diff --git a/src/features/tmux-subagent/pane-state-querier-runner.test.ts b/src/features/tmux-subagent/pane-state-querier-runner.test.ts
new file mode 100644
index 000000000..e3965c34b
--- /dev/null
+++ b/src/features/tmux-subagent/pane-state-querier-runner.test.ts
@@ -0,0 +1,76 @@
+import { beforeEach, describe, expect, it, mock } from "bun:test"
+
+import type { TmuxCommandResult } from "../../shared/tmux"
+
+const paneStateQuerierSpecifier = import.meta.resolve("./pane-state-querier")
+const loggerSpecifier = import.meta.resolve("../../shared")
+const runnerSpecifier = import.meta.resolve("../../shared/tmux")
+const tmuxPathResolverSpecifier = import.meta.resolve("../../tools/interactive-bash/tmux-path-resolver")
+
+const runTmuxCommandMock = mock(async (): Promise<TmuxCommandResult> => ({
+	success: true,
+	output: "",
+	stdout: "",
+	stderr: "",
+	exitCode: 0,
+}))
+const getTmuxPathMock = mock(async (): Promise<string | undefined> => "sh")
+const logMock = mock(() => undefined)
+
+async function loadQueryWindowState(): Promise<typeof import("./pane-state-querier").queryWindowState> {
+	const module = await import(`${paneStateQuerierSpecifier}?test=${crypto.randomUUID()}`)
+	return module.queryWindowState
+}
+
+function registerModuleMocks(): void {
+	mock.module(loggerSpecifier, () => ({ log: logMock }))
+	mock.module(runnerSpecifier, () => ({ runTmuxCommand: runTmuxCommandMock }))
+	mock.module(tmuxPathResolverSpecifier, () => ({ getTmuxPath: getTmuxPathMock }))
+}
+
+describe("queryWindowState runner integration", () => {
+	beforeEach(() => {
+		mock.restore()
+		registerModuleMocks()
+		runTmuxCommandMock.mockClear()
+		getTmuxPathMock.mockClear()
+		logMock.mockClear()
+
+		runTmuxCommandMock.mockResolvedValue({
+			success: true,
+			output: "%0\t120\t40\t0\t0\t1\t120\t40\t\n%1\t60\t40\t60\t0\t0\t120\t40\tagent",
+			stdout: "%0\t120\t40\t0\t0\t1\t120\t40\t\n%1\t60\t40\t60\t0\t0\t120\t40\tagent",
+			stderr: "",
+			exitCode: 0,
+		})
+		getTmuxPathMock.mockResolvedValue("sh")
+	})
+
+	it("#given source pane id #when queryWindowState called #then delegates list-panes to shared runner", async () => {
+		// given
+		const queryWindowState = await loadQueryWindowState()
+
+		// when
+		const result = await queryWindowState("%0")
+
+		// then
+		expect(result).not.toBeNull()
+		if (!result?.mainPane) {
+			throw new Error("Expected window state")
+		}
+		expect(result.mainPane.paneId).toBe("%0")
+		expect(result.agentPanes.map((pane) => pane.paneId)).toEqual(["%1"])
+		expect(runTmuxCommandMock.mock.calls).toEqual([
+			[
+				expect.any(String),
+				[
+					"list-panes",
+					"-t",
+					"%0",
+					"-F",
+					"#{pane_id}\t#{pane_width}\t#{pane_height}\t#{pane_left}\t#{pane_top}\t#{pane_active}\t#{window_width}\t#{window_height}\t#{pane_title}",
+				],
+			],
+		])
+	})
+})