Heyang Zhou is building Willow, an agent harness for Bridge that uses mvSQLite to store AI agent state and serve agent-generated web apps in production.

Willow keeps the state of an agent's virtual filesystem at every point in time in persistent storage as an SQLite table, with large blobs offloaded to S3. Thanks to mvSQLite's multi-versioned data storage, reading a filesystem snapshot from any past point in time incurs no extra cost compared to reading the current version.

Willow packs up to 1,000 agents per OS process, each with its own SQLite database backed by mvSQLite. Agent execution is single-threaded and spends most time waiting for LLMs, making it well-suited to SQLite despite SQLite's limitations with high-throughput concurrent transactions.

Willow can serve millions of agents and agent-generated web apps on mvSQLite. mvSQLite delegates data replication, backups, high availability, and transaction processing to FoundationDB, while clients are stateless and do not touch the local disk.