feat(workspace): lead the chart with tonight's first action

AGENTS.md

@@ -1,7 +1,7 @@
 # AGENTS.md
 
 ## Project overview
-- BandScope is a local-first desktop app for rehearsal prep: a practical song view with likely harmony by section and by instrument or vocal role, form and groove cues, stems, playable ranges, simplification guidance, transposition or setup cues, part-overlap cues, visible confidence, and rehearsal priorities.
+- BandScope is a local-first desktop app for rehearsal prep: a practical song view with likely harmony by section and by instrument or vocal role, form and groove cues, stems, playable ranges, simplification guidance, transposition or setup cues, part-overlap cues, visible confidence, and rehearsal priorities. The ready workspace names tonight's first playable range and offers a download of tonight's first-action chart, so the chart file starts with what to play first.
 - Authoritative delivery rules live in `ARCHITECTURE.md`, `docs/plans/`, and the root verification scripts.
 - Brand, tone, UX copy, and prioritization rules live in `docs/brand-story.md` and must be applied to PRDs, TRDs, UI copy, onboarding, empty states, and error messages.
 - App security rules live in `docs/security/app-security.md` and must be applied to file handling, URL intake, subprocesses, IPC, WebView usage, model loading, updates, logging, cache handling, and export behavior.

ARCHITECTURE.md

@@ -82,10 +82,10 @@ Last updated: 2026-03-11
   - likely harmony by section and by role
   - section roadmap with entries, dropouts, pickups, stops, tags, and handoffs
   - groove and timing cues relevant to locking the band together
-  - playable ranges and density or overlap warnings, with the ready workspace naming tonight's first span and the next instrument check
+  - playable ranges and density or overlap warnings, with the ready workspace naming tonight's first span, the next instrument check, and a download of tonight's first-action chart
   - simplification, transposition, capo, tuning, or setup cues where applicable
   - role-specific rehearsal priorities and confidence flags
-  - cue-sheet or chart-style exports that summarize the analysis in rehearsal-friendly form
+  - cue-sheet or chart-style exports that summarize the analysis in rehearsal-friendly form, with the chart JSON leading with tonight's first playable-range action
 
 ## Confidence, edits, and provenance
 

CHANGELOG.md

@@ -4,6 +4,7 @@
 
 ### Added
 
+- Lead the chart JSON with tonight's first playable-range action and name that download on the rehearsal map.
 - Name tonight's first playable range on the ready rehearsal map and tell the player to check that span on their instrument before the section.
 - Display the analyzed song tempo (BPM) as a badge in the rehearsal workspace.
 - 각 합주 역할(Role)별 개인 연습 진행도를 0~100% 범위로 기록 및 시각화할 수 있는 연습 진척도(`practiceProgress`) 트래커 기능 추가. UI 컨트롤(슬라이더 및 +/- 버튼)과 한/영 다국어 지원 포함.

CLAUDE.md

@@ -51,7 +51,7 @@ BandScope is a local-first desktop app for rehearsal prep: it turns a song into
 
 Three layers, decoupled through shared contracts:
 
-- `apps/desktop` — Tauri 2 + Vite + React 19 shell (Tailwind 4, Base UI, Storybook). Feature screens live in `src/features/` (home, workspace, chords, ranges, player, settings). The ready workspace names tonight's first playable range and the next instrument check. `src/lib/analysis.ts` and `src/lib/job_runner.ts` call typed Tauri IPC commands, with a browser fallback that serves demo data when not running inside Tauri.
+- `apps/desktop` — Tauri 2 + Vite + React 19 shell (Tailwind 4, Base UI, Storybook). Feature screens live in `src/features/` (home, workspace, chords, ranges, player, settings). The ready workspace names tonight's first playable range, the next instrument check, and a download of tonight's first-action chart. `src/lib/analysis.ts` and `src/lib/job_runner.ts` call typed Tauri IPC commands, with a browser fallback that serves demo data when not running inside Tauri.
 - `apps/desktop/src-tauri/src/main.rs` — the Rust orchestration boundary. Tauri commands (`start_analysis_job`, `get_analysis_job_status`, `select_local_audio_source`, `import_youtube_url`) validate untrusted input (project IDs, file paths, URLs) and spawn the Python engine as a subprocess. There is no loopback HTTP listener and no network path for local analysis.
 - `services/analysis-engine` — Python package `bandscope_analysis` (librosa/numpy). Entry point `cli.py` reads a JSON job request on stdin and prints a structured job-status JSON envelope on stdout (`--progress-jsonl` streams progress lines). `api.py` orchestrates the pipeline across the `separation`, `sections`, `roles`, `chords`, `ranges`, `temporal`, `transcription`, and `youtube` modules.
 

