[Bug]: Documentation mismatch: A2AStarletteApplication uses `http_handler` not `request_handler`

[trunksio]

What happened?

Title

Documentation mismatch: A2AStarletteApplication uses http_handler not request_handler

Description

Summary

The documentation and examples show using request_handler as a parameter when creating an A2AStarletteApplication, but the actual implementation expects http_handler.

Environment

• a2a-sdk version: 0.3.0
• Python version: 3.12
• OS: Linux

Steps to Reproduce

1. Follow the documentation example:

from a2a.server.apps import A2AStarletteApplication
from a2a.server.request_handlers import DefaultRequestHandler
from a2a.server.tasks import InMemoryTaskStore

# Create components
task_store = InMemoryTaskStore()
request_handler = DefaultRequestHandler(
    agent_executor=agent_executor,
    task_store=task_store
)

# This fails
app = A2AStarletteApplication(
    agent_card=agent_card,
    request_handler=request_handler  # <-- Documentation shows this
)

2. Error received:

TypeError: JSONRPCApplication.__init__() got an unexpected keyword argument 'request_handler'

Expected Behavior

The code should work as documented.

Actual Behavior

The constructor expects http_handler instead of request_handler.

Investigation

Using inspect.signature() on the constructor reveals:

A2AStarletteApplication(
    agent_card: AgentCard,
    http_handler: RequestHandler,  # <-- Actual parameter name
    extended_agent_card: AgentCard | None = None,
    context_builder: CallContextBuilder | None = None,
    card_modifier: Callable[[AgentCard], AgentCard] | None = None,
    extended_card_modifier: Callable[[AgentCard, ServerCallContext], AgentCard] | None = None
)

Workaround

Use http_handler instead of request_handler:

app = A2AStarletteApplication(
    agent_card=agent_card,
    http_handler=request_handler  # <-- Works
)

Suggested Fix

Either:

1. Update the documentation and examples to use http_handler
2. Update the code to accept request_handler (with deprecation warning for http_handler)
3. Accept both parameter names for backward compatibility

Additional Context

This affects anyone following the official documentation or examples, particularly in:

• The a2a-samples repository
• Any tutorials or blog posts based on the documentation
• The helloworld example

The parameter naming inconsistency makes it difficult for developers to get started with the SDK.

Relevant log output

Code of Conduct

• I agree to follow this project's Code of Conduct

[lkawka]

Hi trunksio,

Thanks for reporting the issue!

Could you provide a link to the documentation that you're referencing here? I can see that the helloword sample that is used in the A2A's tutorial docs already uses http_handler=request_handler.

Thanks,
Lukasz