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Introduction

What is PRECC?

PRECC (Correção preditiva de erros para o 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.

Gratuito para usuários da comunidade.

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

Correção de contexto (cd-prepend)

Detecta quando comandos como cargo build ou npm test são executados no diretório errado e adiciona cd /caminho/correto && antes da execução.

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

Se um comando falhar após compressão, PRECC automaticamente pula a compressão na próxima tentativa para que Claude obtenha a saída completa não comprimida para debug.

Live Usage Statistics

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

Os números são estimativas. Cada falha prevenida evita um ciclo completo de retry: saída de erro, raciocínio do modelo e comando de retry. These numbers update automatically from anonymized telemetry.