Researching Azure AI SDK

CRITICAL: Don't guess SDK usage. Follow this research workflow.

Subagent Delegation for Research

Multi-repo research blows up context (1000+ tokens per file). Delegate to subagent for:

• Searching across 3+ repositories
• Reading 5+ files for patterns
• Comprehensive API surface exploration
• Finding all usages of a method/type

Delegation Pattern

runSubagent(
  prompt: "RESEARCH task - do NOT write code.
    
    **Question**: [specific SDK question]
    
    **Search these sources in order**:
    1. Azure.AI.Projects SDK: github.com/Azure/azure-sdk-for-net/tree/main/sdk/ai/Azure.AI.Projects
    2. Azure.AI.Agents.Persistent samples: .../Azure.AI.Agents.Persistent/samples
    3. Microsoft Foundry Samples: github.com/microsoft-foundry/foundry-samples
    
    **Find**:
    - Method signatures for [specific API]
    - Usage examples (pseudocode only)
    - Any gotchas or edge cases
    
    **Return** (max 20 lines):
    - Key method name and signature
    - Code pattern (pseudocode)
    - File path where found (for later reference)
    
    Do NOT include full file contents.",
  description: "SDK research: [topic]"
)

When to Delegate vs Inline

SDK Architecture Overview

The Foundry Agent Service SDK has two API surfaces for agents:

/agents/

dadjokes

AIProjectClient.Agents

/assistants/

asst_xxx

PersistentAgentsClient

This project uses v2 Agents API for human-readable agent IDs.

Azure.AI.Projects (Main Entry Point)
├── AIProjectClient
│   ├── .Agents.GetAgentAsync() → AgentRecord (v2 Agents API)
│   ├── .GetPersistentAgentsClient() → PersistentAgentsClient (Assistants API)
│   └── .OpenAI.GetProjectResponsesClientForAgent() → ProjectResponsesClient (Responses API)
└── Sub-namespaces:
    ├── Azure.AI.Projects.OpenAI (Responses API, conversations)
    └── OpenAI.Responses (streaming types)

1. Primary SDK Repository (Start Here)

Azure.AI.Projects SDK: https://github.com/Azure/azure-sdk-for-net/tree/main/sdk/ai/Azure.AI.Projects

• README: Core client patterns, authentication, basic operations
• Samples:

  tests/Samples/

  folder with full examples

Azure.AI.Agents.Persistent SDK: https://github.com/Azure/azure-sdk-for-net/tree/main/sdk/ai/Azure.AI.Agents.Persistent

• 33+ samples covering streaming, file search, Bing grounding, MCP, Azure Functions
• Key samples:

  • Sample9_PersistentAgents_Streaming.md

    - Basic streaming pattern

  • Sample8_PersistentAgents_FunctionsWithStreaming.md

    - Tool calls with streaming

  • Sample27_PersistentAgents_MCP_Streaming.md

    - MCP server integration

2. Official Quickstart Samples

Microsoft Foundry Samples: https://github.com/microsoft-foundry/foundry-samples

• samples/csharp/quickstart/quickstart-chat-with-agent.cs

  - Responses API pattern

• samples/csharp/quickstart/

  - Multiple quickstart examples

Key pattern from official quickstart:

AIProjectClient projectClient = new(new Uri(projectEndpoint), new AzureCliCredential());
ProjectConversation conversation = projectClient.OpenAI.Conversations.CreateProjectConversation();
ProjectResponsesClient responsesClient = projectClient.OpenAI.GetProjectResponsesClientForAgent(
    defaultAgent: agentName,
    defaultConversationId: conversation.Id);
ResponseResult response = responsesClient.CreateResponse("Your prompt");

3. Azure Architecture Center Samples

Baseline Chat App: https://github.com/Azure-Samples/microsoft-foundry-baseline

• Full production architecture with Entra ID auth

• website/chatui/Controllers/ChatController.cs

  - SSE streaming pattern

Basic Chat Example: https://github.com/Azure-Samples/microsoft-foundry-basic

• Simpler example of Foundry agent chat integration

Semantic Kernel + Foundry: https://github.com/Azure-Samples/app-service-agentic-semantic-kernel-ai-foundry-agent

