diff --git a/src/tools/filesystem/grep_files.zig b/src/tools/filesystem/grep_files.zig
index f2244c6f3..561136e22 100644
--- a/src/tools/filesystem/grep_files.zig
+++ b/src/tools/filesystem/grep_files.zig
@@ -1,4 +1,5 @@
 const std = @import("std");
+const build_options = @import("build_options");
 const glob_pattern = @import("../../core/workspace/glob_pattern.zig");
 const grep_search = @import("../../core/workspace/grep_search.zig");
 const tool_files = @import("../../core/workspace/tool_files.zig");
@@ -165,7 +166,22 @@ pub fn validate(_: tool_dispatch.DispatchContext, _: tool_dispatch.ToolInput) to
 
 /// Searches the resolved root and returns an owned tool result body.
 pub fn call(ctx: tool_dispatch.DispatchContext, erased: tool_dispatch.ToolInput) tool_dispatch.DispatchError!tool_dispatch.ToolResult {
-    return callWithOps(ctx, erased, .{});
+    const result = try callWithOps(ctx, erased, .{});
+    holdForTest();
+    return result;
+}
+
+// Only `tests/e2e/tui-interrupt-recovery.test.ts` sets
+// `FX_E2E_GREP_RELEASE`: a finished search then waits until the file it
+// names exists, so the test can cancel the turn while the tool is still
+// running. The libfx artifacts leave it out.
+fn holdForTest() void {
+    if (comptime build_options.libfx) return;
+    const release_path = io_mod.getenv("FX_E2E_GREP_RELEASE") orelse return;
+    while (true) : (io_mod.sleep(std.time.ns_per_ms)) {
+        std.Io.Dir.accessAbsolute(io_mod.getIo(), release_path, .{}) catch continue;
+        return;
+    }
 }
 
 const StatRootFn = *const fn ([]const u8) anyerror!std.Io.File.Stat;
diff --git a/tests/e2e/tui-interrupt-recovery.test.ts b/tests/e2e/tui-interrupt-recovery.test.ts
index b67d7bfdb..96dcfdb26 100644
--- a/tests/e2e/tui-interrupt-recovery.test.ts
+++ b/tests/e2e/tui-interrupt-recovery.test.ts
@@ -853,20 +853,14 @@ while :; do sleep 1; done
       const corpus = join(workspace, "corpus");
       const stderrPath = join(root, "stderr.log");
       const tracePath = join(root, "trace.log");
+      const releasePath = join(root, "grep-release");
       const pattern = "LATE_SUCCESS_NEEDLE";
       const callId = "late_success_grep";
       mkdirSync(join(home, ".fx"), { recursive: true });
       mkdirSync(corpus, { recursive: true });
       writeFileSync(join(home, ".fx", "settings.json"), "{}");
-      // The search must still be running when the second Escape lands, about
-      // half a second after it starts. Linux searches 30,000 files in about a
-      // third of a second, so it needs a larger corpus than macOS.
-      const corpusFiles = process.platform === "darwin" ? 30_000 : 120_000;
-      for (let index = 0; index < corpusFiles; index += 1) {
-        writeFileSync(
-          join(corpus, `candidate-${String(index).padStart(6, "0")}.txt`),
-          "ordinary corpus text\n",
-        );
+      for (let index = 0; index < 3; index += 1) {
+        writeFileSync(join(corpus, `candidate-${index}.txt`), "ordinary corpus text\n");
       }
 
       gateway = startFakeGateway([
@@ -892,6 +886,9 @@ while :; do sleep 1; done
           FX_MODEL: FAKE_GATEWAY_MODEL,
           FX_TRACE_SCOPES: `${TRACE_SCOPES},tool,ui_activity`,
           FX_TRACE_LOG: tracePath,
+          // The search holds its result until this file exists, so it is
+          // still running when the turn is cancelled.
+          FX_E2E_GREP_RELEASE: releasePath,
         },
       });
       await session.waitForComposer(TIMEOUT);
@@ -909,6 +906,10 @@ while :; do sleep 1; done
       await session.sendKeys("Escape");
       await session.waitForText("What can fx do differently?", TIMEOUT);
       expect(Date.now() - cancelStartedAt).toBeLessThan(500);
+      expect(readTrace(tracePath)).not.toContain(
+        `event=after_tool_execution call_id=${callId}`,
+      );
+      writeFileSync(releasePath, "");
       await waitForTrace(tracePath, `event=after_tool_execution`, TIMEOUT);
       await waitForTrace(tracePath, "finish processing queued=0", TIMEOUT);