Claude Code 2.1.257 release notes

Version

2.1.257

Released

1 September 2026

Status

Stable release

What's new in Claude Code 2.1.257

The official notes for Claude Code 2.1.257 list 104 changes: 6 new features, 60 fixes, 3 performance improvements, 6 security changes and 29 other changes.

• 6 new features
• 60 fixes
• 3 performance improvements
• 6 security changes
• 29 other changes

Highlights

• security change Added a Containment Escape rule to auto mode so cloud metadata-credential fetches, egress evasion, and cross-tenant reach are no longer…
• security change Fixed a doubly-listed custom Authorization header overriding the configured credential on Bedrock, Mantle, Vertex, and WIF, and the Vertex setup…
• security change Fixed claude mcp remove leaving a remote server's stored OAuth credentials behind when strictPluginOnlyCustomization locks MCP to plugin-only servers
• security change Fixed cloud sessions losing git/GitHub credentials for the rest of the session when the session's network proxy failed to start…
• security change Improved MCP connection and OAuth debug/error logs so credentials carried in a server's URL or request headers are redacted

Our short summary: changes are counted and classified automatically from the official notes, and highlights are shortened. The complete, authoritative list is in the official release notes on GitHub.

Full release notes on GitHub (Claude Code 2.1.257)

All Claude Code release notes · All releases

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