Zipcoil

Zipcoil is a Python library that simplifies OpenAI tool usage, helping developers build simple AI agents with ease. It provides a clean, decorator-based approach to define tools and an Agent class that handles the OpenAI tool-calling loop automatically.

Why Zipcoil?

Building AI agents that can use tools typically involves:

• Converting Python functions to OpenAI's JSON schema format 😕
• Handling the complex tool-calling conversation flow 🙁
• Managing multiple iterations of tool calls and responses ☹️
• Dealing with error handling and edge cases 😣

Zipcoil eliminates this boilerplate by providing:

• A simple @tool decorator to help convert Python functions into OpenAI tools
• Automatic schema generation from type hints and docstrings
• Built-in agent loop that handles tool calling iterations
• Type safety with comprehensive type hints including Optional, Union, Enum, and more
• Error handling for malformed tool calls and execution errors
• Minimal dependencies, built on top of the official OpenAI library
• Works with both OpenAI and AzureOpenAI clients, in both sync and async modes

Installation

Zipcoil requires Python 3.11 or higher.

pip install zipcoil

Quick Start

Here's a simple example of creating an AI agent with tools:

import os
from enum import Enum

from openai import AzureOpenAI, OpenAI

from zipcoil import Agent, tool

# Initialize OpenAI client
# client = OpenAI(api_key=os.getenv("OPENAI_API_KEY"))
# or the Azure OpenAI client
client = AzureOpenAI(
    api_key=os.getenv("AZURE_OPENAI_API_KEY"),
    azure_endpoint=os.getenv("AZURE_OPENAI_API_BASE"),
    api_version=os.getenv("AZURE_OPENAI_API_VERSION"),
)


# Define tools using the @tool decorator
@tool
def get_weather(city: str, unit: str = "celsius") -> str:
    """Get the current weather for a city.

    Args:
        city: The name of the city
        unit: Temperature unit (celsius or fahrenheit)
    """
    # Your weather API call here
    return f"The weather in {city} is 22°{unit[0].upper()}"


class MathOp(Enum):
    ADD = 1
    SUBTRACT = 2
    MULTIPLY = 3
    DIVIDE = 4


@tool
def calculate(x: float, y: float, operation: MathOp) -> float:
    """Perform a mathematical calculation.

    Args:
        x: First number
        y: Second number
        operation: Operation to perform (add, subtract, multiply, divide)
    """
    # normalise int -> MathOp
    if isinstance(operation, int):
        try:
            operation = MathOp(operation)
        except ValueError as exc:
            raise ValueError(f"Unsupported operation value: {operation}") from exc

    operations = {
        MathOp.ADD: x + y,
        MathOp.SUBTRACT: x - y,
        MathOp.MULTIPLY: x * y,
        MathOp.DIVIDE: x / y if y != 0 else float("inf"),
    }
    return operations.get(operation, 0)


# Create an agent with tools
agent = Agent(model="gpt-4o", client=client, tools=[get_weather, calculate])

# Run a conversation
messages = [{"role": "user", "content": "What's the weather in Paris? Also calculate 15 * 23."}]

result = agent.run(messages)
print(result.choices[0].message.content)

Advanced Usage

Complex Type Support

Zipcoil supports various Python types including enums, optionals, and unions:

from enum import Enum
from typing import Optional, List, Dict

class Priority(Enum):
    LOW = 1
    MEDIUM = 2
    HIGH = 3

@tool
def create_task(
    title: str,
    description: Optional[str],
    priority: Priority,
    tags: List[str],
    metadata: Dict[str, str]
) -> str:
    """Create a new task.

    Args:
        title: Task title
        description: Optional task description
        priority: Task priority level
        tags: List of tags for the task
        metadata: Additional metadata as key-value pairs
    """
    return f"Created task '{title}' with priority {priority.name}"

Error Handling

Zipcoil automatically handles tool execution errors:

@tool
def divide_numbers(a: float, b: float) -> float:
    """Divide two numbers.

    Args:
        a: Numerator
        b: Denominator
    """
    if b == 0:
        raise ValueError("Cannot divide by zero")
    return a / b

# The agent will catch the error and include it in the conversation

Custom Agent Configuration

You can pass additional parameters to the underlying OpenAI API:

result = agent.run(
    messages=messages,
    temperature=0.7,
    max_completion_tokens=1000,
    max_iterations=5  # Limit tool calling iterations
)

Type Support

Zipcoil automatically converts Python types to OpenAI's JSON schema:

Python Type	JSON Schema Type	Notes
str	string
int	integer
float	number
bool	boolean
list	array
dict	object
Optional[T]	[T, "null"]	Union with null
Union[T, U]	Mixed type	For Optional types
Enum	enum	Extracts enum values

API Reference

@tool Decorator

Converts a Python function into an OpenAI tool. The function should:

• Have type hints for all parameters
• Have a docstring with Google-style Args section

Example:

@tool
def get_weather(city: str, unit: str = "celsius") -> str:
    """Get the current weather for a city.

    Args:
        city: The name of the city
        unit: Temperature unit (celsius or fahrenheit)
    """
    return f"The weather in {city} is 22°{unit[0].upper()}"

Agent and AsyncAgent Classes

Agent(
    model: Uniont[str, ChatModel],
    client: OpenAI,
    tools: Iterable[ToolProtocol]
)

AsyncAgent(
    model: Union[str, ChatModel],
    client: AsyncOpenAI,
    tools: Iterable[Union[ToolProtocol, AsyncToolProtocol]]
)

The main abstraction of the agentic event loop. It will take in a model name (more on this below), an OpenAI or AzureOpenAI client, and a list of tools decorated with the @tool decorator.

While Agent will accept only sync tools and will reject async ones, AsyncAgent will accept both sync and async tools and will await async tools. Use @tool for both sync and async functions.

Note: As opposed to standard OpenAI usage, Zipcoil associates the model with an agent to avoid having to specify it every time you call run.

Agent.run()

Runs the agentic loop, calling all tools as needed and iterating until the underlying model doesn't need to call any tools anymore, until it's ready to return a ChatCompletion.

Parameters:

• max_iterations: Maximum number of tool calling iterations (default: 10)
• All other parameters are passed through to OpenAI's chat completion API
• Returns the standard OpenAI ChatCompletion object

Error Handling

Zipcoil handles several types of errors gracefully:

1. Tool execution errors: Caught and passed back to the model as error messages
2. JSON parsing errors: Invalid tool arguments are reported to the model
3. Missing tools: Requests for non-existent tools return error messages
4. Iteration limits: Prevents infinite loops with configurable max iterations

Contributing

Contributions are welcome! Please see our development setup:

# Install development dependencies
uv sync --group dev

# Run tests
uv run pytest

# Format code
uv run ruff format src/ tests/

Requirements

• Python 3.11+
• OpenAI Python library (≥1.0.0)
• docstring-parser (≥0.16)

License

This project is open-source, licensed under the GNU Lesser General Public License v3.0 - see the LICENSE file for details.

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Zipcoil - Making AI tool usage as simple as decorating a function.