Cloudflare documents nine agent harnesses, including Codex, Nanocode and Exo

Cloudflare published a new Harnesses section of the Agents SDK docs on November 9, 2026, together with a changelog post showing how to run agent harnesses such as Codex, Nanocode and Exo inside Durable Objects so coding agents keep their state across restarts.

What the new docs cover

• Nine harnesses are documented: Pi, Flue, OpenCode, Container, Think, Codex, Nanocode, Exo, and Self-modifying.
• Codex runs as WebAssembly inside a Durable Object, exposing workspace_write and workspace_read file tools with SQLite-backed persistent conversations, and defaults to a maxRounds of 128 model rounds per turn.
• The Codex example uses internal, non-exported Agents SDK APIs, and its routes are unauthenticated by default, so authentication must be added before production use.
• Exo runs via Durable Objects coordinating conversations plus Cloudflare Sandboxes running Linux tools, with agents defined in Markdown and deployed through Exo's own CLI or HTTP API.
• Nanocode runs as WebAssembly in its own Durable Object host, needs a custom adapter, and some of its tools cannot recover after an interruption.
• Cloudflare recommends that most people building new agents start with the Pi harness for standard use cases.

What it means for people building with AI

For developers, this gives an official, documented path to deploy popular open coding-agent harnesses on Cloudflare's serverless Durable Objects, so agent state survives restarts without having to build or operate that infrastructure themselves. Because several harnesses, including Codex and Nanocode, still carry caveats such as unauthenticated routes or tools that cannot recover after an interruption, teams evaluating them for production coding agents will need to budget time for hardening before going live.

Trying the Codex example

Running the Codex harness example requires Git, Node.js 24 or newer, pnpm, rustup and a Cloudflare account, with model calls routed through Workers AI.

Sources

• Harnesses - Agents SDK docs (Cloudflare Developers, November 9, 2026, official)
• Codex harness (Cloudflare Developers, November 9, 2026, official)
• Run Exo agents on Cloudflare (Cloudflare Changelog, November 9, 2026, official)

Written with AI assistance, strictly from the sources listed above. Before it went live, automated checks verified its dates, sources and every language edition.