Aex

Agent Executor. An open-source agent execution engine, and a hosted platform that runs it for you.

An aex session is a durable, resumable thread that a model drives with real tools — a shell, a filesystem, editors, web fetch and search, background commands, code execution, git, and subagents — inside an isolated runtime, with every event, file, and cost accounted for. It is the same problem AWS Bedrock AgentCore and Anthropic's managed agents solve, with the engine published under Apache 2.0 instead of held behind a service boundary.

npm version

Start

npm i @aexhq/sdk

Model access is managed: name a model by its creator/model gateway slug and the platform's key routes it. You supply no provider API key.

import { Aex } from "@aexhq/sdk";

const aex = new Aex(process.env.AEX_API_KEY!);
const session = await aex.sessions.create({
  model: "anthropic/claude-haiku-4-5"
});

const result = await session.messages.send(
  "Write a short report and save it as a file."
).finished();

console.log(result.status, result.text, result.checkpoint);

const resumed = await aex.sessions.open(session.id);
await resumed.messages.send("Validate the report.").finished();

Reusable inputs are published through aex.workspace.files, .skills, .tools, or .instructions, then submitted as version-pinned refs under assets. Session outputs are read through checkpoint-aware session.files.

The same thing from a terminal:

npx aex start \
  --api-key "$AEX_API_KEY" \
  --model anthropic/claude-haiku-4-5 \
  --prompt "Write a short report." \
  --follow

Open core, stated plainly

aex is open core. This repository is the open half, under Apache License 2.0:

• the public wire contracts, the TypeScript SDK, and the CLI — published today;
• the agent execution engine — the session loop, the builtin tool implementations, the runtime adapters, and the runtime-side protocol. These are being extracted from the private history package by package, with their commit lineage preserved; the packages table is the set that has landed so far.

The hosted half is a separate private repository: accounts, authentication, billing and pricing, scheduling, the storage and database schema, the dashboard, and the infrastructure definitions that run them.

Running the hosted plane yourself is out of scope for this repository. It ships no control plane, no infrastructure definitions, and no deployment path, and nothing in this documentation should be read as offering one. What Apache 2.0 gives you is the engine, its contracts, and the right to build on both.

If you are reading the engine source and hit a hostname that does not resolve — egress.internal, journal.internal, and four siblings — see references/internal-protocol.md. Those are virtual hosts terminated by the managed boundary, not missing services.

Packages

Package	What it is
@aexhq/sdk	The TypeScript SDK. Bundles the CLI as the aex binary.
@aexhq/cli	The CLI on its own, for callers that do not want the SDK.
@aexhq/contracts	Wire schemas, the event envelope, id formats, and the generated OpenAPI document.

Each is an independently versioned npm package with its own checks and its own canary. Promotion of a canary to the stable dist-tag is always a manual gate.

The engine packages are being extracted into this repository from the private history, package by package. Until that lands, this table is the whole published set.

Docs

• Quickstart
• Composition
• Events
• Files
• Model access
• Architecture — how the pieces fit, and where the boundary between this repository and the hosted plane falls.
• Glossary — brain, hands, plane, and the rest of the vocabulary the source uses without explaining.

The rendered documentation site is aex.dev/docs.

Examples

Runnable TypeScript, CLI, and skill projects live in the canonical aexhq/examples repository.

Contribute

• Contributor flow — including the deliberate asymmetry between contributor pull requests and maintainer pushes.
• Code of conduct
• Security disclosures
• Apache License 2.0 and third-party attribution