SudoCode is the declarative, constraint-first dialect of structured prompting in the PseudoLang family. Where PseudoScript reads as a procedure — numbered steps the model walks through — SudoCode leans toward stating what must be true: the constraints, the contract, the shape of a valid result, and letting the model find the path. Both are the same core bet: a structured notation the model can follow beats an ambiguous paragraph.
Why structure beats prose
That bet is now well-supported. Prompting with Pseudo-Code Instructions (Mishra et al.) showed pseudo-code prompts beating natural-language prompts across 132 tasks, because the structure removes the ambiguity prose carries by default. Code Prompting Elicits Conditional Reasoning found the mechanism in improved variable-state tracking — the model holds the moving parts of a problem more reliably when they are named and structured. Declaring constraints explicitly is a clean way to get that benefit when the task is defined more by its rules than by a fixed sequence of steps.
A declarative example
GOAL: produce an invoice-line decision for {line_item}.
CONSTRAINTS:
- decision in {approve, hold, reject}
- reject IF amount > contract.cap OR vendor not in approved_list
- hold IF missing(po_number) OR missing(receipt)
- approve OTHERWISE
- every decision MUST cite the constraint that determined it
RETURN: {decision, citing_constraint, amount}
Nothing here dictates an order of operations; it states the conditions for a valid answer and requires the model to justify which one fired. That justification requirement is what makes a declarative prompt auditable.
Keep it real, not decorative
The same honesty test applies as for all structured notation: the constraints have to be ones the model actually evaluates and a human can maintain. Declaring a tidy-looking rule the model cannot check, or wrapping the whole thing in ceremonial syntax, adds nothing. State constraints the model can act on, require it to cite the one it used, and SudoCode gives you a precise, reviewable way to specify intent — particularly for the rule-heavy tasks where a step-by-step procedure would be the wrong shape.
