Agent

Write agent logic once. Run it anywhere. Switch providers anytime.

Agent is a clean Python runtime for multi-provider LLM apps and agent workflows. One elegant, provider-agnostic interface for building LLM applications and tool-using agents.

Features

• One API, Many Providers: OpenAI, Anthropic, Gemini, DeepSeek, and more
• Provider Portability: Switch providers with minimal code changes
• Structured Outputs: Pydantic-based typed responses
• Tool Calling: Register Python functions as tools with automatic schema generation
• Sessions: Multi-turn conversations with pluggable persistence
• Streaming: Normalized streaming events across providers
• Routing & Fallback: Automatic failover and smart routing strategies
• Middleware: Extensible hooks for logging, tracing, and policy control

Installation

pip install agent-core-py

# With provider extras
pip install agent-core-py[openai]
pip install agent-core-py[anthropic]
pip install agent-core-py[all]

Quick Start

from agent import Agent

# Create an agent
agent = Agent(
    provider="anthropic",
    model="claude-sonnet-4-20250514",
)

# Simple text generation
response = agent.run("Explain quantum computing in one paragraph")
print(response.text)

Structured Outputs

from pydantic import BaseModel
from agent import Agent

class Summary(BaseModel):
    title: str
    bullets: list[str]
    sentiment: str

agent = Agent(provider="openai", model="gpt-4o")
response = agent.json("Summarize this article about AI progress", schema=Summary)
print(response.output)  # Typed Summary object

Tool Calling

from agent import Agent, tool

@tool
def search_code(query: str) -> str:
    """Search the codebase for matching patterns."""
    # Your implementation
    return f"Found 5 matches for: {query}"

@tool
def read_file(path: str) -> str:
    """Read contents of a file."""
    with open(path) as f:
        return f.read()

agent = Agent(
    provider="anthropic",
    model="claude-sonnet-4-20250514",
    tools=[search_code, read_file],
)

response = agent.run("Find all TODO comments in the codebase")

Sessions

from agent import Agent

agent = Agent(provider="openai", model="gpt-4o")

# Create a session for multi-turn conversation
session = agent.session()
session.run("My name is Alice")
response = session.run("What's my name?")
print(response.text)  # "Your name is Alice"

Streaming

from agent import Agent

agent = Agent(provider="anthropic", model="claude-sonnet-4-20250514")

for event in agent.stream("Write a short poem about coding"):
    if event.type == "text_delta":
        print(event.text, end="", flush=True)

Router & Fallback

from agent import AgentRouter

router = AgentRouter(
    agents=[
        Agent(provider="anthropic", model="claude-sonnet-4-20250514"),
        Agent(provider="openai", model="gpt-4o"),
    ],
    strategy="fallback",
)

# Automatically falls back if first provider fails
response = router.run("Hello, world!")

Middleware

from agent import Agent, Middleware

class LoggingMiddleware(Middleware):
    def before(self, request):
        print(f"Request: {request.input[:50]}...")
        return request
    
    def after(self, request, response):
        print(f"Response: {response.text[:50]}...")
        return response

agent = Agent(
    provider="openai",
    model="gpt-4o",
    middleware=[LoggingMiddleware()],
)

Configuration

from agent import Agent

# Explicit configuration
agent = Agent(
    provider="openai",
    model="gpt-4o",
    api_key="sk-...",
    timeout=120.0,
    max_retries=3,
    temperature=0.7,
)

# Or use environment variables
# OPENAI_API_KEY, ANTHROPIC_API_KEY, etc.
agent = Agent(provider="openai", model="gpt-4o")

CLI

# Quick chat
agent chat --provider openai --model gpt-4o

# Single prompt
agent run "What is the capital of France?" --provider anthropic

# List providers
agent providers

# Test configuration
agent doctor

Supported Providers

Documentation

• Installation Guide
• Provider Setup
• Structured Outputs
• Tool System
• Sessions
• Routing & Fallback
• Middleware
• Custom Providers

Documentation

Full docs at agent-core.readthedocs.io.

Contributing

See CONTRIBUTING.md for development setup and guidelines.

License

MIT License - see LICENSE for details.