# Claude Code 2.1.216: sandbox filesystem toggle, quadratic long-session slowdown fixed

> Adds `sandbox.filesystem.disabled` to skip filesystem isolation while keeping network egress control, and fixes message normalization cost growing quadratically with turn count, which caused multi-second stalls and slow resumes. Several worktree and symlink isolation holes are closed.

| | |
|---|---|
| **Tool** | Claude Code |
| **Version** | 2.1.216 |
| **Kind** | release |
| **Published** | 2026-07-20 |
| **Observed** | 2026-08-11 |
| **Significance** | 3/5 |
| **Breaking** | no |
| **Categories** | feature, fix, security |

## What changed


- New `sandbox.filesystem.disabled` setting: skip filesystem isolation, keep network egress control
- Fixed quadratic message-normalization cost in long sessions (multi-second stalls, slow resumes)
- Fixed worktree-isolated subagents redirecting git into the shared checkout via `git -C`, `--git-dir`, `GIT_DIR`/`GIT_WORK_TREE`
- Fixed workflow saves and scheduled-task writes following a `.claude` symlink, which could write outside the project
- Fixed read-only commands on Windows reaching network paths without a permission prompt
- `/rewind` no longer restores or deletes through symlinks/hard links at tracked paths and reports skipped paths
- Fixed Bash permission checking for compound statements with redirects inside `&&` lists or negations, non-ASCII word boundaries, and invisible Unicode in PowerShell commands
- Fixed auto mode denying commands with "HTTP 401" classifier errors after mid-session OAuth token rotation
- Fixed resumed background agent sessions reverting to the default agent, losing the agent's prompt and tool restrictions
- Fixed worktree sessions landing in another project's leftover worktree; undeletable sessions whose worktree has no git repo
- Fixed `claude daemon stop --any` potentially killing an unrelated process via a stale legacy lockfile
- Fixed MCP re-authenticate revoking working credentials before the new sign-in succeeded
- Fixed skills and commands changed mid-session not appearing in the slash menu until restart
- `/context` warns explicitly when the conversation exceeds the context window; a failed `/compact` shows as an error
- Telemetry: failed permission prompts no longer counted as user rejections; interrupts reported as aborts
- Fixed cloud sessions dropping an in-flight message when the container restarts mid-turn


## Sources

- [changelog_md](https://github.com/anthropics/claude-code/blob/main/CHANGELOG.md) — retrieved 2026-08-11

## Community

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and never blended._

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Canonical: https://changelogs.info/claude-code/2-1-216
Entity: https://changelogs.info/claude-code
Event ID: `evt_2026-07-20_claude-code_2-1-216`
Licence: event synthesis © changelogs.info, CC BY 4.0. Linked sources belong to their vendors.