Claude Code 2.1.307
By Steven Van ·
The release adds an API version migration command and a safety-event telemetry signal, plus fixes for MCP connections on macOS and Linux.
Claude Code 2.1.307 adds a command for moving Claude API code to a newer API version and a new OpenTelemetry event for safety interventions. It also fixes several MCP and model-configuration bugs. The changelog entry is on GitHub, and the product page for Claude Code is on this site.
What was added
- /claude-api api-version moves Claude API code to API version 2026-10-21.
- The claude_code.safety_event OpenTelemetry event is emitted for each tool call that a permission rule, auto mode, a safety check, a hook or the sandbox stopped, prompted or sent back.
Fixes
- Requests no longer fail with a model-not-found error when CLAUDE_CODE_DISABLE_1M_CONTEXT is set and the model is an alias with the [1m] suffix, such as opus[1m].
- The prompt-caching-scope beta header is no longer sent behind custom ANTHROPIC_BASE_URL gateways or on Foundry, where it has no effect.
- A turn no longer sometimes starts without an SDK MCP server's latest tools when a background task is running.
MCP connection fixes
- On macOS, MCP servers no longer show "needs authentication" in claude -p while the login keychain is locked. They now say why, and the next run after an unlock connects without a new sign-in.
- MCP servers are no longer reported as timed out, or left failed in headless runs, when a macOS or Linux computer went to sleep while they were connecting.
- HTTP MCP tool calls are no longer sent twice when the connection closes mid-call. Only read-only or idempotent tools are now retried.
Claude Code
Anthropic's agentic coding tool — Claude in your terminal, IDE, desktop app and browser, reading and editing your codebase, running commands, opening pull requests and working on tasks in the cloud.
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