Tweet by KentonVarda
April 13, 2026
A fun new lego piece for your Cloud Agents set: Durable Object Facets. https://t.co/ypdid1Q2rt When sandboxing agent code with Dynamic Workers, you can now give the sandbox access to a SQLite database. The sandboxed code accesses this by literally just writing a Durable Object implementation, the same way any DO would be written. The full SQLite API is available (with fast synchronous reads/writes). Importantly, you DON'T have to create a regular DO namespace to attach to the sandboxed code. Instead, you provide the specific database for any particular instance to use. Where do you get this database? Your own Durable Object, acting as a supervisor, is now able to create one or more attached databases, which in can then pass into Dynamic Workers. We call these "facets", since all the databases are part of the same Durable Object. A bit wonky but it works out really nice. Previously, you would have had to give your Dynamic Worker an RPC interface that talks to some remote storage, which is a lot slower and forces async I/O which can lead to concurrency bugs. More importantly, your RPC interface would be unfamiliar to the agent, whereas now it can just write against the standard Durable Object storage APIs that all models already have in their training set.
- Author
- KentonVarda
- Date
- April 13, 2026
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- /tweets/kentonvarda-2043684025454170438-b68ce2