet-stream",
            },
        },
        "required": ["p"],
        "title": body_model_name,
        "type": "object",
    }


@pytest.mark.parametrize(
    "path",
    [

    @classmethod
    def __get_pydantic_json_schema__(
        cls, core_schema: Mapping[str, Any], handler: GetJsonSchemaHandler
    ) -> dict[str, Any]:
        return {"type": "string", "contentMediaType": "application/octet-stream"}

    @classmethod
    def __get_pydantic_core_schema__(
        cls, source: type[Any], handler: Callable[[Any], Mapping[str, Any]]
    ) -> Mapping[str, Any]:

                        )
                        item_schema["required"] = ["data"]
                        item_schema["properties"]["data"] = {
                            "type": "string",
                            "contentMediaType": "application/json",
                            "contentSchema": content_schema,
                        }
                    sse_content["itemSchema"] = item_schema

    # and dropping support for any version of Pydantic before that one (so, in a very long time)
    def bytes_schema(self, schema: CoreSchema) -> JsonSchemaValue:
        json_schema = {"type": "string", "contentMediaType": "application/octet-stream"}
        bytes_mode = (
            self._config.ser_json_bytes
            if self.mode == "serialization"
            else self._config.val_json_bytes
        )

    # A Vocabulary for the Contents of String-Encoded Data
    contentEncoding: str | None = None
    contentMediaType: str | None = None
    contentSchema: Optional["SchemaOrBool"] = None
    # Ref: JSON Schema Validation 2020-12: https://json-schema.org/draft/2020-12/json-schema-validation.html#name-a-vocabulary-for-basic-meta

## 0.129.1 (2026-02-21)

### Fixes

* ♻️ Fix JSON Schema for bytes, use `"contentMediaType": "application/octet-stream"` instead of `"format": "binary"`. PR [#14953](https://github.com/fastapi/fastapi/pull/14953) by [@tiangolo](https://github.com/tiangolo).

### Docs