Anthropic SDK

Use the Anthropic SDK’s Beta Tool Runner through Motus to get full tracing and HTTP serving with a single import. Define your tools, create a ToolRunner, and serve it.

Installation

uv pip install "anthropic>=0.49.0"

pip install "anthropic>=0.49.0"

The Anthropic SDK is a core dependency of Motus. You need anthropic>=0.49.0 for tool runner support.

Basic usage

Import ToolRunner and beta_async_tool from motus.anthropic. Use @beta_async_tool to decorate your tool functions, then pass them to ToolRunner:

from motus.anthropic import ToolRunner, beta_async_tool

@beta_async_tool
async def get_weather(city: str) -> str:
    """Get the weather for a city."""
    return f"Sunny in {city}"

runner = ToolRunner(
    model="claude-sonnet-4-20250514",
    max_tokens=1024,
    tools=[get_weather],
    system="You are a helpful assistant.",
)

ToolRunner holds your model configuration and tool list. It creates a fresh BetaAsyncToolRunner on each turn. Tool runners are single-use generators that cannot be re-iterated, so ToolRunner handles that lifecycle for you.

Tool types

You can pass several tool types to ToolRunner.tools:

Functions decorated with @beta_async_tool or @beta_tool
Plain async or sync Python functions (auto-wrapped on each turn)
Motus @tool-decorated functions (unwrapped and re-wrapped automatically)

from motus.anthropic import ToolRunner, beta_async_tool, beta_tool

@beta_async_tool
async def search(query: str) -> str:
    """Search the web."""
    return f"Results for: {query}"

@beta_tool
def calculate(expression: str) -> str:
    """Evaluate a math expression."""
    return str(eval(expression))  # noqa: S307

runner = ToolRunner(
    model="claude-sonnet-4-20250514",
    max_tokens=1024,
    tools=[search, calculate],
)

Limiting the tool-use loop

Pass max_iterations to stop after a fixed number of tool-use rounds:

runner = ToolRunner(
    model="claude-sonnet-4-20250514",
    max_tokens=1024,
    tools=[get_weather],
    max_iterations=5,
)

Deployment

Local serving

Pass the runner object directly to motus serve start:

motus serve start myapp:runner --port 8000

Where runner is a ToolRunner instance defined at module level in myapp.py.

Cloud deployment

cd my_project
motus deploy --name my-agent tools_runner:runner

When deploying to Motus cloud, include requirements.txt with anthropic>=0.49.0 (the SDK is not in the base image). No API key secrets are needed - the platform routes Anthropic API calls through the model proxy. Session state (conversation history) is persisted in DynamoDB and survives backend restarts, failovers, and scaling events.

State management

Motus manages conversation state across turns. Each turn receives the full prior conversation as a list of ChatMessage objects. ToolRunner converts that state into Anthropic message format and prepends it to every request, so the model always sees the full conversation context. You do not need to manage history yourself. Motus passes prior state in and stores the updated state after each turn automatically.

# myapp.py
from motus.anthropic import ToolRunner, beta_async_tool

@beta_async_tool
async def get_weather(city: str) -> str:
    """Get the weather for a city."""
    return f"Sunny in {city}"

runner = ToolRunner(
    model="claude-sonnet-4-20250514",
    max_tokens=1024,
    tools=[get_weather],
    system="You are a helpful assistant.",
)

motus serve start myapp:runner --port 8000

Tracing

Tracing is automatic when the Motus runtime is active (as it is inside motus serve). Each turn produces three span types in TraceManager:

Span type	Source	Contents
`agent_call`	Root span for the turn	Model name, start/end timestamps
`model_call`	Each request to the Claude API	Model name, input messages, token usage, response content
`tool_call`	Each tool invocation	Tool name, input arguments, output, error status

All model_call and tool_call spans are parented to the root agent_call span for the turn. Traces are auto-exported on process exit.

On the Motus cloud platform, the AsyncAnthropic() client picks up platform-injected environment variables that route requests through the model proxy. You do not need to set ANTHROPIC_API_KEY at deploy time.

Exports

motus.anthropic re-exports the following from the Anthropic SDK, plus Motus-specific additions:

Export	Description
`ToolRunner`	Motus serve adapter which holds config and creates a fresh runner per turn
`beta_async_tool`	Decorator for async tool functions
`beta_tool`	Decorator for sync tool functions
`BetaAsyncFunctionTool`	Anthropic SDK async function tool type
`BetaFunctionTool`	Anthropic SDK sync function tool type
`BetaAsyncBuiltinFunctionTool`	Anthropic SDK async built-in tool type
`BetaBuiltinFunctionTool`	Anthropic SDK sync built-in tool type
`MotusBetaToolRunner`	Instrumented sync tool runner
`MotusBetaAsyncToolRunner`	Instrumented async tool runner
`MotusBetaStreamingToolRunner`	Instrumented sync streaming tool runner
`MotusBetaAsyncStreamingToolRunner`	Instrumented async streaming tool runner
`get_tracer()`	Returns the `TraceManager` instance

Get Started

Run and Deploy

Motus Cloud

Motus Library

Integrations

Contributing

Anthropic SDK

Installation

Basic usage

Tool types

Limiting the tool-use loop

Deployment

Local serving

Cloud deployment

State management

Tracing

Exports

​Installation

​Basic usage

​Tool types

​Limiting the tool-use loop

​Deployment

​Local serving

​Cloud deployment

​State management

​Tracing

​Exports

Installation

Basic usage

Tool types

Limiting the tool-use loop

Deployment

Local serving

Cloud deployment

State management

Tracing

Exports