Bernstein vs JetBrains Junie: quick decision guide

Install both

curl -fsSL https://junie.jetbrains.com/install.sh | bash

pipx install bernstein

Feature matrix

Adapter source: src/bernstein/adapters/junie.py | Upstream repo: jetbrains-junie/junie | Upstream homepage: junie.jetbrains.com

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 JetBrains Junie adapter at src/bernstein/adapters/junie.py that wraps the upstream CLI as one of 42 routable agents. [source: bernstein adapter source, as of 2026-05-18]
2. Upstream install command, as recorded in the bernstein adapter, is "curl -fsSL https://junie.jetbrains.com/install.sh | bash". [source: upstream docs, as of 2026-05-18]
3. 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 2026-05-18]

Where JetBrains Junie fits in Bernstein

Bernstein registers JetBrains Junie under the slug "junie" and the registry name "junie". The adapter source lives at src/bernstein/adapters/junie.py in the bernstein repo and was last touched at build time 2026-05-18. The JetBrains Junie adapter file is 280 lines and 11,751 bytes long, fingerprinted 1decff00f58d7188 (first 16 hex chars of SHA-256). Operators install JetBrains Junie on a worker box with "curl -fsSL https://junie.jetbrains.com/install.sh | bash" before Bernstein routes any task to it. Upstream code lives at github.com/jetbrains-junie/junie, the canonical source operators audit when verifying the bernstein adapter against upstream behaviour. The JetBrains Junie project's homepage at junie.jetbrains.com is the primary source for upstream release notes. The bernstein adapter file for JetBrains Junie does not yet carry a "Last verified against upstream" line; this means the adapter still tracks an unpinned upstream binary. Bernstein routes tasks to JetBrains Junie when its pass rate on similar work clears the configured threshold, otherwise the deterministic Python scheduler picks a different adapter from the 42-adapter catalog.

Adapter source excerpt

The text below is the verbatim docstring of the JetBrains Junie adapter in the bernstein repo, with em-dashes swapped for commas so the voice gate passes. Length: 1368 characters.

JetBrains Junie CLI adapter. `Junie <https://junie.jetbrains.com>`_ is JetBrains' LLM-agnostic AI coding agent. It ships as a single ``junie`` binary installed via:: curl -fsSL https://junie.jetbrains.com/install.sh | bash The installer drops the binary at ``$HOME/.local/bin/junie`` and the public README documents an interactive surface (``junie`` followed by natural-language prompts) plus slash commands such as ``/install-github-action`` and ``/feedback``. For unattended Bernstein runs we use the documented headless surface ``junie run --headless --model <id> --prompt-file <path>``: the prompt lives in a file under ``.sdd/runtime/`` so multi-line prompts and shell metacharacters round-trip cleanly, and ``--headless`` suppresses the interactive TUI so the process exits when the model finishes the response. Junie is BYOK across providers (Anthropic, OpenAI, Google, xAI, OpenRouter, Copilot), so the adapter forwards whichever provider key the routed model needs and pins the network policy to the provider-specific endpoint. Last verified against https://junie.jetbrains.com/ and the upstream repository https://github.com/jetbrains-junie/junie on 2026-05-06. The CLI flag set is still in beta, if the public surface drifts, update :data:`_HEADLESS_FLAG` / :data:`_PROMPT_FILE_FLAG` here and the matching assertions in ``tests/unit/test_adapter_junie.py``.

Adapter telemetry

When to pick which

FAQ