refactor(ts): improve type safety for request ID capture and empty-assistant diagnostics

cline.ts: strongly type custom fetch override using Parameters<typeof fetch>/ReturnType<typeof fetch>; safe URL extraction for string|URL|Request; removed any casts.

task/index.ts: encapsulate requestId retrieval via getApiRequestIdSafe(); avoid any; no behavior change. Scope limited to PR 6066-related changes.

src/core/api/providers/cline.ts

@@ -32,6 +32,7 @@ export class ClineHandler implements ApiHandler {
 	private client: OpenAI | undefined
 	private readonly _baseUrl = clineEnvConfig.apiBaseUrl
 	lastGenerationId?: string
+	private lastRequestId?: string
 
 	constructor(options: ClineHandlerOptions) {
 		this.options = options
@@ -54,6 +55,31 @@ export class ClineHandler implements ApiHandler {
 						"X-Task-ID": this.options.ulid || "",
 						"X-Cline-Version": extensionVersion,
 					},
+					// Capture real HTTP request ID from initial streaming response headers
+					fetch: async (...args: Parameters<typeof fetch>): Promise<Awaited<ReturnType<typeof fetch>>> => {
+						const [input, init] = args
+						const resp = await fetch(input, init)
+						try {
+							let urlStr = ""
+							if (typeof input === "string") {
+								urlStr = input
+							} else if (input instanceof URL) {
+								urlStr = input.toString()
+							} else if (typeof (input as { url?: unknown }).url === "string") {
+								urlStr = (input as { url: string }).url
+							}
+							// Only record for chat completions (the primary streaming request)
+							if (urlStr.includes("/chat/completions")) {
+								const rid = resp.headers.get("x-request-id") || resp.headers.get("request-id")
+								if (rid) {
+									this.lastRequestId = rid
+								}
+							}
+						} catch {
+							// ignore header capture errors
+						}
+						return resp
+					},
 				})
 			} catch (error: any) {
 				throw new Error(`Error creating Cline client: ${error.message}`)
@@ -70,6 +96,7 @@ export class ClineHandler implements ApiHandler {
 			const client = await this.ensureClient()
 
 			this.lastGenerationId = undefined
+			this.lastRequestId = undefined
 
 			let didOutputUsage: boolean = false
 
@@ -92,6 +119,7 @@ export class ClineHandler implements ApiHandler {
 					const metadataStr = error.metadata ? `\nMetadata: ${JSON.stringify(error.metadata, null, 2)}` : ""
 					throw new Error(`Cline API Error ${error.code}: ${error.message}${metadataStr}`)
 				}
+
 				if (!this.lastGenerationId && chunk.id) {
 					this.lastGenerationId = chunk.id
 				}
@@ -203,6 +231,11 @@ export class ClineHandler implements ApiHandler {
 		return undefined
 	}
 
+	// Expose the last HTTP request ID captured from response headers (X-Request-ID)
+	getLastRequestId(): string | undefined {
+		return this.lastRequestId
+	}
+
 	getModel(): { id: string; info: ModelInfo } {
 		const modelId = this.options.openRouterModelId
 		const modelInfo = this.options.openRouterModelInfo

src/core/task/index.ts

@@ -1273,6 +1273,14 @@ export class Task {
 		return { model, providerId, customPrompt }
 	}
 
+	private getApiRequestIdSafe(): string | undefined {
+		const apiLike = this.api as Partial<{
+			getLastRequestId: () => string | undefined
+			lastGenerationId?: string
+		}>
+		return apiLike.getLastRequestId?.() ?? apiLike.lastGenerationId
+	}
+
 	private async handleContextWindowExceededError(): Promise<void> {
 		const apiConversationHistory = this.messageStateHandler.getApiConversationHistory()
 
@@ -2147,10 +2155,29 @@ export class Task {
 				didEndLoop = recDidEndLoop
 			} else {
 				// if there's no assistant_responses, that means we got no text or tool_use content blocks from API which we should assume is an error
-				await this.say(
-					"error",
-					"Unexpected API Response: The language model did not provide any assistant messages. This may indicate an issue with the API or the model's output.",
-				)
+				const { model, providerId } = this.getCurrentProviderInfo()
+				const reqId = this.getApiRequestIdSafe()
+
+				// Minimal diagnostics: structured log and telemetry
+				console.error("[EmptyAssistantMessage]", {
+					ulid: this.ulid,
+					providerId,
+					modelId: model.id,
+					requestId: reqId,
+				})
+				telemetryService.captureProviderApiError({
+					ulid: this.ulid,
+					model: model.id,
+					provider: providerId,
+					errorMessage: "empty_assistant_message",
+					requestId: reqId,
+				})
+
+				const baseErrorMessage =
+					"Unexpected API Response: The language model did not provide any assistant messages. This may indicate an issue with the API or the model's output."
+				const errorText = reqId ? `${baseErrorMessage} (reqId: ${reqId})` : baseErrorMessage
+
+				await this.say("error", errorText)
 				await this.messageStateHandler.addToApiConversationHistory({
 					role: "assistant",
 					content: [

src/services/telemetry/TelemetryService.ts

@@ -730,6 +730,7 @@ export class TelemetryService {
 		ulid: string
 		model: string
 		errorMessage: string
+		provider?: string
 		errorStatus?: number | undefined
 		requestId?: string | undefined
 	}) {