docs: Claude Code v2.1.268 - copyOnSelect setting, SSH clipboard docs, sandbox per-session flag, checkpointing mid-turn clarification

[claude-yolo]

Night shift report

WHY THIS MATTERS: This batch documents several real behavioral changes and new settings in Claude Code v2.1.268 that users will encounter and may not understand without the docs. The SSH clipboard section in particular explains a genuinely confusing failure mode (OSC 52 silently not working). The checkpointing clarification closes a doc gap: queued mid-turn messages have always behaved this way, but it was never written down. The copyOnSelect setting is new surface area in /config. Taken together this is a docs-forward release — the behavior shipped before the docs caught up, and now they have.

HIGHLIGHTS:

• New copyOnSelect setting (settings-reference.md): Controls whether mouse selection in fullscreen rendering and agent view auto-copies to clipboard. Off by default for keyboard-first users; appears in /config. Global config only, not project-scoped.
• SSH clipboard / OSC 52 troubleshooting (troubleshooting.md): New section explaining why /copy reports "Copied to clipboard" over SSH but text may not arrive. Documents per-terminal OSC 52 support gaps (iTerm2 needs a toggle; Terminal.app doesn't support it at all) and offers CLAUDE_CODE_DISABLE_MOUSE=1 as a session-wide escape hatch.
• Sandbox per-session via --settings (sandboxing.md): Documents that claude --settings '{"sandbox": ...}' can enable/configure sandboxing for one session without touching any settings file — and that this also prevents Claude from escaping the sandbox with an unsandboxed retry.
• Checkpointing: mid-turn messages not checkpointed (checkpointing.md): Messages queued while Claude works and delivered within the running turn don't create checkpoints and don't appear in the rewind menu. To undo them, rewind to the prompt that started the turn. Propagated as a wording fix across best-practices.md and glossary.md.
• macOS EPERM troubleshooting (errors.md): EPERM on ~/Desktop, ~/Documents, ~/Downloads, or iCloud Drive on macOS is a Privacy & Security gate, not a permissions bug. Fix: quit terminal with Cmd+Q, reopen, then check System Settings if ls still fails.
• MCP OAuth client secret lifecycle (mcp.md): Secret is set only at add-time; to change it, remove and re-add the server. Also: skipDangerousModePermissionPrompt for skipping MCP approval only applies from user or managed settings (not project settings).
• context: fork ≠ conversation fork (skills.md, slash-commands.md): Added a Note clarifying that a forked skill doesn't inherit conversation history — "fork" here means isolated subagent, not a copy of the current context tree.
• disallowedTools with specifiers removes the whole tool (sub-agents.md): Bash(git push *) in a subagent's disallowedTools removes Bash entirely, not just matching commands. To keep Bash and block commands, use permissions.deny instead.
• --system-prompt-snapshot preserved on fullscreen relaunch (fullscreen.md): Added to the list of flags Claude Code carries into a relaunched session.
• modelPicker added to host-managed overrides (settings.md): Apps that set CLAUDE_CODE_PROVIDER_MANAGED_BY_HOST now override modelPicker in addition to model, fallbackModel, and modelOverrides.
• Dynatrace plugin added to marketplace (marketplace.json): DQL queries, app/infra monitoring, log analysis, incident response — includes MCP server for live platform access.

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Created by night-shift claude-yolo
Day-shift claude-yolo will review and merge this in the morning