• Integration pattern for Semantic Kernel with Foundry Agents

4. UI Reference Samples (React Patterns)

Primary UI Reference

Azure AI Agents React Sample: https://github.com/Azure-Samples/get-started-with-ai-agents

This is the primary UI reference for this project. Many UI patterns were borrowed from here:

• Chat interface components
• Message rendering with citations/annotations
• Streaming text display
• Responsive layout patterns

Agent Framework DevUI (Python)

Agent Framework DevUI: https://github.com/microsoft/agent-framework/tree/main/python/packages/devui

Alternative UI patterns for agent development:

• Development-focused chat interface
• Multi-agent visualization
• Tool call debugging UI

UI Component Inspiration

When implementing new UI features, check these sources in order:

1. get-started-with-ai-agents

   - React + TypeScript patterns for chat UI

2. agent-framework/devui

   - Development UI patterns
3. Fluent UI Copilot Components - Base component library (already used)

5. Semantic Kernel Integration

Repository: https://github.com/microsoft/semantic-kernel

Relevant paths:

• dotnet/src/Agents/OpenAI/

  - OpenAI Responses API integration

• dotnet/samples/GettingStartedWithAgents/AzureAIAgent/

• dotnet/samples/Concepts/Agents/

  (Step##_*.cs files)

6. OpenAI .NET SDK (Streaming Types)

Repository: https://github.com/openai/openai-dotnet

• docs/guides/streaming-responses/

  - Streaming patterns
• Source of

  StreamingResponseOutputTextDeltaUpdate

  and related types

7. GitHub Code Search (For Specific Patterns)

Use GitHub search to find usage examples:

# Find streaming patterns
"StreamingResponseOutputTextDeltaUpdate language:csharp"

# Find Responses API usage
"ProjectResponsesClient CreateResponseStreamingAsync language:csharp"

# Find conversation patterns
"ProjectConversation GetProjectResponsesClientForAgent language:csharp"

Current SDK Packages

Azure.AI.Projects

AIProjectClient

Azure.Identity

AzureDeveloperCliCredential

ManagedIdentityCredential

Microsoft.Identity.Web

Note: This project uses

Azure.AI.Projects

AIProjectClient.Agents

Sub-namespaces available (not separate packages):

• Azure.AI.Projects.OpenAI

  - Responses API, conversations

• OpenAI.Responses

  - Streaming types

Available Package:

Microsoft.Agents.AI.AzureAI

AIProjectClient

Key Resources:

• NuGet (Azure.AI.Projects): https://www.nuget.org/packages/Azure.AI.Projects
• SDK Source: https://github.com/Azure/azure-sdk-for-net/tree/main/sdk/ai/Azure.AI.Projects
• v2 Migration Guide: https://learn.microsoft.com/en-us/azure/ai-foundry/agents/how-to/migrate
• API Reference: https://learn.microsoft.com/en-us/dotnet/api/azure.ai.projects
• Product Docs: https://learn.microsoft.com/azure/ai-studio/

Official Azure AI Foundry Agent Service Documentation

Start here when researching agent capabilities, limits, or new features:

Agent Framework (Microsoft.Agents) docs:

Annotation Types in Responses

The SDK provides several annotation types for citations (from

OpenAI.Responses

UriCitationMessageAnnotation

Uri

Title

StartIndex

EndIndex

FileCitationMessageAnnotation

FileId

Filename

Index

FilePathMessageAnnotation

FileId

Index

ContainerFileCitationMessageAnnotation

FileId

Filename

StartIndex

EndIndex

Note:

FileCitationMessageAnnotation

Index

StartIndex

EndIndex

ExtractAnnotations()

AgentFrameworkService.cs

AnnotationInfo

Streaming Response Types (from OpenAI.Responses namespace)

