A long take says modern coding-agent harnesses were already 75–85% solved by 2025
Promptmethus · x · 2026-07-26
A long technical take argues that by May 2025 the design of a modern frontier coding harness was already largely solved at the architectural level, even if production hardening was still missing.
Main points
- The system had already converged on multi-layer persistent memory with different timescales.
- It favored multi-phase cognitive loops over one-shot generation.
- Agents needed to write and execute code natively, keep long-horizon state and identity, and use adversarial self-critique / continuous QA.
- Clean interfaces and a shared telemetry/common-language layer were essential for sub-agents and specialised processes.
- The writeup distinguishes the model as the brain from the harness as the body and nervous system.
Bottom line
The author claims the design was about 75–85% of the way to a fully solved frontier harness on the architectural side. The remaining gap was mostly production realities: permissions, context discipline under load, recovery, and tool reliability at scale.
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