Method backoffAndAnnounce

src/core/task/Task.ts:4386–4458

(retryAttempt: number, error: any)

	// Shared exponential backoff for retries (first-chunk and mid-stream)
	private async backoffAndAnnounce(retryAttempt: number, error: any): Promise<void> {
		try {
			const state = await this.providerRef.deref()?.getState()
			const baseDelay = state?.requestDelaySeconds || 5

			let exponentialDelay = Math.min(
				Math.ceil(baseDelay * Math.pow(2, retryAttempt)),
				MAX_EXPONENTIAL_BACKOFF_SECONDS,
			)

			// Respect provider rate limit window
			let rateLimitDelay = 0
			const rateLimit = (state?.apiConfiguration ?? this.apiConfiguration)?.rateLimitSeconds || 0
			const lastRequestTime = this.rateLimitClock.getLastRequestTime()
			if (lastRequestTime && rateLimit > 0) {
				const elapsed = performance.now() - lastRequestTime
				rateLimitDelay = Math.ceil(Math.min(rateLimit, Math.max(0, rateLimit * 1000 - elapsed) / 1000))
			}

			// Prefer RetryInfo on 429 if present
			if (error?.status === 429) {
				const retryInfo = error?.errorDetails?.find(
					(d: any) => d["@type"] === "type.googleapis.com/google.rpc.RetryInfo",
				)
				const match = retryInfo?.retryDelay?.match?.(/^(\d+)s$/)
				if (match) {
					exponentialDelay = Number(match[1]) + 1
				}
			}

			const finalDelay = Math.max(exponentialDelay, rateLimitDelay)
			if (finalDelay <= 0) {
				return
			}

			// Build header text; fall back to error message if none provided
			let headerText
			if (error.status) {
				// Include both status code (for ChatRow parsing) and detailed message (for error details)
				// Format: "<status>\n<message>" allows ChatRow to extract status via parseInt(text.substring(0,3))
				// while preserving the full error message in errorDetails for debugging
				const errorMessage = error?.message || "Unknown error"
				headerText = `${error.status}\n${errorMessage}`
			} else if (error?.message) {
				headerText = error.message
			} else {
				headerText = "Unknown error"
			}

			headerText = headerText ? `${headerText}\n` : ""

			// Show countdown timer with exponential backoff
			for (let i = finalDelay; i > 0; i--) {
				// Check abort flag during countdown to allow early exit
				if (this.abort) {
					throw new Error(`[Task#${this.taskId}] Aborted during retry countdown`)
				}