durable-objects dynamic-workers cloudflare sandbox ai-agents

Durable Object Facets load agent code with storage

Run AI-generated Durable Object classes inside a supervisor isolate, each with isolated SQLite storage and request interception for logging, metering, and control.

Summary

Eliminates the choice between disposable agent code (no persistence) and pre-provisioned infrastructure (no containment). Developers can now sandbox persistent user-generated applications with fine-grained storage limits and observability baked in.

Why it matters

Implementation verdict

Replaces the pattern of forwarding requests from a Durable Object to external storage APIs. Requires Cloudflare Workers environment; available in open beta now. Worth trying immediately if you're building any form of code generation → persistent app platform. Syntax is straightforward: `this.ctx.facets.get()` with dynamic class loading.

Sources

1.Durable Object Facets allow you to load and instantiate a Durable Object class dynamically, while providing it with a SQLite database to use for storage
2.The facet gets its own SQLite database, which it can use via the normal Durable Object storage APIs. This database is separate from the supervisor's database
3.isolates, not containers. Isolates are much lighter-weight than containers, and as such, can load 100x faster using 1/10 the memory

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