PRECC Tool Cuts Claude Code API Costs with Pre-Tool-Call Compression

PRECC is an open source tool that reduces Claude Code API costs by compressing redundant context before it reaches the model. It uses a pre-tool-call hook that intercepts Bash, Read, and Grep calls to apply compression algorithms.

How It Works

The tool addresses cost issues where API bills were climbing due to redundant context being sent multiple times. Common sources of waste include:

• Same file contents sent repeatedly
• Verbose shell output
• Overlapping grep results that the model doesn't need in full

The pre-tool-call hook runs RTK (Redundancy-aware Token Kompression) on tool output before it reaches Claude. The compression process:

• Deduplicates repeated spans
• Strips noise
• Summarises large reads
• Returns compressed version to the model

Performance Results

The hook runs in approximately 2.93ms, adding no perceptible latency to operations. In practice, users see 40-66% fewer input tokens across typical coding sessions. Model output quality remains unchanged because the compression preserves signal while stripping redundancy.

This type of optimization is particularly useful for developers using Claude Code extensively, where repeated file reads and tool outputs can significantly increase token usage and costs.