AWS's open-source Strands Harness claims 45% cheaper than Claude Code, reigniting harness debate

blaizedsouza · x · 2026-11-02

Context: Matt Shumer's viral post argued harness engineering is usually stupid—just use the harness the model was trained for and write good behavior prompts.
Strands Harness: A fully assembled open-source agent harness from AWS's Strands Agents team, with Python/TypeScript SDKs, runnable locally or on any cloud, model-agnostic and not locked to Bedrock. Announced September 2025.
AWS's benchmark claims: 45% cheaper than Claude Code and Codex across six benchmarks (gap narrows to 28% in some comparisons); 28% fewer tokens per launch post; with Fable 5, 77% less cost and +7.9 points on Terminal Bench 2.1; Oh-My-Pi config hits 69.7 accuracy at 54% higher cost.
Takeaway: The release re-ignites the industry debate over using a model's native harness versus building your own control layer for agent workflows.

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