feat: Change Cognee data models to work with Gemini [COG-1352] (#594)

<!-- .github/pull_request_template.md -->

## Description
Change data models and Gemini adapter so it can run custom ontologies

## DCO Affirmation
I affirm that all code in every commit of this pull request conforms to
the terms of the Topoteretes Developer Certificate of Origin


<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->

## Summary by CodeRabbit

- **New Features**
- Improved AI response handling now provides more direct and reliable
output.
- Enhanced knowledge graph displays now include additional descriptive
details under advanced configurations.

- **Refactor**
- Streamlined processing logic reduces complexity and improves
consistency.
- Updated data structures now adapt automatically based on your AI
service configuration for a smoother experience.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

cognee/infrastructure/llm/gemini/adapter.py

@@ -42,81 +42,12 @@ class GeminiAdapter(LLMInterface):
     ) -> BaseModel:
         try:
             if response_model is str:
-                simplified_prompt = system_prompt
                 response_schema = {"type": "string"}
             else:
-                response_schema = {
-                    "type": "object",
-                    "properties": {
-                        "summary": {"type": "string"},
-                        "description": {"type": "string"},
-                        "nodes": {
-                            "type": "array",
-                            "items": {
-                                "type": "object",
-                                "properties": {
-                                    "name": {"type": "string"},
-                                    "type": {"type": "string"},
-                                    "description": {"type": "string"},
-                                    "id": {"type": "string"},
-                                    "label": {"type": "string"},
-                                },
-                                "required": ["name", "type", "description", "id", "label"],
-                            },
-                        },
-                        "edges": {
-                            "type": "array",
-                            "items": {
-                                "type": "object",
-                                "properties": {
-                                    "source_node_id": {"type": "string"},
-                                    "target_node_id": {"type": "string"},
-                                    "relationship_name": {"type": "string"},
-                                },
-                                "required": [
-                                    "source_node_id",
-                                    "target_node_id",
-                                    "relationship_name",
-                                ],
-                            },
-                        },
-                    },
-                    "required": ["summary", "description", "nodes", "edges"],
-                }
-
-                simplified_prompt = f"""
-    {system_prompt}
-
-    IMPORTANT: Your response must be a valid JSON object with these required fields:
-    1. summary: A brief summary
-    2. description: A detailed description
-    3. nodes: Array of nodes with name, type, description, id, and label
-    4. edges: Array of edges with source_node_id, target_node_id, and relationship_name
-
-    Example structure:
-    {{
-      "summary": "Brief summary",
-      "description": "Detailed description",
-      "nodes": [
-        {{
-          "name": "Example Node",
-          "type": "Concept",
-          "description": "Node description",
-          "id": "example-id",
-          "label": "Concept"
-        }}
-      ],
-      "edges": [
-        {{
-          "source_node_id": "source-id",
-          "target_node_id": "target-id",
-          "relationship_name": "relates_to"
-        }}
-      ]
-    }}"""
+                response_schema = response_model
 
             messages = [
-                {"role": "system", "content": simplified_prompt},
+                {"role": "system", "content": system_prompt},
                 {"role": "user", "content": text_input},
             ]
 
@@ -127,7 +58,7 @@ class GeminiAdapter(LLMInterface):
                     api_key=self.api_key,
                     max_tokens=self.max_tokens,
                     temperature=0.1,
-                    response_format={"type": "json_object", "schema": response_schema},
+                    response_format=response_schema,
                     timeout=100,
                     num_retries=self.MAX_RETRIES,
                 )

cognee/shared/data_models.py

@@ -4,36 +4,67 @@ from enum import Enum, auto
 from typing import Any, Dict, List, Optional, Union
 
 from pydantic import BaseModel, Field
+from cognee.infrastructure.llm.config import get_llm_config
 
+if get_llm_config().llm_provider.lower() == "gemini":
+    """
+    Note: Gemini doesn't allow for an empty dictionary to be a part of the data model
+    so we created new data models to bypass that issue, but other LLMs have slightly worse performance
+    when creating knowledge graphs with these data models compared to the old data models
+    so now there's an if statement here so that the rest of the LLMs can use the old data models.
+    """
 
-class Node(BaseModel):
-    """Node in a knowledge graph."""
+    class Node(BaseModel):
+        """Node in a knowledge graph."""
 
-    id: str
-    name: str
-    type: str
-    description: str
-    properties: Optional[Dict[str, Any]] = Field(
-        None, description="A dictionary of properties associated with the node."
-    )
+        id: str
+        name: str
+        type: str
+        description: str
+        label: str
 
+    class Edge(BaseModel):
+        """Edge in a knowledge graph."""
 
-class Edge(BaseModel):
-    """Edge in a knowledge graph."""
+        source_node_id: str
+        target_node_id: str
+        relationship_name: str
 
-    source_node_id: str
-    target_node_id: str
-    relationship_name: str
-    properties: Optional[Dict[str, Any]] = Field(
-        None, description="A dictionary of properties associated with the edge."
-    )
+    class KnowledgeGraph(BaseModel):
+        """Knowledge graph."""
 
+        summary: str
+        description: str
+        nodes: List[Node] = Field(..., default_factory=list)
+        edges: List[Edge] = Field(..., default_factory=list)
+else:
 
-class KnowledgeGraph(BaseModel):
-    """Knowledge graph."""
+    class Node(BaseModel):
+        """Node in a knowledge graph."""
 
-    nodes: List[Node] = Field(..., default_factory=list)
-    edges: List[Edge] = Field(..., default_factory=list)
+        id: str
+        name: str
+        type: str
+        description: str
+        properties: Optional[Dict[str, Any]] = Field(
+            None, description="A dictionary of properties associated with the node."
+        )
+
+    class Edge(BaseModel):
+        """Edge in a knowledge graph."""
+
+        source_node_id: str
+        target_node_id: str
+        relationship_name: str
+        properties: Optional[Dict[str, Any]] = Field(
+            None, description="A dictionary of properties associated with the edge."
+        )
+
+    class KnowledgeGraph(BaseModel):
+        """Knowledge graph."""
+
+        nodes: List[Node] = Field(..., default_factory=list)
+        edges: List[Edge] = Field(..., default_factory=list)
 
 
 class GraphQLQuery(BaseModel):