apps/desktop/src/features/workspace/Workspace.chartExport.test.tsx

@@ -0,0 +1,60 @@
+import { fireEvent, render, screen } from "@testing-library/react";
+import { createDemoRehearsalSong } from "@bandscope/shared-types";
+import { afterEach, describe, expect, it, vi } from "vitest";
+import { Workspace } from "./Workspace";
+
+const originalLanguage = navigator.language;
+const originalCreateObjectUrl = URL.createObjectURL;
+const originalRevokeObjectUrl = URL.revokeObjectURL;
+
+function setNavigatorLanguage(language: string) {
+  Object.defineProperty(navigator, "language", {
+    configurable: true,
+    value: language
+  });
+}
+
+describe("Workspace chart export contract", () => {
+  afterEach(() => {
+    setNavigatorLanguage(originalLanguage);
+    vi.restoreAllMocks();
+    Object.defineProperty(URL, "createObjectURL", {
+      configurable: true,
+      value: originalCreateObjectUrl
+    });
+    Object.defineProperty(URL, "revokeObjectURL", {
+      configurable: true,
+      value: originalRevokeObjectUrl
+    });
+  });
+
+  it("keeps the full-band chart lead stable when the UI role changes", async () => {
+    setNavigatorLanguage("en-US");
+    const song = createDemoRehearsalSong();
+    const createObjectUrl = vi.fn(() => "blob:full-band-chart");
+    vi.spyOn(HTMLAnchorElement.prototype, "click").mockImplementation(() => undefined);
+    Object.defineProperty(URL, "createObjectURL", {
+      configurable: true,
+      value: createObjectUrl
+    });
+    Object.defineProperty(URL, "revokeObjectURL", {
+      configurable: true,
+      value: vi.fn()
+    });
+
+    render(<Workspace song={song} />);
+    fireEvent.click(screen.getByRole("tab", { name: "Lead Vocal" }));
+    fireEvent.click(screen.getByRole("button", { name: "Download tonight's first-action chart" }));
+
+    const blob = createObjectUrl.mock.calls[0]?.[0] as Blob;
+    const payload = JSON.parse(await blob.text()) as {
+      firstAction?: { role?: string };
+      sections?: Array<{ roles?: Array<{ name?: string }> }>;
+    };
+
+    expect(payload.firstAction?.role).toBe("Bass Guitar");
+    expect(payload.sections?.[0]?.roles?.map((role) => role.name)).toEqual(
+      expect.arrayContaining(["Bass Guitar", "Lead Vocal"])
+    );
+  });
+});

apps/desktop/src/features/workspace/Workspace.test.tsx

@@ -196,6 +196,68 @@ describe("Workspace", () => {
     );
   });
 
+  it("names tonight's first-action chart download and leads the file with that action", async () => {
+    setNavigatorLanguage("en-US");
+    const song = createDemoRehearsalSong();
+    const createObjectUrl = vi.fn(() => "blob:chart");
+    const revokeObjectUrl = vi.fn();
+    const click = vi.spyOn(HTMLAnchorElement.prototype, "click").mockImplementation(() => undefined);
+    Object.defineProperty(URL, "createObjectURL", {
+      configurable: true,
+      value: createObjectUrl
+    });
+    Object.defineProperty(URL, "revokeObjectURL", {
+      configurable: true,
+      value: revokeObjectUrl
+    });
+
+    render(<Workspace song={song} />);
+
+    const download = screen.getByRole("button", { name: "Download tonight's first-action chart" });
+    fireEvent.click(download);
+
+    const blob = createObjectUrl.mock.calls[0]?.[0] as Blob;
+    const payload = JSON.parse(await blob.text());
+    expect(Object.keys(payload)[1]).toBe("firstAction");
+    expect(payload.firstAction).toEqual({
+      section: "verse",
+      role: "Bass Guitar",
+      lowestNote: "C#2",
+      highestNote: "E3",
+      next: "Bass Guitar sits C#2–E3 in verse. Hear that clash on your instrument before the verse."
+    });
+    expect(click).toHaveBeenCalledTimes(1);
+    expect(revokeObjectUrl).toHaveBeenCalledWith("blob:chart");
+  });
+
+  it("does not invent a first-action chart lead when the first range still needs an ear check", async () => {
+    setNavigatorLanguage("en-US");
+    const song = createDemoRehearsalSong();
+    song.sections[0]!.roles = song.sections[0]!.roles.map((role) => ({
+      ...role,
+      range: { lowestNote: "", highestNote: "none" },
+      overlapWarnings: []
+    }));
+    const createObjectUrl = vi.fn(() => "blob:chart-missing");
+    vi.spyOn(HTMLAnchorElement.prototype, "click").mockImplementation(() => undefined);
+    Object.defineProperty(URL, "createObjectURL", {
+      configurable: true,
+      value: createObjectUrl
+    });
+    Object.defineProperty(URL, "revokeObjectURL", {
+      configurable: true,
+      value: vi.fn()
+    });
+
+    render(<Workspace song={song} />);
+    fireEvent.click(screen.getByRole("button", { name: "Download tonight's first-action chart" }));
+
+    const blob = createObjectUrl.mock.calls[0]?.[0] as Blob;
+    const payload = JSON.parse(await blob.text());
+    expect(payload.firstAction).toBeUndefined();
+    expect(Object.keys(payload)).toEqual(["title", "headline", "sections"]);
+  });
+
   it("falls back from blank planning copy and tolerates partial collaboration payloads", () => {
     setNavigatorLanguage("en-US");
     const song = createDemoRehearsalSong();
@@ -325,5 +387,6 @@ describe("Workspace", () => {
     expect(screen.getByText("스템")).toBeTruthy();
     expect(screen.getByText("합주 우선순위")).toBeTruthy();
     expect(screen.getByText("역할과 화성")).toBeTruthy();
+    expect(screen.getByRole("button", { name: "오늘 먼저 할 일 차트 받기" })).toBeTruthy();
   });
 });

