Let me start with an example, a very standard CRUD API:

@strawberry.type
class User
  name: str
  birthday: date
  ...
  @strawberry.field
  async def something(self) -> Something

@strawberry.input
class UserInput
  name: str = UNSET
  birthday: date = UNSET
  ...

@strawberry.type
class Query:
  @strawberry.field
  get_user(id: ID) -> User:
    ...

@strawberry.type
class Mutation:
  @strawberry.mutation
  create_user(user: UserInput) -> User:
    ...
  @strawberry.mutation
  update_user(id: ID, user: UserInput) -> User:
    ..

The types User and UserInput are essentially the same thing all over again -- Except the inputs don't have resolvers
Keeping the fields and docs in sync is just boring repetitive work.

Suggestion 1

Would be great if we could reuse the same type declaration in our arguments, and strawberry would just create an input type in the schema under the hood containing only the dataclass fields

@strawberry.type
class Mutation:
  @strawberry.mutation
  create_user(user: User) -> User:
    ...
---
type Mutation {
  createUser(user: UserInput!): User!
}

GraphQL-Kotlin does that

IMHO this is a simple and reasonable approach

Suggestion 2

Another suggestion is to keep the Main/Input types distinct, but generate the Type.Input automatically:

• The python class for the input would be added as a nested class User.Input
• dataclass-style fields would be kept by default
• resolver fields are discarded by default
• default values would be set to UNSET or removed entirely
• If the field type if a graphQL SomeTime, it gets replaced by SomeTypeInput
• These option could be overriden using strawberry.field()

strawberry.field(
  input_options=InputFieldOptions(
    keep=True,  # Keep/discard this field in the Input type,
    type=DataType,  # Modify the field type. e.g., a NestedObject-type field might be replaced by an ID in an input
    default=DataType()  # Uses this as the default value
    default_factory=lambda: DataType()  # Uses this as the factory
    description="Same field, now in an input"
  )
)

This would look like this:

@strawberry.type
class Mutation:
  @strawberry.mutation
  create_user(user: User.Input) -> User:
    ...