diff --git a/src/gateway/server-discovery-runtime.ts b/src/gateway/server-discovery-runtime.ts
index e2179391a..22f56621f 100644
--- a/src/gateway/server-discovery-runtime.ts
+++ b/src/gateway/server-discovery-runtime.ts
@@ -17,7 +17,12 @@ export async function startGatewayDiscovery(params: {
   logDiscovery: { info: (msg: string) => void; warn: (msg: string) => void };
 }) {
   let bonjourStop: (() => Promise<void>) | null = null;
-  const tailnetDns = await resolveTailnetDnsHint();
+  const bonjourEnabled =
+    process.env.CLAWDBOT_DISABLE_BONJOUR !== "1" &&
+    process.env.NODE_ENV !== "test" &&
+    !process.env.VITEST;
+  const needsTailnetDns = bonjourEnabled || params.wideAreaDiscoveryEnabled;
+  const tailnetDns = needsTailnetDns ? await resolveTailnetDnsHint() : undefined;
   const sshPortEnv = process.env.CLAWDBOT_SSH_PORT?.trim();
   const sshPortParsed = sshPortEnv ? Number.parseInt(sshPortEnv, 10) : NaN;
   const sshPort = Number.isFinite(sshPortParsed) && sshPortParsed > 0 ? sshPortParsed : undefined;
diff --git a/src/gateway/test-helpers.server.ts b/src/gateway/test-helpers.server.ts
index 24e71d829..526eed1e1 100644
--- a/src/gateway/test-helpers.server.ts
+++ b/src/gateway/test-helpers.server.ts
@@ -29,6 +29,10 @@ import {
   testTailnetIPv4,
 } from "./test-helpers.mocks.js";
 
+// Preload the gateway server module once per worker.
+// Important: `test-helpers.mocks` must run before importing the server so vi.mock hooks apply.
+const serverModulePromise = import("./server.js");
+
 let previousHome: string | undefined;
 let previousUserProfile: string | undefined;
 let previousStateDir: string | undefined;
@@ -105,7 +109,7 @@ export function installGatewayTestHooks() {
     embeddedRunMock.waitResults.clear();
     drainSystemEvents(resolveMainSessionKeyFromConfig());
     resetAgentRunContextForTest();
-    const mod = await import("./server.js");
+    const mod = await serverModulePromise;
     mod.__resetModelCatalogCacheForTest();
     piSdkMock.enabled = false;
     piSdkMock.discoverCalls = 0;
@@ -184,7 +188,7 @@ export function onceMessage<T = unknown>(
 }
 
 export async function startGatewayServer(port: number, opts?: GatewayServerOptions) {
-  const mod = await import("./server.js");
+  const mod = await serverModulePromise;
   return await mod.startGatewayServer(port, opts);
 }
 
diff --git a/src/infra/machine-name.ts b/src/infra/machine-name.ts
index 04c0825a1..b6a6f3a75 100644
--- a/src/infra/machine-name.ts
+++ b/src/infra/machine-name.ts
@@ -31,6 +31,9 @@ function fallbackHostName() {
 export async function getMachineDisplayName(): Promise<string> {
   if (cachedPromise) return cachedPromise;
   cachedPromise = (async () => {
+    if (process.env.VITEST || process.env.NODE_ENV === "test") {
+      return fallbackHostName();
+    }
     if (process.platform === "darwin") {
       const computerName = await tryScutil("ComputerName");
       if (computerName) return computerName;
diff --git a/src/test-utils/ports.ts b/src/test-utils/ports.ts
index e3d6c145e..2bf6e6734 100644
--- a/src/test-utils/ports.ts
+++ b/src/test-utils/ports.ts
@@ -1,4 +1,5 @@
 import { type AddressInfo, createServer } from "node:net";
+import { isMainThread, threadId } from "node:worker_threads";
 
 async function isPortFree(port: number): Promise<boolean> {
   if (!Number.isFinite(port) || port <= 0 || port > 65535) return false;
@@ -45,7 +46,11 @@ export async function getDeterministicFreePortBlock(params?: {
 
