feat(vlm): Dynamic prompts (#1808)

* Unify temperature options for Vlm models

* Dynamic prompt support with example

* DCO Remediation Commit for Shkarupa Alex <shkarupa.alex@gmail.com>

I, Shkarupa Alex <shkarupa.alex@gmail.com>, hereby add my Signed-off-by to this commit: 34d446cb98
I, Shkarupa Alex <shkarupa.alex@gmail.com>, hereby add my Signed-off-by to this commit: 9c595d574f

Signed-off-by: Shkarupa Alex <shkarupa.alex@gmail.com>

* Replace Page with SegmentedPage

* Fix example HF repo link 

Signed-off-by: Christoph Auer <60343111+cau-git@users.noreply.github.com>

* Sign-off

Signed-off-by: Shkarupa Alex <shkarupa.alex@gmail.com>

* DCO Remediation Commit for Shkarupa Alex <shkarupa.alex@gmail.com>

I, Shkarupa Alex <shkarupa.alex@gmail.com>, hereby add my Signed-off-by to this commit: 1a162066dd

Signed-off-by: Shkarupa Alex <shkarupa.alex@gmail.com>

Signed-off-by: Shkarupa Alex <shkarupa.alex@gmail.com>

* Use lmstudio-community model

Signed-off-by: Christoph Auer <60343111+cau-git@users.noreply.github.com>

* Swap inference engine to LM Studio

Signed-off-by: Shkarupa Alex <shkarupa.alex@gmail.com>

---------

Signed-off-by: Shkarupa Alex <shkarupa.alex@gmail.com>
Signed-off-by: Christoph Auer <60343111+cau-git@users.noreply.github.com>
Co-authored-by: Christoph Auer <60343111+cau-git@users.noreply.github.com>

docling/datamodel/pipeline_options_vlm_model.py

@@ -1,6 +1,7 @@
 from enum import Enum
-from typing import Any, Dict, List, Literal, Optional, Union
+from typing import Any, Callable, Dict, List, Literal, Optional, Union
 
+from docling_core.types.doc.page import SegmentedPage
 from pydantic import AnyUrl, BaseModel
 from typing_extensions import deprecated
 
@@ -9,9 +10,10 @@ from docling.datamodel.accelerator_options import AcceleratorDevice
 
 class BaseVlmOptions(BaseModel):
     kind: str
-    prompt: str
+    prompt: Union[str, Callable[[Optional[SegmentedPage]], str]]
     scale: float = 2.0
     max_size: Optional[int] = None
+    temperature: float = 0.0
 
 
 class ResponseFormat(str, Enum):
@@ -51,7 +53,6 @@ class InlineVlmOptions(BaseVlmOptions):
         AcceleratorDevice.MPS,
     ]
 
-    temperature: float = 0.0
     stop_strings: List[str] = []
     extra_generation_config: Dict[str, Any] = {}
 

docling/models/api_vlm_model.py

@@ -29,12 +29,9 @@ class ApiVlmModel(BasePageModel):
 
             self.timeout = self.vlm_options.timeout
             self.concurrency = self.vlm_options.concurrency
-            self.prompt_content = (
-                f"This is a page from a document.\n{self.vlm_options.prompt}"
-            )
             self.params = {
                 **self.vlm_options.params,
-                "temperature": 0,
+                "temperature": self.vlm_options.temperature,
             }
 
     def __call__(
@@ -56,9 +53,14 @@ class ApiVlmModel(BasePageModel):
                         if hi_res_image.mode != "RGB":
                             hi_res_image = hi_res_image.convert("RGB")
 
+                    if callable(self.vlm_options.prompt):
+                        prompt = self.vlm_options.prompt(page.parsed_page)
+                    else:
+                        prompt = self.vlm_options.prompt
+
                     page_tags = api_image_request(
                         image=hi_res_image,
-                        prompt=self.prompt_content,
+                        prompt=prompt,
                         url=self.vlm_options.url,
                         timeout=self.timeout,
                         headers=self.vlm_options.headers,

docling/models/vlm_models_inline/hf_transformers_model.py

@@ -128,7 +128,11 @@ class HuggingFaceTransformersVlmModel(BasePageModel, HuggingFaceModelDownloadMix
                     )
 
                     # Define prompt structure
-                    prompt = self.formulate_prompt()
+                    if callable(self.vlm_options.prompt):
+                        user_prompt = self.vlm_options.prompt(page.parsed_page)
+                    else:
+                        user_prompt = self.vlm_options.prompt
+                    prompt = self.formulate_prompt(user_prompt)
 
                     inputs = self.processor(
                         text=prompt, images=[hi_res_image], return_tensors="pt"
@@ -162,7 +166,7 @@ class HuggingFaceTransformersVlmModel(BasePageModel, HuggingFaceModelDownloadMix
 
                 yield page
 
-    def formulate_prompt(self) -> str:
+    def formulate_prompt(self, user_prompt: str) -> str:
         """Formulate a prompt for the VLM."""
 
         if self.vlm_options.repo_id == "microsoft/Phi-4-multimodal-instruct":
@@ -173,7 +177,7 @@ class HuggingFaceTransformersVlmModel(BasePageModel, HuggingFaceModelDownloadMix
             assistant_prompt = "<|assistant|>"
             prompt_suffix = "<|end|>"
 
-            prompt = f"{user_prompt}<|image_1|>{self.vlm_options.prompt}{prompt_suffix}{assistant_prompt}"
+            prompt = f"{user_prompt}<|image_1|>{user_prompt}{prompt_suffix}{assistant_prompt}"
             _log.debug(f"prompt for {self.vlm_options.repo_id}: {prompt}")
 
             return prompt
@@ -187,7 +191,7 @@ class HuggingFaceTransformersVlmModel(BasePageModel, HuggingFaceModelDownloadMix
                         "text": "This is a page from a document.",
                     },
                     {"type": "image"},
-                    {"type": "text", "text": self.vlm_options.prompt},
+                    {"type": "text", "text": user_prompt},
                 ],
             }
         ]

docling/models/vlm_models_inline/mlx_model.py

@@ -56,8 +56,6 @@ class HuggingFaceMlxModel(BasePageModel, HuggingFaceModelDownloadMixin):
             elif (artifacts_path / repo_cache_folder).exists():
                 artifacts_path = artifacts_path / repo_cache_folder
 
-            self.param_question = vlm_options.prompt
-
             ## Load the model
             self.vlm_model, self.processor = load(artifacts_path)
             self.config = load_config(artifacts_path)
@@ -86,8 +84,12 @@ class HuggingFaceMlxModel(BasePageModel, HuggingFaceModelDownloadMixin):
                         if hi_res_image.mode != "RGB":
                             hi_res_image = hi_res_image.convert("RGB")
 
+                    if callable(self.vlm_options.prompt):
+                        user_prompt = self.vlm_options.prompt(page.parsed_page)
+                    else:
+                        user_prompt = self.vlm_options.prompt
                     prompt = self.apply_chat_template(
-                        self.processor, self.config, self.param_question, num_images=1
+                        self.processor, self.config, user_prompt, num_images=1
                     )
 
                     start_time = time.time()

docling/pipeline/vlm_pipeline.py

@@ -117,6 +117,7 @@ class VlmPipeline(PaginatedPipeline):
             page._backend = conv_res.input._backend.load_page(page.page_no)  # type: ignore
             if page._backend is not None and page._backend.is_valid():
                 page.size = page._backend.get_size()
+                page.parsed_page = page._backend.get_segmented_page()
 
         return page