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What is Marvin?

Marvin is a Python framework for building AI applications with LLMs.

Marvin provides a clean, intuitive interface for working with large language models (LLMs) while handling all the complexity of state management, conversation history, and agent coordination.

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Quick Examples

Using uv? Run the examples below by copying them to your clipboard and executing:

pbpaste | uv run --with marvin -

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Simple Tasks

The fastest way to use Marvin is with marvin.run():

import marvin

print(marvin.run("Write a haiku about artificial intelligence"))

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Specialized Agents

Create agents with specific skills and personalities:

import marvin

# Create specialized agents
poet = marvin.Agent(
    name="Poet",
    instructions="You are an expert poet who writes in various styles."
)

scientist = marvin.Agent(
    name="Scientist",
    instructions="You are a scientist who explains complex topics clearly."
)

# Use them for specific tasks
explanation = marvin.run(
    "Explain entropy briefly",
    agents=[scientist]
)

poem = marvin.run(
    "Write a haiku about entropy",
    agents=[poet],
    context={"scientific_background": explanation}
)

print(poem)

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Structured Data

Get results in exactly the format you need:

from typing import Annotated, Literal
import marvin
from pydantic import BaseModel, Field

class Character(BaseModel):
    name: str
    role: Literal["hero", "villain", "sidekick"]
    aura: Annotated[float, Field(ge=0, le=1)]

# Get structured results
characters = marvin.run(
    "Create three characters for a mystery story",
    result_type=list[Character]
)

for char in characters:
    print(f"{char.name} - {char.role} - {char.aura}")

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Persistent Memory

Give your agents memory that persists across conversations:

import marvin

# Create a memory module
preferences = marvin.Memory(
    key="user_preferences",
    instructions="Remember user preferences and style"
)

# Create an agent with memory
assistant = marvin.Agent(memories=[preferences])

# The agent will remember information across conversations
marvin.run(
    "Learn about the user's writing style preferences",
    agents=[assistant],
    cli=True
)

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Why Marvin?

  • 🎯 Simple Interface: Start with one line of code, scale to complex applications
  • 🧠 Smart Defaults: Sensible defaults that just work, with customization when you need it
  • 🔄 State Management: Built-in conversation history and memory management
  • 📝 Structured Data: Get results in exactly the format you need
  • 🤝 Multi-Agent: Create specialized agents that work together
  • 🔌 Extensible: Easy to integrate with your existing Python code

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Next Steps