docs: Claude Code v2.1.251 - spend limit tracking, agent team final answers, /radio now universal, cross-session @ mention behavior change

[claude-yolo]

Night shift report

WHY THIS MATTERS: v2.1.251 ships several behavior changes that directly affect how users and enterprises interact with Claude Code — spend limit visibility in the status line is new surface area for enterprise admins, the agent team notification fix removes a communication gap that caused orchestration stalls, and the cross-session @ mention change is a breaking behavior reversal that existing workflows may have been relying on.

HIGHLIGHTS:

• Spend limit now visible in statusline and /usage (statusline.md, claude-apps-gateway-spend-limits.md): Enterprise users behind a Claude apps gateway can now see a rate_limits.spend_limit object in the statusline JSON input and a "Spend limit" bar in /usage, showing percentage used and reset time. Requires v2.1.251 on the developer's machine; no gateway upgrade needed.
• /radio command removed from unavailability lists (feature-availability.md): All four provider tabs (Bedrock, Claude Platform on AWS, GCP Agent Platform, Microsoft Foundry) no longer list /radio as unavailable. The command appears to have gone universal — previously it was blocked on all non-first-party providers.
• Cross-session @ mentions no longer auto-attach files (cross-session-messaging.md): Before v2.1.251, an @filename in a message that started a new turn would auto-attach the file on the receiving machine. Now @ mentions in messages from other sessions are always plain text — Claude must open the file explicitly with its own tools. Breaking change for any workflow that relied on the auto-attach behavior.
• Agent team idle notifications now include the teammate's final answer (agent-teams.md): Previously, a teammate's completion notification carried no output — teammates had to message the lead or update the shared task list to pass results. Now the notification includes the final answer directly, fixing the gap that caused lead agents to stall waiting for results from named subagents running as teammates.
• Background session cloud provider gateway forwarding fixed (agent-view.md): If you dispatch a background session from a shell authenticated only through ANTHROPIC_VERTEX_BASE_URL or ANTHROPIC_BEDROCK_BASE_URL, the endpoint and auth-bypass flag are now forwarded to the worker. Before this fix, every request from such a session failed silently.
• Background sessions can edit files in linked git worktrees (agent-view.md): A background session (or its subagents) can now write to files inside a linked git worktree they created. Previously this was blocked.
• Plugin marketplace availability during concurrent refresh fixed (agent-view.md): A background session that starts while another process is refreshing a marketplace no longer loses all of that marketplace's skills, agents, hooks, and MCP servers for its entire run.
• New effortUltra terminal color token (terminal-config.md): Allows customizing the ultracode tag color on the input box border. Takes effect on v2.1.239+.
• Clarified diff color token behavior (terminal-config.md): diffAddedDimmed and diffRemovedDimmed now documented as the dimmed diff shown after you reject an edit, not just "unchanged context lines."
• OTel debug log distinction (monitoring-usage.md): [3P telemetry] errors in --debug output mean your exporter is failing; [Anthropic telemetry] lines are Anthropic's own operational telemetry and don't indicate a problem with your setup.
• Proxy bypass for localhost WebSockets (network-config.md): Explicitly documented that Claude Code never routes localhost/::1/127.0.0.0/8 WebSocket connections through the proxy — no NO_PROXY entry needed.
• ScheduleWakeup gets a noop field (agent-sdk/typescript.md): New field for reporting a wake-up where nothing changed, part of the self-paced /loop tool contract.
• claude_code preset description simplified (agent-sdk/modifying-system-prompts.md): Docs dropped claims that the preset includes "code style and formatting guidelines" and "response tone and verbosity rules" — description now focuses on tool guidance, safety instructions, and environment context.

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