oma-pdf

# PDF Skill - PDF to Markdown Conversion

## Scheduling

### Goal
Convert PDF files into structured Markdown or another requested extraction format while preserving readable document structure for LLM context, RAG, or downstream review.

### Intent signature
- User asks to convert, parse, read, extract, or transform a PDF.
- User needs PDF text, headings, lists, tables, or images prepared for AI consumption.
- User mentions "PDF to markdown", "parse PDF", "read this PDF", or equivalent wording.

### When to use
- Converting PDF documents to Markdown for LLM context or RAG
- Extracting structured content such as tables, headings, lists, images, footnotes, or hyperlinks
- Preparing PDF data for AI consumption
- Checking whether a PDF has a text layer before choosing OCR

### When NOT to use
- Generating or creating PDFs -> use document-generation tools
- Editing existing PDFs -> out of scope
- Reading an already-text file -> use direct file reading
- Processing HWP, HWPX, DOCX, XLSX, or slide decks -> use the matching document skill

### Expected inputs
- `input_path`: PDF file or folder path
- `output_dir`: optional target directory
- `format`: optional output format, default `markdown`
- `ocr_languages`: optional OCR language list for scanned or image-based PDFs
- `extraction_options`: optional flags for tagged structure, image extraction, or hybrid conversion

### Expected outputs
- Markdown, text, JSON, HTML, or combined extraction output
- Normalized Markdown when Markdown is produced
- A short report with output path, page count, and conversion issues

### Dependencies
- `uvx opendataloader-pdf` for standard conversion
- `uvx opendataloader-pdf-hybrid` for OCR or hybrid conversion
- `uvx mdformat` for Markdown normalization
- Local filesystem access to input and output paths
- Optional OCR runtime via the hybrid server

### Control-flow features
- Branches on text-layer quality, tagged PDF availability, scan/OCR needs, and user-requested output format
- Calls external CLI tools through `uvx`
- Reads local files and writes local extraction outputs
- Uses a hybrid server only when OCR or complex extraction needs justify it

## Structural Flow

### Entry
1. Confirm that the input path exists and is a PDF file, PDF folder, or supported batch input.
2. Check file size and warn when the input is large enough to risk slow conversion or memory pressure.
3. Resolve `output_dir` and the expected output filename.

### Scenes
1. **PREPARE**: Validate the input path, output target, and requested extraction options.
2. **ACQUIRE**: Assess whether the PDF has a readable text layer by extracting a text preview.
3. **ACT**: Convert using standard mode, tagged-structure mode, or hybrid OCR mode.
4. **VERIFY**: Run `mdformat` for Markdown output and inspect the result for readable structure.
5. **FINALIZE**: Report output path, page count, format, and any extraction quality issues.

### Transitions
- If the preview text is readable, use standard conversion.
- If the PDF is tagged and standard output is garbled, retry with `--use-struct-tree`.
- If the PDF is scanned or image-based, start or reuse the hybrid OCR server and convert with hybrid mode.
- If conversion fails because the PDF is encrypted, stop and ask for the password or an unlocked copy.
- If conversion hits memory or size limits, process smaller page ranges or batches.

### Failure and recovery
| Failure | Recovery |
|---------|----------|
| `uvx` unavailable | Ask user to install `uv` before conversion |
| Password-protected PDF | Ask for password or unlocked PDF |
| Garbled output | Retry with tagged structure or hybrid mode |
| Missing tables | Retry with hybrid mode for complex or borderless tables |
| OCR language mismatch | Retry with explicit OCR languages, for example `ko,en` |
| Large file or memory pressure | Split into page ranges or batch smaller inputs |

### Exit
- Success: output file exists, Markdown is formatted when applicable, and extracted structure is readable.
- Partial success: output exists but quality issues are reported explicitly.
- Failure: no reliable output is produced and the blocking cause is reported.

## Logical Operations

### Actions
| Action | SSL primitive | Evidence |
|--------|---------------|----------|
| Validate path and options | `VALIDATE` | Input preflight in execution protocol |
| Probe text layer | `READ` | Text preview extraction |
| Choose conversion strategy | `SELECT` | Standard, tagged, or hybrid mode decision |
| Run converter | `CALL_TOOL` | `uvx opendataloader-pdf` |
| Start OCR server | `CALL_TOOL` | `uvx opendataloader-pdf-hybrid` |
| Write output artifact | `WRITE` | Markdown, text, JSON, or HTML output |
| Normalize Markdown | `CALL_TOOL` | `uvx mdformat` |
| Inspect extraction quality | `VALIDATE` | Structure/readability verification |
| Report result | `NOTIFY` | Final user-facing summary |

### Tools and instruments
- `opendataloader-pdf`: primary PDF extraction CLI
- `opendataloader-pdf-hybrid`: hybrid OCR and complex extraction path
- `mdformat`: Markdown normalization
- Filesystem commands such as `file`, `wc`, or `pdfinfo` may be used for preflight when available

### Canonical command path
```bash
uvx opendataloader-pdf "{input_path}" --format markdown --output-dir "{output_dir}"
uvx mdformat "{output_path}"
```

For scanned/image-based PDFs, start OCR first and then convert through hybrid mode:
```bash
uvx opendataloader-pdf-hybrid --port 5002 --force-ocr --ocr-lang "{languages}"
uvx opendataloader-pdf --hybrid docling-fast "{input_path}" --format markdown --output-dir "{output_dir}"
```

### Resource scope
| Scope | Resource target |
|-------|-----------------|
| `LOCAL_FS` | Input PDFs and generated output files |
| `PROCESS` | `uvx` subprocesses and optional hybrid server |
| `MEMORY` | Extracted previews and validation notes |
| `OTHER` | OCR model/runtime behavior inside hybrid mode |

### Preconditions
- The input PDF path exists and is readable.
- The output locati