fix(viewer): hold file-path clicks to the card's modifier promise

showFileCard now records modifierPromised like the OSC 8 hover, and the
file-path provider's gate goes through the handler's new opensFileLink,
so a "Shift+click to open" card cannot be answered by a bare click after
the container drops mouse tracking. A click before the session's project
is known now toasts instead of doing nothing. Refusal-card tests assert
the card is present; a misplaced test comment is back on its test.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

app/src/components/terminal/TerminalView.test.tsx

@@ -1625,11 +1625,14 @@ describe("createOsc8LinkHandler — clicking a link Claude Code printed", () =>
     h.hover?.(new MouseEvent("mousemove"), "javascript:alert(1)", range);
     expect(onOpenFile).not.toHaveBeenCalled();
     expect(openUrlExternal).not.toHaveBeenCalled();
-    // The card, if any, is the refusal — never the target, never an offer to
-    // open it. (The brief asked for no card here; the existing test "says so
-    // on hover when the target would be refused" requires the refusal card.)
-    expect(hoverCard()?.textContent ?? "").not.toContain("javascript:");
-    expect(hoverCard()?.textContent ?? "").not.toContain("Open in viewer");
+    // The refusal card (ruling (a)): present, no origin, never the target,
+    // never an offer to open it.
+    const card = hoverCard();
+    expect(card).not.toBeNull();
+    expect(card!.querySelector('[data-testid="osc8-hover-origin"]')).toBeNull();
+    expect(card!.textContent).toContain("will not be opened");
+    expect(card!.textContent).not.toContain("javascript:");
+    expect(card!.textContent).not.toContain("Open in viewer");
   });
 
   it("refuses a file: target whose escapes do not decode", () => {
@@ -1638,7 +1641,11 @@ describe("createOsc8LinkHandler — clicking a link Claude Code printed", () =>
     h.activate(click(), "file:///workspace/%E0%A4%A", range);
     h.hover?.(new MouseEvent("mousemove"), "file:///workspace/%E0%A4%A", range);
     expect(onOpenFile).not.toHaveBeenCalled();
-    expect(hoverCard()?.textContent ?? "").not.toContain("Open in viewer");
+    const card = hoverCard();
+    expect(card).not.toBeNull();
+    expect(card!.querySelector('[data-testid="osc8-hover-origin"]')).toBeNull();
+    expect(card!.textContent).toContain("will not be opened");
+    expect(card!.textContent).not.toContain("Open in viewer");
   });
 
   it("the file: hover card names the viewer and the path", () => {
@@ -1657,6 +1664,19 @@ describe("createOsc8LinkHandler — clicking a link Claude Code printed", () =>
     expect(hoverCard()).toBeNull();
   });
 
+  it("holds a file-path click to the modifier its card promised", () => {
+    const h = createOsc8LinkHandler(() => host, () => state, vi.fn());
+    state.mouseTracking = true;
+    h.showFileCard("src/foo.ts");
+    expect(hoverCard()?.textContent).toContain("Shift+click");
+    state.mouseTracking = false;
+    expect(h.opensFileLink(click())).toBe(false);
+    expect(h.opensFileLink(click({ shiftKey: true }))).toBe(true);
+    // A card drawn with nothing tracking promises nothing.
+    h.showFileCard("src/foo.ts");
+    expect(h.opensFileLink(click())).toBe(true);
+  });
+
   it("declares allowNonHttpProtocols so file: targets reach it", () => {
     expect(createOsc8LinkHandler(() => host, () => state).allowNonHttpProtocols).toBe(true);
   });
@@ -1711,9 +1731,6 @@ describe("the link handler is wired into the terminal, and reads its live mode",
     expect(typeof handler.hover).toBe("function");
   });
 
-  // The gate has to ask the terminal, not a boolean captured at construction:
-  // the mode changes whenever the container prints a DECSET, which is several
-  // times a second in Claude Code.
   it("opens a file: target in the viewer against the session's project", async () => {
     vi.mocked(openFileViewer).mockClear();
     mountSession("bash");
@@ -1727,7 +1744,9 @@ describe("the link handler is wired into the terminal, and reads its live mode",
       await Promise.resolve();
     });
 
