Multi-Seed Exploration
A single root seed reaches a particular region of the state space. No amount of continuation can explore regions that the root timeline’s early execution path never touches: if the first 100 RNG calls establish a specific dungeon layout or network topology, every recipe extension shares that foundation. Variations on a theme, not different themes.
The builder’s ordinary multi-seed loop provides the themes. Exploration makes each additional theme cheap.
Novelty Is Cumulative
The discovery latches in the shared assertion region — the CAS guards that make each discovery fire exactly once — are deliberately not reset between seeds, and neither is the sancov history map. Novelty is a property of the whole run, not of one seed:
- If seed 1 already discovered “key found L1”, seed 2’s timelines that find the same key journal nothing.
- If seed 1’s exploration drove the “dungeon level reached” watermark to 5, seed 2 only journals a discovery by beating 5.
- Assertion pass/fail counts also accumulate, so the final report and contract validation reflect every seed.
The consequence is a naturally progressive bar: each seed only earns exploration budget for behavior no earlier timeline exhibited.
Barren Seeds Die After One Run
max_runs_per_seed is a ceiling, not a quota. Each seed’s exploration starts from its root run’s journal; a root run that discovers nothing globally new produces no expansion, no exemplars, and therefore no continuations — the seed finishes after a single timeline:
━━━ Seeds ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
#1 seed=16797655684637781087 1,500 timelines ← did the deep work
#2 seed=6458319710110286448 1 timelines ← nothing new here
#3 seed=10665710964006250804 1 timelines ← nothing new here
This replaces the previous design’s warm-start heuristics (warm_min_timelines, coverage-yield ramp-downs): there is no machinery deciding how much to invest in an already-explored seed, because an unproductive seed simply generates no work. Under UntilCoverageStable, cheap barren seeds mean the run samples many more root themes per unit of wall-clock time while the plateau detector watches the same cumulative coverage signals as always.
The Complete Picture
The problem: bugs that require sequences of unlikely events are exponentially hard to find with random seeds.
The frontier controller: deterministic replay turns executions into recipes; discoveries (CAS-latched, exactly-once) turn productive runs into a small number of follow-up jobs; barren branches die. No energy accounting.
Bounded workers: fork() executes jobs cheaply via copy-on-write, but the process tree is never the exploration tree — one controller plus a fixed worker pool, on Linux and macOS alike.
Exemplars and continuations: a few retained recipes per semantic state, scheduled from the under-explored, depth-weighted frontier, keep converting run budget into deeper progress.
Multi-seed exploration: cumulative novelty makes extra seeds nearly free, so breadth across themes composes with depth within them.
The developer’s job is to write good assertions — they are simultaneously the correctness spec and the exploration map. The controller handles the rest, and every timeline it ever visits can be replayed from a one-line recipe.