StreamingResponseOutputTextDeltaUpdate

StreamingResponseOutputItemDoneUpdate

StreamingResponseCompletedUpdate

ResponseItem

Pattern used in this project:

await foreach (var update in responsesClient.CreateResponseStreamingAsync(...))
{
    if (update is StreamingResponseOutputTextDeltaUpdate textUpdate)
        yield return new StreamChunk { Text = textUpdate.Delta };
    if (update is StreamingResponseOutputItemDoneUpdate itemDone)
        // Extract annotations from itemDone.Item
}

Microsoft Agent Framework (Used — Hybrid Approach)

Package:

Microsoft.Agents.AI.AzureAI

Status: ✅ Installed and active. Agent Framework supports v2 Agents API via

AIProjectClient

Current Usage Pattern

This project uses a hybrid approach:

• Agent Framework for simplified agent loading and metadata
• Direct SDK for streaming (required for specialized response types)

// ✅ Agent loading via Agent Framework (simple)
ChatClientAgent agent = await aiProjectClient.GetAIAgentAsync(
    name: "dadjokes",           // Human-readable agent name
    cancellationToken: ct);

// Access AgentVersion for metadata
AgentVersion? version = agent.GetService<AgentVersion>();
var definition = version?.Definition as PromptAgentDefinition;

// ❌ Direct SDK for streaming (Agent Framework can't do this yet)
ProjectResponsesClient responsesClient = projectClient.OpenAI.GetProjectResponsesClientForAgent(
    new AgentReference(_agentId), conversationId);
await foreach (var update in responsesClient.CreateResponseStreamingAsync(...)) { }

Why Not Full Agent Framework for Streaming?

ChatClientAgent.RunStreamingAsync()

IAsyncEnumerable<AgentRunResponseUpdate>

• Text

  — text content (✅ works)

• RawRepresentation

  — underlying SDK object (can cast at runtime)

The problem: The

IChatClient

• McpToolCallApprovalRequestItem

  for MCP approval flows

• FileSearchCallResponseItem

  for file search quotes

• MessageResponseItem.OutputTextAnnotations

  for citations

Workaround exists but adds complexity: Cast

RawRepresentation

await foreach (var update in agent.RunStreamingAsync(message, thread))
{
    if (update.RawRepresentation is StreamingResponseOutputItemDoneUpdate itemDone)
    {
        if (itemDone.Item is McpToolCallApprovalRequestItem mcpApproval)
        {
            // Handle MCP approval...
        }
    }
}

Why we use direct SDK instead:

1. Casting

   RawRepresentation

   defeats the abstraction benefit
2. MCP approval flow requires

   ResponseItem.CreateMcpApprovalResponseItem()

   anyway
3. Direct SDK approach is clearer and matches SDK samples

What Agent Framework IS Good For

• Simple streaming — just text output with

  .Text

  property
• Multi-agent orchestration — sequential, concurrent, handoff patterns
• Graph-based workflows — streaming with checkpointing
• Built-in observability — OpenTelemetry integration
• Tool invocation — automatic

  AIFunction

  handling

Future Consideration

When Agent Framework matures to expose annotations/MCP through its abstractions, we could simplify to:

// Hypothetical future API
await foreach (var update in agent.RunStreamingAsync(message, thread))
{
    if (update.IsMcpApproval) { }       // Doesn't exist yet
    if (update.HasAnnotations) { }      // Doesn't exist yet  
}

Track progress at: https://github.com/microsoft/Agents-for-net

Resources:

• NuGet: https://www.nuget.org/packages/Microsoft.Agents.AI.AzureAI
• Documentation: https://learn.microsoft.com/agent-framework/
• Source: https://github.com/microsoft/Agents-for-net/tree/main/src/libraries
• API Reference: https://learn.microsoft.com/en-us/dotnet/api/microsoft.agents.ai.chatclientagent.runstreamingasync

Migration Notes

The SDK has evolved from connection string-based auth to project endpoint:

Old pattern (deprecated):

// DON'T USE - connection string deprecated in v1.0.0-beta.9+
var projectClient = new AIProjectClient(connectionString, new DefaultAzureCredential());

New pattern (current):

// USE THIS - project endpoint
var projectClient = new AIProjectClient(new Uri(projectEndpoint), new DefaultAzureCredential());

