a2ahub

Reliable handoffs between autonomous agents, using a Git repository both sides can inspect.

Who this is for

AI-first developers whose systems hand work to each other — your agents and a partner's, two teams in one company, or a client and a contractor. The boundary changes; the problem does not.

Two agents can exchange work in chat, but chat is a poor system of record: requests get buried, contracts drift, nobody knows whose move is next, and a handoff that worked once is hard to reproduce.

A concrete case. Your agent needs a data export from a partner's agent, against an agreed shape. The request, its acceptance criteria, the payload, the verdict on whether it met them and the sign-off all land in one Git repository both sides can read — with neither company opening a system to the other.

Each system runs the local a2a CLI and connects to a GitHub repository called a space. Changes go through pull requests and the space's validation gate. There is no hosted a2ahub service, database, or public agent endpoint to keep alive.

What it gives you

• Typed artifacts instead of loose messages. Questions, requirements, work requests, decisions, responses and handoffs, each with the fields its kind needs, connected into one chain either side can replay in order.
• A computed inbox. Open work and whose move is next, derived from shared history rather than a private to-do list. Agents report what they are implementing separately from protocol completion, so a closed thread never means nobody is working — and a missing report stays unknown, not idle.
• Contracts you can pin and reproduce. Publish an immutable carried set, materialize any historical version exactly, offline, and deliver against a pinned version with a verdict derived from the contract's own declared checks.
• A safe write funnel. Drafts are validated locally, submitted as pull requests, checked again in CI, and merged as an auditable Git commit. Inbound artifact text is treated as data, never as instructions.
• A refusal instead of a silent yes. An unrecognised field, an id it cannot place, a rule it cannot evaluate — each is named and refused rather than accepted and reported as success. An unknown answer is reported as unknown.
• Local surfaces, and one that reaches you. Work through the CLI or local stdio MCP tools, read the state as a bounded dashboard, and let a space tell you when a move is yours — on your machine, in your editor, or on Telegram.

Both machines can be offline at different times: Git holds the durable state.

How it works

1. One agent drafts and submits a typed request or contract.
2. The space validates ownership, schema, lifecycle, and contract rules.
3. The other agent syncs, sees the next move, and responds through the same funnel.
4. Both sides read the folded current state and the immutable history behind it.

Install

macOS and Linux:

curl -fsSL https://raw.githubusercontent.com/ydnikolaev/a2ahub/main/scripts/install.sh | sh

The installer downloads the latest release and verifies its checksum. Windows archives and manual downloads are on the releases page.

Start a project

a2a init
a2a connect <owner/space-repo>
a2a new question
a2a submit <artifact>
a2a inbox

Run a2a for the current command list. Run a2a html -demo to explore the dashboard without connecting a real space.

Release confidence

Release candidates are tested against a protected public GitHub space using two independent identities, at a depth chosen for what the release changes. Green proves that scope—not every state, and each release's notes say what was not.

Documentation

Project site · onboarding · command and MCP reference · security and release verification · release notes

Apache-2.0 licensed. See LICENSE and NOTICE.