Claude Code (v2.1.251) introduces new hook events for model switching, live streaming of s

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Aug 28, 2026 20:57 UTC github_releases+npm+pages https://raw.githubusercontent.com/anthropics/claude-code/main/CHANGELOG.md

Claude Code (v2.1.251) introduces new hook events for model switching, live streaming of subagent tool calls, spend limits, prompt cache metrics, and CLI improvements, alongside numerous bug fixes.

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anthropic's claude-code v2.1.251 just dropped with some interesting new features! model switch hooks and live subagent tool call streaming could be super useful.

devs using claude-code: check out the new spend limit bar, prompt cache metrics, and expanded cli commands in v2.1.251. lots of fixes too!

[MERGED across 3 sources: github_releases, npm, pages] shared signal: claude-code --- npm :: @anthropic-ai/claude-code --- @anthropic-ai/claude-code 2.1.250 -> 2.1.251: +4 strings, -5 strings, 1 flagged as interesting [sentence] (1) + s model frontmatter and the configured default subagent model. If omitted, uses the agent definition --- github_releases :: anthropics/claude-code --- anthropics/claude-code release: v2.1.251 name: v2.1.251 published: 2026-08-28T18:19:32Z url: https://github.com/anthropics/claude-code/releases/tag/v2.1.251 ## What's changed - Added `PreModelSwitch` and `PostModelSwitch` hook events (block, confirm, or annotate a model switch); `SessionStart` resume hooks now receive session staleness and the estimated re-cache cost - Added live streaming of a foreground subagent's tool calls and results to Remote Control clients (background subagents, the default, still show status only) - Added a Spend limit bar to `/usage` and a `rate_limits.spend_limit` status line field for developers behind a Claude apps gateway with spend limits - Added a per-session prompt-cache line to `/cost` (hit ratio, misses, tokens re-cached, warm/cold) and a matching `prompt_cache` object for status line scripts - Added `attach`, `logs`, `stop`, `respawn`, and `rm` to `claude --help`; the `--resume` message for a running background session now names the exact `claude attach <id>` command - Fixed file tools (Read, Write, Edit) following a symlink swapped inside the working directory after the permission check, which could read or write outside the approved location - Fixed plugin commands declared in a marketplace entry being able to point outside the plugin directory; such paths are now rejected with a path-traversal error - Fixed project settings being able to enable detailed beta tracing or raw API body logging, and a lower-scope beta tracing endpoint bypassing an OTLP collector pinned by managed settings or a host app - Fixed the Workflow tool reading (and quoti