AI library

Source · release

Claude Code releases 2.1.302 and 2.1.303

Author
Anthropic
Published
16 October 2026
Added
19 October 2026
Original
https://github.com/anthropics/claude-code/releases/tag/v2.1.302

Summary

Claude Code 2.1.302 is a large release that changes defaults for headless and SDK use. Fork subagents are now on everywhere, the desktop app and VS Code always run subagents in the background, and headless sessions on third-party providers start in default permission mode. It also fixes MCP servers on the 2026-07-28 protocol that omit some fields. 2.1.303 only lists "bug fixes and reliability improvements".

Key points

  • CLAUDE_CODE_AUTO_MODE_MODEL picks the model used by the client-side auto mode classifier. With the server-side classifier, a conversation too long for the safety check is now compacted instead of every checked tool call being denied.
  • Fork subagents (subagent_type: "fork") are on by default in claude -p, the Agent SDK, the desktop app, and VS Code; CLAUDE_CODE_FORK_SUBAGENT=0 turns them off.
  • claude -p and Agent SDK sessions with no permission mode start in default mode on third-party providers (with telemetry off or on a fresh install); --permission-mode auto keeps auto.
  • At most 12 prompt or agent hooks for one event run at a time.
  • Fix: MCP servers that negotiate protocol 2026-07-28 but omit resultType, ttlMs, or cacheScope showed no tools or failed every call.
  • Fix: a prompt cache miss when a tool added mid-session was reloaded through ToolSearch or after compaction. The Read tool now refuses image sources over 128 MB.
  • /config gains an "Idle compaction" toggle. A notice says standalone Claude Design (claude.ai/design) closes by 2026-12-14.

Why it matters

Headless and SDK runs now behave more like the terminal, which matters for unattended pipelines: check whether a script relied on auto permission mode or foreground subagents. The MCP fix shows that servers on the new spec still vary in which fields they send.