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Introduction

What is PRECC?

PRECC (Correction prédictive des erreurs pour Claude Code) is a Rust tool that intercepts Claude Code bash commands via the official PreToolUse hook mechanism. It fixes errors before they happen, saving tokens and eliminating retry loops.

Gratuit pour les utilisateurs communautaires.

The Problem

Claude Code wastes significant tokens on preventable mistakes:

  • Wrong-directory errors – Running cargo build in a parent directory that has no Cargo.toml, then retrying after reading the error.
  • Retry loops – A failed command produces verbose output, Claude reads it, reasons about it, and retries. Each cycle burns hundreds of tokens.
  • Verbose output – Commands like find or ls -R dump thousands of lines that Claude must process.

The Four Pillars

Correction de contexte (cd-prepend)

Détecte quand des commandes comme cargo build ou npm test sont exécutées dans le mauvais répertoire et ajoute cd /bon/chemin && avant l’exécution.

GDB Debugging

Detects opportunities to attach GDB for deeper debugging of segfaults and crashes, providing structured debug information instead of raw core dumps.

Session Mining

Mines Claude Code session logs for failure-fix pairs. When the same mistake recurs, PRECC already knows the fix and applies it automatically.

Automation Skills

A library of built-in and mined skills that match command patterns and rewrite them. Skills are defined as TOML files or SQLite rows, making them easy to inspect, edit, and share.

How It Works (30-Second Version)

  1. Claude Code is about to run a bash command.
  2. The PreToolUse hook sends the command to precc-hook as JSON on stdin.
  3. precc-hook runs the command through the pipeline (skills, directory correction, compression) in under 3 milliseconds.
  4. The corrected command is returned as JSON on stdout.
  5. Claude Code executes the corrected command instead.

Claude never sees the error. No tokens wasted.

Adaptive Compression

Si une commande échoue après compression, PRECC ignore automatiquement la compression lors de la prochaine tentative pour que Claude obtienne la sortie complète non compressée pour le débogage.

Live Usage Statistics

MetricValue
Hook invocations–
Tokens saved–
Saving ratio–%
RTK rewrites–
CD corrections–
Hook latency– ms (p50)

Les chiffres sont des estimations. Chaque échec évité épargne un cycle complet de nouvelle tentative : sortie d’erreur, raisonnement du modèle et commande de nouvelle tentative. These numbers update automatically from anonymized telemetry.