E2B implementation of the @deepseek-ai/dsh-fs provider seam. It has no config: load @deepseek-ai/dsh-e2b first, then this service in place of dsh-fs-local. The provider uses the owner's remote cwd and SDK handle, so file tools observe the same world as E2B-backed Bash processes.

Behavior

Remote identity and metadata — relative paths resolve as POSIX paths against the caller cwd or ctx.e2b.cwd; realpath -m supplies canonical target identity without requiring the final file to exist. stat, no-follow lstat, and stable one-level directory listings project E2B metadata into the filesystem seam. Versions are opaque hashes of E2B metadata plus a per-write extended attribute.
UTF-8 reads — whole reads and streamed reads preserve cross-chunk decoding, reject invalid UTF-8, and use the seam's 8192-byte NUL sample for binary detection. The model-facing tool still owns size selection and line windowing.
Atomic mutations — writes upload a mode-0600 temporary sibling, preserve an existing file's POSIX mode, and publish through same-directory Linux mv -f. E2B creates missing parent directories. Literal edits LF-normalize for matching, restore dominant CRLF storage, and serialize mutations per canonical target within the host process. Optional create/version guards keep the base seam's observed-state semantics.
Failures and cancellation — E2B not-found, permission, abort, and other controller failures map to the existing FsError vocabulary. Cancellation is best-effort at SDK request boundaries; a successful rename is the commit point.

The provider does not copy, mount, or reconcile the host workspace. Giving it a host path as cwd creates a remote directory with the same spelling only.

Model Experience

Indirectly, through dsh-tool-fs, which renders remote UTF-8 content, directory results, mutation acknowledgements, and provider errors while E2B identity and transport remain internal.

KV Cache effect

No direct invalidation; the named consumer owns any request-prefix changes.

Known Limitations and Deferred Work

No host synchronization — an empty E2B cwd stays empty until a tool, command, template, or external process populates it; local files are neither uploaded nor reflected back.
Mutation coordination is host-process-local — another harness connection or remote command can race the adapter; version guards detect only metadata changes represented by E2B.
Whole-file mutation costs remain — overwrite diffs and literal edits read complete files into host memory, and every operation incurs E2B controller latency.
Custom templates must support the used Linux and envd features — realpath, chmod, mv, same-filesystem POSIX rename, streaming reads, and file metadata extended attributes are required; unsupported templates fail rather than degrade silently.