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Noether

Typed, content-addressed composition for agent-built pipelines.

A stage is an immutable unit of computation addressed by SHA-256(signature + implementation). Stages compose into graphs that the type checker verifies before execution. Effects (Pure, Network, Llm, Cost, Process, FsRead, FsWrite, …) are declared in the signature and enforced pre-flight by policy.

Status

One active maintainer, pre-1.0. Current tag: v0.8.0 (tagged 2026-04-21).

Breaking changes are possible between minor versions per STABILITY.md. See CHANGELOG.md for release notes and roadmap.md for what ships vs. what's planned.

What v0.8 shipped

Closes M3 — Optimizer + Richer Types:

  • Parametric polymorphism — stage signatures can carry NType::Var("T"); check_graph threads substitutions through every edge.
  • Row polymorphism — NType::RecordWith { fields, rest } captures unknown extra fields; { name, age } >> mark_done resolves the tail to Record { name, age, done } instead of silently dropping extras.
  • Refinement types — NType::Refined { base, refinement } attaches runtime-checkable predicates (Range, OneOf, NonEmpty).
  • Graph optimizer — three passes run between type-check and plan: canonical_structural (flattens nested wrappers), dead_branch (folds Branch(Const(bool), …)), memoize_pure (caches Pure-stage invocations within a run).
  • Stdlib grew to 85 — added identity, head, tail, mark_done, clamp_percent for the new type machinery.
  • Filesystem-scoped effects — Effect::FsRead(path) / Effect::FsWrite(path) drive IsolationPolicy::from_effects, so path-scoped bind mounts fall out of the declared signature.

On main, ships in the next tag: runtime enforcement of refinement predicates at stage boundaries via ValidatingExecutor.

Where to go next

  • Install — five minutes from zero to running.
  • Concepts — stages, types, effects, composition graphs, content addressing. The reference you'll come back to.
  • Usage — the CLI surface: stage, compose, run, trace.
  • Examples — worked end-to-end runs.

Not the right tool for

  • Request/response with SLAs, autoscaling, sticky sessions — use a regular service framework. Noether runs graphs and returns.
  • Hardened sandbox for hostile multi-tenant code — the bwrap layer is sized for "LLM-generated stages I haven't audited", not "adversaries targeting a shared kernel". See SECURITY.md.
  • Airflow / Prefect / Dagster territory — those are mature for scheduled DAGs with UI ops, lineage, alerting. Noether has none of that surface.
  • One-shot scripts — content-addressing pays off on run N+1. If there is no run 2, a plain script is simpler.
  • Non-JSON data — the type system is structural over JSON. Streaming video, arbitrary binary, or live-network protocols are doable but you'll fight the model.