haiku.rag/docs/configuration/processing.md

# Document Processing & Monitoring

This guide covers how haiku.rag converts, chunks, and monitors documents.

## Document Processing

Configure how documents are converted and chunked:

```yaml
processing:
  # Chunking configuration
  chunk_size: 256                            # Maximum tokens per chunk

  # Converter selection
  converter: docling-local                   # docling-local or docling-serve

  # Chunker selection and configuration
  chunker: docling-local                     # docling-local or docling-serve
  chunker_type: hybrid                       # hybrid or hierarchical
  chunking_tokenizer: "Qwen/Qwen3-Embedding-0.6B"  # HuggingFace model for tokenization
  chunking_merge_peers: true                 # Merge undersized successive chunks
  chunking_use_markdown_tables: false        # Use markdown tables vs narrative format

  # Automatic title generation
  auto_title: false                          # Auto-generate titles on ingestion
  title_model:                               # LLM for title generation (fallback)
    provider: ollama
    name: gpt-oss
    enable_thinking: false

  # Picture handling (none / description / image)
  pictures: none                             # See "Picture Handling" below

  # Conversion options (works with both local and remote converters)
  conversion_options:
    # OCR settings
    do_ocr: true                             # Enable OCR for bitmap content
    force_ocr: false                         # Replace existing text with OCR
    ocr_engine: auto                         # OCR engine: auto, easyocr, rapidocr, tesseract, tesserocr, ocrmac
    ocr_lang: []                             # OCR languages (e.g., ["en", "fr", "de"])

    # Table extraction
    do_table_structure: true                 # Extract table structure
    table_mode: accurate                     # fast or accurate
    table_cell_matching: true                # Match table cells back to PDF cells

    # Image settings
    images_scale: 2.0                        # Image scale factor
    generate_page_images: true               # Include rendered page images (for visualize_chunk)

    # VLM picture description settings (only effective when pictures: description)
    picture_description:
      model:
        provider: ollama
        name: ministral-3
```

### Conversion Options

The `conversion_options` section allows fine-grained control over document conversion. These options work with both `docling-local` and `docling-serve` converters.

#### OCR Settings

```yaml
conversion_options:
  do_ocr: true          # Enable OCR for bitmap/scanned content
  force_ocr: false      # Replace all text with OCR output
  ocr_engine: auto      # OCR engine selection
  ocr_lang: []          # List of OCR languages, e.g., ["en", "fr", "de"]
```

- **do_ocr**: When `true`, applies OCR to images and scanned pages. Disable for faster processing if documents contain only native text.
- **force_ocr**: When `true`, replaces existing text layers with OCR output. Useful for documents with poor text extraction.
- **ocr_engine**: Select the OCR engine to use. Options:
  - `auto` (default): Automatically select the best available engine
  - `easyocr`: EasyOCR - supports many languages, good accuracy
  - `rapidocr`: RapidOCR - fast processing
  - `tesseract`: Tesseract OCR
  - `tesserocr`: Tesseract via tesserocr Python binding
  - `ocrmac`: macOS native OCR (macOS only)
- **ocr_lang**: List of language codes for OCR. Empty list uses default language detection. Examples: `["en"]`, `["en", "fr", "de"]`.

#### Table Extraction

```yaml
conversion_options:
  do_table_structure: true    # Extract structured table data
  table_mode: accurate        # fast or accurate
  table_cell_matching: true   # Match cells back to PDF
```

- **do_table_structure**: When `true`, extracts table structure. Disable for faster processing if tables aren't important.
- **table_mode**:
  - `accurate`: Better table structure recognition (slower)
  - `fast`: Faster processing with simpler table detection
- **table_cell_matching**: When `true`, matches detected table cells back to PDF cells. Disable if tables have merged cells across columns.

#### Image Settings

```yaml
conversion_options:
  images_scale: 2.0               # Image resolution scale factor
  generate_page_images: true      # Include rendered page images
```

- **images_scale**: Scale factor for extracted images. Higher values = better quality but larger size. Typical range: 1.0-3.0.
- **generate_page_images**: When `true` (default), rendered images of each PDF page are included in the document. Required for `visualize_chunk()` to show visual grounding. When `false`, page images are excluded to reduce document size.

