Claude Code v2.1.132: SIGINT Shutdown, MCP Fixes, Terminal Overhaul

Anthropic shipped Claude Code v2.1.132 with a heavy focus on terminal reliability, MCP server robustness, and edge-case fixes that matter when you're running AI coding agents for hours on end. Here's what changed for developers and CI pipelines.

Environment Variables and Session Plumbing

CLAUDE_CODE_SESSION_ID is now exported into the Bash tool subprocess environment, matching the session_id passed to hooks. Useful for tracking tool calls back to a session.
CLAUDE_CODE_DISABLE_ALTERNATE_SCREEN=1 lets you opt out of the fullscreen alternate-screen renderer, keeping the conversation in the terminal's native scrollback.

Graceful Shutdown and Resume Fixes

External SIGINT (e.g., IDE stop button, kill -INT) now triggers a graceful shutdown: terminal modes are restored and the --resume hint is printed instead of an abrupt exit.
--resume no longer fails with no low surrogate in string when a tool error truncation split an emoji; pre-corrupted sessions are sanitized on load.
--permission-mode flag is now respected when resuming a plan-mode session with -p --continue / --resume, and plan mode is re-applied after ExitPlanMode within the same session.

Terminal and Input Handling

Fullscreen mode no longer shows a blank screen after laptop sleep/wake or Ctrl+Z/fg until the next keystroke or stream output.
Cursor now lands correctly on Ctrl+E/A/K/U/arrow keys when an Indic conjunct or ZWJ emoji wraps across lines.
Vim operators no longer corrupt text containing decomposed (NFD) accented characters.
Pasting text starting with / no longer swallows input or triggers an unknown-command reply.
Stray escape sequences from focus events or mouse-tracking reports interleaved with bracketed paste are no longer dumped into the prompt.
Mouse wheel scrolling speed normalized in Cursor and VS Code 1.92–1.104 (upstream xterm.js bug) and in JetBrains IDE 2025.2 terminals (spurious arrow keys, wrong-direction events, runaway acceleration).
/usage Ctrl+S no longer hangs when copying the stats screenshot to the clipboard on Linux/X11.
/terminal-setup no longer shows a contradictory error in Windows Terminal — Shift+Enter is natively supported there.
/effort picker now reflects the CLAUDE_CODE_EFFORT_LEVEL env var override.
/status fixed for showing the wrong default model for some users.
Slash command autocomplete popup now scales vertically with terminal height instead of being capped at ~3–5 visible commands.
Statusline context_window token counts now reflect current context usage, not cumulative session totals.
Alt+T (thinking toggle) works on macOS terminals without 'Option as Meta' enabled (iTerm2, Terminal.app defaults).
Dead keyboard input on Windows after re-opening a background session from claude agents is fixed.

MCP Server Stability

Unbounded memory growth (10GB+ RSS) when a stdio MCP server writes non-protocol data to stdout is fixed.
MCP servers that connect but fail tools/list now retry once and show 'connected · tools fetch failed' in /mcp instead of silently showing 0 tools.
Unauthorized claude.ai MCP connectors now show as 'needs auth' instead of 'failed', and headless -p mode no longer retries non-transient 4xx connection failures.

Other Improvements

Visual consistency improved in slash command dialogs and /login, /upgrade, /extra-usage dialog spacing.
/tui fullscreen startup banner updated to describe additional renderer benefits (lower memory usage, mouse support, auto-copy on select).
Fixed Bedrock and Vertex 400 errors when ENABLE_PROMPT_CACHING_1H is set.

This release is particularly relevant for developers running Claude Code in headless CI environments (where graceful shutdown and session resume matter), users of IDE terminals with non-standard escape handling, and teams relying on MCP servers for custom tool integrations.

📖 Read the full source: GitHub Claude-Code