Dewey classification

Dewey Classification

Assign Dewey codes and determine shelf location in BOOKS_DIR/.

Assignment Process

1. Identify primary subject matter
2. ALWAYS read data/codes.md to find the correct code and category name
3. Check existing BOOKS_DIR/ directory structure
4. Apply leafing rules to determine final path

CRITICAL: Directory Naming

NEVER invent or guess category names. Before creating any directory:

1. Read data/codes.md
2. Find the exact line matching the code (e.g., - 130 Parapsychology and occultism)
3. Use the EXACT name from that file: 130 - Parapsychology and occultism

Format: XXX - [exact name from codes.md]

Examples from data/codes.md:

• - 110 Metaphysics → directory: 110 - Metaphysics
• - 130 Parapsychology and occultism → directory: 130 - Parapsychology and occultism
• - 160 Philosophical logic → directory: 160 - Philosophical logic

If you cannot find a code in data/codes.md, ask the user.

Leafing Rules

Directories stay flat until thresholds trigger subdivision. Do not create empty directories.

Hierarchy: centennials (X00) → decades (XY0) → integrals (XYZ)

Rule: When to Create Subdirectory

Create XY0 subdirectory under X00 ONLY when BOTH conditions met:

1. X00 contains 6+ books total
2. 3+ books share the same Y value (would belong in XY0)

Same rule applies recursively: create XYZ under XY0 when XY0 has 6+ books and 3+ share same Z.

Rule: Do NOT Create Preemptively

• Never create empty directories
• Never create a subdivision with fewer than 3 books
• Keep books at the parent level until the threshold is reached
• Example: If you have 2 ethics books in 100/, leave them in 100/. Do not create 170/ until you have 3+ ethics books AND 6+ total in 100/.

The goal is minimal bureaucratic structure. Only subdivide when the volume justifies separating material from the pack.

Example

500 - Natural Sciences and Mathematics/
  (5 physics books, 2 math books, 1 astronomy book)

Total: 8 books. Physics has 5 (3+ threshold met). Create 530 subdirectory:

500 - Natural Sciences and Mathematics/
  530 - Physics/
    (5 physics books)
  (2 math books, 1 astronomy book remain in 500)

When math reaches 3+ books, create 510 subdirectory.

Current Structure

Check BOOKS_DIR/ before placing. Always verify directory names against data/codes.md.

Subdirectories are created dynamically based on leafing rules. Do not assume a fixed structure - scan the actual directory and cross-reference with data/codes.md.

Category Guidelines

Always look up the exact code and name in data/codes.md. Common top-level categories:

• 000 - Computer science, information, general works
• 100 - Philosophy & psychology (includes 150 Psychology)
• 300 - Social sciences (economics, politics, law)
• 500 - Natural sciences and mathematics
• 600 - Technology (includes 640 Home economics)
• 700 - Arts
• 800 - Literature (810 N. American, 820 English, 890 other languages)
• 900 - History & geography (includes 920 Biography)

Classification Examples

When classifying, find the most specific applicable code:

• Philosophy of mind → look up 12X codes in data/codes.md
• Ethics → 170 Ethics (Moral philosophy)
• Psychology → 150 Psychology
• Cooking → 641 Food & drink (check data/codes.md for exact name)

Always verify against data/codes.md before creating directories.

Code Reference

The authoritative source is data/codes.md. Read it before every classification decision.

When to Ask User

• Book spans multiple primary subjects equally
• Subject is specialized and code unclear
• Purpose ambiguous (philosophy about X vs history of X)
• New directory creation uncertain