rustev

An embeddable Rust engine for making, evaluating and recording decisions over evolving, partially trusted information. A versioned decision definition is compiled into a plan: exact computation in Rust, semantic questions answered by interchangeable backends that disclose what they can return, explicit abstention, bounded execution, and an evidence record for every decision.

Rustev produces proposals, never grants. It does not authorize, own knowledge, or execute effects; those belong to the application and to neighbouring components (Aicortex, Rahi, statecraft-cli), each optional. Rustev is usable without any of them.

Status

Implemented, under approved and complete specs:

• rustev-contract and rustev-core (002): versioned documents, bounded parsing, canonical identities, value kinds, exact operators, the plan compiler with typed refusals, staged evaluation and selection policy.
• rustev-runtime (003, amended by 013): bounded admission and concurrency, one end-to-end deadline on an injectable clock, cost budgets reserved before dispatch, declared retries and fallback that are part of the plan's identity, honest cancellation, remote state on attempts that end without a stop, and run records delivered under a declared sink policy.
• rustev-eval (004, amended by 014 and 015): offline reproduction of retained decisions from bounded replay bundles, candidate comparison, evaluation reports with task adapter rules bound into their identity, per-case reporting of unusable bundles, regression gates and temperature fits. Live re-execution is not implemented (spec 026).
• rustev-backend-rules (005): a deterministic rules backend; authored, identified rules programs, not a model.
• rustev (crates/rustev-cli, 006): plan check, compile and show; run; replay; eval; gate; calibrate fit and qualify.
• integrations/rustev-remote-http (009): the versioned remote adapter protocol over HTTP, client and server, including adapter-scoped shared-state batching that is off by default until qualified.
• integrations/rustev-jev (012): a remote decision backend over TypeSafe's Jev through the Vercel AI Gateway. Its evidence is development evidence: the Gateway reports the served model as unknown, and the production transport (spec 022) is approved but not implemented.
• Reference packages rustev-pkg-support-routing (007, amended by 016) and rustev-pkg-lodging (008); neither amends a core crate.

Runtime optimization (spec 017) is in progress: increment 1 (runtime-planned batching and a bounded memory cache with invalidation, opt-in per plan) is implemented; increment 2 (concurrent duplicate suppression and persistent caches) is not. There is no local model backend (spec 011 is approved, not implemented), and no quality or calibration claim: datasets and reports are synthetic or of synthetic provenance, and real labeled data is admitted only under spec 023 (R-04, R-37). Nothing is released; every manifest is 0.1.0 with publish = false (spec 021 is approved, not implemented).

Approved specs not yet implemented: 010 optional integrations and serving, 019 dynamic questions, 020 remote protocol refinements, 021 packaging and first release, 022 Jev production transport, 023 real labeled data qualification, 026 live re-execution, 011 first local semantic backend. Drafts: 024 second local semantic backend, 025 wire-witness replay input. 017 is approved and in progress. Every other spec (000 to 009, 012 to 016, 018) is approved and complete.

The current roadmap is tracking issue #76; it describes planned work, not current behavior. Remaining unscheduled and research items are in docs/backlog.md.

• Design (proposed): docs/design/001-decision-engine-architecture.md
• Decisions: docs/decisions/00-founding-decisions.md
• Specs: specs/; spec-spine registry list shows each status.

Release

No version is published. The intended first family version is 0.1.0 (spec 021, as amended by 031): rustev-contract, rustev-core, rustev-runtime, rustev-eval, rustev-backend-rules, rustev-remote-http, rustev-pkg-support-routing and rustev-cli (whose binary is rustev), source archives only, MSRV 1.88, edition 2024, no Cargo features. make release-candidate produces candidate evidence for a clean commit; it uploads, tags and signs nothing. A candidate is not a release, and a release is publicly accessible only once a fresh registry-only consumer has passed against it (spec 021, 3.10).

Governance

Governed by spec-spine, pinned in spec-spine.toml, and initialized with statecraft-cli.

make tools   # install the pinned spec-spine into .bin
make gate    # read-only corpus gate, including ownership coverage
make code    # build, test, clippy, fmt, boundary check
make verify  # run each approved spec's declared acceptance

Apache-2.0.