diff --git a/sdk-node/package.json b/sdk-node/package.json
index 1fa989c5..b93cfde7 100644
--- a/sdk-node/package.json
+++ b/sdk-node/package.json
@@ -54,4 +54,4 @@
     "email": "hi@inferable.ai",
     "url": "https://github.com/inferablehq/inferable/issues"
   }
-}
+}
\ No newline at end of file
diff --git a/sdk-node/src/Inferable.ts b/sdk-node/src/Inferable.ts
index bce5c287..bc2cddaf 100644
--- a/sdk-node/src/Inferable.ts
+++ b/sdk-node/src/Inferable.ts
@@ -23,6 +23,7 @@ import {
   validateFunctionSchema,
   validateServiceName,
 } from "./util";
+import { Assertions, assertRun } from "./assertions";
 
 // Custom json formatter
 debug.formatters.J = (json) => {
@@ -108,8 +109,8 @@ export class Inferable {
    */
   constructor(options?: {
     apiSecret?: string;
-    endpoint?: string
-    machineId?: string
+    endpoint?: string;
+    machineId?: string;
   }) {
     if (options?.apiSecret && process.env.INFERABLE_API_SECRET) {
       log(
@@ -257,14 +258,18 @@ export class Inferable {
       }
     }
 
-    return {
+    const returnable = {
       id: runResult.body.id,
       /**
        * Polls until the run reaches a terminal state (!= "pending" && != "running" && != "paused") or maxWaitTime is reached.
        * @param maxWaitTime The maximum amount of time to wait for the run to reach a terminal state. Defaults to 60 seconds.
        * @param interval The amount of time to wait between polling attempts. Defaults to 500ms.
        */
-      poll: async (options?: { maxWaitTime?: number; interval?: number }) => {
+      poll: async <T = unknown>(options?: {
+        maxWaitTime?: number;
+        interval?: number;
+        assertions?: Assertions<T>;
+      }): Promise<T> => {
         if (!this.clusterId) {
           throw new InferableError(
             "Cluster ID must be provided to manage runs",
@@ -299,8 +304,23 @@ export class Inferable {
             continue;
           }
 
-          return pollResult.body;
+          const assertionsResult = await assertRun<T>({
+            clusterId: this.clusterId,
+            runId: runResult.body.id,
+            client: this.client,
+            result: pollResult.body.result as T,
+            functionCalls: [], // TODO: Add function calls
+            assertions: options?.assertions || [],
+          });
+
+          if (!assertionsResult.assertionsPassed) {
+            return returnable.poll(options);
+          }
+
+          return pollResult.body.result as T; // Cast the result to the inferred type
         }
+
+        throw new InferableError("Run timed out");
       },
       /**
        * Retrieves the messages for a run.
@@ -325,6 +345,8 @@ export class Inferable {
         };
       },
     };
+
+    return returnable;
   }
 
   /**
diff --git a/sdk-node/src/assertions.test.ts b/sdk-node/src/assertions.test.ts
new file mode 100644
index 00000000..e8193d2f
--- /dev/null
+++ b/sdk-node/src/assertions.test.ts
@@ -0,0 +1,50 @@
+import { Inferable } from "./Inferable";
+import { z } from "zod";
+import { TEST_ENDPOINT } from "./tests/utils";
+import { TEST_API_SECRET } from "./tests/utils";
+
+describe("assertions", () => {
+  it("should be able to assert a run", async () => {
+    const client = new Inferable({
+      apiSecret: TEST_API_SECRET,
+      endpoint: TEST_ENDPOINT,
+    });
+
+    let timesRun = 0;
+
+    client.default.register({
+      name: "generateRandomNumber",
+      func: async ({ seed }: { seed: number }) => {
+        timesRun++;
+
+        return seed * timesRun;
+      },
+    });
+
+    await client.default.start();
+
+    const resultSchema = z.object({
+      result: z.number().describe("The result of the function"),
+    });
+
+    const run = await client.run({
+      initialPrompt:
+        "Use the available functions to generate a random number between 0 and 100",
+      resultSchema: resultSchema,
+    });
+
+    const result = await run.poll<z.infer<typeof resultSchema>>({
+      assertions: [
+        function assertCorrect(result) {
+          if (timesRun === 1) {
+            throw new Error(
+              `The result ${result.result} is unacceptable. Try again with a different seed.`,
+            );
+          }
+        },
+      ],
+    });
+
+    expect(result.result).toBeGreaterThan(0);
+  });
+});
diff --git a/sdk-node/src/assertions.ts b/sdk-node/src/assertions.ts
new file mode 100644
index 00000000..53cbaa41
--- /dev/null
+++ b/sdk-node/src/assertions.ts
@@ -0,0 +1,65 @@
+import { createApiClient } from "./create-client";
+
+type FunctionCall = {
+  service: string;
+  function: string;
+};
+
+type AssertionFunction<T> = (
+  result: T,
+  functionCalls: FunctionCall[],
+) => void | Promise<void>;
+
+export type Assertions<T> = AssertionFunction<T>[];
+
+export async function assertRun<T>({
+  clusterId,
+  runId,
+  client,
+  result,
+  functionCalls,
+  assertions,
+}: {
+  clusterId: string;
+  runId: string;
+  client: ReturnType<typeof createApiClient>;
+  result: T;
+  functionCalls: FunctionCall[];
+  assertions: Assertions<T>;
+}): Promise<{
+  assertionsPassed: boolean;
+}> {
+  const results = await Promise.allSettled(
+    assertions.map(async (a) => await a(result, functionCalls)),
+  );
+
+  const hasRejections = results.some((r) => r.status === "rejected");
+
+  if (hasRejections) {
+    await client.createMessage({
+      body: {
+        message: [
+          `You attempted to return a result, but I have determined the result is possibly incorrect due to failing assertions.`,
+          `<failures>`,
+          ...results
+            .filter((r) => r.status === "rejected")
+            .map((r) => r.reason),
+          `</failures>`,
+        ].join("\n"),
+        type: "human",
+      },
+      params: {
+        clusterId,
+        runId,
+      },
+    });
+
+    return {
+      assertionsPassed: false,
+    };
+  }
+
+  return {
+    assertionsPassed: true,
+  };
+}