feat: Add optional debug flag to LLM providers

This commit introduces an optional `debug` boolean configuration to the OpenAI, Gemini, and WebLlm providers.

When `debug` is set to `true` in the provider's configuration, the provider will print useful debugging information to the console. This includes:

- For OpenAI and Gemini providers:
    - The HTTP method being used.
    - The endpoint URL (API keys in Gemini's direct mode URL are redacted).
    - Request headers (with 'Authorization' header redacted for OpenAI).
    - The request body.
- For WebLlmProvider:
    - The model being used.
    - The system message.
    - The response format.
    - The engine configuration.
    - Chat completion options.
    - The messages being processed.

This feature is intended to help you troubleshoot issues with LLM provider integrations, especially when using proxy mode or when unexpected responses are received. The `debug` option defaults to `false` if not specified.

Author: google-labs-jules[bot]

src/providers/GeminiProvider.ts

@@ -14,6 +14,7 @@ class GeminiProvider implements Provider {
 	private systemMessage?: string;
 	private responseFormat!: 'stream' | 'json';
 	private messageParser?: (messages: Message[]) => GeminiProviderMessage[];
+	private debug: boolean = false;
 
 	/**
 	 * Sets default values for the provider based on given configuration. Configuration guide here:
@@ -27,6 +28,7 @@ class GeminiProvider implements Provider {
 		this.systemMessage = config.systemMessage;
 		this.responseFormat = config.responseFormat ?? 'stream';
 		this.messageParser = config.messageParser;
+		this.debug = config.debug ?? false;
 		this.headers = {
 			'Content-Type': 'application/json',
 			Accept: this.responseFormat === 'stream' ? 'text/event-stream' : 'application/json',
@@ -52,6 +54,20 @@ class GeminiProvider implements Provider {
 	 * @param messages messages to include in the request
 	 */
 	public async *sendMessages(messages: Message[]): AsyncGenerator<string> {
+		if (this.debug) {
+			const sanitizedEndpoint = this.endpoint.replace(/\?key=([^&]+)/, '?key=[REDACTED]');
+			// Headers in Gemini usually don't contain sensitive info like 'Authorization'
+			// as the API key is in the URL, but we'll keep a general sanitization pattern.
+			const sanitizedHeaders = { ...this.headers };
+			// If any sensitive header were to be added in the future, it should be removed here.
+			// delete sanitizedHeaders['Some-Sensitive-Header'];
+			console.log('[GeminiProvider] Request:', {
+				method: this.method,
+				endpoint: sanitizedEndpoint,
+				headers: sanitizedHeaders,
+				body: this.constructBodyWithMessages(messages),
+			});
+		}
 		const res = await fetch(this.endpoint, {
 			method: this.method,
 			headers: this.headers as HeadersInit,

src/providers/OpenaiProvider.ts

@@ -14,6 +14,7 @@ class OpenaiProvider implements Provider {
 	private systemMessage?: string;
 	private responseFormat!: 'stream' | 'json';
 	private messageParser?: (messages: Message[]) => OpenaiProviderMessage[];
+	private debug: boolean = false;
 
 	/**
 	 * Sets default values for the provider based on given configuration. Configuration guide here:
@@ -27,6 +28,7 @@ class OpenaiProvider implements Provider {
 		this.systemMessage = config.systemMessage;
 		this.responseFormat = config.responseFormat ?? 'stream';
 		this.messageParser = config.messageParser;
+		this.debug = config.debug ?? false;
 		this.headers = {
 			'Content-Type': 'application/json',
 			Accept: this.responseFormat === 'stream' ? 'text/event-stream' : 'application/json',
@@ -54,6 +56,16 @@ class OpenaiProvider implements Provider {
 	 * @param messages messages to include in the request
 	 */
 	public async *sendMessages(messages: Message[]): AsyncGenerator<string> {
+		if (this.debug) {
+			const sanitizedHeaders = { ...this.headers };
+			delete sanitizedHeaders['Authorization'];
+			console.log('[OpenaiProvider] Request:', {
+				method: this.method,
+				endpoint: this.endpoint,
+				headers: sanitizedHeaders,
+				body: this.constructBodyWithMessages(messages),
+			});
+		}
 		const res = await fetch(this.endpoint, {
 			method: this.method,
 			headers: this.headers as HeadersInit,

src/providers/WebLlmProvider.ts

@@ -15,6 +15,7 @@ class WebLlmProvider implements Provider {
 	private chatCompletionOptions: Record<string, unknown>;
 	private messageParser?: (messages: Message[]) => WebLlmProviderMessage[];
 	private engine?: MLCEngine;
+	private debug: boolean = false;
 
 	/**
 	 * Sets default values for the provider based on given configuration. Configuration guide here:
@@ -29,6 +30,7 @@ class WebLlmProvider implements Provider {
 		this.messageParser = config.messageParser;
 		this.engineConfig = config.engineConfig ?? {};
 		this.chatCompletionOptions = config.chatCompletionOptions ?? {};
+		this.debug = config.debug ?? false;
 		this.createEngine();
 	}
 
@@ -52,6 +54,17 @@ class WebLlmProvider implements Provider {
 			await this.createEngine();
 		}
 
+		if (this.debug) {
+			console.log('[WebLlmProvider] Request:', {
+				model: this.model,
+				systemMessage: this.systemMessage,
+				responseFormat: this.responseFormat,
+				engineConfig: this.engineConfig,
+				chatCompletionOptions: this.chatCompletionOptions,
+				messages: this.constructBodyWithMessages(messages).messages, // Log messages being sent
+			});
+		}
+
 		const result = await this.engine?.chat.completions.create(this.constructBodyWithMessages(messages));
 		if (result && Symbol.asyncIterator in result) {
 			for await (const chunk of result as AsyncIterable<ChatCompletionChunk>) {

src/types/provider-config/GeminiProviderConfig.ts

@@ -15,6 +15,7 @@ type DirectConfig = {
 	headers?: Record<string, string>;
 	body?: Record<string, string>;
 	messageParser?: (messages: Message[]) => GeminiProviderMessage[];
+	debug?: boolean;
 };
 
 /**
@@ -30,6 +31,7 @@ type ProxyConfig = {
 	headers?: Record<string, string>;
 	body?: Record<string, string>;
 	messageParser?: (messages: Message[]) => GeminiProviderMessage[];
+	debug?: boolean;
 };
 
 /**

src/types/provider-config/OpenaiProviderConfig.ts

@@ -15,6 +15,7 @@ type DirectConfig = {
 	headers?: Record<string, string>;
 	body?: Record<string, string>;
 	messageParser?: (messages: Message[]) => OpenaiProviderMessage[];
+	debug?: boolean;
 };
 
 /**
@@ -30,6 +31,7 @@ type ProxyConfig = {
 	headers?: Record<string, string>;
 	body?: Record<string, string>;
 	messageParser?: (messages: Message[]) => OpenaiProviderMessage[];
+	debug?: boolean;
 };
 
 /**

src/types/provider-config/WebLlmProviderConfig.ts

@@ -12,6 +12,7 @@ type WebLlmProviderConfig = {
 	engineConfig?: MLCEngineConfig;
 	chatCompletionOptions?: Record<string, unknown>;
 	messageParser?: (messages: Message[]) => WebLlmProviderMessage[];
+	debug?: boolean;
 };
 
 export type { WebLlmProviderConfig };