--session-tunnel

A Claude Code CLI flag, read out of the shipped bundle. It has been in the build since v2.1.295, including the newest one read.

Releases whose published page names --session-tunnel.

1. v2.1.295 8 Oct 2026
   claude mcp serve gains an HTTP mode, limited to remote cloud sessions

   In remote cloud sessions only, claude mcp serve can now listen over HTTP with --transport, --port and --session-tunnel

   found in this entry's text

2. v2.1.295 8 Oct 2026
   mcp serve gains a session tunnel mode and can return tool output

   claude mcp serve has a new --session-tunnel mode that connects through a relay, and can return tool output and relay permission asks

   found in this entry's text, named in this entry

3. v2.1.295 8 Oct 2026
   Session tunnel startup reads sign-in and proxy tokens from a file descriptor

   Started with --session-tunnel, Claude Code can read its sign-in token and an agent proxy token from a launcher-supplied channel

   found in this entry's text, named in this entry

The earliest release whose published evidence quoted --session-tunnel was v2.1.295, 8 Oct 2026. That is the oldest release this project wrote about it, so it is a floor on the name's age and not the release that introduced it. It is not a presence reading: which builds carried the name is the table below.

One row per release since the first build this name was read out of. Absent means the build was read and the name was not in it, never mined means no bundle for that release was ever archived, and a declared type or a default is only ever what that release's own bundle stated.

Read out of the published npm bundle release by release, and out of Anthropic's own documentation as this site captured it. Nothing on this page is a description anybody here wrote about what the CLI flag does. All CLI flags.