# documents - Functional Specification

**Version**: v1.1.9 | **Status**: Active | **Last Updated**: March 2026

## Purpose

Provides robust, abstractable methods for reading and writing various document formats. The Documents module handles the mechanics of document I/O operations, distinct from the `documentation` module which focuses on the semantics of technical documentation.

## Design Principles

- **Format Abstraction**: Unified interface for all document formats
- **Encoding Safety**: Automatic encoding detection and handling
- **Metadata Preservation**: Maintain and update document metadata during operations
- **Zero-Mock Testing**: Mandatory real-world functional verification
- **Extensible Design**: Easy addition of new formats and operations

## Functional Requirements

1. **Document Reading**: Read documents from files with format and encoding detection
2. **Document Writing**: Write documents to files with format validation
3. **Format Conversion**: Convert documents between supported formats (e.g., Markdown to HTML, JSON to YAML)
4. **Document Merging**: Merge multiple documents of the same or different formats
5. **Document Splitting**: Split documents into chunks based on sections, size, lines, or rows
6. **Metadata Operations**: Comprehensive extraction and update of document metadata
7. **Document Validation**: Validate documents against schemas and format rules
8. **Search and Indexing**: In-memory indexing and scored search operations

## Interface Contracts

### Core Classes & Functions

- `read_document` / `DocumentReader`: Unified reading interface
- `write_document` / `DocumentWriter`: Unified writing interface
- `Document`: Central model with `DocumentMetadata`
- `convert_document`: Format transformation
- `merge_documents`: Multi-document merging
- `split_document`: Document chunking

### Metadata

- `DocumentMetadata`: Dedicated container for standard and custom metadata
- `extract_metadata`: Unified metadata extraction utility

### Search

- `InMemoryIndex`: Inverted index for fast searching
- `search_documents`: Scored search against an index

## Supported Formats

- **Markdown**: Full read/write/convert support
- **JSON**: Structured data support with schema validation
- **YAML**: Structured data support
- **HTML**: Read/write/convert and tag stripping
- **XML**: Basic read/write with validation
- **CSV**: List-of-dicts structured support
- **PDF**: Text extraction and basic generation
- **Plain Text**: Basic fallback support

## Error Handling

All operations raise module-specific exceptions derived from `DocumentsError`:

- `DocumentReadError`, `DocumentWriteError`, `DocumentParseError`, `DocumentValidationError`, `DocumentConversionError`, `UnsupportedFormatError`, `EncodingError`, `MetadataError`

## Configuration

Module configuration via `DocumentsConfig`:

- `default_encoding`, `max_file_size`, `strict_validation`, `cache_directory`

## Testing

```bash
uv run python -m pytest src/codomyrmex/tests/unit/documents/ -v
```

## Navigation

- **Self**: `SPEC.md`
- **Parent**: [../README.md](../README.md)
- **Readme**: [README.md](README.md)
- **Agents**: [AGENTS.md](AGENTS.md)
- **Repository Root**: [README.md](../../../README.md)
