Adds JSON mode to Ollama and ChatOllama

langchain/src/chat_models/ollama.ts

@@ -94,6 +94,8 @@ export class ChatOllama
 
   vocabOnly?: boolean;
 
+  format?: string;
+
   constructor(fields: OllamaInput & BaseChatModelParams) {
     super(fields);
     this.model = fields.model ?? this.model;
@@ -130,6 +132,7 @@ export class ChatOllama
     this.useMLock = fields.useMLock;
     this.useMMap = fields.useMMap;
     this.vocabOnly = fields.vocabOnly;
+    this.format = fields.format;
   }
 
   _llmType() {
@@ -145,6 +148,7 @@ export class ChatOllama
   invocationParams(options?: this["ParsedCallOptions"]) {
     return {
       model: this.model,
+      format: this.format,
       options: {
         embedding_only: this.embeddingOnly,
         f16_kv: this.f16KV,

langchain/src/chat_models/tests/chatollama.int.test.ts

@@ -4,7 +4,10 @@ import { AIMessage, HumanMessage } from "../../schema/index.js";
 import { LLMChain } from "../../chains/llm_chain.js";
 import { PromptTemplate } from "../../prompts/prompt.js";
 import { BufferMemory } from "../../memory/buffer_memory.js";
-import { BytesOutputParser } from "../../schema/output_parser.js";
+import {
+  BytesOutputParser,
+  StringOutputParser,
+} from "../../schema/output_parser.js";
 
 test.skip("test call", async () => {
   const ollama = new ChatOllama({});
@@ -129,3 +132,25 @@ test.skip("should stream through with a bytes output parser", async () => {
   console.log(chunks.join(""));
   expect(chunks.length).toBeGreaterThan(1);
 });
+
+test.skip("JSON mode", async () => {
+  const TEMPLATE = `You are a pirate named Patchy. All responses must be in pirate dialect and in JSON format, with a property named "response" followed by the value.
+
+  User: {input}
+  AI:`;
+
+  // Infer the input variables from the template
+  const prompt = PromptTemplate.fromTemplate(TEMPLATE);
+
+  const ollama = new ChatOllama({
+    model: "llama2",
+    baseUrl: "http://127.0.0.1:11434",
+    format: "json",
+  });
+  const outputParser = new StringOutputParser();
+  const chain = prompt.pipe(ollama).pipe(outputParser);
+  const res = await chain.invoke({
+    input: `Translate "I love programming" into German.`,
+  });
+  expect(JSON.parse(res).response).toBeDefined();
+});

langchain/src/llms/ollama.ts

@@ -82,6 +82,8 @@ export class Ollama extends LLM<OllamaCallOptions> implements OllamaInput {
 
   vocabOnly?: boolean;
 
+  format?: string;
+
   constructor(fields: OllamaInput & BaseLLMParams) {
     super(fields);
     this.model = fields.model ?? this.model;
@@ -119,6 +121,7 @@ export class Ollama extends LLM<OllamaCallOptions> implements OllamaInput {
     this.useMLock = fields.useMLock;
     this.useMMap = fields.useMMap;
     this.vocabOnly = fields.vocabOnly;
+    this.format = fields.format;
   }
 
   _llmType() {
@@ -128,6 +131,7 @@ export class Ollama extends LLM<OllamaCallOptions> implements OllamaInput {
   invocationParams(options?: this["ParsedCallOptions"]) {
     return {
       model: this.model,
+      format: this.format,
       options: {
         embedding_only: this.embeddingOnly,
         f16_kv: this.f16KV,

langchain/src/llms/tests/ollama.int.test.ts

@@ -1,7 +1,10 @@
 import { test } from "@jest/globals";
 import { Ollama } from "../ollama.js";
 import { PromptTemplate } from "../../prompts/prompt.js";
-import { BytesOutputParser } from "../../schema/output_parser.js";
+import {
+  BytesOutputParser,
+  StringOutputParser,
+} from "../../schema/output_parser.js";
 
 test.skip("test call", async () => {
   const ollama = new Ollama({});
@@ -86,3 +89,25 @@ test.skip("should stream through with a bytes output parser", async () => {
   console.log(chunks.join(""));
   expect(chunks.length).toBeGreaterThan(1);
 });
+
+test.skip("JSON mode", async () => {
+  const TEMPLATE = `You are a pirate named Patchy. All responses must be in pirate dialect and in JSON format, with a property named "response" followed by the value.
+
+  User: {input}
+  AI:`;
+
+  // Infer the input variables from the template
+  const prompt = PromptTemplate.fromTemplate(TEMPLATE);
+
+  const ollama = new Ollama({
+    model: "llama2",
+    baseUrl: "http://127.0.0.1:11434",
+    format: "json",
+  });
+  const outputParser = new StringOutputParser();
+  const chain = prompt.pipe(ollama).pipe(outputParser);
+  const res = await chain.invoke({
+    input: `Translate "I love programming" into German.`,
+  });
+  expect(JSON.parse(res).response).toBeDefined();
+});

langchain/src/util/ollama.ts

@@ -34,11 +34,13 @@ export interface OllamaInput {
   useMLock?: boolean;
   useMMap?: boolean;
   vocabOnly?: boolean;
+  format?: string;
 }
 
 export interface OllamaRequestParams {
   model: string;
   prompt: string;
+  format?: string;
   options: {
     embedding_only?: boolean;
     f16_kv?: boolean;