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Module: mellea.stdlib.requirement

Requirements are a special type of Component used as input to the “validate” step in Instruct/Validate/Repair design patterns.

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Functions

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mellea.stdlib.requirement.default_output_to_bool(x: CBlock | str)

Checks if a given output should be marked converted to True. Checks if the output is exactly equal to “yes” or “y” (case-insensitive). If not, it will also check if any of the words in the output are “yes” (case-insensitive).

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mellea.stdlib.requirement.reqify(r: str | Requirement)

Maps strings to Requirements. This is a utility method for functions that allow you to pass in Requirements as either explicit Requirement objects or strings that you intend to be interpreted as requirements.

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mellea.stdlib.requirement.req(*args, **kwargs)

Shorthand for Requirement.init.

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mellea.stdlib.requirement.check(*args, **kwargs)

Shorthand for Requirement.init(…, check_only=True).

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mellea.stdlib.requirement.simple_validate(fn: Callable[[str], bool])

Syntactic sugar for writing validation functions that only operate over the last output from the model (interpreted as a string). This is useful when your validation logic only depends upon the most recent model output. For example: Requirement("Answer 'yes' or 'no'", simple_validate(lambda x: x == 'yes' or x == 'no') Validation functions operate over Context. Often you do not care about the entire context, and just want to consider the most recent output from the model. Important notes:
  • this operates over the more recent model output, not the most recent message.
  • Model outputs are sometimes parsed into more complex types (eg by a Formatter.parse call or an OutputProcessor). This validation logic will interpret the most recent output as a string, regardless of whether it has a more complex parsed representation.

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Classes

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class mellea.stdlib.requirement.Requirement(description: str | None = None, validation_fn: Callable[[Context], Any] | None = None, output_to_bool: Callable[[CBlock | str], bool] | None = default_output_to_bool, check_only: bool = False)

Requirements are a special type of Component used as input to the Validate step in Instruct/Validate/Repair patterns.

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Constructor

A Requirement, interpreted over a Context. By default, requirements are validated by the model using LLM-as-a-Judge (or a constraint LoRA when available). However, you can also provide a validate function with arbitrary behavior.

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Arguments

  • description: A natural-language description of the requirement. This will sometimes be included in Instruction prompts; if you do not want the requirement to be included in the prompt to avoid [Purple Elephant Effects](https: //$/llm-requirement-engineering-and-purple-elephants/) use check_only=True.
  • validation_fn: If provided, this function will be executed instead of using LLM-as-a-Judge. The bool() for the function’s output defines whether the requirement passes.
  • output_to_bool: An output_to_bool may be provided so that the library can translate the LLM-as-a-judge or ALora output into a boolean value. If none is provided, we will look for ‘yes’ (case-insensitive) in the LLMaJ output.
  • check_only: If set, then Instruction will not include this requirement in its prompt.

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Methods

mellea.stdlib.requirement.Requirement.validate(backend: Backend, ctx: Context, format: type[BaseModelSubclass] | None = None, model_options: dict | None = None, generate_logs: list[GenerateLog] | None = None)
Chooses the appropriate validation strategy and applies that strategy.
mellea.stdlib.requirement.Requirement.parts()
Returns all of the constituent parts of a Requirement.
mellea.stdlib.requirement.Requirement.format_for_llm()
Some object protocol magic happens here with management of the output.

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class mellea.stdlib.requirement.LLMaJRequirement()

A requirement that always uses LLM-as-a-Judge. Any available constraint ALoRA will be ignored.

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class mellea.stdlib.requirement.ALoraRequirement(description: str, alora: Alora | None = None)

A requirement that always uses an (possibly specified) ALora. If an exception is thrown during the ALora execution path, mellea will fall back to LLMaJ. But that is the only case where LLMaJ will be used.

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Constructor

A requirement that is validated by an ALora.

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Arguments

  • description: See Requirement.__init__
  • alora: if None, the ALora with name “constraint” will be used.