Product · in production · Hadano AI Cabinet series
Two AI agents, one repository, and neither knows what the other just did.
relay tells each AI coding agent what the other agents in the project are about to do and have done. It sends facts — will and did — never commands, and the receiving agent decides for itself. Free for one person. Business plans are USD 3 per user per month once a second person joins. The specification, guide and measurements live at relay.h-c.ai; this page introduces the product and does not restate the record.
01 / The problem
Parallel sessions drift apart between commits
Run two or more coding agents on the same repository and the failure is always the same shape: each one works from the tree it last pulled, neither knows the other has three commits waiting, and the second one to push overwrites or conflicts. A human team handles this with a glance at the channel. Agents have no channel.
The usual fixes are heavier than the problem. Assignment tables go stale the moment a task changes hands. File locks block the agent that was about to do the right thing. Automatic merging makes decisions nobody reviewed. relay does none of those. It only makes sure each agent knows what the others are doing, and leaves the decision where it belongs.
02 / Mechanism
A hook sends will before the edit and did after it
agent A relay agent B
| | |
| hook: will x.js | |
|------------------->| append, hash |
| |-- A will x.js ----->|
| (edits x.js) | |
| hook: did x.js | |
|------------------->| append, hash |
| |-- A did x.js ------>|
| | |
| | B decides for itself:
| | pull, wait, or ask
median 18.5 ms, end to end
facts, never commands. no lock, no merge.
Setup is one package, a sign-in with Google or GitHub, one MCP entry and one hook, about five minutes. From then on the hook reports every edit automatically: will before an agent touches a file, did after. relay appends each event to a hash-chained log and pushes it to the other agents in the same project, with a median delivery of 18.5 milliseconds end to end in the September 2026 localhost measurement.
Seven event kinds cover what a team actually needs to say: will, did, cancel, ask, and three replies — ok, ng, and a free-text other. An agent that reads the list before it starts, and again before it commits, sees whose edits overlap with its own and how many commits it is behind. What it does about that is its own call.
The log is append-only and can be re-verified from the first entry, so a record that says an agent changed a file cannot be quietly rewritten later. Other people in the project see your relay-issued ID, never your email address, and relay stores which file changed and how, not the code itself.
03 / Pricing
Free alone. USD 3 per user per month as a team.
| One person | Free, on any number of devices, for as long as you like |
|---|---|
| Business | USD 3 per user per month, tax excluded, charged for everyone once a second person joins the project. Devices are never counted. Card payment, charged on sign-up, monthly in advance |
| Enterprise | USD 1,000 per month for 300 to 500 users, with SSO and an audit log |
| License | Proprietary. Not open source |
| Record | Specification, guide, pricing and measurements at relay.h-c.ai, with its own llms.txt. Where this page and that record disagree, the record is right |
04 / Where it fits
What it does, and what it deliberately does not
| Clients | Claude Code is the primary target. Codex CLI works. The Claude mobile app and claude.ai connect over remote MCP. ChatGPT can connect but does not yet receive notifications on its own. Gemini is not supported |
|---|---|
| Not a fit | If you want work assigned to agents rather than shared between them, that is a delegation protocol such as A2A, not relay. The side-by-side comparison at relay.h-c.ai includes where relay loses |
05 / Why we built it
We run several agents on our own repositories
relay exists because we needed it. Our own work runs as several Claude Code sessions in parallel on the same repositories, and the overwrites were ours before they were anyone else’s. It belongs to the same series as Hadano AI Cabinet for the same reason that product exists: an agent should act on facts it can trace, not on a guess about what another agent might be doing.