> Canonical guide: https://developers.foxlight.ai/build/sdk/storage/
> Contract snapshots: Skulk 2.0.0 (b0af39c79b6b7102b2478062904f1d7cc8619975); SDK 0.4.0 (31bb090b8f64689f87514e48385e22b6ad94a6c2). Check the installed runtime when versions differ.

# Protected storage and _locks_

A managed child uses the paths and identity assigned to its installation. `storage` provides owner-only directories, bounded reads, atomic writes, and exclusive host locks.

## Startup and identity

`read_startup(descriptor)` reads the bounded host-provided startup record. `identity(path)` creates or reads the retained identity at its protected location. A restart should read the same identity, rather than replace the node’s identity or settings store.

## Files

Use `secure_directory()` for protected directories and `read_private()` for bounded reads. `atomic_private()` replaces a file through the SDK’s protected atomic-write path; its explicit `executable` option is for artifacts that require execution. Validate application content before persisting it.

`load_manifest()` reads and validates a manifest. `executable_digest()` computes the artifact identity used by the managed contract. Hashing a file establishes its content identity; publisher trust and installation authorization remain host responsibilities.

## Ownership

`HostLock` fences operations that require exclusive ownership. Keep the lock for the full operation it protects and close it in a guaranteed cleanup path. A lock conflict is an admission problem; it is not a reason to steal another process’s lock.

Never put credentials into descriptors, ordinary configuration, diagnostic responses, or rendered pages. Use the host’s declared credential and protected-reference flow.

[Storage API reference](https://developers.foxlight.ai/build/sdk/reference/storage/)