Run Cloudflare agent work in the background with the new Agents SDK update

Cloudflare has shipped a confirmed Agents SDK update for Workers that makes long-running agent work less fragile. The main change is detached background sub-agent runs with progress, durable milestones, and better recovery after deploys, evictions, reconnects, and stalled streams.

What changed

Cloudflare's June 26, 2026 changelog says the Agents SDK now supports first-class detached sub-agent runs. A parent agent can start work with runAgentTool(..., { detached: ... }), receive a handle immediately, and let the child run continue under a durable backbone instead of tying it to the caller's turn.

The same update adds runTurn(options) as a public entry point across wait, submit, and stream modes. Cloudflare also lists repair and recovery fixes for interrupted tool calls, stalled streams, reconnect behavior, sub-agent recovery, optional AI SDK peers, Code Mode cleanup, Voice support, MCP callbacks, and experimental server actions/channels.

Key takeaways

• Detached sub-agents can keep running after the parent turn ends.
• Progress and milestones can be surfaced back to the parent and client UI.
• runTurn gives agent apps a single turn-admission path across common modes.
• Recovery fixes target deploys, Durable Object evictions, reconnects, and interrupted tool calls.
• Experimental server actions and channels are present, but Cloudflare warns their APIs may change.

Availability and access

Cloudflare's upgrade command points developers to update agents, @cloudflare/think, @cloudflare/ai-chat, @cloudflare/codemode, and @cloudflare/voice to the latest versions. This is a developer SDK update, not a one-click hosted product release.

Teams already building on Cloudflare Workers and Durable Objects should check package versions, TypeScript types, and runtime behavior in staging before using detached runs for user-visible workflows.

Practical LinkLoot angle

This update matters when an agent task should outlive a chat turn: importing orders, reviewing a repository, generating a report, running browser or code work, or waiting on external systems. Before this pattern is useful, the app still needs cancellation, budgets, progress UI, and clear failure messages.

For teams comparing agent infrastructure, Cloudflare's move is worth tracking beside hosted agent tools and local orchestrators. Keep the model choice separate from orchestration: LinkLoot's /guides/ai-agent-tools guide can help frame that decision.

What to verify before you act

• Confirm your installed package versions include the June 26 Agents SDK changes.
• Test detached runs through deploys, reconnects, and Durable Object evictions.
• Add a maxBudgetMs ceiling and cancellation path for every background run.
• Check whether experimental server actions or channels are stable enough for your use case.
• Validate UI progress handling with slow tasks, failed tasks, and interrupted streams.

Source check

Confirmed by: Cloudflare's official changelog lists detached background sub-agents, durable progress and milestones, runTurn, recovery fixes, upgrade commands, and experimental caveats.

Independent context: Releasebot's Cloudflare update page corroborates the update as a major Agents SDK release and summarizes the same background sub-agent, unified turn, and recovery themes.