Show HN: Bernstein – run 44 CLI coding agents from one deterministic scheduler

Bernstein, a deterministic orchestrator for CLI coding agents, is now in beta, enabling users to run 44 CLI coding agents from a single scheduler. Developed by sipyourdrink-ltd, Bernstein coordinates agents like Claude Code, Codex, and Gemini CLI in parallel, with no LLM in the coordination loop, isolated worktrees, and an optional HMAC-chained audit log for verifiable runs. The tool is Apache-2.0 licensed and supports air-gapped installation.

"To achieve great things, two things are needed: a plan and not quite enough time."- attributed to Leonard Bernstein website https://bernstein.run · docs https://bernstein.readthedocs.io/ · install https://bernstein.readthedocs.io/en/latest/getting-started/install/ · first run https://github.com/sipyourdrink-ltd/bernstein/blob/main/docs/getting-started/first-run.md · glossary https://github.com/sipyourdrink-ltd/bernstein/blob/main/docs/reference/GLOSSARY.md · limitations https://github.com/sipyourdrink-ltd/bernstein/blob/main/docs/reference/KNOWN LIMITATIONS.md · name policy https://github.com/sipyourdrink-ltd/bernstein/blob/main/TRADEMARKS.md · sponsor https://github.com/sponsors/chernistry Status: beta.Solo-maintained, under active development. The version number counts releases, not maturity - minor versions may change interfaces. Pin the version for anything you depend on; regressions get fixed fast, file them . Bernstein is a deterministic orchestrator for CLI coding agents Claude Code, Codex, Gemini CLI, and 40+ more . It runs them in parallel, gates what they produce, and records enough of the run that you can check it afterwards. Air-gap install profile included. Apache-2.0. Four things set it apart; everything after is detail. No LLM in the coordination loop. Scheduling is plain Python, so a run is reproducible end to end. Replay yesterday's plan and get yesterday's task graph. Checkable after the fact. The replay journal records every run, and the always-on lineage spine records every lineage-bearing step; the opt-in HMAC-chained audit log BERNSTEIN AUDIT=1 adds receipts you verify offline. Non-determinism surfaces as a hash mismatch at the exact step, not a flaky re-run. Non-code deliverables get the same treatment. A task can declare an artifact contract — report, dataset, action log, ops result — from a plan step, a backlog entry, or the task CLI, and completes on a signed lineage receipt rather than a git commit. Isolated by construction. Each coding task gets its own git worktree behind merge gates; artifact-mode tasks get working-directory separation under .sdd/workspaces/ . Under this default isolation agents share no mutable workspace; coordination state the task backlog is shared and claimed atomically. Filesystem enforcement beyond that separation is opt-in, from the sandbox backends https://github.com/sipyourdrink-ltd/bernstein/blob/main/docs/architecture/sandbox.md . Disable worktrees and every task runs in the shared checkout. Broad and local. 40+ CLI agent adapters plus a generic --prompt wrapper, file-based state, no SaaS hop, no third-party data plane. The full list is on the capabilities page https://github.com/sipyourdrink-ltd/bernstein/blob/main/docs/reference/capabilities.md ; the feature matrix https://github.com/sipyourdrink-ltd/bernstein/blob/main/docs/reference/FEATURE MATRIX.md is the exhaustive index. uv tool install bernstein or: pipx install bernstein bernstein init bernstein doctor checks a CLI agent is installed and authenticated bernstein -g "fix the failing test in tests/test foo.py" pipx, pip, brew, dnf, npm, and Docker are covered in the install guide https://bernstein.readthedocs.io/en/latest/getting-started/install/ ; the air-gapped wheelhouse has its own air-gap guide https://bernstein.readthedocs.io/en/latest/installation/air-gap/ . The recording above is a real run, and it ships with its own proof. The cast, the signed run receipt derived from that run's journal, and the public key that pins it all live in docs/assets/demo-run/ https://github.com/sipyourdrink-ltd/bernstein/tree/main/docs/assets/demo-run . Verify the run you just watched, offline: bernstein verify receipt docs/assets/demo-run/run-receipt.json \ --public-key docs/assets/demo-run/run-receipt.pub.pem CI re-verifies the committed