Tuning & environment knobs

ferroplan's defaults are chosen so that a plain ff -o domain -f problem is the measured-best path — you should rarely need any of these. When you do, every knob is an environment variable, read at solve time. Reads are panic-free on wasm32; the boolean features additionally have in-process overrides in ferroplan::features (set_overrides, set_escalate_override, set_espc_override) for WASM/embedded callers, where std::env::set_var panics.

Almost every knob is a restore hatch: it exists to reproduce an earlier behavior or to run an experiment, and the default is the recommended setting. All results are deterministic and thread-count independent.

Temporal

var	default	effect
`FF_TDEMAND`	numeric-only	force the Full demand tier (also seed demand from predicate-goal thresholds) first, for conjunctive/structural builds.
`FF_NO_TDEMAND`	—	master switch to the pristine pre-v0.2 path: no demand guidance, no relevance pruning, no escalation.
`FF_NOREL`	—	disable goal-relevance pruning alone (keep demand guidance).
`FF_NO_ESCALATE`	ladder on	disable the on-failure escalation ladder (retry Full tier, then decomposer). Only affects would-be failures.
`FF_TDECOMP`	off	route the temporal path through the partition-and-resolve decomposer first (the `decompose` API always does, regardless).
`FF_TCONC`	off	run the concurrent scheduling phase — repack a plan onto actor objects to minimize makespan.
`FF_TDEMAND_W`	`3`	weight of the temporal demand seed.

PDDL3 preference optimizer

The default path is the exact-closure metric optimizer; these restore its predecessor pieces or tune its budget.

var	default	effect
`FF_PREF_EVAL_BUDGET`	`2000000`	deterministic per-solve eval budget — the real quality dial. Higher = more optimization time on hard instances.
`FF_PREF_NO_ESCALATE`	escalate	disable the budget-escalating retry (abandon a probe on its first capped iteration).
`FF_PREF_GREEDY`	anytime	restore first-improvement sweeps: return at the first plan under the bound and restart, instead of tightening the bound in place and draining the sweep.
`FF_PREF_NO_RESTARTS`	ladder on	disable the diversified restart ladder (rotated open-list weight profiles on a capped no-improvement sweep) — the lever behind the storage p06/p07 and pathways p05 wins.
`FF_PREF_SEED`	off	experimental: forgo-aware second seed — price each preference's completion with a cost-aware relaxed plan and pre-forgo those priced over their weight. Measured neutral on rovers (the EHC seed already lands there).
`FF_PREF_SEED3`	off	experimental: partitioned closure seed — compose a per-preference-component incumbent (mutex-conflict-pruned, sibling-protected stages) before the tightening loop. Composes genuinely (tpp p05: 99 vs the 105 init-tail) but measured neutral on finals: the anytime+ladder loop reaches the same metric from either bound.
`FF_PREF_NO_SELECT`	select on	disable the 0.6 selection layer (exact preference-subset selection solved combinatorially, then planned as a hard-goal target; `docs/forensics-tpp.md`). Selection is what ties SGPlan5 on tpp p06 and widened the rovers totals lead; its bounded seed runs outside the tightening budget.
`FF_PREF_NO_STATIC`	simplify	disable static preference simplification at compile (keep statically-satisfied instances).
`FF_PREF_NO_BARRIER`	barrier on	exclude init-satisfied preferences from the guidance (the 0.4–0.5.0 behavior). Keeping them (the 0.5.1 default) protects high-weight trap preferences — the storage 8/8 sweep — see `docs/forensics-tpp.md`. `FF_PREF_BARRIER` is accepted, now redundant.
`FF_PREF_COMPILED`	closure	route through the legacy compiled-goal B&B instead of the exact-closure optimizer.
`FF_PREF_NUMLEGACY`	closure	folded numeric metrics only (rovers-shaped): restore the pre-0.5 routing to the legacy B&B. The closure path now dominates it (rovers flipped to a domain lead).
`FF_PREF_COST_WEIGHT`	domain-dependent	cost-aware open-list weight (`SearchCfg::w_c`). Experimental — a measured dead end on rovers; default 0 there.
`FF_RES_WEIGHT` / `FF_RES_THRESH`	tuned / `0`	satisfaction-guidance resource penalty weight / threshold.
`FF_DEADLINE_WEIGHT`	`0`	extra penalty on deadline-pair triggers in satisfaction guidance.
`FF_RES_DEBUG`	—	print resource/preference simplification diagnostics.

ESPC penalty loop (default-on where it bites)

The extended-saddle-point penalty loop for resource-coupled preference domains (openstacks-shaped). On by default since 0.5, with a deterministic evaluated-state budget; it engages only when the compiled task carries once-only conditional-achievement deadline pairs — on every other task it is a verified no-op.

var	default	effect
`FF_NO_ESPC`	espc on	opt out — restore the closure-optimizer-only default path.
`FF_ESPC_EVAL_BUDGET`	`6000000`	deterministic eval pool for the loop (λ iterations + polish) — the primary budget contract, thread-count independent.
`FF_ESPC_TIME_MS`	unset	optional additional wall-clock cap for interactive use. Applies only when set; setting it trades determinism for latency.
`FF_ESPC_MONO`	partitioned	reproduce the earlier monolithic (pre-0.4.0) loop.
`FF_ESPC`	—	accepted for compatibility (pre-0.5 opt-in); redundant now.

Advanced ESPC schedule tuning (rarely needed): FF_ESPC_OUTER (outer iterations), FF_ESPC_RATE (initial penalty rate, 20), FF_ESPC_K (consecutive-violation rate bump, 2), FF_ESPC_LAMBDA0 (initial λ, 0), FF_ESPC_STALL (stall limit before termination, 4).

PDDL3 trajectory constraints

var	default	effect
`FF_CONSTRAINTS_REJECT`	enforce	restore the 0.4.1–0.6 blanket rejection of every `(:constraints ...)` block, instead of compiling the untimed operators into enforced monitor automata (0.7) — hard constraints as goal conjuncts, soft `(preference ...)` constraints priced through the PDDL3 metric machinery. The hatch restores rejection, not ignoring — no setting makes ferroplan silently drop a constraint.

Reproducing a specific benchmark

The IPC-5 scoreboard records the exact env for each domain — e.g. openstacks's domain lead is FF_ESPC=1 FF_ESPC_TIME_MS=90000.