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Vercel has open-sourced and released durable-harness. According to a MarkTechPost report, it is an npm package that can wrap coding agent frameworks such as Pi, OpenCode, fx, Claude Code, and Codex, writing sessions to a durable log; after a function crashes, a queue hands that turn to a new function to continue execution. Completed model and tool calls are read directly from the log and are not billed again, and tools can be marked as safe to replay or never to replay. The package is at version 0.0.x under the Apache-2.0 license, and can run on Vercel Functions plus Queues, on Node.js 22+ with Postgres, or on local files; Claude Code and Codex must run in Vercel Sandbox, and no performance benchmarks have been published. Another report says the tool is runtime-agnostic, extending the durable infrastructure behind eve and Workflows to all harnesses such as Pi and OpenCode, and can run locally, on Vercel, or in self-hosted environments, automatically recovering after an agent fails.
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Vercel open-sources durable-harness, letting coding agents keep running after a crashDevelopments
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- Source:MarkTechPost
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Oct 22
MarkTechPost
Vercel open-sources durable-harness, letting coding agents keep running after a crash
Vercel has open-sourced durable-harness, an npm package that can wrap coding agent frameworks such as Pi, OpenCode, fx, Claude Code, and Codex, writing sessions to a persistent log so that after a function crashes, a queue hands that turn to a new function to continue execution. Completed model and tool calls are read directly from the log and are not billed twice; tools can be marked as safe to replay or never to replay. The package is at version 0.0.x under the Apache-2.0 license, and can run on Vercel Functions plus Queues, on Node.js 22+ with Postgres, or on local files; Claude Code and Codex must run in Vercel Sandbox, and no performance benchmarks have been published.
Oct 21
Guillermo Rauch
Vercel launches durable-harness, enabling agent harnesses such as Pi and OpenCode to run durably
Vercel has launched the open-source, runtime-agnostic durable-harness, extending the durable infrastructure that powers eve and Workflows to all harnesses, including Pi and OpenCode, and it can run locally, on Vercel, or in self-hosted environments. Agents can automatically recover after failures and keep running for hours, days, or even months. Guillermo Rauch added that Claude Code and Codex can also achieve durability and observability through it, but they are currently not designed for embedding, are less efficient and portable, and require an extra layer of sandboxing compared with Pi or Fx.