diff --git a/packages/core/src/integrations/GptTokenizerTokenizer.ts b/packages/core/src/integrations/GptTokenizerTokenizer.ts
index 3a166fb35..318abcf33 100644
--- a/packages/core/src/integrations/GptTokenizerTokenizer.ts
+++ b/packages/core/src/integrations/GptTokenizerTokenizer.ts
@@ -3,6 +3,7 @@ import type { Tokenizer, TokenizerCallInfo } from './Tokenizer.js';
 import { encode, encodeChat } from 'gpt-tokenizer';
 import Emittery from 'emittery';
 import { getError } from '../utils/errors.js';
+import { sum } from 'lodash';
 
 export class GptTokenizerTokenizer implements Tokenizer {
   emitter = new Emittery<{
@@ -19,13 +20,16 @@ export class GptTokenizerTokenizer implements Tokenizer {
 
   getTokenCountForMessages(messages: ChatMessage[], _info: TokenizerCallInfo): number {
     try {
-      return encodeChat(
+      const encodedChat = encodeChat(
         messages.map((message) => ({
           role: message.type as 'system' | 'user' | 'assistant', // Doesn't support 'function' yet
           content: message.message,
           name: message.name,
         })),
-      ).length;
+        (_info.model as any) ?? 'gpt-3.5-turbo',
+      );
+
+      return encodedChat.length;
     } catch (err) {
       this.emitter.emit('error', getError(err));
       return 0;
diff --git a/packages/core/src/model/GraphProcessor.ts b/packages/core/src/model/GraphProcessor.ts
index c5c67bfbb..4588c8f8c 100644
--- a/packages/core/src/model/GraphProcessor.ts
+++ b/packages/core/src/model/GraphProcessor.ts
@@ -654,6 +654,12 @@ export class GraphProcessor {
       this.#graphInputs = inputs;
       this.#contextValues ??= contextValues;
 
+      if (this.#context.tokenizer) {
+        this.#context.tokenizer.on('error', (error) => {
+          this.#emitter.emit('error', { error });
+        });
+      }
+
       if (!this.#isSubProcessor) {
         this.#emitter.emit('start', {
           contextValues: this.#contextValues,
@@ -1326,10 +1332,16 @@ export class GraphProcessor {
 
     const plugin = this.#registry.getPluginFor(node.type);
 
+    let tokenizer = this.#context.tokenizer;
+    if (!tokenizer) {
+      tokenizer = new GptTokenizerTokenizer();
+      tokenizer.on('error', (e) => this.#emitter.emit('error', { error: e }));
+    }
+
     const context: InternalProcessContext = {
       ...this.#context,
       node,
-      tokenizer: this.#context.tokenizer ?? new GptTokenizerTokenizer(),
+      tokenizer,
       executor: this.executor ?? 'nodejs',
       project: this.#project,
       executionCache: this.#executionCache,