# GPT-5.6 Luna (low reasoning effort) vs Plumb-4B (crh225, JevK5 v0.2 + LoRA)

> Side-by-side benchmark comparison for GPT-5.6 Luna (low reasoning effort) and Plumb-4B (crh225, JevK5 v0.2 + LoRA) across agentic, coding, multimodal, knowledge, reasoning, multilingual, and math tasks.

- Canonical page: https://benchlm.ai/compare/jevbench-gpt-5-6-luna-vs-jevbench-plumb-4b
- Last updated: September 30, 2026

- Shared sourced benchmarks: 2
- HTML indexing: indexable
- Ranking lane: BenchAlign v5.8

## Quick Verdict

Evidence is too thin for a benchmark verdict: GPT-5.6 Luna (low reasoning effort) and Plumb-4B (crh225, JevK5 v0.2 + LoRA) share only 2 sourced benchmark rows.

## Summary

- Only 2 shared sourced benchmark rows are available. That is not enough for a broad capability verdict, so this mirror does not name an overall winner.

## Model Snapshot

| Property | GPT-5.6 Luna (low reasoning effort) | Plumb-4B (crh225, JevK5 v0.2 + LoRA) |
|----------|----------|----------|
| Creator | OpenAI | crh225 |
| Type | Proprietary | Open Weight |
| Reasoning | Reasoning | Non-Reasoning |
| Context | null | null |
| Independent public score (not head-to-head) | null | null |
| Benchmarks Covered | 2 | 2 |
| Pricing (input/output) | Pricing unavailable / Pricing unavailable | Pricing unavailable / Pricing unavailable |

## Category Breakdown

### Reasoning

- Winner: Insufficient shared evidence
- GPT-5.6 Luna (low reasoning effort) public-lane score: Coming soon
- Plumb-4B (crh225, JevK5 v0.2 + LoRA) public-lane score: Coming soon

| Benchmark | GPT-5.6 Luna (low reasoning effort) | Plumb-4B (crh225, JevK5 v0.2 + LoRA) | Winner |
|-----------|-----------|-----------|--------|
| JevBench 1.4 | 18.51 | 65.84 | Plumb-4B (crh225, JevK5 v0.2 + LoRA) |
| JevBench 1.5 | 22.37 | 71.56 | Plumb-4B (crh225, JevK5 v0.2 + LoRA) |

## FAQ

### Is there enough evidence to pick between GPT-5.6 Luna (low reasoning effort) and Plumb-4B (crh225, JevK5 v0.2 + LoRA)?

Not yet. The models share only 2 sourced benchmark rows, so this mirror reports the available measurements and metadata without naming a broad winner.

### What can I compare safely on this page?

Published pricing, context windows, model type, and individual shared benchmark rows are directly comparable. Independent overall scores and non-overlapping benchmark coverage are labeled separately and should not be read as a controlled head-to-head result.

## Related Comparisons

- [GPT-5.6 Luna (low reasoning effort) vs GPT-6 Astra](/compare/gpt-6-astra-vs-jevbench-gpt-5-6-luna)
- [Plumb-4B (crh225, JevK5 v0.2 + LoRA) vs GPT-6 Astra](/compare/gpt-6-astra-vs-jevbench-plumb-4b)
- [GPT-5.6 Luna (low reasoning effort) vs Claude Opus 5.5](/compare/claude-opus-5-5-vs-jevbench-gpt-5-6-luna)
- [Plumb-4B (crh225, JevK5 v0.2 + LoRA) vs Claude Opus 5.5](/compare/claude-opus-5-5-vs-jevbench-plumb-4b)

## Explore More

- [GPT-5.6 Luna (low reasoning effort) profile](/models/jevbench-gpt-5-6-luna)
- [Plumb-4B (crh225, JevK5 v0.2 + LoRA) profile](/models/jevbench-plumb-4b)
- [Compare Pricing](/llm-pricing)
- [Alternative Finder](/tools/alternative-finder)
- [LLM Selector](/tools/llm-selector)
- [Overall Rankings](/best/overall)