cchistory

Extract and compare system prompts and tools from different Claude Code versions.

Prerequisites

• You must be logged in to Claude Code (authentication required for all modes)
• Claude Code installation is optional if using --binary-path with a custom binary
• Note: Each version tested will send a single haiku request to Claude, which may incur costs if you're on a pay-per-token plan instead of Claude Max

Installation

npm install -g @mariozechner/cchistory

Usage

cchistory [version] [--latest] [--binary-path <path>] [--claude-args "<args>"]

Options

• version - NPM version of Claude Code to extract (e.g., 1.0.0)
• --latest - Extract all versions from the specified version to the latest published version
• --binary-path <path> - Use a custom/local Claude Code binary instead of downloading from npm
• --claude-args "<args>" - Pass additional arguments to Claude Code during execution
• --version, -v - Show cchistory version
• --help, -h - Show help message

Examples

# Extract prompts from a single version
cchistory 1.0.0

# Extract prompts from version 1.0.0 to latest
cchistory 1.0.0 --latest

# Test a custom/local build of Claude Code
cchistory --binary-path /path/to/custom/cli.js

# Test with additional Claude Code arguments
cchistory 1.0.0 --claude-args "--mcp-config /path/to/config.json"

# Combine custom binary with custom arguments
cchistory --binary-path ./build/cli.js --claude-args "--verbose"

# Pass system prompt modifiers to any version
cchistory 1.5.0 --claude-args "--append-system-prompt"

How it works

Standard Mode (NPM versions)

1. Downloads the specified Claude Code version from npm
2. Patches the version check to prevent auto-updates
3. Runs the patched version with claude-trace to intercept API requests
4. Sends a single test haiku request to trigger an API call
5. Extracts the system prompt, user message format, and available tools from the intercepted request
6. Saves the results to prompts-{version}.md

Custom Binary Mode (--binary-path)

1. Uses the specified binary directly (skips download and patching)
2. Runs it with claude-trace to intercept API requests
3. Sends a single test haiku request to trigger an API call
4. Extracts the system prompt, user message format, and available tools from the intercepted request
5. Saves the results to prompts-custom-{timestamp}.md

Existing prompt files are automatically skipped to avoid redundant downloads and API calls.

Output Format

Each prompts-{version}.md file contains:

• User Message: The format of user messages sent to Claude
• System Prompt: The system instructions Claude receives
• Tools: Available tools with their descriptions and input schemas (excluding MCP tools)

Advanced Usage

Testing Local/Development Builds

The --binary-path flag is particularly useful for:

• Testing local modifications to Claude Code before publishing
• Comparing development builds against released versions
• Debugging prompt or tool changes in your fork

# Test your local development build
cchistory --binary-path /path/to/your/fork/cli.js

# Compare with a released version
cchistory 1.0.0
# Now you have both prompts-1.0.0.md and prompts-custom-*.md to compare

Passing Arguments to Claude Code

The --claude-args flag allows you to test Claude Code with different configurations:

# Test with MCP server configuration
cchistory 1.5.0 --claude-args "--mcp-config ~/.config/claude/mcp.json"

# Test with verbose logging
cchistory --binary-path ./build/cli.js --claude-args "--verbose"

# Combine multiple flags
cchistory 1.0.0 --claude-args "--debug --no-cache"

Note: Arguments are parsed safely using shell-quote to prevent command injection. Shell operators and control characters are filtered out.

Debugging

Enable debug output to see detailed information about the extraction process:

DEBUG=1 cchistory 1.0.0

This will show:

• All API requests found in the claude-trace log
• Model names and tool counts for each request
• Full stack traces for any errors

Security Notes

• All shell commands use proper escaping via the shell-quote library
• The --claude-args parameter filters out shell operators for safety
• Version patching only modifies the version check function (no other code changes)
• Custom binaries are executed directly without modification