# Handoff: Research to Planning - Rate Limiting System

**Date**: 2025-11-19
**From**: Research Agent
**To**: Plan Agent
**Status**: Ready for Planning

## Summary

Research into Redis-based rate limiting strategies is complete. We have evaluated three approaches: Fixed Window, Sliding Window Log, and Sliding Window Counter. The Sliding Window Counter (using Redis Lua scripts) is recommended for its balance of accuracy and memory efficiency.

## Key Findings

- **Fixed Window**: Simple but allows bursts at window edges (2x limit).
- **Sliding Window Log**: Accurate but high memory usage (stores every timestamp).
- **Sliding Window Counter**: Best compromise. 99.9% accuracy, low memory.
- **Library**: `ioredis` is the preferred client for Lua script support.

## Context Files

- @.opencode/memory/research/2025-11-19-rate-limiting.md (Simulated)
- @src/lib/redis.ts (Simulated)

## Next Steps (Prompt)

@plan Review the research findings above. Create a technical specification for implementing the Sliding Window Counter rate limiter in our Node.js/TypeScript backend.

1. Define the Redis key schema.
2. Draft the Lua script logic.
3. Design the TypeScript interface for the `RateLimiter` class.
4. Identify necessary environment variables.
