diff --git a/packages/coding-agent/test/tools/lsp-regressions.test.ts b/packages/coding-agent/test/tools/lsp-regressions.test.ts
index 9403e673b..0030b8ec0 100644
--- a/packages/coding-agent/test/tools/lsp-regressions.test.ts
+++ b/packages/coding-agent/test/tools/lsp-regressions.test.ts
@@ -1,4 +1,4 @@
-import { afterEach, describe, expect, it, vi } from "bun:test";
+import { afterEach, beforeEach, describe, expect, it, vi } from "bun:test";
 import * as fs from "node:fs";
 import * as fsp from "node:fs/promises";
 import * as os from "node:os";
@@ -281,6 +281,33 @@ function textResult(result: AgentToolResult<LspToolDetails>): string {
 		.join("\n");
 }
 
+/**
+ * `loadConfig` walks the user config directories (~/.omp/agent, ~/.pi/agent,
+ * ~/.claude), which resolve from os.homedir(). A developer with a real
+ * lsp.json there flips loadConfig off its auto-detect path onto the override
+ * path, where their rootMarkers replace the packaged ones — so these tests
+ * would assert against that machine's config instead of the defaults. Point
+ * HOME at an empty directory so every case sees a pristine environment.
+ */
+let lspHomeOverride: string | undefined;
+let lspOriginalHome: string | undefined;
+
+beforeEach(() => {
+	lspOriginalHome = process.env.HOME;
+	lspHomeOverride = fs.mkdtempSync(path.join(os.tmpdir(), "omp-lsp-test-home-"));
+	process.env.HOME = lspHomeOverride;
+	// Bun's os.homedir() reads the passwd entry rather than $HOME, so the env
+	// var alone does not redirect the config walk.
+	vi.spyOn(os, "homedir").mockReturnValue(lspHomeOverride);
+});
+
+afterEach(() => {
+	if (lspOriginalHome === undefined) delete process.env.HOME;
+	else process.env.HOME = lspOriginalHome;
+	if (lspHomeOverride) fs.rmSync(lspHomeOverride, { recursive: true, force: true });
+	lspHomeOverride = undefined;
+});
+
 describe("lsp regressions", () => {
 	afterEach(() => {
 		vi.restoreAllMocks();