FunctionCallingAgent

FunctionCallingAgent uses native LLM function calling — OpenAI tool_calls or Anthropic tool_use. More reliable tool selection than ReAct, especially with multiple tools.

Requirements

• OpenAILLM, AnthropicLLM, GeminiLLM, or MistralLLM (all support call_with_tools())
• For other providers, use ReActAgent instead

Usage

from synapsekit import FunctionCallingAgent, CalculatorTool, FileReadTool
from synapsekit.llm.openai import OpenAILLM
from synapsekit.llm.base import LLMConfig

llm = OpenAILLM(LLMConfig(model="gpt-4o-mini", api_key="sk-..."))

agent = FunctionCallingAgent(
    llm=llm,
    tools=[CalculatorTool(), FileReadTool()],
    max_iterations=10,
    system_prompt="You are a helpful data analyst.",
)

answer = await agent.run("Read ./data.csv and tell me the row count.")

How it works

1. Tool schemas are sent to the LLM as JSON
2. LLM responds with tool_calls (or text if no tool is needed)
3. Each tool is called, results appended as role: tool messages
4. Repeat until the LLM returns text with no tool calls

Anthropic example

from synapsekit.llm.anthropic import AnthropicLLM
from synapsekit.llm.base import LLMConfig

llm = AnthropicLLM(LLMConfig(
    model="claude-sonnet-4-6",
    api_key="sk-ant-...",
))

agent = FunctionCallingAgent(llm=llm, tools=[CalculatorTool()])
answer = await agent.run("What is 144 / 12?")

Gemini example

from synapsekit.llm.gemini import GeminiLLM
from synapsekit.llm.base import LLMConfig

llm = GeminiLLM(LLMConfig(
    model="gemini-1.5-pro",
    api_key="your-google-api-key",
    provider="gemini",
))

agent = FunctionCallingAgent(llm=llm, tools=[CalculatorTool()])
answer = await agent.run("What is 2 to the power of 10?")

Mistral example

from synapsekit.llm.mistral import MistralLLM
from synapsekit.llm.base import LLMConfig

llm = MistralLLM(LLMConfig(
    model="mistral-large-latest",
    api_key="your-mistral-key",
    provider="mistral",
))

agent = FunctionCallingAgent(llm=llm, tools=[CalculatorTool()])
answer = await agent.run("What is the square root of 256?")

Parameters

Parameter	Type	Default	Description
llm	BaseLLM	required	Must implement call_with_tools()
tools	list[BaseTool]	required	Available tools
max_iterations	int	10	Max tool-call rounds
memory	AgentMemory | None	auto	Custom memory instance
system_prompt	str	"You are a helpful AI assistant."	System instruction