Breaking

Anthropic Adds 'You should know' Side Agent to Claude Code

October 2, 2026 at 18:52 EDT

Software Dev & Coding
AI Agents

Anthropic has added You should know, an opt-in built-in mod for Claude Code that runs a side agent to flag details the user or Claude may miss during longer coding sessions. The feature arrived with Claude Code v2.1.287 on October 1, 2026, alongside the broader rollout of Claude Mods, a new plugin capability for changing deeper behavior inside Claude Code.

Oct. 1, 2026 · Anthropic

Claude Code gets a watcher

You should know is an opt-in built-in mod that runs a side agent during longer coding sessions and flags details a developer or the main agent may miss.

v2.1.287

Release that added Claude Mods and You should know

Opt-in

Disabled by default and enabled from the plugin menu

Unsupported sample mods listed for developers

Built-in watcher vs sample mods

1 mod

You should know

3 mods

Sample set

The launch pairs one built-in side-agent mod with a small sample gallery for mod developers.

How the feature fits the loop

Enable

Turn on the built-in mod from Claude Code.

→

Watch

A side agent follows longer tasks while Claude works.

→

Flag

A note appears above the prompt when something is worth attention.

Developer upside

Long tasks get a second pass for missed tests, changed assumptions or loose ends before the session moves on.

Open questions

Availability depends on first-party sessions with telemetry on, and public docs do not list benchmarks or flagging criteria.

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