A flight simulator for agent failures

Your agent failed.Which decision actually mattered?

WorldLine forks a failed multi-agent run at the decision that caused it, re-simulates the future live, proves the repair — then files it as fleet memory so the same failure never ships twice. Tracing shows what happened; WorldLine makes your agents stop repeating it.

The problem

Multi-agent failures aren't reproducible — and you can't tell which decision caused them.

The same input yields different paths, so failures are hard to reproduce and harder to attribute. When a 7-step agent pipeline returns the wrong answer, which decision broke it? Today you read traces and guess. Replay and forking exist — but you still pick the checkpoint, and nothing proves the fix.

See it think

Watch Claude debug a failed agent run — live.

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Institutional memory

The same mistake never ships twice.

Every intervention-tested fix becomes a durable lesson your whole fleet inherits. When any agent — even a different one — is about to repeat a known failure class, WorldLine catches it from memory and applies the verified fix before it ships. Observability shows what happened; this makes your agents get more reliable over time.

The reliability lifecycle

Detect → repair → remember → prevent.

01
Detect

A multi-agent run returns the wrong outcome. WorldLine treats the failure as a signal, not a dead end.

02
Attribute

Claude intervention-tests every decision in parallel — only the one whose correction flips the outcome is the culprit, even when last-touch blame points elsewhere.

03
Repair

Claude (effort=max) explains the root cause and rewrites the offending prompt or policy.

04
Verify

The full workflow re-runs with the patch; a code assertion proves the outcome flipped.

05
Remember

The verified fix becomes a durable lesson in fleet memory — failure class, root cause, proof, and the agents it protects.

06
Prevent

Any agent — even a different one — about to repeat that failure class is caught from memory and fixed before it ships.

Existing tools vs WorldLine

Replay and forking exist. We build the loop on top.

Only WorldLine
  • Auto-finds the culprit decision
  • Authors the repair
  • Verifies the repair flips the outcome
Tracing · Replay · Forking

Show, repeat, or explore one alternate path — but you still pick the checkpoint, and nothing proves the fix.

LangGraph time-travel (updateState+ resume) and AgentOps already support replay and forking from checkpoints — we don't claim otherwise. WorldLine's wedge is the autonomous loop on top: intervention-tested attribution → repair → verification.

Not a movie

Everything you saw runs live on Opus 4.8.

Hit re-run and the whole loop — audit, fork, repair, verify — recomputes on the deployed backend.

View the code