Turn On Claude Code's "You Should Know" Mod to Catch What Claude Doesn't Mention

Switch on a second agent that reviews long sessions and leaves you notes about decisions you might miss.

Overview

By the end of this guide, you'll have:

  • The "You should know" mod enabled in Claude Code.

  • A habit for answering its notes quickly.

  • A backup handoff routine for very long sessions.

Who This Is For

  • You run long Claude Code sessions and worry about decisions made without you noticing.

  • Claude sometimes forgets or changes things halfway through a job.

  • You want a second set of eyes without doing the review yourself.

What You'll Need

  • Claude Code v2.1.287 or newer.

  • Claude Code signed in with your Claude account, with telemetry on.

  • The terminal, or the Code tab of the Desktop app. The mod does not appear in the VS Code panel.

The Core Idea

In a long task, Claude makes many small calls. Some matter to you. The mod runs a second agent that reads the session every six steps and leaves a short note above your prompt when Claude made a call it did not mention. Claude keeps working while you read.

Quick Terms

  • Mod: a built-in add-on that changes how Claude Code behaves. This one is off until you switch it on.

  • Compaction: when Claude shrinks a long conversation into a summary to make room, which can drop details.

Going Further

  • Keep a short list of notes you marked as already known, so you can see what you keep ignoring.

  • Pair it with a written handoff for sessions that run very long.

  • Keep long-term project knowledge outside the chat - Guide: Give Claude Infinite Memory With NotebookLM (AI Foundations)