diff --git a/test/collections-config.test.ts b/test/collections-config.test.ts
index 3d961d1..b6b15fe 100644
--- a/test/collections-config.test.ts
+++ b/test/collections-config.test.ts
@@ -23,6 +23,8 @@ beforeEach(() => {
 });
 
 afterEach(() => {
+  // Reset index name to default (prevents leaking into other test files under bun test)
+  setConfigIndexName("index");
   for (const [key, val] of Object.entries(savedEnv)) {
     if (val === undefined) {
       delete process.env[key];
diff --git a/test/mcp.test.ts b/test/mcp.test.ts
index 881874d..e09df8b 100644
--- a/test/mcp.test.ts
+++ b/test/mcp.test.ts
@@ -16,6 +16,7 @@ import { join } from "node:path";
 import { tmpdir } from "node:os";
 import YAML from "yaml";
 import type { CollectionConfig } from "../src/collections";
+import { setConfigIndexName } from "../src/collections";
 
 // =============================================================================
 // Test Database Setup
@@ -206,6 +207,9 @@ describe("MCP Server", () => {
     // Use shared singleton to avoid creating multiple instances with separate GPU resources
     getDefaultLlamaCpp();
 
+    // Reset index name in case another test file mutated it (bun test shares process)
+    setConfigIndexName("index");
+
     // Set up test config directory
     const configPrefix = join(tmpdir(), `qmd-mcp-config-${Date.now()}-${Math.random().toString(36).slice(2)}`);
     testConfigDir = await mkdtemp(configPrefix);