| | | 1 | | #pragma warning disable IDE0052 // Positional properties used by JSON serialization |
| | | 2 | | using System.Net.Http.Json; |
| | | 3 | | using System.Text.Json; |
| | | 4 | | using System.Text.Json.Serialization; |
| | | 5 | | using Intentum.AI.Http; |
| | | 6 | | using Intentum.Core.Behavior; |
| | | 7 | | |
| | | 8 | | namespace Intentum.AI.Classification; |
| | | 9 | | |
| | | 10 | | /// <summary> |
| | | 11 | | /// LLM prompt-based intent classifier. Sends behavior events to an LLM API |
| | | 12 | | /// and receives structured JSON with intent name, confidence, and reasoning. |
| | | 13 | | /// Supports OpenAI-compatible chat completion APIs. |
| | | 14 | | /// </summary> |
| | | 15 | | public sealed class PromptIntentClassifier : IIntentClassifier |
| | | 16 | | { |
| | | 17 | | private readonly HttpClient _httpClient; |
| | | 18 | | private readonly PromptClassifierOptions _options; |
| | | 19 | | |
| | 6 | 20 | | public PromptIntentClassifier(HttpClient httpClient, PromptClassifierOptions options) |
| | 6 | 21 | | { |
| | 6 | 22 | | _httpClient = httpClient ?? throw new ArgumentNullException(nameof(httpClient)); |
| | 5 | 23 | | _options = options ?? throw new ArgumentNullException(nameof(options)); |
| | 4 | 24 | | } |
| | | 25 | | |
| | | 26 | | public async Task<IntentClassificationResult> ClassifyAsync( |
| | | 27 | | BehaviorSpace behaviorSpace, |
| | | 28 | | IReadOnlyList<string>? candidateIntents = null, |
| | | 29 | | CancellationToken cancellationToken = default) |
| | 4 | 30 | | { |
| | 4 | 31 | | var events = behaviorSpace.Events |
| | 4 | 32 | | .Select(e => $" - {e.Actor}:{e.Action}") |
| | 4 | 33 | | .ToList(); |
| | | 34 | | |
| | 4 | 35 | | var candidateList = candidateIntents is { Count: > 0 } |
| | 4 | 36 | | ? $"\nCandidate intents (pick one): {string.Join(", ", candidateIntents)}" |
| | 4 | 37 | | : ""; |
| | | 38 | | |
| | 4 | 39 | | var systemPrompt = _options.SystemPrompt ?? DefaultSystemPrompt; |
| | 4 | 40 | | var jsonExample = """{"intent":"...","confidence":0.0-1.0,"reasoning":"..."}"""; |
| | 4 | 41 | | var userPrompt = $""" |
| | 4 | 42 | | Behavior events observed: |
| | 4 | 43 | | {string.Join("\n", events)} |
| | 4 | 44 | | {candidateList} |
| | 4 | 45 | | |
| | 4 | 46 | | Classify the intent. Respond with JSON only: {jsonExample} |
| | 4 | 47 | | """; |
| | | 48 | | |
| | 4 | 49 | | var request = new ChatCompletionRequest( |
| | 4 | 50 | | _options.Model, |
| | 4 | 51 | | [ |
| | 4 | 52 | | new ChatMessage("system", systemPrompt), |
| | 4 | 53 | | new ChatMessage("user", userPrompt) |
| | 4 | 54 | | ], |
| | 4 | 55 | | new ResponseFormat("json_object")); |
| | | 56 | | |
| | 4 | 57 | | var response = await EmbeddingHttpRetryHandler.SendWithRetryAsync( |
| | 4 | 58 | | ct => _httpClient.PostAsJsonAsync(_options.Endpoint ?? "chat/completions", request, ct), |
| | 0 | 59 | | (_, body) => throw new HttpRequestException($"LLM rate limited: {body}"), |
| | 4 | 60 | | cancellationToken: cancellationToken); |
| | | 61 | | |
| | 4 | 62 | | var completion = await response.Content |
| | 4 | 63 | | .ReadFromJsonAsync<ChatCompletionResponse>(cancellationToken); |
| | | 64 | | |
| | 4 | 65 | | var content = completion?.Choices?.FirstOrDefault()?.Message?.Content; |
