Add sendAndWait API for all SDKs

[SteveSandersonMS]

Summary

Adds a new \sendAndWait()\ method to all SDK languages that waits for the agent turn to complete. This accompanies the CLI change in https://github.com/github/copilot-agent-runtime/pull/1539 which makes \send()\ return immediately instead of blocking.

Changes

New API: \sendAndWait()\

All SDKs now have a method that sends a message and waits for \session.idle:

Language	Method	Return Type	Default Timeout
Node.js	\sendAndWait(options, timeout?)\	\Promise\	60s
.NET	\SendAndWaitAsync(options, timeout?, ct?)\	\Task<AssistantMessageEvent?>\	60s
Go	\SendAndWait(options, timeout)\	(*SessionEvent, error)\	60s
Python	\send_and_wait(options, timeout?)\	\SessionEvent\	60s

All implementations:

• Return the last \�ssistant.message\ event received before \session.idle\
• Handle \session.error\ events by throwing/returning an error
• Support configurable timeout (default 60 seconds)

Updated E2E Tests

All e2e tests updated to use \sendAndWait()\ instead of \send()\ + \getFinalAssistantMessage().

Backward Compatibility

• Old SDK + New CLI: Works (old \send()\ still works, just returns faster)
• New SDK + Old CLI: Works (old CLI blocks anyway)

Related

• CLI PR: https://github.com/github/copilot-agent-runtime/pull/1539
• Issue: Question: Is there a way to configure the request timeout? (Currently hitting 30s limit) #17
• Depends on: React to CLI update and Anthropic response format changes #27

[Copilot]

Pull request overview

This PR adds a new sendAndWait() method to all SDK languages (Node.js, Python, Go, and .NET) that sends a message and blocks until the agent turn completes. This accompanies a CLI change where send() now returns immediately instead of blocking.

Changes:

• Implements sendAndWait() API across all four SDK languages with consistent 60-second default timeout behavior
• Updates all e2e tests to use sendAndWait() instead of send() + helper functions
• Adds forward compatibility for unknown event types in Python and .NET

Reviewed changes

Copilot reviewed 23 out of 25 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
nodejs/src/session.ts	Implements sendAndWait() method with timeout and error handling
nodejs/src/index.ts	Exports new AssistantMessageEvent type
nodejs/test/e2e/*.test.ts	Updates tests to use sendAndWait() and adds new blocking behavior tests
nodejs/examples/basic-example.ts	Updates example to use sendAndWait()
nodejs/README.md	Documents new sendAndWait() API
python/copilot/session.py	Implements send_and_wait() method
python/copilot/generated/session_events.py	Adds forward compatibility for unknown event types
python/e2e/*.py	Updates tests to use send_and_wait()
go/session.go	Implements SendAndWait() method
go/e2e/*.go	Updates tests to use SendAndWait()
dotnet/src/Session.cs	Implements SendAndWaitAsync() method
dotnet/src/Generated/SessionEvents.cs	Adds forward compatibility for unknown event types
dotnet/src/Client.cs	Adds null check for unknown events
dotnet/test/*.cs	Updates tests to use SendAndWaitAsync() and adds new blocking behavior tests
test/snapshots/session/*.yaml	New test snapshots for blocking behavior tests

Comments suppressed due to low confidence (1)

nodejs/test/e2e/session.test.ts:1

• The code accesses assistantMessages[assistantMessages.length - 1] without checking if the array is empty. If no assistant messages exist, this will throw an error. Add a check to ensure the array has at least one element before accessing it.

import { describe, expect, it, onTestFinished } from "vitest";

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[Copilot]

The return type documentation is inconsistent with the actual implementation. The method returns Promise<AssistantMessageEvent | undefined> but the documentation states Promise<SessionEvent | undefined>. This should be corrected to Promise<AssistantMessageEvent | undefined> to match the implementation and provide more precise type information.

Suggested change

	##### `sendAndWait(options: MessageOptions, timeout?: number): Promise<SessionEvent | undefined>`
	##### `sendAndWait(options: MessageOptions, timeout?: number): Promise<AssistantMessageEvent | undefined>`

[Copilot]

The use of the null-forgiving operator ! after ToList() is potentially unsafe. While the .Where(e => e != null) filters out nulls, the compiler doesn't recognize this pattern. Consider using .OfType<SessionEvent>() instead of .Where(e => e != null) to properly narrow the type, eliminating the need for the null-forgiving operator.

Suggested change

	.Where(e => e != null)
	.ToList()!;
	.OfType<SessionEvent>()
	.ToList();