golem-file-io-rust

Use the standard std::fs module, such as fs::read_to_string for text files or fs::read for binary files. Golem Rust agents compile to wasm32-wasip1, which provides WASI filesystem access, so std::fs works out of the box.

Use fs::write for simple writes or OpenOptions with append(true) and create(true) for appending. Only files provisioned with read-write permission, or files in non-provisioned paths like /tmp, can be written to.

Yes, third-party crates that use std::fs internally, such as serde_json's file reading, work in Golem agents because the wasm32-wasip1 target provides WASI filesystem support for the standard library.

Files provisioned via golem-add-initial-files with read-only permission cannot be written to. Write to non-provisioned paths such as /tmp, or provision the file with read-write permission instead.

No, the filesystem is per-agent-instance, so each agent has its own isolated filesystem. File changes within an agent are persistent across invocations as durable state.