feat(diagnostics): add opt-in cache trace diagnostics (#35)

Add privacy-preserving cache trace diagnostics behind deepseek-copilot.debug.
Include request fingerprints, summary prefix comparison, tool schema hashes, reasoning cache warnings, vision resolution markers, and cache usage logs.

Refactor provider request, stream, model, and token helpers without changing vision, conversion, or reasoning replay behavior.

Author: Vizards

README.md

@@ -85,6 +85,7 @@ Both support optional thinking mode, tool calling, and 1M token context.
 | `deepseek-copilot.baseUrl` | `https://api.deepseek.com` | API endpoint — change for self-hosted / proxied deployments |
 | `deepseek-copilot.maxTokens` | `0` | Max output tokens (`0` = no limit). Useful for cost control |
 | `deepseek-copilot.modelIdOverrides` | prefilled official ID map | API model IDs to send for DeepSeek V4 Flash / Pro. Change only for compatible third-party APIs with different model names |
+| `deepseek-copilot.debug` | `false` | Enable privacy-preserving diagnostic debug logs for troubleshooting. Does not log prompt text |
 | `deepseek-copilot.visionModel` | *(auto)* | Which Copilot model to proxy images through |
 | `deepseek-copilot.visionPrompt` | *(built-in)* | Prompt used to describe image attachments |
 

package.json

@@ -120,6 +120,11 @@
           "minimum": 0,
           "description": "%deepseek-copilot.config.maxTokens.description%"
         },
+        "deepseek-copilot.debug": {
+          "type": "boolean",
+          "default": false,
+          "description": "%deepseek-copilot.config.debug.description%"
+        },
         "deepseek-copilot.modelIdOverrides": {
           "type": "object",
           "default": {

package.nls.json

@@ -17,6 +17,7 @@
   "deepseek-copilot.config.title": "DeepSeek Copilot",
   "deepseek-copilot.config.baseUrl.description": "DeepSeek API base URL. Defaults to official DeepSeek API endpoint.",
   "deepseek-copilot.config.maxTokens.description": "Maximum number of output tokens per request. Set to 0 to use the API default (no limit). Useful for controlling costs.",
+  "deepseek-copilot.config.debug.description": "Enable diagnostic debug logging for troubleshooting. Logs privacy-preserving metadata such as request hashes, prefix overlap, tool schema changes, and missing reasoning_content. Does not log prompt text.",
   "deepseek-copilot.config.modelIdOverrides.description": "Override the API model ID sent for each DeepSeek model. Defaults are prefilled with official DeepSeek IDs; change them only when using a compatible third-party API that uses different model names.",
   "deepseek-copilot.config.modelIdOverrides.deepseek-v4-flash.description": "API model ID for DeepSeek V4 Flash",
   "deepseek-copilot.config.modelIdOverrides.deepseek-v4-pro.description": "API model ID for DeepSeek V4 Pro",

package.nls.zh-cn.json

@@ -17,6 +17,7 @@
   "deepseek-copilot.config.title": "DeepSeek 助手",
   "deepseek-copilot.config.baseUrl.description": "DeepSeek API 基础 URL，默认为官方 DeepSeek API 端点。",
   "deepseek-copilot.config.maxTokens.description": "每次请求的最大输出 Token 数，设为 0 则不限制，可用于控制成本。",
+  "deepseek-copilot.config.debug.description": "启用用于排查问题的诊断调试日志。日志只包含请求哈希、前缀重合度、工具定义变化、缺失 reasoning_content 等隐私保护后的元数据，不记录提示词原文。",
   "deepseek-copilot.config.modelIdOverrides.description": "覆盖各 DeepSeek 模型实际使用的 API 模型 ID，默认使用官方 DeepSeek ID，仅在对接不同模型名称的第三方 API 时需要修改。",
   "deepseek-copilot.config.modelIdOverrides.deepseek-v4-flash.description": "DeepSeek V4 Flash 的 API 模型 ID。",
   "deepseek-copilot.config.modelIdOverrides.deepseek-v4-pro.description": "DeepSeek V4 Pro 的 API 模型 ID。",

src/config.ts

@@ -33,3 +33,11 @@ export function getMaxTokens(): number | undefined {
 	const value = config.get<number>('maxTokens', 0);
 	return value > 0 ? value : undefined;
 }
+
+/**
+ * Whether to log privacy-preserving diagnostic debug information.
+ */
+export function getDebugLoggingEnabled(): boolean {
+	const config = vscode.workspace.getConfiguration(CONFIG_SECTION);
+	return config.get<boolean>('debug', false);
+}

src/extension.ts

@@ -1,4 +1,5 @@
 import vscode from 'vscode';
+import { getDebugLoggingEnabled } from './config';
 import { WALKTHROUGH_ID, WELCOME_SHOWN_KEY } from './consts';
 import { t } from './i18n';
 import { logger } from './logger';
@@ -7,7 +8,10 @@ import { DeepSeekChatProvider } from './provider';
 let activeProvider: DeepSeekChatProvider | undefined;
 
 export function activate(context: vscode.ExtensionContext) {
-	logger.info('Activating extension');
+	logger.info(
+		`Activating extension version=${context.extension.packageJSON.version}` +
+			` debug=${getDebugLoggingEnabled()}`,
+	);
 
 	context.subscriptions.push(
 		vscode.commands.registerCommand('deepseek-copilot.showLogs', () => logger.show()),
@@ -57,7 +61,7 @@ export function activate(context: vscode.ExtensionContext) {
 			logger.warn(t('extension.welcomeFailed'), error);
 		});
 
-		logger.info('Extension activated');
+		logger.info(`Extension activated version=${context.extension.packageJSON.version}`);
 	} catch (error) {
 		activeProvider = undefined;
 		logger.error('Failed to activate DeepSeek extension', error);