What's new in Claude Code v2.1.132

Claude Code v2.1.132 fixes a 10GB+ RSS leak from stdio MCP servers writing to stdout, adds CLAUDE_CODE_DISABLE_ALTERNATE_SCREEN and CLAUDE_CODE_SESSION_ID env vars, corrects the statusline context_window counter, and unblocks 1-hour prompt cache TTL on Bedrock and Vertex.

Stdio MCP non-protocol stdout no longer leaks 10GB+ RSS

Why: A common MCP-author footgun: writing logs or stray output to stdout caused unbounded memory growth in the parent Claude Code process.

What: Fixed unbounded memory growth (10GB+ RSS) when a stdio MCP server writes non-protocol data to stdout.

How: No action — but MCP authors should still log to stderr, not stdout.

MCP tools/list failures now surface clearly in /mcp

Why: Servers that connected but couldn't list tools showed zero tools with no explanation, looking like silent failures.

What: They now retry once and display "connected · tools fetch failed" in /mcp.

How: Run /mcp to see the new badge for any server in this state.

claude.ai MCP unauthorized = "needs auth"; headless stops retrying 4xx

Why: Unauthorized connectors looked like a hard failure, hiding the actual cause; headless mode was burning retries on permanent 4xx.

What: Unauthorized claude.ai MCP connectors now show "needs auth"; headless -p mode no longer retries non-transient 4xx connection failures.

How: No config — the diagnostic just becomes accurate.

CLAUDE_CODE_SESSION_ID in Bash subprocesses

Why: Hooks already received session_id; Bash subprocesses didn't, so external scripts couldn't correlate to the session that invoked them.

What: Added CLAUDE_CODE_SESSION_ID to the Bash tool subprocess env, matching the value passed to hooks.

How: Read $CLAUDE_CODE_SESSION_ID inside any Bash invocation; no config required.

CLAUDE_CODE_DISABLE_ALTERNATE_SCREEN to keep terminal scrollback

Why: Fullscreen alternate-screen renderer hides the conversation from native terminal scrollback — users want both options.

What: New env var opts out of the fullscreen renderer and keeps the conversation in the terminal's native scrollback.

How: CLAUDE_CODE_DISABLE_ALTERNATE_SCREEN=1 claude

--permission-mode flag now respected on plan-mode resume

Why: Resuming a plan-mode session with -p --continue silently ignored --permission-mode, leaving users in the wrong mode.

What: Flag is now honored on resume, and plan mode is re-applied after ExitPlanMode within the same session.

How: Set --permission-mode as usual; existing scripts start working again.

/effort picker now reflects CLAUDE_CODE_EFFORT_LEVEL

Why: Users setting CLAUDE_CODE_EFFORT_LEVEL saw the picker show a different value, hiding their actual config.

What: /effort picker now reflects the env var override.

How: No action — the picker matches your env on next launch.

Statusline context_window shows current, not cumulative

Why: The statusline context_window token count was reflecting cumulative session totals, making the number nearly useless for compaction decisions.

What: Counter now shows current context usage instead of cumulative.

How: No action — restart Claude Code and the statusline reflects current usage.

Slash command autocomplete scales with terminal height

Why: The popup was capped at three to five visible commands; bigger terminals wasted space and required scrolling.

What: Autocomplete popup now scales with terminal height.

How: No config — automatic.

Bedrock/Vertex 1h cache TTL 400 errors fixed

Why: Users on Bedrock or Vertex who opted into 1h cache TTL were hitting hard 400 errors instead of getting cache.

What: Fixed Bedrock and Vertex 400 errors when ENABLE_PROMPT_CACHING_1H is set.

How: No action — re-enable the env var if you'd disabled it as a workaround.

Hosts: Alex Chen & Sarah Kim · Generated from the official Claude Code CHANGELOG.

Full changelog: github.com/anthropics/claude-code/CHANGELOG.md

Claude Code docs: docs.claude.com/en/docs/claude-code

• (00:00) - Stdio MCP memory leak fix (10GB+ RSS)