# Taurus harness cuts CT annotation costs by half with LLM review

Digest AI · Research · published 2026-11-03T05:00:00Z

Canonical: https://digestai.news/story/taurus-harness-cuts-ct-annotation-costs-by-half-with-llm-review

## Summary

Researchers at an unnamed lab tested whether an LLM could label CT scans more efficiently when guided by a structured harness (Taurus) versus free-form coding. They compared Taurus to a free-form agent using Claude Opus 5.5 across six public datasets (939 volumes total). The harness’s first version improved results on only two datasets by a negligible margin. However, refining the automated pass to mimic the agent’s strengths and adding LLM review for edge cases—like underestimating aneurysm size—closed the gap entirely. The final version matched free-form accuracy at **$1.22 per case**, half the **$2.71** cost of the standalone agent. The study suggests most gains came from automation, not the LLM itself, and could shift expert labor toward oversight rather than manual labeling.

## Key points

- Taurus harness reduces CT annotation cost to **$1.22 per case**, half of Claude Opus 5.5’s **$2.71**
- Final version matches free-form agent accuracy on six public datasets (939 volumes total)
- Most efficiency gains stem from automation, not the LLM’s review step

## Why it matters

If validated, this could slash costs for medical imaging annotation, a bottleneck for AI training. Hospitals and labs might adopt similar harnesses to cut labor without sacrificing precision.

## Sources

1. [Taurus: LLM-in-the-Loop CT Annotation Matches Coding Agents at Half the Cost](https://arxiv.org/abs/2611.00247) (arXiv cs.AI, 2026-11-03, primary source)

## Cite

Digest AI, "Taurus harness cuts CT annotation costs by half with LLM review", 3 November 2026, https://digestai.news/story/taurus-harness-cuts-ct-annotation-costs-by-half-with-llm-review

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