-    expect(openFileViewer).toHaveBeenCalledWith("p1", "/workspace/api/src/a b.ts");
+    expect(openFileViewer).toHaveBeenCalledWith(
+      "p1", "/workspace/api/src/a b.ts", undefined, undefined, undefined,
+    );
     expect(openUrlExternal).not.toHaveBeenCalled();
   });
 
@@ -1774,6 +1793,65 @@ describe("the link handler is wired into the terminal, and reads its live mode",
     expect(toasts.at(-1)?.dedupeKey).toBe("file-viewer-open");
   });
 
+  it("holds a plain-text file link to the modifier its hover card promised", async () => {
+    vi.mocked(openFileViewer).mockClear();
+    const platform = navigator.platform;
+    Object.defineProperty(navigator, "platform", { value: "Linux x86_64", configurable: true });
+    const register = vi.spyOn(Terminal.prototype, "registerLinkProvider");
+    try {
+      mountSession("claude");
+      const provider = register.mock.calls.at(-1)?.[0];
+      if (!provider) throw new Error("no link provider was registered");
+      await write("Edited src/foo.ts:42 today");
+      const links = vi.fn();
+      provider.provideLinks(1, links);
+      const [link] = links.mock.calls[0][0];
+
+      await write("\x1b[?1002h");
+      link.hover?.(new MouseEvent("mousemove"), link.text);
+      expect(document.body.textContent).toContain("Shift+click to open");
+      await write("\x1b[?1002l");
+
+      await act(async () => {
+        link.activate(new MouseEvent("click", { button: 0, detail: 1 }), link.text);
+        await Promise.resolve();
+      });
+      expect(openFileViewer).not.toHaveBeenCalled();
+
+      await act(async () => {
+        link.activate(
+          new MouseEvent("click", { button: 0, detail: 1, shiftKey: true }),
+          link.text,
+        );
+        await Promise.resolve();
+      });
+      expect(openFileViewer).toHaveBeenCalledWith("p1", "src/foo.ts", 42, undefined, undefined);
+    } finally {
+      register.mockRestore();
+      Object.defineProperty(navigator, "platform", { value: platform, configurable: true });
+    }
+  });
+
+  it("says the project is not ready rather than doing nothing", async () => {
+    vi.mocked(openFileViewer).mockClear();
+    useAppState.setState({ sessions: [] });
+    render(<TerminalView sessionId="s-unknown" active />);
+
+    wiredHandler().activate(
+      new MouseEvent("click", { button: 0, detail: 1 }),
+      "file:///workspace/api/README.md",
+      range,
+    );
+
+    expect(openFileViewer).not.toHaveBeenCalled();
+    const toasts = useAppState.getState().toasts;
+    expect(toasts.at(-1)?.detail).toContain("not ready yet");
+    expect(toasts.at(-1)?.dedupeKey).toBe("file-viewer-open");
+  });
+
+  // The gate has to ask the terminal, not a boolean captured at construction:
+  // the mode changes whenever the container prints a DECSET, which is several
+  // times a second in Claude Code.
   it("refuses a plain click once the container turns mouse tracking on", async () => {
     mountSession("claude");
     await write("\x1b[?1002h");

