Files
2026-07-13 12:20:32 +08:00

199 lines
5.9 KiB
JavaScript

const { NativeEmbedder } = require("../../EmbeddingEngines/native");
const { MODEL_MAP } = require("../modelMap");
const {
LLMPerformanceMonitor,
} = require("../../helpers/chat/LLMPerformanceMonitor");
const {
handleDefaultStreamResponseV2,
} = require("../../helpers/chat/responses");
class CohereLLM {
constructor(embedder = null, modelPreference = null) {
const { OpenAI: OpenAIApi } = require("openai");
if (!process.env.COHERE_API_KEY)
throw new Error("No Cohere API key was set.");
this.className = "CohereLLM";
// Cohere exposes an OpenAI-compatible API which lets us reuse the OpenAI SDK
// across the app instead of the cohere-ai package. https://docs.cohere.com/docs/compatibility-api
this.openai = new OpenAIApi({
baseURL: "https://api.cohere.ai/compatibility/v1",
apiKey: process.env.COHERE_API_KEY,
});
this.model = modelPreference || process.env.COHERE_MODEL_PREF;
this.limits = {
history: this.promptWindowLimit() * 0.15,
system: this.promptWindowLimit() * 0.15,
user: this.promptWindowLimit() * 0.7,
};
this.embedder = embedder ?? new NativeEmbedder();
this.defaultTemp = 0.7;
this.#log(
`Initialized with model ${this.model}. ctx: ${this.promptWindowLimit()}`
);
}
#log(text, ...args) {
console.log(`\x1b[32m[${this.className}]\x1b[0m ${text}`, ...args);
}
#appendContext(contextTexts = []) {
if (!contextTexts || !contextTexts.length) return "";
return (
"\nContext:\n" +
contextTexts
.map((text, i) => {
return `[CONTEXT ${i}]:\n${text}\n[END CONTEXT ${i}]\n\n`;
})
.join("")
);
}
streamingEnabled() {
return "streamGetChatCompletion" in this;
}
static promptWindowLimit(modelName) {
return MODEL_MAP.get("cohere", modelName) ?? 4_096;
}
promptWindowLimit() {
return MODEL_MAP.get("cohere", this.model) ?? 4_096;
}
async isValidChatCompletionModel() {
return true;
}
constructPrompt({
systemPrompt = "",
contextTexts = [],
chatHistory = [],
userPrompt = "",
}) {
const prompt = {
role: "system",
content: `${systemPrompt}${this.#appendContext(contextTexts)}`,
};
return [prompt, ...chatHistory, { role: "user", content: userPrompt }];
}
async getChatCompletion(messages = null, { temperature = 0.7 }) {
const result = await LLMPerformanceMonitor.measureAsyncFunction(
this.openai.chat.completions
.create({
model: this.model,
messages,
temperature,
})
.catch((e) => {
throw new Error(e.message);
})
);
if (
!result.output.hasOwnProperty("choices") ||
result.output.choices.length === 0
)
return null;
const promptTokens = result.output.usage?.prompt_tokens || 0;
const completionTokens = result.output.usage?.completion_tokens || 0;
return {
textResponse: result.output.choices[0].message.content,
metrics: {
prompt_tokens: promptTokens,
completion_tokens: completionTokens,
total_tokens: promptTokens + completionTokens,
outputTps: completionTokens / result.duration,
duration: result.duration,
model: this.model,
provider: this.className,
timestamp: new Date(),
},
};
}
async streamGetChatCompletion(messages = null, { temperature = 0.7 }) {
const measuredStreamRequest = await LLMPerformanceMonitor.measureStream({
func: this.openai.chat.completions.create({
model: this.model,
stream: true,
stream_options: { include_usage: true },
messages,
temperature,
}),
messages,
runPromptTokenCalculation: false,
modelTag: this.model,
provider: this.className,
});
return measuredStreamRequest;
}
handleStream(response, stream, responseProps) {
return handleDefaultStreamResponseV2(response, stream, responseProps);
}
/**
* Returns the capabilities of the model by querying Cohere's models endpoint.
* A model supports tool calling when its `features` array includes `tools` or `tool_choice`.
* The OpenAI-compatible route does not expose this, so we hit the native REST API.
* @returns {Promise<{tools: boolean, reasoning: boolean, imageGeneration: boolean, vision: boolean}>}
*/
async getModelCapabilities() {
try {
if (!process.env.COHERE_API_KEY)
throw new Error("No Cohere API key was set.");
const features = await fetch(
`https://api.cohere.com/v1/models/${this.model}`,
{
method: "GET",
headers: { Authorization: `Bearer ${process.env.COHERE_API_KEY}` },
}
)
.then((res) => {
if (!res.ok)
throw new Error(`Cohere:getModelCapabilities - ${res.statusText}`);
return res.json();
})
.then((data) => data?.features || []);
return {
tools: features.includes("tools"),
reasoning: features.includes("reasoning"),
imageGeneration: false,
vision: features.includes("vision"),
};
} catch (error) {
console.error("Cohere:getModelCapabilities", error.message);
return {
tools: false,
reasoning: false,
imageGeneration: false,
vision: false,
};
}
}
// Simple wrapper for dynamic embedder & normalize interface for all LLM implementations
async embedTextInput(textInput) {
return await this.embedder.embedTextInput(textInput);
}
async embedChunks(textChunks = []) {
return await this.embedder.embedChunks(textChunks);
}
async compressMessages(promptArgs = {}, rawHistory = []) {
const { messageArrayCompressor } = require("../../helpers/chat");
const messageArray = this.constructPrompt(promptArgs);
return await messageArrayCompressor(this, messageArray, rawHistory);
}
}
module.exports = {
CohereLLM,
};