by VibecodedThis

Claude Code 2.1.142: Fast Mode Moves to Opus 4.7, Agent Sessions Get Config Flags

Claude Code 2.1.142 landed May 14 with two headline changes: fast mode now defaults to Opus 4.7 instead of Opus 4.6, and the claude agents command gains eight new flags for configuring dispatched background sessions.

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Claude Code 2.1.142 shipped May 14 with two headline changes, a handful of quality-of-life improvements, and the usual round of bug fixes.

Fast mode is now Opus 4.7

Fast mode, the /fast toggle that trades cost for speed, now uses Opus 4.7 by default. The previous default was Opus 4.6. Anthropic describes fast mode as delivering roughly 2.5x higher output speeds compared to the standard model.

If you want to stay on Opus 4.6 for fast mode specifically, set CLAUDE_CODE_OPUS_4_6_FAST_MODE_OVERRIDE=1 in your environment. That pins the fast-mode model to 4.6 while leaving everything else unchanged.

This makes Claude Code consistent with Windsurf, which also added Opus 4.7 in fast mode to its editor on May 12.

Agent session config flags

The claude agents command can now dispatch background sessions with fine-grained configuration. Eight new flags cover the same options you’d normally set in a CLAUDE.md or settings file:

  • --add-dir — add an additional working directory
  • --settings — path to a settings file
  • --mcp-config — MCP server configuration
  • --plugin-dir — directory for plugins
  • --permission-mode — permission level for the session
  • --model — model override
  • --effort — effort level
  • --dangerously-skip-permissions — skip confirmation prompts

These flags let you dispatch sessions with different tool sets, models, or permission levels without touching your global config. Useful if you’re running agent fleets where different tasks need different setups.

Bug fixes

A few of the more significant ones:

  • MCP_TOOL_TIMEOUT wasn’t raising the per-request fetch timeout for remote HTTP and SSE MCP servers. Fixed.
  • Background sessions could crash-loop when the Claude-in-Chrome extension was running. Fixed.
  • Background sessions disappeared after macOS sleep/wake. Fixed.
  • The daemon wasn’t exiting cleanly after binary upgrades. Fixed.
  • Network-drive working directories on Windows caused deadlocks. Fixed.
  • Background sessions weren’t recognizing pre-existing git worktrees. Fixed.

Other changes

Plugins with a root-level SKILL.md file and no skills/ subdirectory are now surfaced as skills automatically. The /plugin details pane and claude plugin details command now list any LSP servers the plugin provides. /web-setup will warn before replacing an existing GitHub App connection.

This release also removes the stale /model claude-sonnet-4-20250514 suggestion from refusal messages, which had become outdated noise.

The 2.1.141 release on May 13 added the terminalSequence hook field for native OS notifications and workspace federation via ANTHROPIC_WORKSPACE_ID. The 2.1.139 release on May 11 introduced the agent view research preview and the /goal command. All three releases together represent Anthropic’s push to make Claude Code a proper multi-session orchestration platform rather than a single-session coding assistant.

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