Book-to-Skill Extractor Output Files: What Gets Generated and Where

The Book-to-Skill extractor produces exactly two output files—full_text.txt and metadata.json—inside a dedicated work directory for every extraction run.

Book-to-Skill is a Python tool that extracts structured text from books and documents to enable skill extraction pipelines. Understanding what output files the Book-to-Skill extractor produces helps you integrate it into larger workflows and locate your extracted data. According to the virgiliojr94/book-to-skill source code, the output generation is deterministic and well-defined.

Primary Output Files

The extractor writes two files to the output directory after processing all input sources:

full_text.txt

full_text.txt contains the consolidated plain-text content from every input document. Each source is clearly demarcated with a banner:

=== SOURCE: mybook.epub ===
[extracted text...]

=== SOURCE: another.pdf ===
[extracted text...]

This file is:

• Written in UTF-8 encoding
• Defined in book_to_skill/config.py as OUTPUT_TEXT = OUTPUT_DIR / "full_text.txt"
• Created at line 1088 of book_to_skill/utils.py

metadata.json

metadata.json captures structured metadata for the entire extraction batch, including:

• Per-source details: file size, format, extraction method, page counts, token estimates
• Document structure: chapter detection, table-of-contents presence
• Aggregate statistics across all processed sources

This JSON file is:

• Written with ensure_ascii=False and 2-space indentation
• Defined in book_to_skill/config.py as OUTPUT_META = OUTPUT_DIR / "metadata.json"
• Created at line 1089 of book_to_skill/utils.py

Where Output Files Are Located

The output directory follows a predictable hierarchy:

Location Type	Path Pattern
Default (temporary)	/tmp/book-to-skill-XXXXXX/
Custom (via environment variable)	$BOOK_SKILL_WORKDIR/

The exact path is stored within metadata.json itself, enabling downstream cleanup scripts to reference OUTPUT_DIR programmatically.

Code Implementation Details

From book_to_skill/utils.py, the final write operations occur in the main() function after all sources complete processing:

# Lines 1088-1089 in book_to_skill/utils.py

OUTPUT_TEXT.write_text(consolidated_text, encoding="utf-8")
OUTPUT_META.write_text(json.dumps(metadata, ensure_ascii=False, indent=2), encoding="utf-8")

Configuration constants reside in book_to_skill/config.py:

# Output path definitions

OUTPUT_DIR = Path(os.getenv("BOOK_SKILL_WORKDIR", tempfile.mkdtemp(prefix="book-to-skill-")))
OUTPUT_TEXT = OUTPUT_DIR / "full_text.txt"
OUTPUT_META = OUTPUT_DIR / "metadata.json"

CLI Usage Example

Running the extractor from command line produces visible output followed by the two files:

$ book-to-skill mybook.epub

# Console: extraction progress and summary

# Files created:

#   /tmp/book-to-skill-a1b2c3/full_text.txt

#   /tmp/book-to-skill-a1b2c3/metadata.json

Key Source Files for Output Generation

File	Responsibility
book_to_skill/config.py	Declares OUTPUT_DIR, OUTPUT_TEXT, and OUTPUT_META paths
book_to_skill/utils.py	Implements extraction pipeline and file writes at lines 1088-1089
scripts/extract.py	CLI entry point invoking book_to_skill.cli.main

Summary

• Two files only: full_text.txt and metadata.json constitute complete extractor output
• Configurable location: Use BOOK_SKILL_WORKDIR environment variable for persistent storage
• UTF-8 encoding: Both files guarantee proper unicode handling
• Self-documenting: Metadata includes the output directory path for cleanup automation
• Deterministic structure: Banner-separated sources in text file, nested JSON with per-source and aggregate statistics

Frequently Asked Questions

Can I change where the Book-to-Skill extractor saves its output files?

Yes. Set the BOOK_SKILL_WORKDIR environment variable to any valid path before running the extractor. Without this variable, the tool creates a temporary directory under your system temp folder with the prefix book-to-skill-.

Does the extractor create any other files besides full_text.txt and metadata.json?

No. According to the source code in book_to_skill/utils.py and book_to_skill/config.py, these are the only two output files generated. The extractor intentionally keeps its surface area minimal for reliable pipeline integration.

What happens to the output directory if I don't set BOOK_SKILL_WORKDIR?

The temporary directory persists after extraction completes because the code does not automatically remove it. However, the metadata.json file contains the OUTPUT_DIR path, so you can implement custom cleanup logic in downstream tools.

{
  "mcpServers": {
    "instagit": {
      "command": "npx",
      "args": ["-y", "instagit@latest"]
    }
  }
}