Anthropic · 2026-10-01 · major
Claude Code 2.1.287 — Claude Mods let plugins change deeper behavior
Claude Code 2.1.287 adds Claude Mods, plugins that can modify deeper behavior, and a built-in "You should know" mod where a side agent flags things you or Claude might miss. Opus 4.7+ and Fable default to 1M context on Bedrock and Vertex.
Claude Code plugins can now reach deeper into how the agent behaves, starting with a side agent that watches your back.
Quick facts
| Version | v2.1.287 |
|---|---|
| Maker | Anthropic |
| Released | 2026-10-01 |
| Headline | Claude Mods: plugins may modify deeper behavior |
| Built-in mod | "You should know" (cc-plugin-you-should-know@builtin) |
| New MCP support | URL prompts on the 2025-11-25 protocol, e.g. to sign in |
What is it?
Claude Mods are the headline of Claude Code 2.1.287: plugins may now modify deeper behavior of the coding agent, not just add commands or tools. Anthropic ships one mod in the box, "You should know", in which a side agent watches the session and flags things you or Claude might miss.
How does it work?
The built-in mod is off by default and is turned on with a /plugin command; it works in first-party sessions with telemetry on. Alongside it, the agents view gains an n:<text> filter for session names and tasks, MCP servers on the 2025-11-25 protocol can show URL prompts such as sign-in pages, and a shell write through a repo-committed symlink onto a sensitive file or out of the working tree now waits for a person.
Why does it matter?
Mods open Claude Code's behavior to the same plugin marketplace that already carries skills and commands, so teams can package review or safety habits as a plugin. Users on Amazon Bedrock, Vertex, Foundry and the Claude apps gateway also get a 1M-token context window by default for Opus 4.7+ and Fable, and screen reader users get more than ten accessibility fixes.
Who is it for?
Claude Code users and plugin authors
Frequently asked questions
- How do I turn on the "You should know" mod in Claude Code?
- Claude Code 2.1.287 ships "You should know" as a built-in mod that is off by default. Turn it on with the command /plugin enable cc-plugin-you-should-know@builtin. Anthropic's release notes say the mod is available for first-party sessions with telemetry on, and it runs a side agent that flags things you or Claude might miss.
- Does Claude Code 2.1.287 change the context window on Bedrock and Vertex?
- Yes. Claude Code 2.1.287 changes Opus 4.7 and later Opus models, plus Fable, to use a 1M-token context window by default on Amazon Bedrock, Google Vertex, Microsoft Foundry and the Claude apps gateway. The same release fixes Bedrock and Vertex startup model checks that ignored an enforced availableModels list.
- What safety changes are in Claude Code 2.1.287?
- Claude Code 2.1.287 makes a shell write through a repo-committed symlink onto a sensitive file, or out of the working tree, wait for a person. Whole-tool Bash allow rules now prompt for shell writes to certain files instead of running them, and a dangerous rm command keeps its always-ask safeguard when it also redirects output to a ~ or wildcard path.
- What is new in the Claude Code VS Code extension in 2.1.287?
- The Claude Code VS Code extension in 2.1.287 adds a "Run in background" action for a running command or sub-agent, and shows the output of background shells and Monitors on their cards in the agent map. It also fixes file links in the plan preview tab, tool-row links shown as plain text, and duplicate Claude processes after a reload.
Try it
npm i -g @anthropic-ai/claude-code@2.1.287