---

name: twinmind-rate-limits description: | Implement TwinMind rate limiting, backoff, and optimization patterns. Use when handling rate limit errors, implementing retry logic, or optimizing API request throughput for TwinMind. Trigger with phrases like "twinmind rate limit", "twinmind throttling", "twinmind 429", "twinmind retry", "twinmind backoff". allowed-tools: Read, Write, Edit version: 1.0.0 license: MIT author: Jeremy Longshore jeremy@intentsolutions.io

TwinMind Rate Limits

Overview

Handle TwinMind rate limits gracefully with exponential backoff and request optimization.

Prerequisites

• TwinMind API access (Pro/Enterprise)
• Understanding of async/await patterns
• Familiarity with rate limiting concepts

Instructions

Step 1: Understand Rate Limit Tiers

Tier	Audio Hours/Month	API Requests/Min	Concurrent Transcriptions	Burst
Free	Unlimited	30	1	5
Pro ($10/mo)	Unlimited	60	3	15
Enterprise	Unlimited	300	10	50

Key Limits:

• Transcription: Based on audio duration ($0.23/hour with Ear-3)
• AI Operations: Token-based (2M context for Pro)
• Summarization: 10/minute (Free), 30/minute (Pro)
• Memory Search: 60/minute (Free), 300/minute (Pro)

Step 2: Implement Exponential Backoff with Jitter

// src/twinmind/rate-limit.ts
interface RateLimitConfig {
  maxRetries: number;
  baseDelayMs: number;
  maxDelayMs: number;
  jitterMs: number;
}

const defaultConfig: RateLimitConfig = {
  maxRetries: 5,
  baseDelayMs: 1000,
  maxDelayMs: 60000, // Max 1 minute
  jitterMs: 500,
};

export async function withRateLimit<T>(
  operation: () => Promise<T>,
  config: Partial<RateLimitConfig> = {}
): Promise<T> {
  const { maxRetries, baseDelayMs, maxDelayMs, jitterMs } = {
    ...defaultConfig,
    ...config,
  };

  for (let attempt = 0; attempt <= maxRetries; attempt++) {
    try {
      return await operation();
    } catch (error: any) {
      if (attempt === maxRetries) throw error;

      const status = error.response?.status;
      if (status !== 429 && status !== 503) throw error; // Only retry on rate limits

      // Check Retry-After header
      const retryAfter = error.response?.headers?.['retry-after'];
      let delay: number;

      if (retryAfter) {
        delay = parseInt(retryAfter) * 1000;
      } else {
        // Exponential backoff with jitter
        const exponential = baseDelayMs * Math.pow(2, attempt);
        const jitter = Math.random() * jitterMs;
        delay = Math.min(exponential + jitter, maxDelayMs);
      }

      console.log(`Rate limited (attempt ${attempt + 1}). Waiting ${delay}ms...`);
      await new Promise(r => setTimeout(r, delay));
    }
  }

  throw new Error('Max retries exceeded');
}

Step 3: Implement Request Queue

// src/twinmind/queue.ts
import PQueue from 'p-queue';

interface QueueConfig {
  concurrency: number;
  intervalMs: number;
  intervalCap: number;
}

const tierConfigs: Record<string, QueueConfig> = {
  free: { concurrency: 1, intervalMs: 60000, intervalCap: 30 },
  pro: { concurrency: 3, intervalMs: 60000, intervalCap: 60 },
  enterprise: { concurrency: 10, intervalMs: 60000, intervalCap: 300 },
};

export class TwinMindQueue {
  private queue: PQueue;
  private tier: string;

  constructor(tier: 'free' | 'pro' | 'enterprise' = 'pro') {
    const config = tierConfigs[tier];
    this.tier = tier;
    this.queue = new PQueue({
      concurrency: config.concurrency,
      interval: config.intervalMs,
      intervalCap: config.intervalCap,
    });
  }

  async add<T>(operation: () => Promise<T>, priority?: number): Promise<T> {
    return this.queue.add(operation, { priority }) as Promise<T>;
  }

  get pending(): number {
    return this.queue.pending;
  }

  get size(): number {
    return this.queue.size;
  }

  pause(): void {
    this.queue.pause();
  }

  resume(): void {
    this.queue.start();
  }

  clear(): void {
    this.queue.clear();
  }
}

// Singleton instance
let queueInstance: TwinMindQueue | null = null;

export function getQueue(tier?: 'free' | 'pro' | 'enterprise'): TwinMindQueue {
  if (!queueInstance) {
    queueInstance = new TwinMindQueue(tier);
  }
  return queueInstance;
}

Step 4: Monitor Rate Limit Headers

// src/twinmind/rate-monitor.ts
export interface RateLimitStatus {
  limit: number;
  remaining: number;
  reset: Date;
  percentUsed: number;
}

export class RateLimitMonitor {
  private limits = new Map<string, RateLimitStatus>();

  updateFromResponse(endpoint: string, headers: Headers): void {
    const limit = parseInt(headers.get('X-RateLimit-Limit') || '60');
    const remaining = parseInt(headers.get('X-RateLimit-Remaining') || '60');
    const resetTimestamp = headers.get('X-RateLimit-Reset');
    const reset = resetTimestamp
      ? new Date(parseInt(resetTimestamp) * 1000)
      : new Date(Date.now() + 60000);

    this.limits.set(endpoint, {
      limit,
      remaining,
      reset,
      percentUsed: ((limit - remaining) / limit) * 100,
    });
  }

  getStatus(endpoint: string): RateLimitStatus | undefined {
    return this.limits.get(endpoint);
  }

  shouldThrottle(endpoint: string, threshold = 10): boolean {
    const status = this.limits.get(endpoint);
    if (!status) return false;

