AWS launches public-domain emulator built by agents, company says

AWS launched AWS Emulator on 11 November, releasing a tool that simulates its cloud services on a developer’s own computer. AWS says superintelligence (SI) agents built the emulator and will maintain it, while human engineers improve the system directing them.

The tool is available under Creative Commons Zero (CC0), a public-domain dedication that lets people use and change the code freely. AWS was unsure whether it could copyright agent-generated work and did not want to assert copyright where none might exist, The New Stack said.

Tom “Spot” Callaway, an AWS principal open source software strategist, said earlier emulators could become outdated quickly and were not always trusted, even inside AWS. The team also saw the emulator as a bounded project with clear goals and testable results for experimenting with agent-built software. The company also wanted coding agents to test against simulated services without giving them AWS credentials.

What developers can test

AWS says the emulator reproduces service APIs—the interfaces applications use to communicate with services—locally and exposes a local HTTP endpoint accessible to the AWS command-line interface, software development kits and coding agents, so developers can test AWS-dependent applications without setting up paid cloud infrastructure. It supports 438 public AWS API models covering more than 200 services, though that coverage does not mean every operation behaves identically to the real service.

It runs on Linux, macOS and Windows without an AWS account or network connection. The emulator is free to download, its source code is on GitHub, and AWS is publishing its testing benchmark so others can run it themselves.

Callaway said the tool was built to test coverage; its simulation of service functions has limits, including the lack of an actual database to return results from a database query. Broadcom senior site reliability engineer Advait Patel said local tests can speed up coding feedback, but passing them does not guarantee the same behavior on AWS; applications still need testing against the real cloud before deployment.

IDC research director Devin Pratt said the emulator does not simulate outages, limits on request rates, snapshots and restoration, or availability by region. Patel warned that tests without a 429 error or timeout leave retry and backoff logic untested. Pratt also warned that it does not isolate the code it executes: a locally tested function given real production credentials could still access actual AWS resources.

How AWS says agents maintain the code

AWS says it assigns the work to three agent teams. One creates test scenarios from public Smithy API models and runs them against real AWS services. A second runs those scenarios against the emulator, investigates differences and files issues; a third changes the code to address them.

Before changes can be merged, they must pass build and test checks and reviews by other agents for security, coding standards and behavioral regressions. Callaway said human engineers handle problems by improving the agents, leaving emulator code changes to the agents.

The same division applies to outside contributors: AWS will accept issue reports and test scenarios, but not pull requests, the proposed code changes contributors normally submit for review.

The project began as an experiment by Matt Goldberg, a senior principal engineer on AWS’s Developer Tools team. He said he asked AWS coding tool Kiro to build an emulator for Amazon Simple Queue Service; a first version arrived in 15 minutes. A broader version followed over a weekend, and his team began testing it the following Monday, although it had gaps.

Callaway expects support for newly launched AWS services within days, though the team has yet to see how that works with the project public. AWS plans to share more at its re:Invent conference, which starts Nov. 30.