Claude Code 2.1.287: Mods in-process extensions; built-in You should know side agent; 1M context default on gateways
Anthropic shipped [`Claude Code 2.1.287`](https://github.com/anthropics/claude-code/releases/tag/v2.1.287) on 2026-10-01 (npm [`@anthropic-ai/[email protected]`](https://www.npmjs.com/package/@anthropic-ai/claude-code)): **Claude Mods** let plugins run in-process JS/TS hooks that rewrite tool calls and UI; opt-in built-in **You should know** side agent; MCP URL elicitation; Opus 4.7+/Fable default to 1M context on Bedrock/Vertex/Foundry/apps gateway. Agent SDK TS [`0.3.287`](https://github.com/anthropics/claude-agent-sdk-typescript/releases/tag/v0.3.287) parity.
- •Release
v2.1.287; npm 2.1.287; GitHub ~2026-10-01T18:00:22Z - •Mods: in-process hooks for UI + tool.call rewrite; ≥2.1.287; docs https://code.claude.com/docs/en/plugins/mods/overview
- •You should know:
/plugin enable cc-plugin-you-should-know@builtin(first-party + telemetry); off by default - •1M context default for Opus 4.7+/Fable on Bedrock/Vertex/Foundry/apps gateway; disable via CLAUDE_CODE_DISABLE_1M_CONTEXT=1
- •Agent SDK TS 0.3.287; MCP URL elicitation / bareElicitationCapability

