You can declare additional validations and metadata for your parameters.

Generic validations and metadata:

* `alias`
* `title`
* `description`
* `deprecated`

Validations specific for strings:

* `min_length`
* `max_length`
* `pattern`

Custom validations using `AfterValidator`.

In these examples you saw how to declare validations for `str` values.

@app.get("/model-optional-validation-alias")
def read_model_optional_validation_alias(
    p: Annotated[CookieModelOptionalValidationAlias, Cookie()],
):
    return {"p": p.p}


@pytest.mark.parametrize(
    "path",
    ["/optional-validation-alias", "/model-optional-validation-alias"],
)
def test_optional_validation_alias_schema(path: str):

@app.get("/model-optional-list-validation-alias")
def read_model_optional_list_validation_alias(
    p: Annotated[HeaderModelOptionalListValidationAlias, Header()],
):
    return {"p": p.p}


@pytest.mark.parametrize(
    "path",
    ["/optional-list-validation-alias", "/model-optional-list-validation-alias"],
)
def test_optional_list_validation_alias_schema(path: str):

@app.get("/model-required-list-validation-alias")
async def read_model_required_list_validation_alias(
    p: Annotated[QueryModelRequiredListValidationAlias, Query()],
):
    return {"p": p.p}


@pytest.mark.parametrize(
    "path",
    ["/required-list-validation-alias", "/model-required-list-validation-alias"],
)
def test_required_list_validation_alias_schema(path: str):

                            "content": {"application/json": {"schema": {}}},
                        },
                        "422": {
                            "description": "Validation Error",
                            "content": {
                                "application/json": {
                                    "schema": {

    assert response.json() == {"file_size": 5}


# =====================================================================================
# Validation alias


@app.post(
    "/optional-bytes-validation-alias", operation_id="optional_bytes_validation_alias"
)
def read_optional_bytes_validation_alias(
    p: Annotated[Optional[bytes], File(validation_alias="p_val_alias")] = None,
):

@app.post(
    "/model-optional-validation-alias", operation_id="model_optional_validation_alias"
)
def read_model_optional_validation_alias(
    p: Annotated[FormModelOptionalValidationAlias, Form()],
):
    return {"p": p.p}


@pytest.mark.parametrize(
    "path",
    ["/optional-validation-alias", "/model-optional-validation-alias"],
)
def test_optional_validation_alias_schema(path: str):

@app.get("/model-optional-list-validation-alias")
def read_model_optional_list_validation_alias(
    p: Annotated[QueryModelOptionalListValidationAlias, Query()],
):
    return {"p": p.p}


@pytest.mark.parametrize(
    "path",
    ["/optional-list-validation-alias", "/model-optional-list-validation-alias"],
)
def test_optional_list_validation_alias_schema(path: str):

# Validation alias


@app.get("/required-validation-alias")
def read_required_validation_alias(
    p: Annotated[str, Query(validation_alias="p_val_alias")],
):
    return {"p": p}


class QueryModelRequiredValidationAlias(BaseModel):
    p: str = Field(validation_alias="p_val_alias")


@app.get("/model-required-validation-alias")

@app.post(
    "/model-required-validation-alias", operation_id="model_required_validation_alias"
)
def read_model_required_validation_alias(
    p: Annotated[FormModelRequiredValidationAlias, Form()],
):
    return {"p": p.p}


@pytest.mark.parametrize(
    "path",
    ["/required-validation-alias", "/model-required-validation-alias"],
)
def test_required_validation_alias_schema(path: str):