bernstein 2.0.0: a web UI ships in the wheel, CLI unchanged

bernstein gui serve

One command boots a FastAPI server with the SPA mounted at /ui and the full /api/v1/* surface attached. Default http://127.0.0.1:8052/ui/. The Vite bundle is committed under src/bernstein/gui/static/, so wheel installs work without a Node toolchain.

bernstein gui serve               # http://127.0.0.1:8052/ui/
bernstein gui serve --dev         # expects `npm run dev` on :5173
bernstein gui serve --minimal     # skip the full /api/v1/* surface

Tabs: Tasks, Agents, Approvals, Audit, Costs, Fleet (scaffold), Settings (placeholder).

Per-task drawer

Click a task row, side drawer with six tabs:

• Summary — KPIs (tokens, cost, branch, approvals), plan steps from progress_log.
• Logs — SSE-streamed live logs with ANSI rendering, virtualised list, search, level filters, keyboard shortcuts, throughput stats.
• Diff — git diff <base>...<branch> rendered split or unified, syntax-highlighted, copy + .patch download.
• Gates — quality-gate report with status buckets (passing / failing / pending / skipped), auto-expand on failures, polling that pauses on terminal tasks.
• Deps — upstream / downstream task graph for depends_on.
• Trace — timeline from .sdd/traces/{task_id}.jsonl with filter chips and search.

Agents

Live grid of running agent sessions. Each card shows status, current task, and a four-metric strip (duration, tokens in, tokens out, cost). Side drawer opens with a stacked token meter (prompt / context / tools), live log tail with INFO / PLAN / PASS / WARN / WAIT / LIVE colouring, and a kill-session action.

Why this is shipped intentionally minimal

This is a solo project. The core orchestrator is already a stretch to keep up with on one set of hands. The web UI is here because operators asked for it and the core was ready for it — not because it's on the immediate roadmap.

What that means in practice:

• A11y audit, dark / light theme toggle, mobile-responsive pass, Settings screen wiring, Fleet UI, front-end test suite, Playwright e2e — all open, all contributor-welcome.
• House rule: no new heavy front-end deps without a strong reason. The current stack is intentionally small (React + React Router + React Query + Tailwind + sse-starlette). No Redux, MUI, Recharts.
• Backend is the source of truth. The SPA should never make a decision the backend can't replay.

If you want to pick something up, the canonical pointer is issue #1262 — list of contributor-scoped items, run-it-locally instructions, and the house rules.

Fixes that came in the same cut

Three orchestrator bugs landed alongside the UI, found while integrating it:

• Per-step cli: / model: directives were silently collapsing onto the role default in plan-driven runs. Three dispatch-pipeline bugs (POST payload dropping model / effort, role config.yaml clobbering per-task pin, merge gate ignoring cli mismatch). Pinned by tests/unit/test_per_step_routing.py. #1259.
• Startup banner had regressed. bernstein run / bernstein conduct regained the banner — an earlier commit had silently dropped it under a false "already printed" comment. Pinned by tests/unit/cli/test_run_banner.py. #1257.
• Manager → task-server auth was failing in nested-process spawn (#1261). Operator reported a manager that posted seed tasks but never created children; root cause was a stripped bearer token in the spawn env. Fixed in #1266, watchdog detector in #1267, regression test in #1265.

Upgrade path

pip install --upgrade bernstein
bernstein gui serve

That's the entire upgrade. v1.10.x configs and plans run unchanged. bernstein (no args), bernstein run, bernstein conduct, bernstein live, bernstein dashboard — all unchanged.

Full release notes (with the wave-4 PR table): docs/release-notes/v2.0.0.md.

related

• v1.10.x recap for the cycle this release closes out.
• community spotlight, april 2026 for the contributor stories that fed the wave-4 wishlist.