mergekit — Skill

Merge multiple LLM checkpoints and LoRA deltas into a single .safetensors artifact.

Updated Apr 20, 2026
One-click install
npx skills add https://github.com/thistleknot/skills --skill mergekit-skill
Or copy as Structured Prompt for Agent▼
Please help me install this Agent Skill.
Skill: mergekit — Skill
Source: https://github.com/thistleknot/skills/tree/main/mergekit
Command: npx skills add https://github.com/thistleknot/skills --skill mergekit-skill

SYSTEM DOCUMENTATION & REQUIREMENTS

What problem does it solve?

It solves the problem of combining multiple pretrained LLM checkpoints, fine-tunes, or LoRA adapters into a single merged .safetensors artifact without doing full retraining.

Core Features & Use Cases

  • Out-of-core tensor streaming merges: run merges without loading entire models into RAM by streaming tensors layer-by-layer.
  • Task-vector and delta-aware merge methods: apply methods such as linear blending, slerp/nuslerp interpolation, task arithmetic, TIES/DARE/DELLA, and breadcrumbs-based pruning for interference reduction.
  • Frankenmerging via layer slices: assemble a model by selecting and optionally blending contiguous layer ranges from different sources.
  • Tokenizer and LoRA handling: configure tokenizer sources and extract LoRA adapters approximating finetune deltas.

Quick Start

Use mergekit to merge two LoRA- or fine-tuned checkpoints into a single .safetensors model by telling the AI to run the mergekit-yaml CLI on a provided YAML config that specifies the merge method, base model (when required), input model paths, and output directory.

Frequently Asked Questions about mergekit — Skill

High-intent search queries and answers about installing and using this skill.

FAQPage Schema
How do I merge multiple fine-tuned LLM checkpoints into a single model without retraining?▼

You can merge fine-tuned LLM checkpoints into a single model by using a YAML configuration to specify merge methods like linear blending or task arithmetic, outputting a combined safetensors file without full retraining.

Can I merge large models with limited RAM using out-of-core tensor streaming?▼

Yes, out-of-core tensor streaming allows you to merge large models with limited RAM by processing and writing tensors layer-by-layer instead of loading entire checkpoints into memory simultaneously.

What is the difference between TIES, DARE, and frankenmerging for model merging?▼

TIES and DARE reduce parameter interference during delta merging, while frankenmerging assembles a new model by selecting and blending contiguous layer ranges from different pretrained source checkpoints.

How do I extract a LoRA adapter from a fine-tune delta during checkpoint blending?▼

Checkpoint blending supports LoRA extraction by approximating finetune deltas, allowing you to derive and merge LoRA adapters alongside other pretrained models using a mergekit YAML configuration.

Do I need a base model for task arithmetic and model soup averaging?▼

Yes, task arithmetic and similar interference-reducing merge methods require a base model in the configuration to calculate parameter deltas correctly and ensure valid composition.

What are the limitations of using slerp and nuslerp interpolation for checkpoint blending?▼

Slerp and nuslerp interpolation methods for checkpoint blending require merging exactly two models at a time and need correct parameter and weight semantics to function properly.