See: https://github.com/Azure/azure-sdk-for-net/blob/main/sdk/ai/Azure.AI.Projects/AGENTS_MIGRATION_GUIDE.md

Additional SDK Resources

Fetch SDK Source from GitHub (Authoritative)

Type definitions live in these repos—read them directly:

• Azure.AI.Projects source: https://github.com/Azure/azure-sdk-for-net/tree/main/sdk/ai/Azure.AI.Projects/src
• Azure.AI.Agents.Persistent samples: https://github.com/Azure/azure-sdk-for-net/tree/main/sdk/ai/Azure.AI.Agents.Persistent/samples
• OpenAI.Responses types: https://github.com/openai/openai-dotnet/tree/main/src

GitHub Code Search

Search across all .NET codebases for real-world usage:

"ProjectResponsesClient CreateResponseStreamingAsync" language:csharp
"StreamingResponseOutputTextDeltaUpdate" language:csharp

This finds how other projects use these APIs, revealing patterns and edge cases.

PowerShell Reflection (When Docs Lag Behind)

Use when SDK docs are outdated or incomplete — the DLLs are the ground truth.

Works even when

dotnet build

cd backend/WebApp.Api; dotnet restore

# Option A: Load from build output (requires successful build)
$asm = [Reflection.Assembly]::LoadFrom((Resolve-Path "bin/Debug/net9.0/Azure.AI.Projects.dll"))

# Option B: Load from NuGet cache (works even if build fails — use for pre-release migrations)
$dll = Get-ChildItem "$env:USERPROFILE\.nuget\packages\azure.ai.projects" -Recurse -Filter "Azure.AI.Projects.dll" | Select-Object -Last 1
$asm = [Reflection.Assembly]::LoadFrom($dll.FullName)

# Find types matching a pattern
$asm.GetExportedTypes() | Where-Object { $_.Name -like "*Streaming*" } | ForEach-Object { $_.FullName }

# Get method signatures with parameter details
$type = $asm.GetType("Azure.AI.Projects.OpenAI.ProjectResponsesClient")
$type.GetMethods() | Where-Object { $_.Name -like "*Async*" } | Select-Object Name, ReturnType, @{N='Params';E={($_.GetParameters() | ForEach-Object { "$($_.ParameterType.Name) $($_.Name)" }) -join ', '}}

Agent Framework assemblies (for Microsoft.Agents.AI.AzureAI migrations):

# Load Agent Framework DLL from NuGet cache
$pkg = Get-ChildItem "$env:USERPROFILE\.nuget\packages\microsoft.agents.ai.azureai" -Recurse -Filter "Microsoft.Agents.AI.AzureAI.dll" | Select-Object -Last 1
$asm = [Reflection.Assembly]::LoadFrom($pkg.FullName)

# Dump all exported types to see what changed between versions
$asm.GetExportedTypes() | ForEach-Object { $_.FullName } | Sort-Object

# Check if types you depend on still exist
@("ChatClientAgent", "AgentVersion", "PromptAgentDefinition", "AgentReference") | ForEach-Object {
    $match = $asm.GetExportedTypes() | Where-Object { $_.Name -eq $_ }
    if ($match) { Write-Host "FOUND: $($match.FullName)" } else { Write-Host "MISSING: $_" -ForegroundColor Red }
}

# Inspect extension methods (GetAIAgentAsync, etc.)
$asm.GetExportedTypes() | Where-Object { $_.GetMethods([Reflection.BindingFlags]::Static -bor [Reflection.BindingFlags]::Public) | Where-Object { $_.IsDefined([Runtime.CompilerServices.ExtensionAttribute], $false) } } | ForEach-Object {
    $_.GetMethods() | Where-Object { $_.IsDefined([Runtime.CompilerServices.ExtensionAttribute], $false) } | ForEach-Object { Write-Host "$($_.DeclaringType.Name).$($_.Name)" }
}

When to use: SDK upgrade with breaking changes, pre-release packages where docs lag, verifying actual API surface before writing migration code.

Key insight: Load from NuGet cache (

$env:USERPROFILE\.nuget\packages\