Claude Code 2.1.128 fixes EnterWorktree branching, OTEL leaks, and MCP reconnect floods

• ClaudeCodeLog's release post says Claude Code 2.1.128 shipped 37 CLI changes, led by a worktree branch fix, OTEL env isolation for subprocesses, and quieter MCP reconnects.
• According to ClaudeCodeLog's changelog thread and Anthropic's Claude Code changelog, EnterWorktree now branches from local HEAD, which stops unpushed local commits from getting dropped.
• As ClaudeCodeLog's changelog thread notes, Bash, hooks, MCP, and LSP subprocesses no longer inherit OTEL_* vars, matching the same privacy and routing fix documented in Anthropic's changelog.
• ClaudeCodeLog's changelog thread also says reconnecting MCP servers now summarize re-announced tools by server prefix, not full tool lists, which trims a specific kind of long-session chat spam.
• Beyond the headline fixes, ClaudeCodeLog's additional updates added seven env vars and cut the tracked prompt set from 80 files to 76, while ClaudeCodeLog's pre-release post showed the release was already being staged hours earlier.

You can read the full diff in Marck Renn's tracked release page, compare it against Anthropic's own changelog entry, and cross-check the worktree behavior against Anthropic's parallel worktrees guide. The weirdly useful bit is that a patch release this small still touched branching semantics, tracing inheritance, and prompt inventory in one shot.

The branch creation bug mattered because Claude Code's docs already frame worktrees as the way to run parallel sessions without edit collisions. Anthropic's common workflows guide says each worktree is a separate checkout, and Anthropic's changelog now matches ClaudeCodeLog's changelog thread in saying new branches come from local HEAD, not origin/<default-branch>.

The other high-signal fix is environment hygiene. Per ClaudeCodeLog's changelog thread, subprocesses spawned through Bash, hooks, MCP, and LSP no longer inherit OTEL_*, so OTEL-instrumented apps stop accidentally targeting Claude Code's own OTLP endpoint. Anthropic's changelog uses the same wording.

MCP reconnect noise got a narrower fix than the headline suggests. Instead of replaying full tool-name lists into the conversation on every reconnect, ClaudeCodeLog's changelog thread says Claude Code now groups re-announced tools by server prefix. The same release also reserves workspace as an MCP server name, according to Anthropic's changelog.

The follow-up metadata is catnip for harness nerds. ClaudeCodeLog's additional updates lists seven new env vars: AGENT_PROXY_AUTH_TOKEN, AGENT_PROXY_URL, CLAUDE_CODE_PROACTIVE, GH_ENTERPRISE_TOKEN, GH_HOST, GH_TOKEN, and GITHUB_ENTERPRISE_TOKEN. The same post says bundle size rose 152 kB, prompt files fell from 80 to 76, and prompt tokens fell by 420, with system-reminder share rising from 32.6% to 39.4%. The tracked release page and linked metadata diffs back those numbers up.