forked

forked is an open-source (Apache-2.0) project with a Rust core that versions an AI agent's structured state with git-like branches, commits and diffs. It pairs that state tree with an effect log so emails, payments and API calls are not executed twice when an agent is retried or rewound. It can be used as a Rust library, a self-hosted server, or a managed cloud service with the same API.

What It Is

forked stores an agent's own structured state (messages, memory, plans, tool results) as a persistent key-to-JSON map. Agents can fork a branch, rewind to any commit, and diff states. It does not snapshot files or processes, only the agent's structured state.

How the effect log works

Side effects are recorded by idempotency key inside commits. When a crashed agent is re-run from the top, already-recorded steps return their stored result instead of executing again, and rewinds never undo a recorded effect. The README notes the guarantee is strict when a session has a single writer at a time, as in forked cloud.

Architecture and deployment

State is a structurally shared, content-addressed tree (SHA-256, deterministic CBOR), so forks write a single ref and diffs skip identical subtrees by hash. The README reports 1,000 branches in about 1.4 ms in memory and about 276 ms on durable SQLite. Storage backends range from in-memory to SQLite and Cloudflare Durable Objects, and the core compiles to WebAssembly.

Clients and integrations

A TypeScript client (@forked-run/client) wraps sessions, branches, commits and effects. @forked-run/langgraph is a LangGraph checkpointer that turns time travel into a real branch rewind, and @forked-run/mcp exposes checkpoint, rewind and effect tools to MCP-capable agents. Self-hosting uses a single binary with SQLite or Docker, and switching to cloud only requires changing baseUrl. The cloud adds a console that draws each session's branch tree.