Fix tool parsing for ollama (#1597)

## Description

Ollama requires a specific formatting for JSONschema tools where
parameter types can only be a string, never a list of strings (which is
actually valid JSONschema). To compensate for this we ensure optional
parameters where the type is `['string', 'null']` is transformed to just
`'string'` to be compatible.
This should not have impact, because we provide a list of "required"
parameters with function definitions.

Fixes #1584 

---------

Co-authored-by: Manthan Gupta <[email protected]>

cookbook/providers/ollama/agent_stream.py

@@ -3,6 +3,7 @@
 from typing import Iterator  # noqa
 from phi.agent import Agent, RunResponse  # noqa
 from phi.model.ollama import Ollama
+from phi.tools.crawl4ai_tools import Crawl4aiTools
 from phi.tools.yfinance import YFinanceTools
 
 agent = Agent(
@@ -20,3 +21,10 @@
 
 # Print the response in the terminal
 agent.print_response("What are analyst recommendations for NVDA and TSLA", stream=True)
+
+
+agent = Agent(model=Ollama(id="llama3.1:8b"), tools=[Crawl4aiTools(max_length=1000)], show_tool_calls=True)
+agent.print_response(
+    "Summarize me the key points in bullet points of this: https://blog.google/products/gemini/google-gemini-deep-research/",
+    stream=True,
+)

phi/model/ollama/chat.py

@@ -134,6 +134,11 @@ def request_kwargs(self) -> Dict[str, Any]:
             request_params["keep_alive"] = self.keep_alive
         if self.tools is not None:
             request_params["tools"] = self.get_tools_for_api()
+            # Ensure types are valid strings
+            for tool in request_params["tools"]:
+                for prop, obj in tool["function"]["parameters"]["properties"].items():
+                    if isinstance(obj["type"], list):
+                        obj["type"] = obj["type"][0]
         if self.request_params is not None:
             request_params.update(self.request_params)
         return request_params

phi/tools/function.py

@@ -158,7 +158,6 @@ def process_entrypoint(self, strict: bool = False):
 
             # Get JSON schema for parameters only
             parameters = get_json_schema(type_hints=param_type_hints, strict=strict)
-
             # If strict=True mark all fields as required
             # See: https://platform.openai.com/docs/guides/structured-outputs/supported-schemas#all-fields-must-be-required
             if strict: