AI AGENT TEST ENVIRONMENT

The frontier of agent verification.

Transcripts are stories. Worlds reads the database. Run your agent against a sealed twin of the systems it touches and get exact, replayable proof of what it did.

● BACKED BY A16Z

ALSO IN THE CATALOG

A RUN, STEP BY STEP

Watch an agent work. Then grade what it did, not what it said.

Worlds grades the state of the system after the run, not the transcript: what changed, what should have, and the dollars wrong per run. Every run replays to the byte.

AGENT

FAILURES INJECTED

WHAT THE AGENT SAID

WHAT THE WORLD RECORDED

STRIPE · 1,000 RUNS · EVERY RUN REPLAYS

SEE THE PUBLISHED RUN

The Stripe session comes from a real, published run. The Okta, Salesforce and Guidewire sessions are illustrations, not recorded runs, and are labeled as such.

ACROSS 1,000 RUNS

ACTION ACCURACY 3.6%

ACTIONS OUTSIDE THE TASK 2

DROP UNDER FAILURES N/A

WHAT YOU CAN DO

Six things teams do with a world.

Create it
A world starts from a seed: the bundled sample account, or a pseudonymized copy of your own. It is ready in milliseconds and identical every time.
Mark it
A mark records the world's state at that moment. Every diff is measured from a mark, so what your agent did is never mixed up with what was already there.
Let the agent act
Point your agent's stock SDK at the world and hand it a ticket. Same URLs, same errors, same state machine. No code changes.
Read the diff
See what changed since the mark: every refund, credit and cancellation, in dollars, and whose money moved. Replay any run byte for byte.
Break it
Inject rate limits, 500s, lock timeouts, slow responses, an expired key and dropped webhooks. Find out whether your retry logic refunds twice.
Move its clock
Advance 45 days and let renewals bill, prorations settle, cancellations resolve and webhooks fire in order. Then read the diff again.

HOW THIS IS DIFFERENT

How Worlds fits with the tools you already use.

Most teams already have an eval platform, a mock, or a sandbox. Here is where each one stops.

EVAL PLATFORMS

Braintrust, Langfuse and Arize grade what the agent said, from its traces. Worlds supplies the system the agent acts on and the record of what it did there. Keep your traces; add the environment and the verdict.

MOCKS AND SANDBOXES

Vendor test modes keep no state, cannot be reset, and have no clock and no failure modes. Hosted sandboxes bill per run and expire by the hour. A world keeps state, resets in milliseconds, and runs on your machine.

CONVERSATION SIMULATORS

Coval and Hamming simulate the customer talking to your agent. Worlds simulates the systems your agent acts on. The other half of the problem.

SEE THE FULL COMPARISON

THE CATALOG

A world for every system your agent uses.

Each one is built to be reset, seeded and broken on purpose, and runs beside your agent, not inside it. When your agent says a task is done, Worlds diffs the environment and tells you what really changed.

● EVERY WORLD CAN SHIP. TELL US WHICH ONE YOU NEED.

BROWSE THE CATALOG

world

A working copy of a system your agent acts on. Same endpoints, same errors, same state machine. No real money and no real customers.