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Bernstein

deterministic orchestrator for CLI coding agents·bernstein.run

Bernstein is an open-source deterministic orchestrator that runs CLI coding agents such as Claude Code, Codex, Gemini CLI, Aider and 40+ others in parallel, each in its own git worktree, gated by lint, type, and test checks. The scheduler is plain Python with no model in the coordination loop, so runs replay byte-identically via an always-on lineage spine and replay journal. An opt-in HMAC-chained audit log and signed receipts let a reviewer verify a run offline without re-executing it. It also offers an MCP server mode and A2A protocol support.

What it's for

orchestrating multiple CLI coding agents in parallelisolating agent work in per-task git worktrees to avoid merge conflictsgating agent output with lint, type, and test verification before mergeproducing an auditable, HMAC-signed run record for offline compliance reviewrunning AI coding agent swarms on-prem or air-gappedforward-deployed engineering: standing up an agent crew on a client repo quicklyexposing the orchestrator as an MCP server or via the A2A protocolrouting tasks to cheapest-passing models via a contextual-bandit router

Features 19

40+ CLI agent adapters (Claude Code, Codex, Gemini CLI, Aider, Cursor, GitHub Copilot, Devin Terminal, AWS Q Developer, OpenAI Agents SDK, and more)
A2A protocol support
ACP bridge (bernstein acp serve)
Air-gap install profile
Always-on lineage spine and replay journal for byte-identical replay
Built-in verification (lint, type checks, tests) before merge
CI autofix daemon (bernstein autofix)
Cloud artifact sinks (S3, GCS, Azure Blob, Cloudflare R2)
Cost-aware / contextual-bandit model routing
Cross-model review before merging
Deterministic scheduling with no LLM in the coordination loop
MCP server mode with tools like bernstein_run, bernstein_status, bernstein_cost
Opt-in HMAC-chained audit log with signed receipts
OS keychain credential vault (bernstein connect)
Per-agent credential scoping
Per-task git worktree isolation
Pluggable sandbox backends (Docker, E2B, Modal, Blaxel, Cloudflare, Daytona, Runloop, Vercel)
Progressive-disclosure skill packs via load_skill MCP tool
Sandboxed preview server (bernstein preview start)

At a glance

free tieropen sourceself-hostableAPI

TypeCLI tool

DeploymentSelf-hosted

Fordevelopers, forward-deployed engineering teams, on-prem / air-gapped enterprise users

CompanyBernstein · 2025

Integrations

Claude CodeCodexGemini CLIAiderCursorGitHub CopilotDevin TerminalAWS Q DeveloperOpenAI Agents SDKCloudflare WorkersCloudflare AgentsDockerE2BModalBlaxelDaytonaRunloopVercelS3GCSAzure BlobCloudflare R2KubernetesDatadogSplunkGitHub SponsorsOpenCollective

Resources

Docs

Pricing

Bernstein itself is free and open source (Apache 2.0); the /cost page is a token-cost calculator for LLM usage during a run, not a product pricing page.

Open SourceFree

Free and open source under Apache 2.0; offers price stated as 0 USD in structured markup.