HarnessRouter goes open source: swap Codex, Claude Code and Hermes behind one API
aigclink · x · 2026-08-19
HarnessRouter has been open-sourced under Apache-2.0. If OpenRouter routes models, HarnessRouter routes agent harnesses: behind a single OpenAI Responses-compatible API, you can swap between Codex, Claude Code and Hermes runtimes, with sessions, streaming, files, cancellation and idempotency unified — your own keys, no cloud, no telemetry.
The motivation is a Composio benchmark showing that with the same model and tasks, switching agent harness alone changed token consumption by up to 30x — harness choice is itself a performance variable, and HarnessRouter provides the infrastructure to switch and compare.
The most substantial piece is the accompanying Unified Harness Protocol (UHP): a ten-chapter spec plus OpenAPI schema and conformance test suite, with the project as reference implementation and one-command Docker self-hosting. The author argues that when a category develops routing + protocol + compliance testing, it is converging from DIY builds into infrastructure — the same pattern as OpenRouter for models and MCP for tool calls.
Related event: HarnessRouter Goes Open Source, Unifying Agent Harness Access(2 posts)→
More from coding & agent
- Grok Bot team shares 11 pro tips: one chief of staff bot beats a mega-chat — brianrkelly · 2026-08-19
- Test finds models get no consistent edge from their own native CLIs — zainhas · 2026-08-19
- GPT-5.6 Risk Recapped: Codex Fixed Destructive Actions Deleting User Files — SIGKITTEN · 2026-08-19
- Train any neural net inside ComfyUI: workflows for autoencoders, UNets included — enspiralart · 2026-08-19
- Paying for Doubao Pro: A Hands-On Test of ByteDance's 200 RMB/Month GUI Agent — 卡尔的AI沃茨 · 2026-08-19
- Help: Adding Video LoRAs to LTX 2.3 for fight scene animations — SayethTwat · 2026-08-19