stdin

The channel through which a program receives data from another. Hooks receive on stdin the details of Claude’s action.

How it appears in the course

When it starts, the hook receives from Claude Code a message in JSON format. The message says what happened. It arrives on stdin (“standard input”, meaning the place where a program receives text).
What does a hook receive, and what does it answer? · Module 07, Hooks: automatic actions

Where you learn it

In module 07 · Hooks: automatic actions, in the Claude Code for Beginners course.

Related terms

Exit codeFormatterHookjqLockfilestderr

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