Why use content-based deduplication instead of session IDs?

Content-based deduplication ensures that the same insight isn't stored twice even if it appears in different sessions, whereas session IDs only prevent duplicates within a single conversation.

How does hash rotation work in this guide?

The guide provides a rotation script that monitors the number of stored hashes and prunes the oldest entries once a set limit (e.g., 10,000) is reached to prevent file bloat.

Does hashing content significantly affect hook performance?

No, SHA256 hashing is extremely efficient, typically taking less than 1ms for standard text content, making it ideal for real-time hook execution.

Where is the hook state data typically stored?

Following the best practices in this skill, state is stored in a centralized directory at ~/.claude/state/hook-state/ to maintain persistence across multiple projects.

Hook Deduplication Guide

Name: Hook Deduplication Guide
Author: cskiro

bycskiro

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Developer Tools

Implements robust content-based deduplication for Claude Code hooks to prevent redundant insight storage across sessions.

This skill provides a comprehensive framework for managing state within Claude Code hooks, specifically focusing on content-based hashing using SHA256. It guides developers through transitioning from session-based tracking to a more persistent deduplication strategy, ensuring that unique insights are captured without cluttering storage with duplicates. The skill includes practical implementation steps for hash generation, state directory management, and automated hash rotation to maintain optimal performance and prevent unbounded file growth.

Key Features

01Content-based deduplication using SHA256 hashing

022 GitHub stars

03Standardized state management patterns for hook development

04Performance-optimized lookups using grep-based filtering

05Automated hash storage and file rotation logic

06Session-independent duplicate detection for persistent insights

Use Cases

01Building Claude Code hooks that extract and store persistent insights

02Refactoring existing hooks to prevent duplicate data entry across conversations

03Implementing bounded state management for high-frequency event hooks

What are Skills?·How to Install

Install with 🐟 Skill.Fish

npx skillfish add cskiro/claudex insight-skill-generator

For use in Claude.ai and ChatGPT

Download Skill