Embedded picture extraction is controlled by `processing.pictures` (see [Picture Handling](#picture-handling) below), not by an image-settings flag.

#### Picture Handling

`processing.pictures` is a single enum that decides how embedded picture images (figures, diagrams) are handled at ingest. Three modes:

| Mode | VLM at ingest | `picture_data` populated | Chunk text contains description |
|---|---|---|---|
| `none` (default) | no | no | no |
| `description` | yes | yes | yes |
| `image` | no | yes | no |

- **`none`**: docling skips picture-image generation. `label="picture"` rows still appear in the items table for structural metadata, but they carry no bytes and no description. Cheapest mode; non-vision QA is unaffected.
- **`description`**: docling generates picture images, the configured VLM produces a description woven into chunk text, and the bytes are also retained in `document_items.picture_data`. Picture-text is searchable via FTS, vision-capable QA models also receive the bytes via the agent's search tool. Bytes are kept (not just thrown away after the VLM runs) so a vision-only QA strategy can be turned on later without reingesting.
- **`image`**: docling generates picture images and stores them in `document_items.picture_data` without running the VLM. Vision-capable QA models reason directly about the figures; non-vision QA only sees the picture's caption/surrounding text.

```yaml
processing:
  pictures: description          # none / description / image
  conversion_options:
    picture_description:         # only effective when pictures: description
      model:
        provider: ollama         # ollama, openai, or custom
        name: ministral-3        # VLM model name
        temperature: 0.0
      timeout: 90                # Request timeout in seconds
      max_tokens: 200            # Maximum tokens in response
```

**Switching modes on an existing database.** No reingest is required if you only need to change between `description` and `image` — the bytes are already there. Run `haiku-rag rebuild --rechunk` after the config change so the chunk-text composition reflects the new mode. Switching *down* to `none` clears `picture_data` on rebuild, reclaiming storage.

#### Pictures × embedder × QA model: how the pieces compose

Three orthogonal settings drive what gets stored, what gets retrieved, and what reaches the QA model. Each setting answers one question:

| Setting | Question it answers | Values |
|---|---|---|
| `processing.pictures` | What gets captured at ingest? | `none` / `description` / `image` |
| `embeddings.model.provider` | Can the embedder index image content? | text-only providers (`ollama`, `openai`, `cohere`, `sentence-transformers`) vs `vllm` (multimodal) |
| `qa.model.vision` | Can the QA model interpret images? | `false` (default) / `true` |

**What gets stored** for each `pictures` × embedder combination:

| `pictures` | Embedder | Text chunks contain… | `document_items.picture_data` | Synthetic picture chunks |
|---|---|---|---|---|
| `none` | text-only or multimodal | regular text only | empty | none |
| `description` | text-only | text + VLM descriptions | populated (kept for later use) | none |
| `description` | multimodal | text + VLM descriptions | populated | one per picture, content = description, vector = image embedding |
| `image` | text-only | text only (caption/surrounding) | populated (kept for later use) | none |
| `image` | multimodal | text only | populated | one per picture, content = caption/empty, vector = image embedding |

**What QA receives** at search time, given stored state and `qa.model.vision`:

| `pictures` at ingest | `qa.model.vision` | QA receives |
|---|---|---|
| `none` | either | text chunks only |
| `description` | `false` | text chunks (descriptions in chunk text answer figure questions in prose) |
| `description` | `true` | text chunks + raw picture bytes; vision model uses both signals |
| `image` | `false` | text chunks only (caption + surrounding text); model has no figure content to draw on |
| `image` | `true` | text chunks + raw picture bytes; vision model reads the figures directly |

A few invariants worth knowing:

- **`qa.model.vision` is independent of ingestion.** It only controls whether the agent's `search` tool attaches picture bytes to its `ToolReturn`. A text-only QA model with `vision: true` won't suddenly understand images — it will silently accept the bytes and confabulate. Default `false` is the safe choice.
- **`description` mode preserves the bytes**, so flipping the QA strategy later (text-only → vision, or vice versa) doesn't require reingesting. Just change `qa.model.vision` and optionally `qa.model` itself.
- **Cross-modal search** (text query → picture-chunk hits) requires a multimodal embedder. With a text-only embedder, picture-chunk vectors aren't generated; figures only surface via section-bounded expansion off matching text chunks.
- **`image` mode + text-only embedder** is rarely the right choice — pictures are stored but neither searchable as image vectors nor described in text. Picture bytes are then only reachable via expand-context's section bounds when an adjacent text chunk matches.

**Recommended combinations** by use case:

| Use case | `pictures` | Embedder | `qa.model.vision` |
|---|---|---|---|
| Pure text RAG, no figures | `none` | text-only | `false` |
| Text RAG, figures answered through descriptions | `description` | text-only | `false` |
| Vision QA on figure-rich docs (no cross-modal search) | `description` | text-only | `true` |
| Cross-modal search + vision QA (the full multimodal stack) | `description` or `image` | multimodal | `true` |
| Cross-modal search, text QA only | `description` | multimodal | `false` |

**`picture_description.model` configuration** (used only under `pictures: description`):

- **model**: Standard model configuration
  - `provider`: `ollama` (default), `openai`, or use `base_url` for custom endpoints
  - `name`: Model name (e.g., `ministral-3`, `granite3.2-vision`, `gpt-4-vision`)
  - `base_url`: Optional custom API endpoint for vLLM, LM Studio, etc.
- **timeout**: Request timeout in seconds
- **max_tokens**: Maximum tokens in the VLM response

**Note:** Requires an OpenAI-compatible `/v1/chat/completions` endpoint. Providers with different API formats (e.g., Anthropic Claude) are not supported.

**Default prompt** (configured in `prompts.picture_description`):

```
Describe this image for a blind user. State the image type
(screenshot, chart, photo, etc.), what it depicts, any visible text,
and key visual details. Be concise and accurate.
```

To customize the prompt globally:

```yaml
prompts:
  picture_description: "Your custom prompt here..."
```

**Using with Ollama:**

```yaml
processing:
  pictures: description
  conversion_options:
    picture_description:
      model:
        provider: ollama
        name: ministral-3
```

Requires Ollama running with a vision-capable model:

```bash
ollama pull ministral-3
ollama serve
```

**Using with vLLM or custom endpoints:**

```yaml
processing:
  pictures: description
  conversion_options:
    picture_description:
      model:
        provider: openai           # Use OpenAI-compatible API format
        name: granite-vision
        base_url: http://my-vllm-server:8000
```

**How it works:**

1. During PDF conversion, docling extracts embedded images
2. Each image is sent to the configured VLM for description
3. Descriptions are added as annotations on the image
4. When exported to markdown, descriptions appear as searchable text

**Using with docling-serve:**

When using `converter: docling-serve`, the VLM calls are made by the docling-serve instance, not by haiku.rag. You must:

1. Set `DOCLING_SERVE_ENABLE_REMOTE_SERVICES=true` when running docling-serve
2. Ensure the VLM endpoint is accessible from where docling-serve is running

**Docker networking:** If docling-serve runs in Docker and your VLM runs on the host, use `host.docker.internal` instead of `localhost`:

```yaml
processing:
  pictures: description
  conversion_options:
    picture_description:
      model:
        provider: ollama
        name: ministral-3
        base_url: http://host.docker.internal:11434  # NOT localhost!
```

See [VLM Picture Description with docling-serve](../remote-processing.md#vlm-picture-description-with-docling-serve) for a complete example.