    // Throttle if remaining < threshold AND reset hasn't happened
    return status.remaining < threshold && new Date() < status.reset;
  }

  getWaitTime(endpoint: string): number {
    const status = this.limits.get(endpoint);
    if (!status) return 0;

    const now = Date.now();
    const resetTime = status.reset.getTime();

    return Math.max(0, resetTime - now);
  }

  getAllStatuses(): Map<string, RateLimitStatus> {
    return new Map(this.limits);
  }
}

export const rateLimitMonitor = new RateLimitMonitor();

Step 5: Implement Adaptive Rate Limiting

// src/twinmind/adaptive-limiter.ts
export class AdaptiveRateLimiter {
  private successCount = 0;
  private failureCount = 0;
  private currentDelay = 0;
  private minDelay = 0;
  private maxDelay = 5000;
  private windowMs = 60000;
  private windowStart = Date.now();

  recordSuccess(): void {
    this.maybeResetWindow();
    this.successCount++;

    // Decrease delay on success (min 0)
    if (this.currentDelay > 0) {
      this.currentDelay = Math.max(0, this.currentDelay - 100);
    }
  }

  recordFailure(isRateLimit: boolean): void {
    this.maybeResetWindow();
    this.failureCount++;

    if (isRateLimit) {
      // Increase delay on rate limit
      this.currentDelay = Math.min(this.maxDelay, this.currentDelay + 500);
    }
  }

  private maybeResetWindow(): void {
    const now = Date.now();
    if (now - this.windowStart > this.windowMs) {
      this.successCount = 0;
      this.failureCount = 0;
      this.windowStart = now;
    }
  }

  getDelay(): number {
    return this.currentDelay;
  }

  getMetrics(): { success: number; failure: number; delay: number; ratio: number } {
    const total = this.successCount + this.failureCount;
    return {
      success: this.successCount,
      failure: this.failureCount,
      delay: this.currentDelay,
      ratio: total > 0 ? this.successCount / total : 1,
    };
  }

  async wait(): Promise<void> {
    if (this.currentDelay > 0) {
      await new Promise(r => setTimeout(r, this.currentDelay));
    }
  }
}

Step 6: Batch Requests for Efficiency

// src/twinmind/batch.ts
export interface BatchOptions {
  maxBatchSize: number;
  maxWaitMs: number;
}

export class TranscriptionBatcher {
  private pending: Array<{
    audioUrl: string;
    resolve: (value: any) => void;
    reject: (error: any) => void;
  }> = [];
  private timer: NodeJS.Timeout | null = null;
  private options: BatchOptions;

  constructor(options: Partial<BatchOptions> = {}) {
    this.options = {
      maxBatchSize: 5,
      maxWaitMs: 1000,
      ...options,
    };
  }

  async transcribe(audioUrl: string): Promise<any> {
    return new Promise((resolve, reject) => {
      this.pending.push({ audioUrl, resolve, reject });

      if (this.pending.length >= this.options.maxBatchSize) {
        this.flush();
      } else if (!this.timer) {
        this.timer = setTimeout(() => this.flush(), this.options.maxWaitMs);
      }
    });
  }

  private async flush(): Promise<void> {
    if (this.timer) {
      clearTimeout(this.timer);
      this.timer = null;
    }

    const batch = this.pending.splice(0, this.options.maxBatchSize);
    if (batch.length === 0) return;

    try {
      // Use batch API if available
      const results = await this.processBatch(batch.map(b => b.audioUrl));

      batch.forEach((item, index) => {
        item.resolve(results[index]);
      });
    } catch (error) {
      batch.forEach(item => item.reject(error));
    }
  }

  private async processBatch(audioUrls: string[]): Promise<any[]> {
    const client = getTwinMindClient();
    const response = await client.post('/transcribe/batch', {
      audio_urls: audioUrls,
      model: 'ear-3',
    });
    return response.data.transcripts;
  }
}

Output

• Reliable API calls with automatic retry
• Request queue with rate limit awareness
• Adaptive throttling based on response patterns
• Batch processing for efficiency
• Real-time rate limit monitoring

Error Handling

Header	Description	Action
X-RateLimit-Limit	Max requests per window	Monitor total quota
X-RateLimit-Remaining	Remaining in window	Throttle when low
X-RateLimit-Reset	Unix timestamp of reset	Wait until reset
Retry-After	Seconds to wait	Honor this value

Rate Limit Best Practices

1. Always handle 429 responses - Never let rate limits crash your app
2. Use request queues - Don't burst requests
3. Monitor remaining quota - Throttle before hitting limits
4. Implement circuit breakers - Fail fast when API is overloaded
5. Cache responses - Avoid redundant requests
6. Batch when possible - Reduce total request count

Resources

• TwinMind Rate Limits
• p-queue Documentation
• Rate Limiting Patterns

Next Steps

For security configuration, see twinmind-security-basics.