diff --git a/packages/trigger-sdk/src/v3/envvars.test.ts b/packages/trigger-sdk/src/v3/envvars.test.ts
new file mode 100644
index 00000000000..247eb67783c
--- /dev/null
+++ b/packages/trigger-sdk/src/v3/envvars.test.ts
@@ -0,0 +1,110 @@
+import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
+import { apiClientManager, taskContext } from "@trigger.dev/core/v3";
+import { configure } from "./auth.js";
+import { update } from "./envvars.js";
+
+type CapturedRequest = {
+  url: string;
+  method: string | undefined;
+  authorization: string | undefined;
+  body?: string;
+};
+
+function installFetchSpy() {
+  const captured: CapturedRequest[] = [];
+  const originalFetch = globalThis.fetch;
+
+  globalThis.fetch = (async (input: any, init?: RequestInit) => {
+    const url = typeof input === "string" ? input : (input?.url ?? String(input));
+    const headers = new Headers(init?.headers);
+    captured.push({
+      url,
+      method: init?.method,
+      authorization: headers.get("authorization") ?? undefined,
+      body: typeof init?.body === "string" ? init.body : undefined,
+    });
+    return new Response(
+      JSON.stringify({
+        name: "DATABASE_URL",
+        value: "postgres://...",
+      }),
+      {
+        status: 200,
+        headers: { "content-type": "application/json" },
+      }
+    );
+  }) as typeof fetch;
+
+  return {
+    captured,
+    restore: () => {
+      globalThis.fetch = originalFetch;
+    },
+  };
+}
+
+describe("envvars", () => {
+  let fetchSpy: ReturnType<typeof installFetchSpy>;
+
+  beforeEach(() => {
+    apiClientManager.disable();
+    taskContext.disable();
+    fetchSpy = installFetchSpy();
+  });
+
+  afterEach(() => {
+    fetchSpy.restore();
+    apiClientManager.disable();
+    taskContext.disable();
+    vi.unstubAllEnvs();
+  });
+
+  describe("update outside task context", () => {
+    it("successfully updates an environment variable without ReferenceError (#4264)", async () => {
+      configure({ accessToken: "tr_test_token" });
+
+      await update("proj_123", "prod", "DATABASE_URL", {
+        value: "postgres://localhost:5432/mydb",
+      });
+
+      expect(fetchSpy.captured).toHaveLength(1);
+      const req = fetchSpy.captured[0]!;
+      expect(req.url).toContain("/api/v1/projects/proj_123/envvars/prod/DATABASE_URL");
+      expect(req.method).toBe("PUT");
+      expect(req.authorization).toBe("Bearer tr_test_token");
+      expect(req.body).toBe(JSON.stringify({ value: "postgres://localhost:5432/mydb" }));
+    });
+
+    it("throws when name is missing or not a string", async () => {
+      configure({ accessToken: "tr_test_token" });
+
+      expect(() =>
+        update("proj_123", "prod", undefined as any, { value: "test" })
+      ).toThrow("name is required");
+    });
+
+    it("throws when projectRef is missing", async () => {
+      configure({ accessToken: "tr_test_token" });
+
+      expect(() =>
+        update("", "prod", "MY_VAR", { value: "test" })
+      ).toThrow("projectRef is required");
+    });
+
+    it("throws when slug is missing", async () => {
+      configure({ accessToken: "tr_test_token" });
+
+      expect(() =>
+        update("proj_123", undefined as any, "MY_VAR", { value: "test" })
+      ).toThrow("slug is required");
+    });
+
+    it("throws when params is missing", async () => {
+      configure({ accessToken: "tr_test_token" });
+
+      expect(() =>
+        update("proj_123", "prod", "MY_VAR", undefined as any)
+      ).toThrow("params is required");
+    });
+  });
+});
diff --git a/packages/trigger-sdk/src/v3/envvars.ts b/packages/trigger-sdk/src/v3/envvars.ts
index 8ff68ab8907..0adc21cbd98 100644
--- a/packages/trigger-sdk/src/v3/envvars.ts
+++ b/packages/trigger-sdk/src/v3/envvars.ts
@@ -332,13 +332,17 @@ export function update(
       throw new Error("projectRef is required");
     }
 
+    if (typeof nameOrRequestOptions !== "string") {
+      throw new Error("name is required");
+    }
+
     if (!params) {
       throw new Error("params is required");
     }
 
     $projectRef = projectRefOrName;
     $slug = slugOrParams;
-    $name = name!;
+    $name = nameOrRequestOptions;
     $params = params;
   }