feat(ollama): Add think Field to ChatOllama for Controlling Thought Process in Responses

libs/langchain-ollama/package.json

@@ -32,7 +32,7 @@
   "author": "LangChain",
   "license": "MIT",
   "dependencies": {
-    "ollama": "^0.5.12",
+    "ollama": "^0.5.17",
     "uuid": "^10.0.0"
   },
   "peerDependencies": {

libs/langchain-ollama/src/chat_models.ts

@@ -109,6 +109,7 @@ export interface ChatOllamaInput
    * @default fetch
    */
   fetch?: typeof fetch;
+  think?: boolean;
 }
 
 /**
@@ -489,6 +490,8 @@ export class ChatOllama
 
   baseUrl = "http://127.0.0.1:11434";
 
+  think?: boolean;
+
   constructor(fields?: ChatOllamaInput) {
     super(fields ?? {});
 
@@ -532,6 +535,7 @@ export class ChatOllama
     this.streaming = fields?.streaming;
     this.format = fields?.format;
     this.keepAlive = fields?.keepAlive;
+    this.think = fields?.think;
     this.checkOrPullModel = fields?.checkOrPullModel ?? this.checkOrPullModel;
   }
 
@@ -604,6 +608,7 @@ export class ChatOllama
       model: this.model,
       format: options?.format ?? this.format,
       keep_alive: this.keepAlive,
+      think: this.think,
       options: {
         numa: this.numa,
         num_ctx: this.numCtx,
@@ -746,11 +751,15 @@ export class ChatOllama
         usageMetadata.input_tokens + usageMetadata.output_tokens;
       lastMetadata = rest;
 
+      // when think is enabled, try thinking first
+      const token = this.think ? responseMessage.thinking ?? responseMessage.content ?? ""
+        : responseMessage.content ?? "" 
+
       yield new ChatGenerationChunk({
-        text: responseMessage.content ?? "",
+        text: token,
         message: convertOllamaMessagesToLangChain(responseMessage),
       });
-      await runManager?.handleLLMNewToken(responseMessage.content ?? "");
+      await runManager?.handleLLMNewToken(token);
     }
 
     // Yield the `response_metadata` as the final chunk.

libs/langchain-ollama/src/tests/chat_models_think.int.test.ts

@@ -0,0 +1,54 @@
+import { test, expect } from "@jest/globals";
+import { HumanMessage } from "@langchain/core/messages";
+import { ChatOllama } from "../chat_models.js";
+
+test("test deep seek model with think=false", async () => {
+  const ollama = new ChatOllama({
+    model: "deepseek-r1:32b",
+    think: false, // Ensure the "think" field is explicitly set to false
+    maxRetries: 1,
+  });
+
+  const res = await ollama.invoke([
+    new HumanMessage({
+      content: "Explain the process of photosynthesis briefly.",
+    }),
+  ]);
+
+  // Ensure the response is defined
+  expect(res).toBeDefined();
+  expect(res.content).toBeDefined();
+
+  const responseContent = res.content;
+
+  // Validate that the response does not include any <think>...</think> blocks
+  // s means allow . to match new line character 
+  expect(responseContent).not.toMatch(/<think>.*?<\/think>/is);
+
+  // Ensure the response is concise and directly answers the question
+  expect(responseContent).toMatch(/photosynthesis/i); // Check it includes the topic
+  expect(responseContent.length).toBeGreaterThan(1);
+});
+
+test("test deep seek model with think=true (default)", async () => {
+  const ollama = new ChatOllama({
+    model: "deepseek-r1:32b",
+    maxRetries: 1,
+  });
+
+  const res = await ollama.invoke([
+    new HumanMessage({
+      content: "Explain the process of photosynthesis briefly.",
+    }),
+  ]);
+
+  // Ensure the response is defined
+  expect(res).toBeDefined();
+  expect(res.content).toBeDefined();
+
+  const responseContent = res.content;
+
+  // Ensure the response is concise and directly answers the question
+  expect(responseContent).toMatch(/photosynthesis/i); // Check it includes the topic
+  expect(responseContent.length).toBeGreaterThan(1);
+});

libs/langchain-ollama/src/utils.ts

@@ -23,7 +23,7 @@ export function convertOllamaMessagesToLangChain(
   }
 ): AIMessageChunk {
   return new AIMessageChunk({
-    content: messages.content ?? "",
+    content: messages.thinking ?? messages.content ?? "",
     tool_call_chunks: messages.tool_calls?.map((tc) => ({
       name: tc.function.name,
       args: JSON.stringify(tc.function.arguments),

yarn.lock

@@ -9109,7 +9109,7 @@ __metadata:
     eslint-plugin-prettier: ^4.2.1
     jest: ^29.5.0
     jest-environment-node: ^29.6.4
-    ollama: ^0.5.12
+    ollama: ^0.5.17
     prettier: ^2.8.3
     release-it: ^18.1.2
     rollup: ^4.5.2
@@ -30693,12 +30693,12 @@ __metadata:
   languageName: node
   linkType: hard
 
-"ollama@npm:^0.5.12":
-  version: 0.5.12
-  resolution: "ollama@npm:0.5.12"
+"ollama@npm:^0.5.17":
+  version: 0.5.17
+  resolution: "ollama@npm:0.5.17"
   dependencies:
     whatwg-fetch: ^3.6.20
-  checksum: 0abc1151d2cfd02198829f706f8efca978c8562691e7502924166798f6a0cd7e1bf51e085d313ddf5a76507a36ffa12b48a66d4dd659b419474c2f33e3f03b44
+  checksum: 151f1b0d69ea1f54927c4e92537f7dafa28f93d7b7d2d362387e046d5fea21eae07997b4c055f9a2579058bb88daad20a953ea300a93799d4ee78736e1a0af71
   languageName: node
   linkType: hard