Agents API launches on OpenAI's open-source Codex harness, betting on harness-as-a-service

omarsar0 · x · 2026-09-12

Firecrawl's stevendcoffey announced the Agents API, a new cloud-based way to build agents powered by OpenAI's open-source Codex harness. It supports your favorite tools and connectors, can attach to any sandbox, and is executed by their agent Astra.

omarsar0 argues the launch is bigger than it looks: open-sourcing the Codex harness means many open and closed models are already deeply knowledgeable about it, so other services can adopt the same agentic architecture and benefit from the compounding effect of that openness. Harness-as-a-service hasn't gone mainstream yet, but serious builders are already adopting it to unlock new types of services.

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