Development & Automation

Claude Code 2.1.286–2.1.287 Update: Claude Mods and 4 Changes You'll Notice Right Away.

What's new in Claude Code 2.1.286–2.1.287: Claude Mods, a verify skill before commits, 1M context by default on cloud providers, and a change to MCP URL login.

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Claude Code 2.1.286–2.1.287 Update: Claude Mods and 4 Changes You'll Notice Right Away

Key takeaways

  1. 1Claude Mods and the You should know mod let plugins extend Claude Code's internal behavior and add a side agent.
  2. 2The verify skill runs right before a commit, and Opus 4.7 and later and Fable use a 1M context by default on supported cloud providers.
  3. 3If an MCP server stops connecting after the update that added URL-prompt login, check the bareElicitationCapability setting.

Claude Code has opened up Claude Mods, which let plugins change even its internal behavior. The first built-in mod, "You should know," is a side agent that watches along and points out what you or Claude missed. Two releases landed back to back, 2.1.286 (October 1, 04:10 KST) and 2.1.287 (October 2, 03:00 KST), and here are four changes that daily users will notice right away.

A brass owl assistant beside a laptop with a blank screen, shining a flashlight on one missed thing

Claude Mods and the built-in You should know mod

With Claude Mods, plugins can change deeper parts of how Claude Code behaves. A mod is a plugin that uses function hooks, and it is installed and distributed the same way as any other plugin. Anthropic's design discussion describes how function hooks connect to internal behavior and the UI. You can see the source for the built-in mods in the mods directory of the Claude Code repository. The design discussion opened on September 4, and mods officially landed on October 1 with a "We're live!" announcement.

Boris Cherny, who created Claude Code, said on September 15 that Claude Mods were on the way, and that someone had already built a Tetris mod that runs inside Claude.

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The first built-in mod, You should know, is a side agent that watches alongside you. It catches things you missed or that Claude missed and tells you. Turn it on with this command.

/plugin enable cc-plugin-you-should-know@builtin

It works only when telemetry is on in first-party sessions. What plugins can extend has gotten one step wider.

The verify skill runs automatically before a commit

If a project or user skill is named verify, Claude runs it right before a commit. Commits that change only docs and commits that change only tests are exempt. A project skill can live at .claude/skills/verify/SKILL.md, and a user skill at ~/.claude/skills/verify/SKILL.md. For how to write skills, see the Claude Code skills docs.

For example, a skill that bundles lint and tests could look like this.

---
name: verify
description: Run lint and tests to check before committing
---
Run npm run lint and npm test, and if either fails, do not commit and tell me why.

Forgetting to verify before a commit becomes structurally less likely.

1M context by default on Bedrock, Vertex, and Foundry

Starting with Claude Code 2.1.287, Opus 4.7 and later and Fable use a 1M context window by default on Bedrock, Vertex, Foundry, and the Claude apps gateway, without the [1m] suffix. To go back to 200K, set CLAUDE_CODE_DISABLE_1M_CONTEXT=1.

Starting with 2.1.286, if a model fallback shrinks the context from 1M to 200K, the notification shows that change. Teams that use Claude Code through a cloud account can work with a long codebase in one pass without extra configuration.

MCP servers can ask you to log in through a URL prompt

Servers that use the MCP 2025-11-25 protocol can show a URL prompt for things like login. If an MCP server fails to connect after you update to Claude Code 2.1.287, add bareElicitationCapability to that server's config entry. For example:

{
  "mcpServers": {
    "my-server": {
      "type": "http",
      "url": "https://example.com/mcp",
      "bareElicitationCapability": true
    }
  }
}

If MCP suddenly dropped after you updated, check this one line first.

Sources

Frequently asked questions

What are Claude Mods?
They are Claude Code plugins that use function hooks and can change Claude Code's deeper behavior.
How do I turn on the You should know mod?
Run /plugin enable cc-plugin-you-should-know@builtin in Claude Code. Telemetry must be on in first-party sessions for it to work.
When does the verify skill run before a commit?
If a project or user skill is named verify, Claude runs it right before a commit. Commits that change only docs or only tests are exempt.
What should I do if an MCP server won't connect after the update?
Add bareElicitationCapability: true to that MCP server's config entry.

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