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-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):

# 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):

@app.get("/model-required-list-validation-alias")
async def read_model_required_list_validation_alias(
    p: Annotated[HeaderModelRequiredListValidationAlias, Header()],
):
    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):

# Validation alias


@app.post("/list-bytes-validation-alias", operation_id="list_bytes_validation_alias")
def read_list_bytes_validation_alias(
    p: Annotated[list[bytes], File(validation_alias="p_val_alias")],
):
    return {"file_size": [len(file) for file in p]}


@app.post(
    "/list-uploadfile-validation-alias",
    operation_id="list_uploadfile_validation_alias",

# Validation alias


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


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


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

@app.post(
    "/model-optional-list-validation-alias",
    operation_id="model_optional_list_validation_alias",
)
def read_model_optional_list_validation_alias(
    p: BodyModelOptionalListValidationAlias,
):
    return {"p": p.p}


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

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


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

# Validation alias


@app.post("/optional-list-bytes-validation-alias")
def read_optional_list_bytes_validation_alias(
    p: Annotated[Optional[list[bytes]], File(validation_alias="p_val_alias")] = None,
):
    return {"file_size": [len(file) for file in p] if p else None}


@app.post("/optional-list-uploadfile-validation-alias")