diff --git a/package.json b/package.json
index 8af8aa2cc..4370bf3c8 100644
--- a/package.json
+++ b/package.json
@@ -13,7 +13,7 @@
   "scripts": {
     "check": "bun run typecheck && bun run lint && bun run test && bun run check:structural",
     "check:all": "bun run check && bun run check:packages",
-    "typecheck": "bun run scripts/run-all.ts typecheck",
+    "typecheck": "bun run scripts/run-all.ts typecheck && bunx tsc -p tsconfig.json --noEmit && bunx tsc -p test/isolation/tsconfig.json --noEmit",
     "lint": "prettier --check --cache . && eslint --cache .",
     "format": "prettier --write .",
     "build": "bun run scripts/run-all.ts build",
diff --git a/packages/hub-client/src/hub.ts b/packages/hub-client/src/hub.ts
index d7016ae6d..547b6e94e 100644
--- a/packages/hub-client/src/hub.ts
+++ b/packages/hub-client/src/hub.ts
@@ -40,7 +40,7 @@ export function createHubAPI(
       response = await fetchImpl(`${baseUrl}${path}`, {
         method,
         headers,
-        body: body === undefined ? undefined : JSON.stringify(body),
+        ...(body !== undefined ? { body: JSON.stringify(body) } : {}),
         redirect: "manual",
       });
     } catch (cause) {
diff --git a/packages/tool-registry-publish/src/publish.ts b/packages/tool-registry-publish/src/publish.ts
index a8e940fc2..a5fe6f3a3 100644
--- a/packages/tool-registry-publish/src/publish.ts
+++ b/packages/tool-registry-publish/src/publish.ts
@@ -208,7 +208,12 @@ async function putTarball(
   if (cookies.length > 0) headers["Cookie"] = cookies.join("; ");
   const response = await fetchImpl(
     `${hubUrl}/api/tenants/${tenantId}/assets/${assetId}/tarballs/${tarball.filename}`,
-    { method: "PUT", headers, body: tarball.bytes, redirect: "manual" },
+    {
+      method: "PUT",
+      headers,
+      body: Uint8Array.from(tarball.bytes),
+      redirect: "manual",
+    },
   );
   if (response.status !== 200) {
     const text = await response.text();
diff --git a/scripts/checks/browser-safe-subpaths.ts b/scripts/checks/browser-safe-subpaths.ts
index 95c4e557d..afce6a839 100644
--- a/scripts/checks/browser-safe-subpaths.ts
+++ b/scripts/checks/browser-safe-subpaths.ts
@@ -121,17 +121,23 @@ export function parseImportSpecifiers(source: string): ImportSpecifier[] {
   const fromPattern =
     /\b(import|export)\s+(type\s+)?[^;]*?\bfrom\s+["']([^"']+)["']/g;
   for (const match of contents.matchAll(fromPattern)) {
-    results.push({ specifier: match[3], typeOnly: match[2] !== undefined });
+    const specifier = match[3];
+    if (specifier === undefined) continue;
+    results.push({ specifier, typeOnly: match[2] !== undefined });
   }
 
   const dynamicPattern = /\bimport\s*\(\s*["']([^"']+)["']/g;
   for (const match of contents.matchAll(dynamicPattern)) {
-    results.push({ specifier: match[1], typeOnly: false });
+    const specifier = match[1];
+    if (specifier === undefined) continue;
+    results.push({ specifier, typeOnly: false });
   }
 
   const sideEffectPattern = /\bimport\s+["']([^"']+)["']\s*;/g;
   for (const match of contents.matchAll(sideEffectPattern)) {
-    results.push({ specifier: match[1], typeOnly: false });
+    const specifier = match[1];
+    if (specifier === undefined) continue;
+    results.push({ specifier, typeOnly: false });
   }
 
   return results;
diff --git a/scripts/e2e/browser/walkthrough.ts b/scripts/e2e/browser/walkthrough.ts
index 06ea5e648..c154fd665 100644
--- a/scripts/e2e/browser/walkthrough.ts
+++ b/scripts/e2e/browser/walkthrough.ts
@@ -433,7 +433,9 @@ async function run(): Promise<void> {
 
     function wireDiagnostics(target: Page): void {
       target.on("pageerror", (error) =>
-        console.error(`  [page error] ${error.message}`),
+        console.error(
+          `  [page error] ${error instanceof Error ? error.message : String(error)}`,
+        ),
       );
       target.on("console", (msg) => {
         if (msg.type() === "error")
@@ -595,6 +597,9 @@ async function run(): Promise<void> {
                 ? { ...seedArgs, baseURLOverride: ollamaBaseUrl }
                 : seedArgs,
             );
+            if (seeded.kind === "seeded-pending-agents") {
+              throw new Error(seeded.message);
+            }
             return {
               status: "pass",
               detail: `stub credential stored and every default workflow deployed: ${seeded.workflows.join(", ")}`,
diff --git a/scripts/e2e/harness.ts b/scripts/e2e/harness.ts
index 33ea0c1ef..3704c9ae7 100644
--- a/scripts/e2e/harness.ts
+++ b/scripts/e2e/harness.ts
@@ -411,7 +411,7 @@ export async function api(
   const res = await fetch(`${base}${route}`, {
     method,
     headers,
-    body: body === undefined ? undefined : JSON.stringify(body),
+    ...(body !== undefined ? { body: JSON.stringify(body) } : {}),
     redirect: "manual",
   });
   const nextCookies = mergeCookies(cookies, res.headers.getSetCookie());
diff --git a/scripts/e2e/smoke-library.test.ts b/scripts/e2e/smoke-library.test.ts
index 7f6f03923..755bf08f9 100644
--- a/scripts/e2e/smoke-library.test.ts
+++ b/scripts/e2e/smoke-library.test.ts
@@ -88,7 +88,10 @@ async function uploadArtifact(
   bytes: Uint8Array,
 ): Promise<{ status: number; data: unknown }> {
   const form = new FormData();
-  form.append("file", new File([bytes], fileName, { type: "application/pdf" }));
+  form.append(
+    "file",
+    new File([Uint8Array.from(bytes)], fileName, { type: "application/pdf" }),
+  );
   const res = await fetch(
     `${baseUrl}/api/tenants/${tenantId}/artifacts/upload`,
     {
diff --git a/scripts/run-all.ts b/scripts/run-all.ts
index 455f25e9e..19830635e 100644
--- a/scripts/run-all.ts
+++ b/scripts/run-all.ts
@@ -136,11 +136,12 @@ async function narrowToAffected(jobs: readonly Job[]): Promise<Job[]> {
   return narrowed;
 }
 
-const script = process.argv[2];
-if (!script) {
+const scriptArg = process.argv[2];
+if (!scriptArg) {
   console.error("usage: bun run scripts/run-all.ts <script-name>");
   process.exit(1);
 }
+const script: string = scriptArg;
 
 let concurrency: number;
 try {