receipt on every push to main — and proves a tampered copy fails — so the published evidence cannot rot into a decorative file. scripts/record demo.sh regenerates the recording, receipt, and key from a fresh real run; nothing inside the terminal is synthesised. A run in flight is watchable from either operator surface. Both read the same task API, so neither is a lagging mirror of the other. bernstein live — the terminal dashboard | bernstein gui serve — the browser dashboard | Determinism here is something you check, not something you take on faith. Run once with audit enabled, then verify what was recorded: BERNSTEIN AUDIT=1 bernstein -g "fix the failing test in tests/test foo.py" bernstein replay list run ids recorded on disk bernstein replay latest --verify recompute the journal head, name the first divergent step bernstein lineage verify <run id recompute the always-on lineage spine bernstein audit verify HMAC chain + Merkle seal written because audit was enabled bernstein audit diagnose <run id --signal gate --sign-key KEY name the exact step a failure entered the run, as a signed receipt bernstein verify run <run id --signing-key-path key.pem sign one portable run receipt bernstein verify receipt .sdd/runs/<run id /run-receipt.json verify it offline: file only The journal is written on every run; the lineage spine is always on and gains an entry for each lineage-bearing step, so a short run can finish with a valid, empty spine. bernstein audit verify only has a chain to check when the run was started with BERNSTEIN AUDIT=1 , a compliance preset, or bernstein run --audit . The --audit flag belongs to bernstein run ; on the bernstein -g form above, set the environment variable. One run receipt binds the journal head, the lineage-spine head when the run wrote spine entries, and — opt-in — an audit-chain range, under a single Ed25519-signed subject with the public key embedded. A reviewer holding that file and the operator's public key can confirm the recorded actions are exactly what executed: no HMAC key, no live .sdd/ , and exit 2 naming the first divergent step on tamper. With the file alone and no --public-key pin, the check is integrity-only — it proves the receipt is internally consistent, not who signed it, and the verdict says so. Details in deterministic replay https://github.com/sipyourdrink-ltd/bernstein/blob/main/docs/operations/deterministic-replay.md signed-run-receipt-one-file-offline-verification . The same checkability applies to evaluation numbers: bernstein bench run <suite --reliability k also spelled bernstein eval --reliability k runs every task k times under fixed coordination and reports a pass^k floor all k attempts must pass alongside the pass@1 ceiling, sealed in a signed receipt that bernstein bench reliability-verify recomputes offline — a fabricated floor fails verification. Details: pass^k reliability floor https://github.com/sipyourdrink-ltd/bernstein/blob/main/docs/eval/reliability.md . Each goal moves through four stages: Decompose . The manager breaks your goal into tasks with roles, owned files, and completion signals. One LLM call, then plain Python from there. Spawn . Agents start in isolated git worktrees https://git-scm.com/docs/git-worktree , one per coding task; an artifact-mode task gets a plain working directory instead. Main branch stays clean. Verify . The janitor checks concrete signals: tests pass, files exist, lint clean, types correct. Merge . Verified work lands in main. Failed tasks get retried or routed to a different model. Why the scheduler is plain Python, and what that trades away: why deterministic https://github.com/sipyourdrink-ltd/bernstein/blob/main/docs/architecture/WHY DETERMINISTIC.md . cd your-project bernstein init creates .sdd/ workspace, bernstein.yaml + templates/ bernstein -g "Add rate limiting" agents spawn, work in parallel, verify, exit bernstein live watch progress in the TUI dashboard bernstein run plan.yaml multi-stage plan: skip LLM planning, execute directly bernstein stop graceful shutdown with drain The full operator surface PR automation, schedules, chat bridges, the autofix daemon is in operator commands https://github.com/sipyourdrink-ltd/bernstein/blob/main/docs/operations/commands.md . Repository hygiene gates: bernstein readme-l10n verify fails a PR whose translated READMEs