bernstein

What it is and what it does

Bernstein is a deterministic orchestrator for running multiple CLI coding agents in parallel. It coordinates tasks without an LLM in the scheduling loop—meaning a run is reproducible byte-for-byte when replayed with the same inputs and agent outputs. Each coding task runs in its own git worktree, isolated by default; coordination state (the task backlog) is shared and claimed atomically. The package records every run in a replay journal and maintains an always-on lineage spine that tracks lineage-bearing steps; an optional HMAC-chained audit log adds cryptographic receipts you can verify offline without rerunning the orchestration.

It ships with adapters for Claude Code, Codex, Gemini CLI, and 40+ other agents, plus a generic `--prompt` wrapper. You can watch runs live via a terminal dashboard (`bernstein live`) or browser dashboard (`bernstein gui serve`), and verify determinism by replaying a recorded run and checking for divergence. The package includes air-gap deployment support and is built on fastapi, cryptography, and opentelemetry for observability. It's beta software, solo-maintained, and actively developed; minor versions may change interfaces.

Use it for:

• Run multiple coding agents on the same task in parallel and compare their outputs deterministically, with cryptographic proof of what each agent produced.
• Verify that a multi-agent workflow produces identical results when replayed with the same inputs, catching non-determinism at the exact step it occurs.
• Build compliance-auditable agent workflows where every step is signed and can be verified offline by a reviewer without access to live infrastructure.
• Coordinate agent tasks across a cluster with per-task isolation, ensuring agents cannot interfere with each other's working directories or shared state.
• Record and replay agent-driven code generation or testing workflows to debug failures or reproduce issues from a previous run.

Worth the install?

AI-flagged interpretation of the facts on this page — verify before relying

Bernstein orchestrates parallel CLI coding agents (Claude Code, Codex, Gemini CLI, and 40+ others) with deterministic replay, cryptographic lineage tracking, and optional audit chains—no LLM in the coordination loop, so runs are reproducible end-to-end.

Yes, if you are orchestrating multiple CLI coding agents and need deterministic replay, cryptographic auditability, and per-task isolation. The low install friction and active maintenance support the use case. No, if you need a stable API—beta status means minor versions may break interfaces, so pin carefully. No, if you are not using CLI agents or do not need replay and audit guarantees.

Install

bernstein on PyPI

pip install bernstein

uv add bernstein

poetry add bernstein

Installing bernstein

Before you install

Low friction: pure Python wheel with 34 runtime dependencies including fastapi, cryptography, and opentelemetry. Active maintenance (last commit 2026-08-14, 882 stars); beta status means minor versions may change interfaces—pin the version if you depend on it. Requires Python 3.12+.

License in practice

Apache-2.0 permissive license; you can use, modify, and distribute freely in commercial and private projects, with attribution and no warranty.

Quickstart

# Install
uv tool install bernstein  # or: pipx install bernstein

# Initialize and verify
bernstein init
bernstein doctor

# Run an agent task
bernstein -g "fix the failing test in tests/test_foo.py"

# Verify determinism
bernstein replay latest --verify

Requires Python 3.12 or later. Requires at least one CLI agent installed and authenticated (e.g., Claude Code, Codex, Gemini CLI). Git must be available for per-task worktree isolation.

Verify before relying

• Whether all 40+ agent adapters are documented or discoverable in the package itself.
• Performance characteristics when running many agents in parallel (latency, resource overhead).
• Compatibility of the air-gap install profile with all runtime dependencies.
• Whether the HMAC audit chain and signed receipts are suitable for regulated compliance workflows.

Package facts

Evidence: bernstein-3.15.1-py3-none-any.whl

Keywords: agents, ai, audit, automation, cli, coding, deterministic, devtools, lineage, llm, multi-agent, orchestration, provenance, replay, worktree

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