Claude Code v2.1.144: Background Sessions, /model Scoping, and 15s Startup Timeout

Claude Code v2.1.144 is out, bringing several quality-of-life improvements and critical bug fixes. The release focuses on better background session management, terminal rendering fixes, and more robust error handling.

Background Sessions Get First-Class Support

• /resume background sessions — sessions started via claude --bg or agent view now appear alongside interactive ones, marked with a bg label. You can list them with claude sessions or pick from the session list.
• Background subagent completion notifications now show elapsed duration (e.g., Agent completed · 3h 2m 5s).
• /bg and ← -detach now preserve the working directory.

/model Scoped to Current Session

/model now changes the model for the current session only. To set a default for new sessions, press d in the model picker. Resumed sessions keep the model they were using, rather than picking up another session's /model choice.

Startup Timeout Reduced

Fixed a bug where startup could hang up to 75 seconds when api.anthropic.com is unreachable (captive portal, firewall, VPN issues). Side-channel API calls now time out after 15 seconds.

Terminal Rendering Fixes

• Garbled output after missed window-resize events (e.g., dragging a VS Code split-pane divider) now self-heals on the next frame instead of requiring Ctrl+L.
• Progressive terminal display corruption (stale/garbled glyphs) in very long sessions — now cleared automatically instead of requiring terminal resize or restart.
• Reduced spinner animation color count to minimize rendering glitches in VS Code.
• Windows: scrolling in attached background sessions fixed (PgUp/PgDn, mouse wheel, Ctrl+O transcript navigation).
• Windows: fix for ghost characters at left edge when switching panes in Agent View with CJK content.

Other Notable Fixes

• File extension mismatch: Reading a file whose image extension doesn't match its contents (e.g., HTML saved as .png) now falls back to text instead of crashing the conversation.
• Search tool errors reduced: head/tail file views now satisfy the read-before-edit check; egrep, fgrep, git grep, git diff with exit code 1 (no matches) no longer reported as command failures.
• MCP pagination: Fixed paginated tools/list responses only returning first page, silently dropping tools.
• MCP unsupported MIME: Images with unsupported MIME types (e.g., SVG) now saved to disk and referenced in tool result instead of breaking the conversation.
• Skill directory file descriptors: Non-.md files in skill directories no longer trigger skill reloads, preventing file descriptor exhaustion.
• macOS Full Disk Access: Background sessions crashing with exit 1 before init when project is under a Full Disk Access–protected folder (regression in v2.1.143) fixed.
• Plugin not cached: Plugins enabled in own settings no longer show not cached errors on first load; plugins from project's .claude/settings.json now show actionable install hint.
• MCP config errors: claude mcp list now shows configuration errors when .mcp.json can't be parsed (e.g., using VS Code's servers key instead of mcpServers).

Command Line Changes

• /extra-usage renamed to /usage-credits; old name still works.
• /plugin browse and discover panes now show when a plugin was last updated.

This release is available now for all Claude Code users. If you use MCP servers heavily or run long background sessions, the rendering and pagination fixes alone are worth the upgrade.