Anthropic Claude Code 2.1.144 Lands with /resume for Background Sessions and a 75-Second Startup Fix
The largest maintenance release in recent weeks adds /resume support so background sessions appear alongside interactive ones, per-session model switching, and a fix for the startup hang that could freeze Claude Code for 75 seconds behind a VPN or captive portal.
Anthropic shipped Claude Code 2.1.144 on May 19, and it’s the heaviest changelog the tool has seen in a while. The headline features are /resume support for background sessions and a fix for a startup hang that could freeze the CLI for up to 75 seconds in restricted network environments. But the full release covers dozens of edge cases across sessions, terminal rendering, MCP servers, and Windows support.
Background sessions get proper /resume support
The biggest workflow addition is /resume for sessions started via claude --bg or from agent view. Previously, background sessions existed somewhat separately from interactive ones. Now they appear in the same list, marked with bg, and you can resume them the same way you’d resume any interactive session.
The release also adds elapsed duration to background subagent completion notifications, so you’ll see something like “Agent completed · 3h 2m 5s” instead of a generic completion message. That’s a small thing that matters when you’re running long background tasks and want to know how long they actually took.
Related improvements include: /bg and the back-arrow detach gesture now preserve directories you’ve added via /add-dir, and resumed sessions keep the model they were using rather than picking up whatever model another session last set.
/model is now per-session
This is a behavioral change worth knowing about. /model now changes the model only for the current session. If you want to set a default for new sessions, press d in the model picker. Previously, switching models in one session could affect others, which caused confusion in multi-session workflows.
Resumed sessions also now correctly inherit the model from the session they’re resuming rather than drifting to whatever default was last set elsewhere.
The 75-second startup hang is fixed
If you’ve ever launched Claude Code behind a VPN, on a restricted corporate network, or on a captive portal and watched it sit there doing nothing for over a minute, this is the fix. Side-channel API calls to api.anthropic.com now time out after 15 seconds instead of blocking startup indefinitely. On a network where the endpoint is unreachable, startup should now fail fast rather than waiting through a full TCP timeout.
Terminal rendering fixes
Three separate terminal rendering issues got fixes in this release:
Window resize handling: Dragging a VS Code split-pane divider or otherwise triggering a window-resize event that Claude Code missed could leave the terminal output garbled. It now self-heals on the next frame without requiring a Ctrl+L refresh.
Long session corruption: In very long sessions, stale or garbled glyphs could accumulate and would only clear on a terminal resize or restart. Fixed.
VS Code spinner colors: The spinner animation’s color count has been reduced, which fixes a class of rendering glitches specific to VS Code’s terminal.
MCP fixes worth noting
Two MCP bugs that could silently break things:
Paginated tools/list: MCP servers that return tools across multiple pages were only having their first page processed. Tools on page two and beyond were silently dropped. This has been fixed.
Unsupported MIME types: An MCP server returning an image with an unsupported MIME type (SVG, for example) would break the entire conversation. Now those images get saved to disk and referenced in the tool result instead of crashing the session.
Also: claude mcp list now shows configuration errors when .mcp.json can’t be parsed (for example, if you’re using VS Code’s "servers" key instead of the expected "mcpServers") rather than silently reporting no servers.
macOS crash fix
Background sessions were crashing with “exit 1 before init” on macOS when the project lived under a folder protected by Full Disk Access (regression from 2.1.143). That’s fixed.
Windows improvements
The Windows-specific fixes in this release are substantial: scrolling in attached background sessions now works (PgUp/PgDn, mouse wheel, Ctrl+O), pressing the back arrow in claude agents no longer leaves the list keyboard-unresponsive, and ghost characters at the left edge when switching panes in Agent View on Windows Terminal with CJK content are gone.
Naming change
“Extra usage” is now “usage credits” throughout the CLI. The old /extra-usage command still works as an alias for /usage-credits.
The full release notes are on GitHub.