drifted from the English source naming the stale section , bernstein readme-l10n sync rebinds them after an English edit. See readme-l10n https://github.com/sipyourdrink-ltd/bernstein/blob/main/docs/playbooks/readme-l10n.md . Claude Code, Codex CLI, Gemini CLI, GitHub Copilot CLI, Cursor, Aider, Goose, Muse Code, OpenAI Agents SDK, Amp, Cody, Continue, Devin Terminal, Junie, Kilo, Kiro, AWS Q Developer, Ollama, OpenCode, OpenHands, Open Interpreter, gptme, Plandex, AIChat, Letta Code, Qwen, and more. The adapter index https://github.com/sipyourdrink-ltd/bernstein/blob/main/docs/adapters/index.md carries install commands for 30 of them. bernstein integrations list enumerates all 51 wired-in integrations from src/bernstein/adapters/registry.py , the single source of truth for what resolves. 49 of them are selectable agent adapters; the other two rows are the mock test stub and the self-hosted-endpoints endpoint profile. Per-adapter copy lives in src/bernstein/adapters/use cases.py . Anything else with a --prompt flag works through the generic wrapper. Mix agents in the same run: cheap local models for boilerplate, heavier cloud models for architecture. bernstein integrations list --installed shows what is available on your machine. Everything deep lives on the docs site https://bernstein.readthedocs.io/ : | page | what it covers | |---|---| | who this is for https://github.com/sipyourdrink-ltd/bernstein/blob/main/docs/use-cases.md workflows https://github.com/sipyourdrink-ltd/bernstein/blob/main/docs/operations/workflow-manifests.md web UI https://github.com/sipyourdrink-ltd/bernstein/blob/main/docs/gui/index.md cloud execution https://github.com/sipyourdrink-ltd/bernstein/blob/main/docs/cloudflare/cloudflare-overview.md api.bernstein.run service is not yet available datasources https://github.com/sipyourdrink-ltd/bernstein/blob/main/docs/operations/datasources.md security https://github.com/sipyourdrink-ltd/bernstein/blob/main/docs/operations/security.md architecture https://github.com/sipyourdrink-ltd/bernstein/blob/main/docs/architecture/ARCHITECTURE.md Bernstein is named after Leonard Bernstein, the American conductor and composer. The project orchestrates a crew of CLI coding agents the way Bernstein conducted the New York Philharmonic: every player on cue, the score deterministic, the conductor accountable for the result. i wrote bernstein because i was paying $400/month in claude bills running three coding agents in parallel and getting nondeterministic merges. Apache 2.0, solo maintained. Live stats: bernstein.run https://bernstein.run . Listed in vinta/awesome-python https://github.com/vinta/awesome-python , covered in Augment Code's open-source agent orchestrators https://www.augmentcode.com/tools/open-source-agent-orchestrators roundup, and listed in Python Weekly 742 https://www.pythonweekly.com/p/python-weekly-issue-742-april-23-2026 . We also wrote up the approach as the deterministic zero-LLM orchestration https://github.com/nibzard/awesome-agentic-patterns/blob/main/patterns/deterministic-zero-llm-orchestration.md pattern in awesome-agentic-patterns. All coverage: 20+ awesome lists, directories, newsletters, and peer citations The full tracked list, including every awesome-list entry, catalog listing, prior-art citation, and newsletter mention, lives in docs/mentions.md https://github.com/sipyourdrink-ltd/bernstein/blob/main/docs/mentions.md . Entries are added as they appear; corrections welcome by issue or PR. PRs welcome; CONTRIBUTING.md https://github.com/sipyourdrink-ltd/bernstein/blob/main/CONTRIBUTING.md has setup and code style. Security reports go through SECURITY.md https://github.com/sipyourdrink-ltd/bernstein/blob/main/SECURITY.md . If Bernstein saves you time: GitHub Sponsors https://github.com/sponsors/chernistry . Contact: forte@bernstein.run mailto:forte@bernstein.run . Citation metadata lives in CITATION.cff https://github.com/sipyourdrink-ltd/bernstein/blob/main/CITATION.cff . License: Apache-2.0 https://github.com/sipyourdrink-ltd/bernstein/blob/main/LICENSE ; the project name is covered separately in TRADEMARKS.md https://github.com/sipyourdrink-ltd/bernstein/blob/main/TRADEMARKS.md . Alex Chernysh https://alexchernysh.com · GitHub https://github.com/chernistry · X https://x.com/alex chernysh · bernstein.run https://bernstein.run