brainy_deco 0.1.2

A decorator that turns Python functions into LLM calls

smart_function / brainy_deco

A Python decorator that converts any function into an LLM call — powered by its docstring and type signature. Callable arguments are automatically exposed as tools the LLM can invoke during reasoning.

How it works

@smart_func("gemma4")
def translate(text: str, target_language: str) -> str:
    """Translate the given text into the target language."""

When you call translate("Hello!", "French"), the decorator:

1. Inspects the function signature and docstring
2. Detects any callable arguments and registers them as LLM-callable tools
3. Assembles a structured prompt describing the task, arguments, and available tools
4. Runs a conversation loop with the configured LLM backend:
   • If the LLM emits _llm_call = {"tool": "...", "args": [...]} → calls the tool, feeds result back
   • If the LLM emits _llm_return = <value> → extracts and returns the Python literal
5. Returns the final result (parsed with ast.literal_eval, no arbitrary code execution)

Requirements

• Python ≥ 3.10
• httpx (pip install httpx)
• A running Ollama instance (default) or an OpenAI-compatible API

Installation

pip install -e .          # editable install
# or
uv pip install -e .

Quick start

Basic usage — Ollama (default, local)

from brainy_deco import smart_func

@smart_func("gemma4")          # model name is the only required argument
def translate(text: str, target_language: str) -> str:
    """Translate the given text into the target language."""

print(translate("Hello, world!", "French"))
# → 'Bonjour, le monde !'

Sentiment analysis (returns a float)

@smart_func("gemma4")
def sentiment_score(text: str) -> float:
    """
    Analyse the sentiment of the text.
    Return a float between -1.0 (very negative) and 1.0 (very positive).
    """

print(sentiment_score("This is amazing!"))   # → 0.95

Structured extraction (returns a dict)

@smart_func("gemma4")
def extract_person(bio: str) -> dict:
    """
    Extract personal information from a biography.
    Return a dict with keys: name, age, occupation. Use None for unknown fields.
    """

print(extract_person("Marie Curie was a 66-year-old physicist."))
# → {'name': 'Marie Curie', 'age': 66, 'occupation': 'physicist'}

Callable parameter as a tool (LLM-driven callback)

If any argument passed at call time is callable, it is automatically exposed to the LLM as a tool the LLM may invoke zero or more times.

from typing import Callable

@smart_func("gemma4")
def recommend_action(ticker: str, get_price: Callable) -> str:
    """
    Fetch the current price of ticker using get_price, then recommend
    one of 'buy', 'hold', or 'sell' with a one-sentence reason.
    Return a string like: "hold – trading near fair value."
    """

def live_price(ticker: str) -> float:
    """Look up the real-time stock price for ticker."""
    ...   # your actual implementation

print(recommend_action("AAPL", live_price))
# LLM calls live_price("AAPL"), receives 175.5, then returns the recommendation.
# → 'hold – the stock is trading around its recent average price.'

tools= dict — tools declared at decoration time

Use tools= to inject callables that are always available to the LLM, independent of call-site arguments. Useful when the helpers are implementation details that callers shouldn't need to know about.

def _km_to_miles(km: float) -> float:
    """Convert kilometres to miles."""
    return km * 0.621371

def _miles_to_km(miles: float) -> float:
    """Convert miles to kilometres."""
    return miles / 0.621371

@smart_func(
    "gemma4",
    tools={
        "km_to_miles": _km_to_miles,
        "miles_to_km": _miles_to_km,
    },
)
def convert_units(value: float, from_unit: str, to_unit: str) -> float:
    """
    Convert value from from_unit to to_unit (supported: km, miles).
    Use the provided tools to perform the conversion.
    """

print(convert_units(100.0, "km", "miles"))   # → 62.1371

Tools from tools= and auto-detected callable arguments are merged into a single registry. On name collision, tools= entries take precedence.

OpenAI-compatible endpoint

@smart_func(
    "gpt-4o-mini",
    backend_type="openai",
    api_key="sk-...",
    base_url="https://api.openai.com/v1",   # optional, this is the default
)
def summarize(article: str, max_words: int = 100) -> str:
    """Summarize the article in at most max_words words."""

Custom backend instance

from brainy_deco import smart_func
from brainy_deco.backends import OpenAIBackend

backend = OpenAIBackend(
    model="gemma4",
    base_url="http://localhost:1234/v1",   # LM Studio, etc.
    temperature=0.2,
)

@smart_func(backend=backend)
def classify(text: str, categories: list) -> str:
    """Classify the text into one of the given categories."""

Decorator parameters

Parameter	Type	Default	Description
model	str	"gemma4"	LLM model name
backend	LLMBackend	None	Pre-built backend (overrides all other connection params)
backend_type	str	"ollama"	"ollama" or "openai"
base_url	str	"http://localhost:11434"	API base URL
api_key	str	None	API key (OpenAI-compatible)
tools	dict[str, Callable]	None	Tools always available to the LLM, by name
debug	bool	False	Log prompt and raw LLM responses
**backend_kwargs			Forwarded to backend (e.g. temperature, timeout)

LLM response protocol

The decorator uses a two-phase protocol:

Phase 1 — Tool call (zero or more times)

_llm_call = {"tool": "<tool_name>", "args": [<arg1>, <arg2>, ...]}

The callable is invoked with the given args and the result is fed back into the conversation as a new message. The loop continues until phase 2.

Phase 2 — Final return (exactly once)

_llm_return = <Python literal>

Extracted with ast.literal_eval (safe — no arbitrary code execution).
Supported types: str, int, float, bool, None, list, dict, tuple.

The loop is capped at 20 tool-call rounds to prevent runaway conversations.

Running the demo

# Make sure Ollama is running and the model is pulled
ollama pull gemma4
uv run examples/demo.py

Running tests

uv run pytest tests/ -v

Project layout

smart_function/
├── brainy_deco/
│   ├── __init__.py      # public API
│   ├── decorator.py     # @smart_func decorator + tool-calling loop
│   ├── prompt.py        # prompt builder (system + user messages)
│   ├── parser.py        # response parser (FinalResult / ToolCall)
│   └── backends.py      # OllamaBackend, OpenAIBackend
├── examples/
│   └── demo.py          # runnable examples (all 6 scenarios)
├── tests/
│   └── test_smart_function.py
└── pyproject.toml