# Claude Code v2.1.304

> Claude Code v2.1.304, released 19 Oct 2026 (2026-10-19). 371 entries read out of the shipped bundle. Unofficial, and not affiliated with Anthropic.

[Web version](https://changelogs.core-directive.com/v/2.1.304)

Claude Code's bundled default model is now Opus 5.5 at medium effort, replacing Opus 5 at high effort. You can set CLAUDE_CODE_SKIP_PLUGIN_LOCAL_MCP_SERVERS to keep only the remote MCP servers that plugins bring. A program that runs `claude mcp serve` can pick which plugins load with CLAUDE_CODE_MCP_SERVE_ENABLED_PLUGINS. A new allowNestedUserNamespaces sandbox setting lets browsers or rootless podman run inside the sandbox on Linux. It is off by default because it weakens the sandbox. Plugin modules can now read and override the settings in effect through a new settings.read event.

Some work in this build is not switched on yet. In-app surveys for enterprise organizations stay off unless turned on remotely. Setting CLAUDE_CODE_DISABLE_FEEDBACK_SURVEY skips them. Groundwork for showing skills as plugins has landed but cannot be reached. Leaving a worktree now checks whether to keep it, but that check always says no in this build. A launch option to turn off plan or auto mode is partly built, with no visible setting yet.

Creating a worktree no longer resets an existing branch with the same name. Claude Code now stops with an error instead. Your cached remote settings are no longer cleared when a proxy answers with a 204 or 404 reply. Very long timeouts are now capped instead of firing immediately. Removing one skill's hooks no longer removes matching hooks added by another skill. Claude Code no longer fetches skills from MCP servers when it connects to them.

## Sections

Each section is its own markdown document of whole entries, in pages of about 40 KB. The whole release in one document is [full.md](https://changelogs.core-directive.com/v/2.1.304/full.md).

- [What probably matters to you](https://changelogs.core-directive.com/v/2.1.304/what-probably-matters-to-you.md): 43 entries, 2 pages
- [New Features](https://changelogs.core-directive.com/v/2.1.304/new-features.md): 2 entries
- [Improvements](https://changelogs.core-directive.com/v/2.1.304/improvements.md): 155 entries, 4 pages
- [Bug Fixes](https://changelogs.core-directive.com/v/2.1.304/bug-fixes.md): 18 entries
- [In Development](https://changelogs.core-directive.com/v/2.1.304/in-development.md): 5 entries
- [Internal Changes](https://changelogs.core-directive.com/v/2.1.304/internal-changes.md): 145 entries, 4 pages
- [Removed](https://changelogs.core-directive.com/v/2.1.304/removed.md): 3 entries

## What probably matters to you

The first 10 of 43, one line each. The section's own pages have every one in full.

- [New environment variables for low-resource warnings, plugin MCP servers and child sessions](https://changelogs.core-directive.com/v/2.1.304/e/new-env-vars-to-skip-plugin-local-mcp-servers-and-gate-plugi.json): New environment variables add low disk and memory warnings, limit plugin MCP servers, and pass startup and project details to child sessions
- [Plugins can now supply setting values through a settings.read event](https://changelogs.core-directive.com/v/2.1.304/e/new-settingsread-plugin-event-mods-runtime.json): A new settings.read event lets plugin hooks see and override your effective settings, re-checked whenever settings or plugins change
- [Memory extraction can keep its place across worker restarts](https://changelogs.core-directive.com/v/2.1.304/e/post-turn-memory-config-gains-a-carry-across-restarts-option.json): A new carry_across_restarts option lets post-turn memory extraction save and restore its progress when its worker restarts
- [Skills from MCP servers are no longer fetched on connect, and their files are now verified](https://changelogs.core-directive.com/v/2.1.304/e/mcp-skill-resources-file-read-validation-and-refusal-messag.json): MCP-served skills are no longer fetched when servers connect, and their files are now checked against what the server listed
- [Prompt filling and plugin hooks gain an answersPress value](https://changelogs.core-directive.com/v/2.1.304/e/plugin-hooks-new-press-drawn-press-fill-and-answers-press.json): prompt.fill and suggest-prompt requests now carry answersPress, plugins get press_drawn and press_fill hook events, plus two new defaults
- [Enterprise organisations can send members a survey inside Claude Code](https://changelogs.core-directive.com/v/2.1.304/e/enterprise-org-survey-feature-added-gated-by-tengu-steady-m.json): A new survey that an enterprise organisation can send its members appears above the prompt, behind a server flag
- [Plugin hook modules gain a ui.render hook and redraw-on-press](https://changelogs.core-directive.com/v/2.1.304/e/uirender-hook-in-the-hooks-module-scan-list.json): Plugin hook modules can now be scanned for a `ui.render` hook, and a UI press can return a freshly drawn tree in one step
- [New `CLAUDE_CODE_ATTRIBUTION_PROJECT` setting checked against claude.ai Project IDs](https://changelogs.core-directive.com/v/2.1.304/e/claude-code-attribution-project-is-validated-as-a-claudeai.json): Claude Code now recognises `CLAUDE_CODE_ATTRIBUTION_PROJECT` and drops a value that is not a valid claude.ai Project ID from saved jobs
- [Bundled default model changes to Opus 5.5 at medium effort](https://changelogs.core-directive.com/v/2.1.304/e/model-catalog-default-for-the-cc-surface-moved-from-claude-o.json): The model catalog shipped with Claude Code now defaults to claude-opus-5-5 at medium effort instead of claude-opus-5 at high effort
- [SDK hosts can mark MCP tools that run code, so auto mode checks them](https://changelogs.core-directive.com/v/2.1.304/e/auto-mode-coderunningmcptools-setting.json): The SDK initialize request accepts codeRunningMcpTools so auto mode judges code-running MCP tools, and the reply reports whether it applied