apps/desktop/src/features/workspace/Workspace.tsx

@@ -5,6 +5,7 @@ import { SectionRoadmap } from "./SectionRoadmap";
 import { GrooveMap } from "./GrooveMap";
 import { PracticeProgress } from "./PracticeProgress";
 import { fillRangeCopy, firstRangeSqueeze } from "./firstRangeSqueeze";
+import { firstChartAction } from "./firstChartAction";
 import { createTranslator, detectPreferredLocale } from "../../i18n";
 import { generateCueSheetCsv, generateChartSummaryJson, generateMetadataHandoffJson, sanitizeFilename } from "../../lib/export";
 import { Button } from "@/components/ui/button";
@@ -234,7 +235,7 @@ export function Workspace({ song, sourceBootstrap = null, onSongUpdate }: Worksp
 
   /** Documented. */
   const handleExportChart = () => {
-    const json = generateChartSummaryJson(song);
+    const json = generateChartSummaryJson(song, { firstAction: firstChartAction(song, activeRole, t) });
     downloadTextFile(json, "application/json;charset=utf-8;", `${sanitizeFilename(song.title)}_chart.json`);
   };
 
@@ -285,7 +286,7 @@ export function Workspace({ song, sourceBootstrap = null, onSongUpdate }: Worksp
                 className="min-h-10 border-white/10 bg-white/5 font-semibold text-slate-100 shadow-sm hover:bg-white/10 hover:text-white"
             >
                 <Download className="mr-2 size-4 text-slate-300" aria-hidden="true" />
-              Export Chart (JSON)
+              {t("workspaceFirstRangeDownloadChart")}
             </Button>
             <Button
               variant="outline"

apps/desktop/src/features/workspace/firstChartAction.test.ts

@@ -0,0 +1,69 @@
+import { createDemoRehearsalSong, type RehearsalSong } from "@bandscope/shared-types";
+import { describe, expect, it } from "vitest";
+import { createTranslator } from "../../i18n";
+import { firstChartAction } from "./firstChartAction";
+
+describe("firstChartAction", () => {
+  const t = createTranslator("en");
+
+  it("leads with the first clashing span and the instrument-check next action", () => {
+    expect(firstChartAction(createDemoRehearsalSong(), null, t)).toEqual({
+      section: "verse",
+      role: "Bass Guitar",
+      lowestNote: "C#2",
+      highestNote: "E3",
+      next: "Bass Guitar sits C#2–E3 in verse. Hear that clash on your instrument before the verse."
+    });
+  });
+
+  it("keeps the full-band lead when a UI role is selected", () => {
+    const action = firstChartAction(createDemoRehearsalSong(), "lead-vocal", t);
+
+    expect(action?.role).toBe("Bass Guitar");
+    expect(action?.lowestNote).toBe("C#2");
+    expect(action?.highestNote).toBe("E3");
+    expect(action?.next).toBe(
+      "Bass Guitar sits C#2–E3 in verse. Hear that clash on your instrument before the verse."
+    );
+  });
+
+  it("uses the check copy when the first span has no clash", () => {
+    const song = createDemoRehearsalSong();
+    song.sections[0]!.roles = song.sections[0]!.roles.map((role) => ({
+      ...role,
+      overlapWarnings: []
+    }));
+
+    expect(firstChartAction(song, null, t)?.next).toBe(
+      "Bass Guitar sits C#2–E3 in verse. Check that span on your instrument before the verse."
+    );
+  });
+
+  it("returns null when no named span exists", () => {
+    const song = createDemoRehearsalSong();
+    song.sections[0]!.roles = song.sections[0]!.roles.map((role) => ({
+      ...role,
+      range: { lowestNote: "", highestNote: "none" },
+      overlapWarnings: []
+    }));
+
+    expect(firstChartAction(song, null, t)).toBeNull();
+  });
+
+  it("fails closed on malformed runtime collections", () => {
+    expect(firstChartAction(null as unknown as RehearsalSong, null, t)).toBeNull();
+  });
+
+  it("keeps formula-shaped role names literal so JSON encoding can neutralize them later", () => {
+    const song = createDemoRehearsalSong();
+    song.sections[0]!.roles[0] = {
+      ...song.sections[0]!.roles[0]!,
+      name: "=HYPERLINK(\"http://evil\")"
+    };
+
+    expect(firstChartAction(song, "bass-guitar", t)).toMatchObject({
+      role: "=HYPERLINK(\"http://evil\")",
+      next: "=HYPERLINK(\"http://evil\") sits C#2–E3 in verse. Hear that clash on your instrument before the verse."
+    });
+  });
+});

