creating-claude-hooks

Create a Claude Code hook by placing an executable script with a shebang (#!/bin/bash, #!/usr/bin/env python, or #!/usr/bin/env node) in .claude/hooks/ or your global hooks directory, then set executable permissions. The hook reads JSON from stdin, processes it, and outputs text to stdout, returning exit code 0 for success, 2 to block execution, or 1 for errors.

Claude Code hooks support multiple events: session-start runs when a session begins, user-prompt-submit triggers on user input, tool-call fires when Claude invokes a tool, and assistant-response executes after Claude responds. Each event type receives specific JSON input and can enforce exit codes to control Claude Code behavior.

Yes, Claude Code hooks can be packaged and published as PRPM packages. Follow the hook format requirements—executable permissions, shebang headers, JSON I/O conventions, and proper exit codes—then structure your package with hooks under .claude/hooks/ directory to make them installable across local, CI, and repository workflows.

Claude Code hooks support bash, TypeScript, and Python. Each language requires the appropriate shebang line (#!/bin/bash, #!/usr/bin/env node, or #!/usr/bin/env python) at the top of the executable file. The hook must parse JSON input from stdin and output text to stdout regardless of language choice.

Exit code 0 indicates successful hook execution and allows Claude Code to continue. Exit code 2 blocks the current operation (e.g., prevents prompt submission or tool execution). Exit code 1 signals an error occurred during hook processing. These codes enforce security and control flow across session-start, user-prompt-submit, tool-call, and assistant-response events.

Claude Code hooks require executable permissions on the file. After creating your hook script with the correct shebang, run chmod +x on the file path. Hooks must be placed in .claude/hooks/ (project-level) or the user-global hooks directory, and the filesystem must preserve executable permissions when stored or deployed.