app/src/components/terminal/TerminalView.tsx

@@ -140,6 +140,30 @@ function reportOpenFailure(e: unknown) {
   });
 }
 
+/**
+ * Open a path in the file viewer for this terminal's project, or say why not.
+ * The session record (and so the project) can arrive after the first render;
+ * a click in that window gets a toast rather than silently doing nothing.
+ */
+function openInViewer(
+  projectId: string | undefined,
+  path: string,
+  line?: number,
+  col?: number,
+  endLine?: number,
+): void {
+  if (!projectId) {
+    useAppState.getState().pushToast({
+      kind: "error",
+      message: "Could not open the file",
+      detail: "This terminal's project is not ready yet",
+      dedupeKey: "file-viewer-open",
+    });
+    return;
+  }
+  openFileViewer(projectId, path, line, col, endLine).catch(reportViewerFailure);
+}
+
 /** Report a file-viewer open that the backend refused (not found, no container, cap). */
 function reportViewerFailure(e: unknown): void {
   useAppState.getState().pushToast({
@@ -164,10 +188,17 @@ export type Osc8LinkHandler = ILinkHandler & {
   /**
    * Draw the "Open in viewer" card for a path matched in plain text by the
    * file-path link provider. Takes the raw path (a relative path stays
-   * relative — `file://src/x` would parse `src` as a host), and leaves
-   * `modifierPromised` alone: the provider applies its own gate.
+   * relative — `file://src/x` would parse `src` as a host). Records the
+   * card's modifier promise exactly as `hover` does, so
+   * {@link opensFileLink} can hold the click to it.
    */
   showFileCard(path: string): void;
+  /**
+   * The file-path provider's click gate: {@link opensOnClick} with whatever
+   * the card on screen promised. There is only ever one card, and `clear()`
+   * resets the promise with it, so sharing the flag with OSC 8 links is exact.
+   */
+  opensFileLink(event: MouseEvent): boolean;
 };
 
 /**
@@ -652,11 +683,19 @@ export function createOsc8LinkHandler(
       clear();
       const host = getHost();
       if (!host) return;
+      const ctx = readState();
+      // Same promise as `hover`: the card names a modifier, so the click is
+      // held to it even if the container drops tracking before it lands.
+      modifierPromised = ctx.mouseTracking;
       card = makeCard();
-      fillFileCard(card, path, readState());
+      fillFileCard(card, path, ctx);
       host.appendChild(card);
     },
 
+    opensFileLink(event) {
+      return opensOnClick(event, readState(), modifierPromised);
+    },
+
     allowNonHttpProtocols: true,
   };
 }
@@ -998,11 +1037,7 @@ export default function TerminalView({ sessionId, active }: Props) {
       linkHandler: (osc8LinkHandlerRef.current = createOsc8LinkHandler(
         () => term.element ?? null,
         () => readClickContext(term),
-        (path) => {
-          if (projectIdRef.current) {
-            openFileViewer(projectIdRef.current, path).catch(reportViewerFailure);
-          }
-        },
+        (path) => openInViewer(projectIdRef.current, path),
       )),
       fontFamily: "'JetBrains Mono', 'Fira Code', 'Cascadia Code', Menlo, Monaco, monospace",
       theme: {
@@ -1073,17 +1108,15 @@ export default function TerminalView({ sessionId, active }: Props) {
 
     // File paths in plain text open in the file viewer. Registered after the
     // addon so URLs are claimed first; the matcher also refuses anything
-    // inside a `scheme://` span. Same gate as the URL branch above. The hover
-    // card is the OSC 8 handler's, fed the raw path (see `showFileCard`).
+    // inside a `scheme://` span. The hover card is the OSC 8 handler's, fed the
+    // raw path, and the click gate honours the modifier that card promised.
     const filePathLinks = term.registerLinkProvider(
       createFilePathLinkProvider(
         term,
-        (m: FilePathMatch) => {
-          const pid = projectIdRef.current;
-          if (!pid) return;
-          openFileViewer(pid, m.path, m.line, m.col, m.endLine).catch(reportViewerFailure);
-        },
-        (event) => opensOnClick(event, readClickContext(term)),
+        (m: FilePathMatch) =>
+          openInViewer(projectIdRef.current, m.path, m.line, m.col, m.endLine),
+        // Held to what the card promised, like OSC 8 links (see `showFileCard`).
+        (event) => osc8LinkHandlerRef.current?.opensFileLink(event) ?? false,
         {
           show: (path) => osc8LinkHandlerRef.current?.showFileCard(path),
           hide: () => osc8LinkHandlerRef.current?.dismiss(),