rskim

Smart code reader - streaming code transformation for AI agents.

Overview

rskim transforms source code by intelligently removing implementation details while preserving structure, signatures, and types - perfect for optimizing code for LLM context windows.

Think of it like cat, but smart about what code to show.

Installation

Via Cargo

cargo install rskim

Via npm (coming soon)

npm install -g rskim

Quick Start

# Read TypeScript with structure mode
rskim file.ts

# Extract Python function signatures
rskim file.py --mode signatures

# Pipe to syntax highlighter
rskim file.rs | bat -l rust

# Read from stdin
cat code.ts | rskim - --language=type-script

Features

• 6 Languages: TypeScript, JavaScript, Python, Rust, Go, Java
• 4 Transformation Modes: Structure, Signatures, Types, Full
• Fast: <50ms for 1000-line files
• Streaming: Outputs to stdout for pipe workflows
• Safe: Built-in DoS protections

Usage

Basic Usage

rskim <FILE>

Options

Options:
  -m, --mode <MODE>         Transformation mode [default: structure]
                            [possible values: structure, signatures, types, full]
  -l, --language <LANGUAGE> Override language detection
                            [possible values: type-script, java-script, python, rust, go, java]
  -h, --help                Print help
  -V, --version             Print version

Transformation Modes

Structure Mode (Default)

Removes function bodies while preserving signatures (70-80% reduction).

rskim file.ts

Input:

function add(a: number, b: number): number {
    const result = a + b;
    console.log(`Adding ${a} + ${b} = ${result}`);
    return result;
}

Output:

function add(a: number, b: number): number { /* ... */ }

Signatures Mode

Extracts only function and method signatures (85-92% reduction).

rskim file.py --mode signatures

Input:

def calculate_total(items: list[Item], tax_rate: float) -> Decimal:
    subtotal = sum(item.price for item in items)
    tax = subtotal * tax_rate
    return subtotal + tax

Output:

def calculate_total(items: list[Item], tax_rate: float) -> Decimal:

Types Mode

Extracts only type definitions (90-95% reduction).

rskim file.ts --mode types

Input:

interface User {
    id: number;
    name: string;
}

function getUser(id: number): User {
    return db.users.find(id);
}

Output:

interface User {
    id: number;
    name: string;
}

Full Mode

Returns original code unchanged (0% reduction).

rskim file.rs --mode full

Examples

Explore a codebase

# Get overview of all TypeScript files
find src -name '*.ts' -exec rskim {} \;

# Extract all Python function signatures
rskim app.py --mode signatures > api.txt

# Review Rust types
rskim lib.rs --mode types | less

Prepare code for LLMs

# Reduce token count before sending to GPT
rskim large_file.ts | wc -w
# Output: 150 (was 600)

# Get just the API surface
rskim server.py --mode signatures | pbcopy

Pipe workflows

# Skim and highlight
rskim file.rs | bat -l rust

# Skim and search
rskim file.ts | grep "interface"

# Skim multiple files
cat *.py | rskim - --language=python

Supported Languages

Performance

• Parse + Transform: <50ms for 1000-line files
• Token Reduction: 60-95% depending on mode
• Streaming: Zero intermediate files

Security

Built-in protections against:

• Stack overflow attacks (max depth: 500)
• Memory exhaustion (max input: 50MB)
• UTF-8 boundary violations
• Path traversal attacks

Library

For programmatic usage, see the rskim-core library crate.

Links

• Repository
• Library Documentation
• npm Package (coming soon)

License

MIT