docs: Claude Code v2.1.251 - new hook events, 5 security fixes, new claude-tag-wif-gateway-sample repo

[claude-yolo]

Night shift report

WHY THIS MATTERS: v2.1.251 patches five security vulnerabilities — file tools could escape the approved directory by following a swapped symlink, plugin commands could path-traverse outside their directory, project settings could sneak in raw API body logging, the Workflow tool could read arbitrary paths before the permission check ran, and Grep/Glob didn't honour Read(...) deny rules through symlinked search paths. Beyond the security fixes, two new hook events (PreModelSwitch/PostModelSwitch) give hooks the ability to block or annotate model switches for the first time, and the discovery run surfaced a new Anthropic public repo (claude-tag-wif-gateway-sample) that we don't yet archive.

HIGHLIGHTS:

• SECURITY (5 fixes): Symlink-swap in file tools (Read/Write/Edit) could read/write outside the permitted location; plugin scriptPath could traverse outside the plugin dir; project settings could enable raw API body logging; Workflow scriptPath read outside session permissions before check ran; Grep/Glob ignored Read(...) deny rules on symlinked paths
• New hooks: PreModelSwitch and PostModelSwitch events let hooks block, confirm, or annotate model switches; SessionStart resume hooks now receive session staleness and estimated re-cache cost
• New discovery.json entry: anthropics/claude-tag-wif-gateway-sample appeared under github_org_anthropics.not_fetched — a new public Anthropic repo, likely a WIF (Workload Identity Federation) gateway sample for Claude Tag. Adding it to the archive is a human decision.
• Remote Control: Foreground subagent tool calls and results now stream live to Remote Control clients (background subagents still show status only)
• Spend/cache visibility: Spend limit bar in /usage; per-session prompt-cache stats (hit ratio, misses, tokens re-cached) in /cost and the prompt_cache status line object
• CLI UX: attach, logs, stop, respawn, rm now appear in claude --help; the "session already running" message names the exact claude attach <id> command
• tombstones.json: Date bump only (2026-08-28 → 2026-08-29), no new entries and no resurrections — clean

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