...tasks.filter((task) => task.status !== "running" && task.status !== "pending"),

              ].slice(0, FLEET_ROWS_MAX);

        for (const child of fleetRows(shown, Math.max(20, width - 9))) {

        const childRows = fleetRows(shown, Math.max(20, width - 9));

        for (const [index, task] of shown.entries()) {

          const child = childRows[index];

          if (child === undefined) continue;

          const color = fleetColor(child.status);

          rows.push(

            `${DIM}${child.branch}${RESET} ${color}${child.mark}${RESET} ${DIM}${child.text}${RESET}`,

          );

          // Three lines of the child's own latest activity, nested under it.

          const activities = latestActivities([task], PREVIEW_ROWS);

          for (const activity of activities) {

            const text = truncate(activityPhrase(activity), Math.max(4, width - 12));

            rows.push(`${DIM}  → ${text}${RESET}`);

          }

        }

        const hidden = tasks.length - shown.length;

        if (hidden > 0) rows.push(`${DIM}   +${String(hidden)} more${RESET}`);

        const activities = latestActivities(tasks, PREVIEW_ROWS);

        if (activities.length > 0) {

          const boxWidth = Math.max(10, width - 4);

          const frame = `${DIM}╭${"─".repeat(boxWidth + 2)}╮${RESET}`;

          const floor = `${DIM}╰${"─".repeat(boxWidth + 2)}╯${RESET}`;

          const lines = activities.map((activity) => {

            const text = truncate(activityPhrase(activity), boxWidth);

            const pad = " ".repeat(Math.max(0, boxWidth - [...text].length));

            return `${DIM}│${RESET} ${text}${pad} ${DIM}│${RESET}`;

          });

          rows.push(frame, ...lines, floor);

        }

      }

      if (open) {

      registry.recordToolUse(id, { toolName: "shell", target: "mix test" });

    });

    const boxed = rows.filter((row) => /[╭╰]/.test(row) || row.includes(" │ "));

    expect(boxed).toHaveLength(5); // top border, three activity rows, floor.

    const text = boxed.join("\n");

    const delegateRow = rows.findIndex((row) => row.includes("delegate"));

    expect(delegateRow).toBeGreaterThan(0);

    const childRow = delegateRow + 1;

    const previews = rows.slice(childRow + 1, childRow + 4);

    expect(previews).toHaveLength(3);

    const text = previews.join("\n");

    expect(text).toContain("shell(mix test)");

    expect(text).toContain("edit(src/b.ts)");

    expect(text).toContain("bash(pnpm test)");

    expect(text).not.toContain("grep(needle)");

    // Newest last, so reading down is reading forward in time.

    const at = (phrase: string) => boxed.findIndex((row) => row.includes(phrase));

    const at = (phrase: string) => previews.findIndex((row) => row.includes(phrase));

    expect(at("bash(pnpm test)")).toBeLessThan(at("edit(src/b.ts)"));

    expect(at("edit(src/b.ts)")).toBeLessThan(at("shell(mix test)"));

  });

      registerChild(registry);

    });

    expect(rows.join("\n")).not.toContain("╭");

    expect(rows.join("\n")).not.toContain(" → ");

  });

});