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Module budget

sublinear_solver

Module budget 

Source
Expand description

PlanBudget — cumulative complexity-class + operation-count accumulator for chained solves.

ADR-001 roadmap item #4’s phase-2 MCP gate refuses one solve that exceeds the caller’s max_complexity_class. That’s necessary but not sufficient: an agent that issues 10 000 SubLinear solves in a tight loop can still blow a real-world J/decision budget without ever tripping a single per-call gate.

This module closes the gap with a budget accumulator that lives across the chain. Callers try_consume(class) once per solve; the budget refuses the call if either:

  1. class exceeds max_class (per-call class gate, same semantics as the existing MCP enforceComplexityBudget), or
  2. the remaining operation count has dropped to zero.

The “operation count” abstraction is number of solves, not number of inner-loop iterations — the unit a budget-aware agent actually reasons about. A 100-event reflex loop with a 100-op budget runs to completion; a 10 000-event one trips the budget at iteration 100 and short-circuits gracefully.

§Composition

Pair this with the per-call class gate that’s already wired into the MCP solve handlers. The MCP layer enforces budget per call; PlanBudget enforces budget per plan.

§Why not Rc<RefCell<...>>?

The accumulator is intentionally &mut self — borrow-checker catches accidental shared mutation. Callers running planners on multiple threads should Arc<Mutex<PlanBudget>> or partition the budget per worker. The single-threaded planning case (the common one) stays zero-cost.

Structs§

PlanBudget
Cumulative budget for a chain of solves.

Enums§

BudgetExhausted
Reason a try_consume was rejected.