fusioncoding.ai

build · for new features

Your next feature should have to win.

Fusion Build runs the same brief across rival agents. Your tests filter the broken, blind judges rank the survivors, and fresh QA checks the final before you ever see the pull request.

get early accessthe full pipeline

01 / the single-draw problem

One fluent answer is still one draw.

Every prompt is a pull of the lever. The answer arrives confident, polished, and statistically alone. Fusion replaces the gamble with a field of rivals and an objective finish line.

draw one · same prompt0.82s
export async function retryCheckout(order) {  const key = idempotencyKey(order)  for (let i = 0; i < MAX_RETRIES; i++) {    const res = await charge(order, key)    if (res.ok) return res  }}
fluent · confidentgate: pass
draw two · same prompt0.79s
export async function retryCheckout(order) {  for (let i = 0; i < MAX_RETRIES; i++) {    const res = await charge(order)    if (res.ok) return res  }}// no idempotency key: double-charge on retry
fluent · confidentgate: fail · double-submit

You watched the bad draws lose. That is different from hoping the first draw was good.

02 / the roster

Bring the agents you already pay for.

Fusion doesn’t replace your coding agents. It arranges them. Every candidate slot is an engine you choose, and more land as adapters ship.

claude codecodexgeminicursoropencode+ adapters landing

03 / the contract

The target is frozen before the race.

Every run opens by turning intent into a Definition of Good: three to seven criteria, each one provable. Candidates build against it. Judges score against it. Billing honors it: if the run doesn’t meet it, you don’t pay.

definition of goodrun #0047 · frozen
  1. retries capped at 3 attempts
  2. idempotent under double-submit
  3. 34/34 protected tests green
  4. no new dependencies
  5. p95 latency unchanged

04 / the integration

Losers still contribute. Winners get better.

After the jury ranks the survivors, an Integrator builds the final: the winning candidate as the base, plus the strongest grafts from the rest. Then the whole thing is re-verified. When someone asks where the code came from, you have an answer.

basewinning implementationfrom candidate a
graftcleaner error taxonomyfrom candidate c
graftproperty test for double-submitfrom candidate c
re-verifyfull gate re-run on the finalpass · 34/34

05 / the handoff

You stay the owner.

Fusion opens the pull request with the receipt attached: the votes, the dissent, the provenance of every line. It opens the door and steps back. You decide what gets merged.

fusion buildrun #0047
$ fusion build "checkout retry logic"→ 3 candidates rostered · worktrees created✓ gate: 2 of 3 candidates survive→ blind jury convened · reasons before verdicts✓ verdict: A wins 2–1 · dissent recorded→ integrator: A + graft(C) · re-verified→ PR #482 opened · receipt attached

Make your next feature earn the branch.

Describe the task. Watch rivals fight for the merge.

get early accessalso: fusion review