An experimental provider-composition POC that places one filesystem/process execution world in an E2B Linux sandbox. E2B supplies only sandbox lifecycle and the two fundamental OS adapters; provider-neutral consumers build higher capabilities above them.

Package	ctx key	Role
`e2b` (`@deepseek-ai/dsh-e2b`)	`ctx.e2b`	Create one sandbox, prepare its working/runtime directories, expose the shared SDK handle, and delete it on timeout or disposal
`fs-e2b` (`@deepseek-ai/dsh-fs-e2b`)	`ctx.fs`	Implement the filesystem seam over E2B Filesystem APIs
`subprocess-e2b` (`@deepseek-ai/dsh-subprocess-e2b`)	`ctx.subprocess`	Implement executable lookup, managed process groups and stdio, remote spill files, and terminal sessions over E2B Commands and PTY APIs

The existing dsh-bash-local, dsh-pty-local, and dsh-lsp-local need no E2B-specific forks. They delegate every execution-world operation to ctx.fs and ctx.subprocess, so mounting the two E2B adapters places their mutable work in the same sandbox. The worker-backed Code Runtime remains host-local and reaches that world only through the tools its programs call.

This boundary does not move the harness process, Cordis objects, model calls, agent/session state, session persistence, skills, higher-level protocol state, or E2B SDK buffers. The portable execution-world decision owns both the generic composition and this POC boundary.