> ## Documentation Index
> Fetch the complete documentation index at: https://praison.ai/docs/llms.txt
> Use this file to discover all available pages before exploring further.
# Managed Backend Protocol • AI Agent SDK
> ManagedBackendProtocol: Protocol for external managed agent backends.
# ManagedBackendProtocol
> Defined in the [**protocols**](../modules/protocols) module.
AI Agent
Protocol for external managed agent backends.
Defines the contract between PraisonAI Agent's delegation layer
(`execution_mixin._delegate_to_backend`) and any managed agent
infrastructure provider (Anthropic Managed Agents, etc.).
The Core SDK defines *what* — this protocol.
The Wrapper implements *how* — the provider-specific adapter.
Lifecycle::
backend = SomeManagedBackend(config=\{...})
agent = Agent(name="coder", backend=backend)
result = agent.start("Write a script") # delegates to backend.execute()
Implementations must handle:
* Agent/environment/session creation and caching
* Event streaming (agent.message, agent.tool\_use, session.status\_idle)
* Custom tool calls (agent.custom\_tool\_use → user.custom\_tool\_result)
* Tool confirmation (always\_ask policy → user.tool\_confirmation)
* Usage tracking (input\_tokens, output\_tokens)
* Session reset for multi-turn isolation
Example::
```python theme={"theme":{"light":"vitesse-light","dark":"vitesse-dark"}}
class MockManagedBackend:
async def execute(self, prompt: str, **kwargs) -> str:
return "mock response"
async def stream(self, prompt: str, **kwargs):
yield "mock "
yield "response"
def reset_session(self) -> None:
pass
def reset_all(self) -> None:
pass
assert isinstance(MockManagedBackend(), ManagedBackendProtocol)
```
## Methods
Execute a prompt on managed infrastructure and return the full response.
Stream a prompt response as text chunks.
Discard the cached session so the next execute() creates a fresh one.
Discard all cached state (agent, environment, session, client).
Update an existing managed agent's configuration.
Send a user interrupt to the active session.
Retrieve the current managed session's metadata and usage.
List sessions for the current agent.
## Source
`praisonaiagents/agent/protocols.py` at line 325