Bernstein vs Agy: quick decision guide

Install both

pipx install bernstein

Feature matrix

Adapter source: src/bernstein/adapters/agy.py

Verifiable facts

The brief for this surface requires at least three facts that a reader can verify against a primary source. The list below is built from the bernstein adapter source and, when available, the upstream project's own pages.

1. Bernstein ships a Agy adapter at src/bernstein/adapters/agy.py that wraps the upstream CLI as one of 42 routable agents. [source: bernstein adapter source, as of 2026-08-10]
2. Bernstein is an open-source Multi-agent orchestrator licensed Apache-2.0, with a deterministic Python scheduler that routes work across CLI agents in parallel git worktrees. [source: bernstein repo, as of 2026-08-10]
3. Bernstein records lineage and a replay journal on every run; with the audit log enabled it also writes an HMAC-SHA256 chained record under .sdd/ that lets a reviewer replay every routing and quality-gate decision. [source: bernstein repo, as of 2026-08-10]

Where Agy fits in Bernstein

Bernstein registers Agy under the slug "agy" and the registry name "agy". The adapter source lives at src/bernstein/adapters/agy.py in the bernstein repo and was last touched at build time 2026-08-10. The Agy adapter file is 303 lines and 11,784 bytes long, fingerprinted 49a84edf239cdc52 (first 16 hex chars of SHA-256). No upstream GitHub repository is recorded in the bernstein adapter for Agy; refer to the upstream vendor's documentation when auditing. The bernstein adapter file for Agy does not yet carry a "Last verified against upstream" line; this means the adapter still tracks an unpinned upstream binary. Bernstein routes tasks to Agy when its pass rate on similar work clears the configured threshold, otherwise the deterministic Python scheduler picks a different adapter from the 40+ adapter catalog.

Adapter source excerpt

The module docstring of the Agy adapter, as it stands in the bernstein repo. Punctuation is normalised for the web; the wording is the author's. Length: 2313 characters.

Antigravity CLI (``agy``) adapter. ``agy`` is the successor CLI for the hosted backend that the legacy ``gemini`` binary served on the free / AI Pro / Ultra path; that backend was discontinued for non-enterprise users in June 2026. The gemini adapter remains registered for enterprise and API-key operators, so the two lanes stay separate: * ``agy`` -- this adapter. Single closed-source binary, headless ``-p``/``--print`` invocation, terminal sandbox pinned, permission prompts auto-approved for unattended runs. * ``gemini`` -- the dual-binary adapter for the legacy ``gemini`` / transitional ``antigravity`` binaries (enterprise / API-key lane). Verified against Antigravity CLI 1.0.0. The upstream surface the adapter relies on (and that the conformance contract pins): * ``-p`` / ``--print`` -- run a single prompt non-interactively and print the response (the headless harness path). * ``--sandbox`` -- run with terminal restrictions enabled; pinned on every spawn so unattended runs stay inside the sandbox. * ``--dangerously-skip-permissions`` -- auto-approve tool permission requests; required for unattended operation. * ``--print-timeout`` -- upstream-side wait bound for print mode; the adapter maps ``timeout_seconds`` onto it so the CLI's own timeout agrees with Bernstein's watchdog. * ``--conversation <id>`` -- resume a previous conversation by id (upstream-minted; native resume is not wired yet, so the strategy matrix declares resume as unsupported and the orchestrator falls back to fresh sessions with scratchpad reinjection). The CLI accepts ``--model`` for explicit model selection. Bernstein's ``default`` sentinel omits that flag so zero-config runs retain the CLI's server-side default. Binary discovery is a two-step cascade: 1. The operator override ``BERNSTEIN_AGY_BINARY`` wins when set (and must resolve on ``PATH``, regardless of ``strict`` mode). 2. Otherwise the ``agy`` binary is used. ``strict=True`` (doctor / ``bernstein adapters check``) raises :class:`AgyBinaryNotInstalledError` when nothing resolves; ``strict=False`` (spawn path, default) returns the default binary name so the downstream :func:`subprocess.Popen` surfaces the natural ``FileNotFoundError`` -- the codex / aider posture, which also keeps tests that mock ``subprocess`` from tripping on eager discovery.

Adapter telemetry

When to pick which

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