crestapps-core-chat

CrestApps.Core Chat - Prompt Templates

Build a Chat Completion Loop

You are a CrestApps.Core expert. Generate code and guidance for deployment-aware chat completions, streaming, and orchestration loops.

Guidelines

• CrestApps.Core exposes IAICompletionService, not IChatCompletionService; it returns Microsoft.Extensions.AI ChatResponse and ChatResponseUpdate values.
• Register the AI suite and at least one provider, then configure a Chat-capable deployment and connection.
• Resolve an AIDeployment through IAIDeploymentManager rather than constructing provider clients in application code.
• Use CompleteAsync(...) for one result and CompleteStreamingAsync(...) with await foreach for incremental output.
• Pass an AICompletionContext for system instructions, sampling settings, deployment names, and tool choices.
• Use IOrchestrator.ExecuteStreamingAsync(...) when the request needs planning, tool scoping, or an iterative agent loop.
• This skill is the completion and orchestration surface. crestapps-core-chat-interactions is the persisted session, history, handler-routing, and SignalR interaction feature.
• The direct completion guidance here corresponds to the AI core and orchestration documentation. The /docs/core/chat topic documents crestapps-core-chat-interactions, not this direct completion loop.

Registration

builder.Services.AddCrestAppsCore(crestApps => crestApps
    .AddAISuite(ai => ai
        .AddOpenAI()
    )
);

Configure an OpenAI connection and a deployment whose Purpose includes AIDeploymentPurpose.Chat.

Stream a Response

using System.Runtime.CompilerServices;
using CrestApps.Core.AI.Completions;
using CrestApps.Core.AI.Deployments;
using CrestApps.Core.AI.Models;
using Microsoft.Extensions.AI;

namespace MyApp;

public sealed class ChatCompletionLoop
{
    private readonly IAICompletionService _completionService;
    private readonly IAIDeploymentManager _deploymentManager;

    public ChatCompletionLoop(
        IAICompletionService completionService,
        IAIDeploymentManager deploymentManager)
    {
        _completionService = completionService;
        _deploymentManager = deploymentManager;
    }

    public async IAsyncEnumerable<ChatResponseUpdate> StreamAsync(
        string prompt,
        [EnumeratorCancellation] CancellationToken cancellationToken = default)
    {
        var deployment = await _deploymentManager.ResolveOrDefaultAsync(
            AIDeploymentPurpose.Chat,
            cancellationToken: cancellationToken)
            ?? throw new InvalidOperationException("No Chat deployment is configured.");

        var context = new AICompletionContext
        {
            SystemMessage = "You are a concise support assistant.",
            Temperature = 0.2f,
        };

        await foreach (var update in _completionService.CompleteStreamingAsync(
            deployment,
            [new ChatMessage(ChatRole.User, prompt)],
            context,
            cancellationToken))
        {
            yield return update;
        }
    }
}