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-terminal-bash, and dsh-lsp-stdio 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.

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.