| | 4 | 66 | | if (string.IsNullOrWhiteSpace(content)) |
| | 1 | 67 | | return new IntentClassificationResult("Unknown", 0, "Empty LLM response"); |
| | | 68 | | |
| | | 69 | | try |
| | 3 | 70 | | { |
| | 3 | 71 | | var parsed = JsonSerializer.Deserialize<LlmClassificationOutput>(content, LlmJsonOptions); |
| | | 72 | | |
| | 2 | 73 | | return new IntentClassificationResult( |
| | 2 | 74 | | parsed?.Intent ?? "Unknown", |
| | 2 | 75 | | Math.Clamp(parsed?.Confidence ?? 0, 0, 1), |
| | 2 | 76 | | parsed?.Reasoning); |
| | | 77 | | } |
| | 1 | 78 | | catch (JsonException) |
| | 1 | 79 | | { |
| | 1 | 80 | | return new IntentClassificationResult("Unknown", 0, $"Failed to parse LLM response: {content}"); |
| | | 81 | | } |
| | 4 | 82 | | } |
| | | 83 | | |
| | 1 | 84 | | private static readonly JsonSerializerOptions LlmJsonOptions = new() { PropertyNameCaseInsensitive = true }; |
| | | 85 | | |
| | | 86 | | private const string DefaultSystemPrompt = |
| | | 87 | | "You are an intent classification system. Given a sequence of behavior events (actor:action pairs), " + |
| | | 88 | | "determine the most likely user intent. Return ONLY valid JSON with fields: intent (string), " + |
| | | 89 | | "confidence (number 0-1), reasoning (string)."; |
| | | 90 | | |
| | 4 | 91 | | private sealed record ChatCompletionRequest( |
| | 0 | 92 | | [property: JsonPropertyName("model")] string Model, |
| | 0 | 93 | | [property: JsonPropertyName("messages")] IReadOnlyList<ChatMessage> Messages, |
| | 4 | 94 | | [property: JsonPropertyName("response_format")] ResponseFormat? ResponseFormat = null); |
| | | 95 | | |
| | 8 | 96 | | private sealed record ChatMessage( |
| | 0 | 97 | | [property: JsonPropertyName("role")] string Role, |
| | 8 | 98 | | [property: JsonPropertyName("content")] string Content); |
| | | 99 | | |
| | 4 | 100 | | private sealed record ResponseFormat( |
| | 4 | 101 | | [property: JsonPropertyName("type")] string Type); |
| | | 102 | | |
| | 4 | 103 | | private sealed record ChatCompletionResponse( |
| | 8 | 104 | | [property: JsonPropertyName("choices")] List<ChatChoice>? Choices); |
| | | 105 | | |
| | 4 | 106 | | private sealed record ChatChoice( |
| | 8 | 107 | | [property: JsonPropertyName("message")] ChatChoiceMessage? Message); |
| | | 108 | | |
| | 4 | 109 | | private sealed record ChatChoiceMessage( |
| | 8 | 110 | | [property: JsonPropertyName("content")] string? Content); |
| | | 111 | | |
| | 2 | 112 | | private sealed record LlmClassificationOutput( |
| | 2 | 113 | | [property: JsonPropertyName("intent")] string? Intent, |
| | 2 | 114 | | [property: JsonPropertyName("confidence")] double? Confidence, |
| | 4 | 115 | | [property: JsonPropertyName("reasoning")] string? Reasoning); |
| | | 116 | | } |
| | | 117 | | #pragma warning restore IDE0052 |
| | | 118 | | |
| | | 119 | | /// <summary> |
| | | 120 | | /// Options for the prompt-based intent classifier. |
| | | 121 | | /// </summary> |
| | | 122 | | public sealed class PromptClassifierOptions |
| | | 123 | | { |
| | | 124 | | public required string Model { get; init; } |
| | | 125 | | public string? Endpoint { get; init; } |
| | | 126 | | public string? SystemPrompt { get; init; } |
| | | 127 | | } |