Lynsea

Lynsea — a fixed-seed paired-counterfactual decision simulator. One hard decision, two side-by-side parallel futures. The problem: When people face a high-stakes life decision — take the higher-paying but high-stress job, end a relationship, move abroad — they have no fair way to compare the two futures. Existing "what-if" tools just generate two unrelated stories, so any difference is noise, not signal. What Lynsea does: You describe a decision, its two options, and the people it affects. Lynsea (1) builds digital-twin personas of you and your social circle from minimal input (Big Five traits inferred, never hand-entered); (2) runs a fixed-seed paired counterfactual — both branches share a byte-identical seeded backbone of exogenous life events (rent rises, a friend moves abroad, flu season), drawn with no LLM, so the only thing that differs between the two futures is the decision itself; and (3) streams back, in real time, two aligned month-by-month timelines, decision-specific metric curves (0–100), the branch points where the futures diverge with a cause chain, and a credibility card with a value-weighted recommendation. The differentiator is that the two branches are a controlled experiment, not two narratives — same seed → same world, personas forked from identical pre-decision state, and everything phrased as probabilities, never prophecy (high-risk outcomes surface a "this is a simulation, not a prophecy" banner plus a "how to change this outcome" hint). It degrades gracefully to deterministic stubs when the LLM is slow or unavailable, so it always runs end-to-end.