apps/desktop/src/features/workspace/firstChartAction.ts

@@ -0,0 +1,43 @@
+import type { RehearsalSong } from "@bandscope/shared-types";
+import type { TranslationKey } from "../../i18n";
+import type { ChartFirstAction } from "../../lib/export";
+import { fillRangeCopy, firstRangeSqueeze } from "./firstRangeSqueeze";
+
+/** Documented. */
+type Translator = (key: TranslationKey) => string;
+
+/**
+ * Build tonight's first-action lead for the full-band rehearsal chart JSON.
+ *
+ * Uses the same playable-span authority as the ready map. Values stay
+ * literal so JSON encoding, not this helper, is the serialization boundary.
+ * Malformed songs and unnamed spans fail closed instead of inventing a lead.
+ */
+export function firstChartAction(
+  song: RehearsalSong,
+  activeRole: string | null,
+  t: Translator
+): ChartFirstAction | null {
+  // The chart body always contains the full band, so a transient UI role filter must not alter its lead.
+  void activeRole;
+  const squeeze = firstRangeSqueeze(song, null);
+  if (!squeeze) {
+    return null;
+  }
+
+  return {
+    section: squeeze.sectionLabel,
+    role: squeeze.roleName,
+    lowestNote: squeeze.lowestNote,
+    highestNote: squeeze.highestNote,
+    next: fillRangeCopy(
+      t(squeeze.overlapWarning ? "workspaceFirstRangeClash" : "workspaceFirstRangeCheck"),
+      {
+        roleName: squeeze.roleName,
+        lowestNote: squeeze.lowestNote,
+        highestNote: squeeze.highestNote,
+        sectionLabel: squeeze.sectionLabel
+      }
+    )
+  };
+}

apps/desktop/src/lib/export.test.ts

@@ -131,6 +131,7 @@ describe("export generation", () => {
     const parsed = JSON.parse(jsonStr);
     expect(parsed.title).toBe("Test");
     expect(parsed.sections[0].roles[0].chord).toBe("=Cmaj7");
+    expect(parsed.firstAction).toBeUndefined();
   });
 
   it("generates chart summary JSON when headline is missing", () => {
@@ -143,6 +144,33 @@ describe("export generation", () => {
     expect(parsed.headline).toBe("");
   });
 
+  it("leads the chart JSON with tonight's first action when a lead is provided", () => {
+    const jsonStr = generateChartSummaryJson(mockSong, {
+      firstAction: {
+        section: "verse",
+        role: "=HYPERLINK(\"http://evil\")",
+        lowestNote: "C2",
+        highestNote: "C3",
+        next: "=HYPERLINK(\"http://evil\") sits C2–C3 in verse. Check that span on your instrument before the verse."
+      }
+    });
+    const parsed = JSON.parse(jsonStr);
+    expect(Object.keys(parsed)).toEqual(["title", "firstAction", "headline", "sections"]);
+    expect(parsed.firstAction).toEqual({
+      section: "verse",
+      role: "=HYPERLINK(\"http://evil\")",
+      lowestNote: "C2",
+      highestNote: "C3",
+      next: "=HYPERLINK(\"http://evil\") sits C2–C3 in verse. Check that span on your instrument before the verse."
+    });
+    expect(parsed.sections[0].roles[0].chord).toBe("=Cmaj7");
+  });
+
+  it("does not invent a first action when the lead is omitted or null", () => {
+    expect(JSON.parse(generateChartSummaryJson(mockSong)).firstAction).toBeUndefined();
+    expect(JSON.parse(generateChartSummaryJson(mockSong, { firstAction: null })).firstAction).toBeUndefined();
+  });
+
   it("generates a metadata-only local handoff without source paths or transcription data", () => {
     const sourceBootstrap: ProjectBootstrapSummary = {
       projectId: "project-1",