diff --git a/src/shared/tmux/tmux-utils/pane-dimensions.test.ts b/src/shared/tmux/tmux-utils/pane-dimensions.test.ts
new file mode 100644
index 000000000..f526035cb
--- /dev/null
+++ b/src/shared/tmux/tmux-utils/pane-dimensions.test.ts
@@ -0,0 +1,51 @@
+import { beforeEach, describe, expect, it, mock } from "bun:test"
+
+import type { TmuxCommandResult } from "../runner"
+
+const paneDimensionsSpecifier = import.meta.resolve("./pane-dimensions")
+const runnerSpecifier = import.meta.resolve("../runner")
+const tmuxPathResolverSpecifier = import.meta.resolve("../../../tools/interactive-bash/tmux-path-resolver")
+
+const runTmuxCommandMock = mock(async (): Promise<TmuxCommandResult> => ({
+	success: true,
+	output: "80,160",
+	stdout: "80,160",
+	stderr: "",
+	exitCode: 0,
+}))
+const getTmuxPathMock = mock(async (): Promise<string | undefined> => "sh")
+
+async function loadGetPaneDimensions(): Promise<typeof import("./pane-dimensions").getPaneDimensions> {
+	const module = await import(`${paneDimensionsSpecifier}?test=${crypto.randomUUID()}`)
+	return module.getPaneDimensions
+}
+
+function registerModuleMocks(): void {
+	mock.module(runnerSpecifier, () => ({ runTmuxCommand: runTmuxCommandMock }))
+	mock.module(tmuxPathResolverSpecifier, () => ({ getTmuxPath: getTmuxPathMock }))
+}
+
+describe("getPaneDimensions runner integration", () => {
+	beforeEach(() => {
+		registerModuleMocks()
+		runTmuxCommandMock.mockClear()
+		getTmuxPathMock.mockClear()
+
+		runTmuxCommandMock.mockResolvedValue({ success: true, output: "80,160", stdout: "80,160", stderr: "", exitCode: 0 })
+		getTmuxPathMock.mockResolvedValue("sh")
+	})
+
+	it("#given pane id #when getPaneDimensions called #then delegates display to shared runner", async () => {
+		// given
+		const getPaneDimensions = await loadGetPaneDimensions()
+
+		// when
+		const result = await getPaneDimensions("%42")
+
+		// then
+		expect(result).toEqual({ paneWidth: 80, windowWidth: 160 })
+		expect(runTmuxCommandMock.mock.calls).toEqual([
+			[[expect.any(String), ["display", "-p", "-t", "%42", "#{pane_width},#{window_width}"]]][0],
+		])
+	})
+})
diff --git a/src/shared/tmux/tmux-utils/pane-dimensions.ts b/src/shared/tmux/tmux-utils/pane-dimensions.ts
index d16238e85..aeda1448e 100644
--- a/src/shared/tmux/tmux-utils/pane-dimensions.ts
+++ b/src/shared/tmux/tmux-utils/pane-dimensions.ts
@@ -1,4 +1,3 @@
-import { spawn } from "../../bun-spawn-shim"
 import { getTmuxPath } from "../../../tools/interactive-bash/tmux-path-resolver"
 
 export interface PaneDimensions {
@@ -11,17 +10,13 @@ export async function getPaneDimensions(
 ): Promise<PaneDimensions | null> {
 	const tmux = await getTmuxPath()
 	if (!tmux) return null
+	const { runTmuxCommand } = await import("../runner")
 
-	const proc = spawn(
-		[tmux, "display", "-p", "-t", paneId, "#{pane_width},#{window_width}"],
-		{ stdout: "pipe", stderr: "pipe" },
-	)
-	const exitCode = await proc.exited
-	const stdout = await new Response(proc.stdout).text()
+	const result = await runTmuxCommand(tmux, ["display", "-p", "-t", paneId, "#{pane_width},#{window_width}"])
 
-	if (exitCode !== 0) return null
+	if (result.exitCode !== 0) return null
 
-	const [paneWidth, windowWidth] = stdout.trim().split(",").map(Number)
+	const [paneWidth, windowWidth] = result.output.trim().split(",").map(Number)
 	if (Number.isNaN(paneWidth) || Number.isNaN(windowWidth)) return null
 
 	return { paneWidth, windowWidth }