Source Intelligence
Reading a new release v2.1.251 Analysing changes · 2/5 Sorting the findings · 1/4 steps 470 findings $18.91 so far

DisclaimerUnofficial, and not affiliated with Anthropic. Nearly all of this is read straight out of what ships: npm bundles, captured prompts, published docs. Anthropic's own notes go in verbatim, marked as theirs. The rest is my reading, and every entry carries the strings behind it. If one looks wrong, vote it down and say why.

All of v2.1.212 Home All releases olderv2.1.211 v2.1.213newer
Claude Code v2.1.212

Windows Sandbox Installation

Feature flag
tengu_nankeen_kestrel Not enough to say

Nothing here resolved what this flag was doing on this version, so nothing here should be read as on or off.

This account: no value returned · anonymous baseline: no value returned · compiled default in v2.1.212: on

These values were read against a different version of Claude Code, so treat them as the nearest reading available instead of one taken on this release.

Read once, for one account on one subscription tier, against v2.1.212. It isn't a statement about your account. What a flag value here can and cannot tell you

Windows sandbox support now includes a full one-time install flow that sets up a dedicated sandbox user and WFP (Windows Filtering Platform) network filters.

Usage
/sandbox install             # install sandbox user and WFP network filters
/sandbox                     # check current sandbox status
Details
  • Requires administrator privileges for the initial install (an elevation prompt appears).
  • After install: Sandbox user and network filters installed — confirmed via /sandbox.
  • If the elevation prompt was missed: re-run /sandbox install and approve within a minute.
  • WFP filter installation is idempotent; passing force: true replaces existing filters if the port range or sandbox user name changed.
  • New error classes: SandboxCommandTooLongError (command too long for the OS argv limit — write to a file instead), SandboxPolicyRefusalError (enterprise policy blocks the command), SandboxUnavailableForShellError (shell not sandboxable).
  • PowerShell commands on Windows are labeled PowerShell command (unsandboxed) to clarify they bypass the sandbox.
  • Feature-gated via tengu_nankeen_kestrel.
Evidence

"Windows sandbox needs a one-time install." (search for "srt-win install" and "ClaudeCodeSandbox")

Strings lifted out of the shipped bundle, so the claim above can be checked against them.

See this entry in the whole of v2.1.212 →