feat: tool for thumbnails (#67)

* add tool for thumnails

Signed-off-by: Michele Dolfi <dol@zurich.ibm.com>

* Update docling_mcp/tools/generation.py

Signed-off-by: Michele Dolfi <97102151+dolfim-ibm@users.noreply.github.com>

* restyle

Signed-off-by: Michele Dolfi <dol@zurich.ibm.com>

* remove fastmcp

Signed-off-by: Michele Dolfi <dol@zurich.ibm.com>

---------

Signed-off-by: Michele Dolfi <dol@zurich.ibm.com>
Signed-off-by: Michele Dolfi <97102151+dolfim-ibm@users.noreply.github.com>

docling_mcp/settings/conversion.py

@@ -0,0 +1,17 @@
+"""This module contains the settings for conversion tools."""
+
+from pydantic_settings import BaseSettings, SettingsConfigDict
+
+
+class Settings(BaseSettings):
+    """Settings for the conversion tools."""
+
+    model_config = SettingsConfigDict(
+        env_prefix="DOCLING_MCP_",
+        env_file=".env",
+        # extra="allow",
+    )
+    keep_images: bool = False
+
+
+settings = Settings()

docling_mcp/tools/conversion.py

@@ -25,6 +25,7 @@ from docling_core.types.doc.labels import (
 
 from docling_mcp.docling_cache import get_cache_key
 from docling_mcp.logger import setup_logger
+from docling_mcp.settings.conversion import settings
 from docling_mcp.shared import local_document_cache, local_stack_cache, mcp
 
 # Create a default project logger
@@ -84,6 +85,7 @@ class ConvertDocumentOutput:
 def _get_converter() -> DocumentConverter:
     pipeline_options = PdfPipelineOptions()
     # pipeline_options.do_ocr = False  # Skip OCR for faster processing (enable for scanned docs)
+    pipeline_options.generate_page_images = settings.keep_images
 
     format_options: dict[InputFormat, FormatOption] = {
         InputFormat.PDF: PdfFormatOption(pipeline_options=pipeline_options),

docling_mcp/tools/generation.py

@@ -5,6 +5,7 @@ from dataclasses import dataclass
 from io import BytesIO
 from typing import Annotated
 
+from mcp.server.fastmcp import Image as MCPImage
 from pydantic import Field
 
 from docling.datamodel.base_models import ConversionStatus, InputFormat
@@ -158,6 +159,54 @@ def save_docling_document(
     return SaveDocumentOutput(md_file, json_file)
 
 
+@mcp.tool(title="Generate the thumbnail of a page in the Docling document")
+def page_thumbnail(
+    document_key: Annotated[
+        str,
+        Field(description="The unique identifier of the document in the local cache."),
+    ],
+    page_no: Annotated[
+        int, Field(description="The number of the page starting at 1")
+    ] = 1,
+    size: Annotated[
+        int, Field(description="The width of the thumbnail in pixels")
+    ] = 300,
+) -> MCPImage:
+    """Generate a thumbnail image for the requested page.
+
+    This tool takes a document that exists in the local cache and generates a thumnail image for the requested page.
+    """
+    if document_key not in local_document_cache:
+        doc_keys = ", ".join(local_document_cache.keys())
+        raise ValueError(
+            f"document-key: {document_key} is not found. Existing document-keys are: {doc_keys}"
+        )
+
+    doc = local_document_cache[document_key]
+    if page_no not in doc.pages:
+        raise ValueError(
+            f"page_no={page_no}: not found in the document. Available pages are: {', '.join(str(k) for k in doc.pages.keys())}"
+        )
+
+    im_ref = doc.pages[page_no].image
+    if im_ref is None:
+        raise ValueError(
+            "The DoclingDocument does not have page images. Please configure your server for generating page images using DOCLING_MCP_KEEP_IMAGES=true."
+        )
+    im = im_ref.pil_image
+    if im is None:
+        raise RuntimeError("Server error. The image cannot be loaded in PIL.")
+    width = size
+    scale = float(width) / im.size[0]
+    im.thumbnail((width, int(im.size[1] * scale)))
+
+    cache_dir = get_cache_dir()
+    im_file = cache_dir / f"{document_key}-{page_no}.png"
+    im.save(im_file, format="PNG")
+
+    return MCPImage(path=im_file, format="png")
+
+
 @dataclass
 class UpdateDocumentOutput:
     """Output of the Docling document content generation tools."""

tests/test_mcp_server.py

@@ -21,6 +21,7 @@ async def test_list_tools(mcp_client: AsyncGenerator[Any, Any]) -> None:
         "create_new_docling_document",
         "export_docling_document_to_markdown",
         "save_docling_document",
+        "page_thumbnail",
         "add_title_to_docling_document",
         "add_section_heading_to_docling_document",
         "add_paragraph_to_docling_document",