### Automatic Title Generation

Enable automatic title generation during document ingestion:

```yaml
processing:
  auto_title: true
  title_model:
    provider: ollama
    name: gpt-oss
    enable_thinking: false
```

When `auto_title` is enabled, haiku.rag attempts to extract a title for each document during ingestion using a two-tier approach:

1. **Structural extraction** (free, no model calls): Scans the DoclingDocument for semantic labels — HTML `<title>` tags, `<h1>` headings, PDF title blocks, and section headers
2. **LLM fallback**: When no structural title is found (e.g., plain text), generates a title using the configured `title_model`

Priority order: HTML `<title>` (furniture layer) → h1/PDF title (body layer) → first section header → LLM generation.

Explicit titles passed via `title=` parameter always take precedence and are never overridden. When updating documents, existing titles are preserved — auto-generation only applies to untitled documents.

To generate titles for existing untitled documents, use [`rebuild --title-only`](../cli.md#rebuild-database).

### Local vs Remote Processing

**Local processing** (default):

- Uses `docling` library locally
- No external dependencies
- Good for development and small workloads

**Remote processing** (docling-serve):

- Offloads processing to docling-serve API
- Better for heavy workloads and production
- Requires docling-serve instance (see [Remote processing setup](../remote-processing.md))

To use remote processing:

```yaml
processing:
  converter: docling-serve
  chunker: docling-serve

providers:
  docling_serve:
    base_url: http://localhost:5001
    api_key: "your-api-key"  # Optional
```

Conversion options work identically for both local and remote processing.

**Note:** When using `chunker: docling-serve`, OCR options (`do_ocr`, `force_ocr`, `ocr_engine`, `ocr_lang`) from `conversion_options` are passed to the chunking API. This is useful when running docling-serve in a read-only container where OCR model downloads fail—set `do_ocr: false` to disable OCR entirely.

### Chunking Strategies

**Hybrid chunking** (default):
- Structure-aware chunking
- Respects document boundaries
- Best for most use cases

**Hierarchical chunking**:
- Creates hierarchical chunk structure
- Preserves document hierarchy
- Useful for complex documents

### Table Serialization

Control how tables are represented in chunks:

```yaml
processing:
  chunking_use_markdown_tables: false  # Default: narrative format
```

- `false`: Tables as narrative text ("Value A, Column 2 = Value B")
- `true`: Tables as markdown (preserves table structure)

### Chunk Size

```yaml
processing:
  chunk_size: 256  # Maximum tokens per chunk
```

Context expansion settings (for enriching search results with surrounding content) are configured in the `search` section. See [Search Settings](qa-research.md#search-settings).

## File Monitoring

Set directories to monitor for automatic indexing:

```yaml
monitor:
  directories:
    - /path/to/documents
    - /another_path/to/documents
```

### Filtering Monitored Files

Use gitignore-style patterns to control which files are monitored:

```yaml
monitor:
  directories:
    - /path/to/documents

  # Exclude specific files or directories
  ignore_patterns:
    - "*draft*"         # Ignore files with "draft" in the name
    - "temp/"           # Ignore temp directory
    - "**/archive/**"   # Ignore all archive directories
    - "*.backup"        # Ignore backup files

  # Only include specific files (whitelist mode)
  include_patterns:
    - "*.md"            # Only markdown files
    - "*.pdf"           # Only PDF files
    - "**/docs/**"      # Only files in docs directories
```

**How patterns work:**

1. **Extension filtering** - Only supported file types are considered
2. **Include patterns** - If specified, only matching files are included (whitelist)
3. **Ignore patterns** - Matching files are excluded (blacklist)
4. **Combining both** - Include patterns are applied first, then ignore patterns

**Common patterns:**

```yaml
# Only monitor markdown documentation, but ignore drafts
monitor:
  include_patterns:
    - "*.md"
  ignore_patterns:
    - "*draft*"
    - "*WIP*"

# Monitor all supported files except in specific directories
monitor:
  ignore_patterns:
    - "node_modules/"
    - ".git/"
    - "**/test/**"
    - "**/temp/**"
```

Patterns follow [gitignore syntax](https://git-scm.com/docs/gitignore#_pattern_format):

- `*` matches anything except `/`
- `**` matches zero or more directories
- `?` matches any single character
- `[abc]` matches any character in the set