Bernstein vs Gemini: quick decision guide

Install both

pipx install bernstein

Feature matrix

Adapter source: src/bernstein/adapters/gemini.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 Gemini adapter at src/bernstein/adapters/gemini.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 Gemini fits in Bernstein

Bernstein registers Gemini under the slug "antigravity" and the registry name "antigravity". The adapter source lives at src/bernstein/adapters/gemini.py in the bernstein repo and was last touched at build time 2026-08-10. The Gemini adapter file is 361 lines and 13,591 bytes long, fingerprinted 8241cb35d741d169 (first 16 hex chars of SHA-256). No upstream GitHub repository is recorded in the bernstein adapter for Gemini; refer to the upstream vendor's documentation when auditing. The bernstein adapter file for Gemini does not yet carry a "Last verified against upstream" line; this means the adapter still tracks an unpinned upstream binary. Bernstein routes tasks to Gemini 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 Gemini adapter, as it stands in the bernstein repo. Punctuation is normalised for the web; the wording is the author's. Length: 1738 characters.

Google Gemini / Antigravity CLI adapter. The upstream CLI is changing binary names ahead of a deprecation date: the legacy ``gemini`` binary stops serving free / AI Pro / Ultra subscribers on 2026-06-18; the replacement ``antigravity`` binary uses the same model set and the same ``--output-format`` semantics. Enterprise customers retain the legacy binary via paid API keys. The adapter is dual-binary aware. At spawn time it discovers which binary is on ``PATH`` using a deterministic cascade defined by ``_DISCOVERY_CASCADE``: 1. The operator override ``BERNSTEIN_GEMINI_BINARY`` wins when set (and must resolve on ``PATH``, regardless of ``strict`` mode). 2. Otherwise ``antigravity`` is preferred. 3. The legacy ``gemini`` binary is used as a fallback. 4. If neither resolves, behavior depends on the ``strict`` flag passed to :func:`resolve_google_cli_binary`: - ``strict=True`` (used by ``bernstein adapters check`` / doctor): the adapter raises :class:`BinaryNotInstalledError`. - ``strict=False`` (default, used by :meth:`GeminiAdapter.spawn`): the resolver returns the first cascade entry as a fallback, letting downstream :func:`subprocess.Popen` raise the natural ``FileNotFoundError`` on actual invocation. This matches the codex / aider adapter posture and keeps tests that mock ``subprocess`` from tripping on eager discovery. The adapter contract (flags, env-isolation allow-list, sandbox profile, rate-limit meter, network policy) is unchanged: only the binary name and the discovery step differ. Recommended models (identical on both binaries): ``gemini-3.1-pro`` (highest reasoning), ``gemini-3-flash`` (default in the Gemini app, Pro-grade reasoning at Flash speed), or ``gemini-3.1-flash-lite`` for the cheapest tier.

Adapter telemetry

When to pick which

FAQ