Claude Code Changelogs Recent Archive Source-level · unofficial Updates
← All changelogs v2.1.138 codex · gpt-5.5
Claude Code · Source-level changelog

Version 2.1.138

Version 2.1.138 is a very small CLI release. The filtered AST diff shows no added or removed declarations and the string-literal diff contains only build metadata, but one existing advanced beta path changed: CLAUDE_CODE_MID_CONVERSATION_SYSTEM can now override the normal Anthropic base URL check for the mid-conversation system beta.

Package @anthropic-ai/claude-code Diff v2.1.137 → v2.1.138Provider codexModel gpt-5.5
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Features & Changes
0
Bug Fixes
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In Development
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Env Vars / Flags

Changes

1 item

Advanced Mid-Conversation System Beta Override #

What

Claude Code now allows the CLAUDE_CODE_MID_CONVERSATION_SYSTEM environment override to enable the mid-conversation-system-2026-04-07 beta even when ANTHROPIC_BASE_URL is set to a non-default host.

Usage
ANTHROPIC_BASE_URL=https://your-compatible-endpoint.example \
CLAUDE_CODE_MID_CONVERSATION_SYSTEM=claude-sonnet-4-5 \
claude
Details
  • This is not a new public command or setting; the environment variable already existed in 2.1.137.
  • In 2.1.137, the mid-conversation beta check returned false whenever the base URL was not api.anthropic.com.
  • In 2.1.138, that base URL check is bypassed when CLAUDE_CODE_MID_CONVERSATION_SYSTEM is present.
  • The beta is still constrained by the surrounding provider and model checks, and CLAUDE_CODE_DISABLE_EXPERIMENTAL_BETAS can still disable experimental betas.
Evidence

Mid-conversation beta gate now checks (!If() && !process.env.CLAUDE_CODE_MID_CONVERSATION_SYSTEM) before adding mid-conversation-system-2026-04-07 (search for "CLAUDE_CODE_MID_CONVERSATION_SYSTEM" and "mid-conversation-system-2026-04-07").

Notes

No new slash commands, CLI flags, settings descriptions, tips, permission syntax, hook types, or user-facing messages were detected in the provided CLI diff.

The only added string literals in the AST-extracted string diff are the build timestamp "2026-05-09T04:04:51Z" and git SHA "d6d494651eb469be2ff763ef8d1b882aba8ca635". There is no migration guidance for this release.