# A protocol for AI agent workspace state and effect management > Source: > Published: 2026-07-26 08:02:03+00:00 reel is a protocol for the boundary between an AI agent's speculative work and the systems it does not own. An agent reasons by attempting things. Some attempts cross that boundary: a message is posted, a row is written, a payment is taken. Once an action has crossed, no later decision — including the decision to abandon the line of reasoning that produced it — can retract it. reel exists to make the boundary transactional, so that an action the system decides to discard is never performed in the first place. reel defines six content-addressed types — `Hash` , `Block` , `Ref` , `Delta` , `Capability` , `View` — three verbs — `fork` , `commit` , `abort` — and three invariants: reachability, the silencing of discarded irreversible effects, and capability narrowing. The load-bearing decision is that a `View` 's pending side-effects are themselves a content-addressed `Block` . `commit` moves that block into the committed log and drains it; `abort` drops the reference, after which the block is unreachable and is collected. No path between the submission of an irreversible effect and `commit` can fire it, because the capability needed to fire one is constructed only inside `commit` 's drain. `abort` constructs none, so on the discard path the effect is, by construction, unable to run. The verbs, the snapshot-isolation reading of a `View` , the capability model and the effect taxonomy are each taken from existing work — Gray (1981), Wang & Zheng (2026), Berenson et al. (1995), Miller, Yee & Shapiro (2003), Garcia-Molina & Salem (1987). reel's contribution is their composition under a single content-addressed representation. State, side-effects and capabilities are represented as the same kind of content-addressed block. One transactional kernel therefore provides rollback, audit and sharing for an entire workspace, rather than each being implemented again for each feature. A system that routes work across many external resources can rebuild its state-and-effect layer on this one kernel instead of reasoning about transactionality resource by resource. **The specification**(`spec/` ): the six types, three verbs and three invariants; the effect classes; the conformance criteria; the adapter interface.**A Rust kernel**(`crates/` ):`reel-spec` — the protocol types. The namespace is a persistent, copy-on-write map, so a fork shares it in constant time.`reel-store` — a content-addressed block-and-ref store, with an in-memory backend and a redb-backed persistent one, and a reachability walker for collection.`reel-effects` — the sealed effect-class traits and the linear fire-capability.`reel-core` — the kernel.`fork` (constant-time copy-on-write inheritance with capability narrowing) and`abort` are implemented;`commit` follows.`adapters/` ,`reel-cli` — the filesystem and remote adapters and the command-line surface, in progress. The workspace builds on stable Rust and passes its test suite, which includes property-based tests over the kernel's invariants. `commit` — precondition validation and the ordered drain of buffered effects.- The command-line tool — a dry-run loop that runs a process, displays its pending effects, and either commits or discards them. - The effect-interception layer — capturing a process's outbound effects through a replaceable backend, so that classifying a new service is the only work a new integration requires. ``` cargo build --workspace cargo test --workspace ``` Rust 1.95 (stable), edition 2024. Pre-release. The specification is settled; the kernel is under construction along the path described above. Interfaces may change. Apache-2.0. See [LICENSE](/eouzoe/reel/blob/master/LICENSE).