Point two agents at the same repo and they collide — one overwrites the other, and both waste time redoing the same work.
Run Claude, Codex, and any agent on one repo — without the collisions.
A repo-local room every agent reads and writes, so they announce what they're touching, split the work by strength, and run in parallel instead of overwriting each other.
cargo install --path crates/rally-cli Rust 1.85+ · Apache-2.0 · any agent, any host · no server
Product walkthroughs
See it at work
Claude and Codex in the same room
Rally isn't tied to one tool. Claude Code, Codex, or any coding agent joins the same repo-local room and reads the same facts — so different agents actually coordinate instead of working blind to each other.
Two agents never touch the same file at once
A `check before-write` step confirms no peer holds a claim on the file you're about to edit. No overwritten commits, no deleted work, no two agents quietly fighting over the same file.
Hand off by lane, play to strengths
Agents claim lanes and hand off by fact. Give the hard refactor to one, the tests to another, and let them run at the same time — each doing what it's best at, all coordinated through the room.
Parallel speed that still leaves a trail
Facts are an append-only ledger; room state is derived from it. Every claim, handoff, and decision is replayable — so working in parallel never costs you the record of who did what, or the ability to rebuild the room from disk.
- Works with any agent or host — not locked to one vendor
- No server, no network — state lives in the repo
- Tolerates agents that crash mid-write — quarantines and rebuilds on corruption
Does it only work with Claude Code?
No — any coding agent or host can join. Claude Code and Codex get auto-coordination hooks out of the box (SessionStart + PreToolUse from a fresh clone); anything else reads and writes the same room through the `rally` CLI.
How do two agents avoid editing the same file?
Before an edit, `check before-write` confirms no peer holds a claim on that path — backed by a warm-snapshot cache and an opt-in fail-closed mode on watchdog timeout. Linked git worktrees share one room through the repo's common dir.
Does it need a server or network connection?
No. The store is an append-only JSONL log in the repo with a derived SQLite cache. Files, Git, rsync, or a shared folder can move facts; Rally just defines what the bytes mean.
What happens if an agent crashes mid-write?
The store tolerates torn ledger lines and quarantines-and-rebuilds on corruption — it's designed for agents that die unexpectedly. The SQLite cache is rebuildable from the log at any time.
The first time I ran a second agent in a repo I already had one working in, they collided immediately: both edited the same file, one quietly overwrote the other’s commit, and neither knew what the other had decided. Two agents, and I got less than one agent’s worth of work.
Rally is the fix. It’s a room that lives in the repo where every agent — Claude, Codex, whatever I’m running — writes down what it’s touching and checks before it steps on anyone. So I can point all of them at the same project at once: they split the work, each takes what it’s best at, and they finish faster instead of fighting over the same files. No server to stand up, no chat to babysit — just an append-only log I can rebuild from disk if anything goes sideways.
cargo install --path crates/rally-cli Rust 1.85+ · Apache-2.0 · any agent, any host · no server