Bernstein vs Cursor Agent: quick decision guide

Install both

curl https://cursor.com/install -fsS | bash  (macOS/Linux/WSL)

pipx install bernstein

Feature matrix

Adapter source: src/bernstein/adapters/cursor.py | Upstream homepage: docs.cursor.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 Cursor Agent adapter at src/bernstein/adapters/cursor.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 https://cursor.com/install -fsS | bash (macOS/Linux/WSL)". [source: upstream docs, as of 2026-05-18]
3. Bernstein last verified its adapter against upstream cursor-agent 2026.05.x on 2026-05-05. [source: bernstein adapter source, as of 2026-05-05]
4. Cursor Agent is flagged parallel-safe in Bernstein's adapter contract, meaning multiple instances can run in separate git worktrees against the same goal. [source: bernstein adapter source, as of 2026-05-18]
5. Cursor Agent supports the Model Context Protocol per the bernstein adapter contract, so Bernstein can inject MCP servers into its session. [source: bernstein adapter source, as of 2026-05-18]
6. Cursor Agent is distributed under Anysphere proprietary, per the operator-curated overlay in data/adapters-overlay.json. [source: upstream docs, as of 2026-05-18]

Where Cursor Agent fits in Bernstein

Bernstein registers Cursor Agent under the slug "cursor" and the registry name "cursor". The adapter source lives at src/bernstein/adapters/cursor.py in the bernstein repo and was last touched at build time 2026-05-18. The Cursor Agent adapter file is 210 lines and 8,494 bytes long, fingerprinted 0453df48848a29cd (first 16 hex chars of SHA-256). Operators install Cursor Agent on a worker box with "curl https://cursor.com/install -fsS | bash (macOS/Linux/WSL)" before Bernstein routes any task to it. No upstream GitHub repository is recorded in the bernstein adapter for Cursor Agent; refer to the upstream vendor's documentation when auditing. The Cursor Agent project's homepage at docs.cursor.com is the primary source for upstream release notes. Bernstein last verified the Cursor Agent adapter against upstream cursor-agent 2026.05.x on 2026-05-05, recorded inline in the adapter source. Cursor Agent accepts MCP servers, so Bernstein injects the same MCP toolset it provides every other MCP-aware adapter. Cursor Agent is flagged parallel-safe, meaning multiple Bernstein workers can spawn it in separate git worktrees against the same goal without file collisions. Cursor Agent ships under Anysphere proprietary per the operator-curated overlay; cross-check against the upstream LICENSE file before production use. Auth model for Cursor Agent is "Cursor account login (`cursor-agent login`)", scoped per adapter so a leaked key never grants access to a different model family. Bernstein routes tasks to Cursor Agent 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 Cursor Agent adapter in the bernstein repo, with em-dashes swapped for commas so the voice gate passes. Length: 1887 characters.

Cursor Agent CLI adapter. Last verified against upstream ``cursor-agent`` 2026.05.x on 2026-05-05. Cursor publicly launched a real terminal CLI on 2026-01-16 and shipped a v3 "agent-first" UX in April plus the Cursor SDK in May 2026, all sharing the same ``cursor-agent`` binary surface. Install: ``curl https://cursor.com/install -fsS | bash`` (macOS/Linux/WSL). The binary is ``cursor-agent``; the docs frequently abbreviate it as ``agent`` in examples, but the executable on PATH is the full hyphenated name. Auth: ``cursor-agent login`` opens a browser for OAuth; for CI use ``CURSOR_API_KEY`` env var. Headless invocation surface (per https://cursor.com/docs/cli): * ``-p / --print`` , non-interactive one-shot mode (without this the CLI starts a TTY chat and never returns). * ``--workspace <path>``, project root the agent operates against. * ``--model <name>`` , e.g. ``claude-sonnet-4-6``, ``claude-opus-4``, ``gpt-5.2``. * ``--output-format stream-json`` , emits JSON deltas suitable for tailing into the runtime log. * ``--trust`` , skip the workspace-trust prompt (required for first-run headless). * ``--approve-mcps`` , auto-approve configured MCP servers. * ``-f / --force`` , actually edit files in print mode; without it the CLI only prints suggestions (silent no-op). Suppressed when ``task_scope == "readonly"``, which switches the run to ``--mode ask``. * ``--mode ask`` , read-only, no edits, no tools that mutate state. MCP: there is no ``--add-mcp`` flag. The CLI shares the editor's ``.cursor/mcp.json`` config (project precedence). When ``mcp_config`` is supplied we write it to ``<workdir>/.cursor/mcp.json`` before spawn. Prompt: written to a temp file in the workdir and fed to ``cursor-agent`` via stdin redirection rather than as a positional argument. This avoids shell escaping pitfalls for multi-line prompts and keeps the argv short in process listings.

Adapter telemetry

When to pick which

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