Prompt Repetition Paper

# Evaluation: Prompt Repetition Paper (arXiv:2512.14982)

**Date**: 2026-01-25
**Paper**: "Prompt Repetition Improves Non-Reasoning LLMs"
**Authors**: Yaniv Leviathan, Matan Kalman, Yossi Matias (Google Research)
**Published**: 17 Dec 2025
**arXiv**: https://arxiv.org/abs/2512.14982

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## 1. Findings Summary

### Core Claim
Repeating the input prompt 2x improves accuracy for LLMs **without reasoning mode**, without increasing output length or latency.

### Tested Models (directly from paper)
- Gemini 2.0 Flash / Flash Lite
- GPT-4o / GPT-4o-mini
- **Claude 3 Haiku**
- **Claude 3.7 Sonnet**
- Deepseek V3

### Benchmarks
ARC (Challenge), OpenBookQA, GSM8K, MMLU-Pro, MATH, NameIndex, MiddleMatch

### Key Results
| Metric | Value |
|--------|-------|
| Wins (no reasoning) | 47/70 benchmark-model combinations |
| Losses | 0 |
| With CoT/reasoning | 5 wins, 1 loss, 22 neutral |

### Claude-Specific Notes (from paper)
- Tested on Claude 3 Haiku and Claude 3.7 Sonnet
- **Latency increase** observed for Claude models on very long requests (repeat x3 or custom benchmarks)
- Likely due to prefill stage taking longer

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## 2. Relevance to Claude Code

### Model Situation (Jan 2026)

| Model | Thinking Mode | Prompt Repetition Applicable? |
|-------|---------------|-------------------------------|
| Opus 4.5 | ON by default (max budget) | NO - thinking already maximizes reasoning |
| Sonnet 4 | Not available | YES - could benefit |
| Haiku 3.5 | Not available | YES - could benefit |

### The Problem

Claude Code uses:
- **Sonnet as default** (85% of usage per guide stats)
- **Haiku for simple tasks** (cost optimization)
- **Opus for complex tasks** (already has thinking mode)

The paper's technique is specifically for **non-reasoning** scenarios. This makes it potentially relevant for Sonnet/Haiku in Claude Code.

### The Catch

1. **Input token cost doubles**: Repeating prompt = 2x input tokens
2. **Claude Code context is already under pressure**: Guide emphasizes context management (100K practical limit)
3. **Gain magnitude unclear**: Paper shows wins/losses but not absolute improvement %
4. **Claude-specific latency issue**: Paper notes increased latency for Claude on long prompts

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## 3. Community Reception

### Academic Impact (as of 2026-01-25)
- **Citations**: 0 (paper is 5 weeks old)
- **Semantic Scholar**: Listed, no citations
- **Replications**: None found

### Community Discussion
- **Hacker News**: 5+ submissions, max 3 points, 0 comments
- **Reddit r/MachineLearning**: No relevant posts
- **Reddit r/LocalLLaMA**: No relevant posts
- **Twitter/X**: No significant discussion found

### Assessment
Extremely low community engagement. No independent validation. No practical adoption reports.

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## 4. Practical Considerations for Claude Code

### Hypothetical Hook Implementation