# Study finds coding agents waste up to 22.75% of task costs

> A new study of Claude Code and Mini-SWE-Agent identifies repeated retrieval, script writing and test runs as common sources of extra cost. The authors say developer-written guidance cut costs by up to 41.73% in their tests.

Oossa · 2026-09-29 · https://oossa.com/en/study-finds-coding-agents-waste-up-to-22-75-of-task-costs

Researchers studied coding agents working on SWE-bench tasks and found three recurring ways they use resources inefficiently: retrieving information they already have, generating similar scripts, and rerunning tests. These behaviors appeared in 79% to 98% of tasks and accounted for as much as 22.75% of task costs. The team tested several ways to reduce the waste, including guidance written by developers. That approach cut costs by up to 41.73%; automatically generated guidance was less effective, while one retrieval method sometimes increased costs.

## The facts

- The study analyzed 1,200 agent trajectories and tested mitigation strategies on more than 10,000.
- Structure-aware retrieval increased costs by as much as 28.14% in some tests.

## Why it matters

For teams paying to run coding agents, carefully written developer guidance may save more than relying on agents to create their own instructions.

## Sources & references

1. [Analyzing and Mitigating Cost-Inefficient Behaviors in Coding Agents](https://arxiv.org/abs/2609.30725) – arXiv, 2026-09-28

Last updated: 2026-09-29