# Model Mixing
**Model Mixing** refers to strategies and techniques for combining multiple [[concepts/large-language-model]]s (LLMs) or leveraging different models within a single system to optimize for specific tasks, balancing cost, latency, and performance.
## Core Principles
- **[[concepts/specialization|Specialization]] vs. [[concepts/abstraction|Generalization]]**: Using smaller, [[concepts/custom-models|specialized models]] for rote tasks (e.g., formatting, parsing) and larger, more capable models for [[concepts/complex-reasoning|complex reasoning]] or creative generation.
- **Ensemble Methods**: Aggregating outputs from multiple models to reduce [[concepts/data-hallucination|hallucination]] rates and improve [[concepts/robustness|robustness]].
- **Routing**: Dynamically directing queries to the most appropriate model based on input complexity or user constraints.
## Critiques and Alternatives
Recent analysis suggests that the efficacy of [[concepts/ai-models|AI systems]] may depend less on the raw capability of the underlying LLM and more on the structural design of the surrounding system.
- **The [[concepts/harness|Harness]] Hypothesis**: The "harness" ([[concepts/context-management|context management]], tool usage, [[concepts/bug-fixing|error correction]] [[concepts/loops|loops]]) often outweighs the [[concepts/incremental-progress|marginal gains]] of switching between top-tier LLMs. See [[lab-notes/2026-05-18-Optimizing-AI-Coding-Agents-Harness-Design-Over-LLM-Choi|Optimizing AI Coding Agents: Harness Design Over LLM Choice]] for details on how [[concepts/ai-prompt|prompt architecture]] and agent [[concepts/open-source-philosophy|logic]] can mitigate model limitations.
- **[[concepts/diminishing-returns|Diminishing Returns]]**: Blindly mixing models without optimizing the orchestration layer can lead to increased latency and complexity without proportional quality improvements.
## Related Concepts
- Agent Design
- [[entities/prompt-engineering]]
- LLM [[concepts/benchmark-testing|Benchmarking]]
- [[concepts/system-prompting]]