   const workerIdRaw = process.env.VITEST_WORKER_ID ?? process.env.VITEST_POOL_ID ?? "";
   const workerId = Number.parseInt(workerIdRaw, 10);
-  const shard = Number.isFinite(workerId) ? Math.max(0, workerId) : Math.abs(process.pid);
+  const shard = Number.isFinite(workerId)
+    ? Math.max(0, workerId)
+    : isMainThread
+      ? Math.abs(process.pid)
+      : Math.abs(threadId);
 
   const rangeSize = 1000;
   const shardCount = 30;
@@ -79,4 +84,3 @@ export async function getDeterministicFreePortBlock(params?: {
 
   throw new Error("failed to acquire a free port block");
 }
-
diff --git a/test/test-env.ts b/test/test-env.ts
index 7560aa0cf..172085521 100644
--- a/test/test-env.ts
+++ b/test/test-env.ts
@@ -62,10 +62,16 @@ export function installTestEnv(): { cleanup: () => void; tempHome: string } {
     { key: "XDG_CACHE_HOME", value: process.env.XDG_CACHE_HOME },
     { key: "CLAWDBOT_STATE_DIR", value: process.env.CLAWDBOT_STATE_DIR },
     { key: "CLAWDBOT_CONFIG_PATH", value: process.env.CLAWDBOT_CONFIG_PATH },
+    { key: "CLAWDBOT_GATEWAY_PORT", value: process.env.CLAWDBOT_GATEWAY_PORT },
+    { key: "CLAWDBOT_BRIDGE_ENABLED", value: process.env.CLAWDBOT_BRIDGE_ENABLED },
+    { key: "CLAWDBOT_BRIDGE_HOST", value: process.env.CLAWDBOT_BRIDGE_HOST },
+    { key: "CLAWDBOT_BRIDGE_PORT", value: process.env.CLAWDBOT_BRIDGE_PORT },
+    { key: "CLAWDBOT_CANVAS_HOST_PORT", value: process.env.CLAWDBOT_CANVAS_HOST_PORT },
     { key: "CLAWDBOT_TEST_HOME", value: process.env.CLAWDBOT_TEST_HOME },
     { key: "COPILOT_GITHUB_TOKEN", value: process.env.COPILOT_GITHUB_TOKEN },
     { key: "GH_TOKEN", value: process.env.GH_TOKEN },
     { key: "GITHUB_TOKEN", value: process.env.GITHUB_TOKEN },
+    { key: "NODE_OPTIONS", value: process.env.NODE_OPTIONS },
   ];
 
   const tempHome = fs.mkdtempSync(path.join(os.tmpdir(), "clawdbot-test-home-"));
@@ -78,10 +84,18 @@ export function installTestEnv(): { cleanup: () => void; tempHome: string } {
   delete process.env.CLAWDBOT_CONFIG_PATH;
   // Prefer deriving state dir from HOME so nested tests that change HOME also isolate correctly.
   delete process.env.CLAWDBOT_STATE_DIR;
+  // Prefer test-controlled ports over developer overrides (avoid port collisions across tests/workers).
+  delete process.env.CLAWDBOT_GATEWAY_PORT;
+  delete process.env.CLAWDBOT_BRIDGE_ENABLED;
+  delete process.env.CLAWDBOT_BRIDGE_HOST;
+  delete process.env.CLAWDBOT_BRIDGE_PORT;
+  delete process.env.CLAWDBOT_CANVAS_HOST_PORT;
   // Avoid leaking real GitHub/Copilot tokens into non-live test runs.
   delete process.env.COPILOT_GITHUB_TOKEN;
   delete process.env.GH_TOKEN;
   delete process.env.GITHUB_TOKEN;
+  // Avoid leaking local dev tooling flags into tests (e.g. --inspect).
+  delete process.env.NODE_OPTIONS;
 
   // Windows: prefer the legacy default state dir so auth/profile tests match real paths.
   if (process.platform === "win32") {