AgenticCode/openspec/changes/archive/2026-04-06-update-extraction-schema/tasks.md

1. Replace Shared Models

• 1.1 Create TradeItem.cs in Shared/Models with fields: Valuedate (string), Counterparty (string), LegalEntity (string?), TradeId (long), DisplayCcy (string), Pv (double), Breakclause (string). Add [JsonPropertyName] attributes for snake_case serialization.
• 1.2 Create ExtractionResult.cs in Shared/Models with List<TradeItem> Items property
• 1.3 Delete the old ExtractedFields.cs
• 1.4 Update ValidationResult.cs to support candidate lists — add List<CandidateMatch>? Candidates property for disambiguation results (each with Name and LegalEntity fields)

2. Configure External API HttpClients

• 2.1 Add ExternalApis section to appsettings.json with base URLs for counterparty, trade, and currency APIs
• 2.2 Create typed HttpClient service CounterpartyApiClient with LookupAsync(string name) method returning candidate tuples
• 2.3 Create typed HttpClient service TradeApiClient with ValidateAsync(long tradeId) method
• 2.4 Create typed HttpClient service CurrencyApiClient with ValidateAsync(string currencyCode) method
• 2.5 Register all typed HttpClients in Program.cs via AddHttpClient<T>() with base URLs from configuration

3. Rewrite ExtractionPlugin

• 3.1 Replace ExtractionPlugin.ValidateExtractedFields() with LookupCounterparty(string name) — calls CounterpartyApiClient, returns candidate list as JSON. Include [KernelFunction] and [Description] attributes explaining the tool returns candidates for disambiguation.
• 3.2 Add ValidateTrade(long tradeId) method — calls TradeApiClient, returns valid/invalid result as JSON
• 3.3 Add ValidateCurrency(string currencyCode) method — calls CurrencyApiClient, returns valid/invalid result as JSON
• 3.4 Add ValidateSchema(string extractionResultJson) method — validates the full ExtractionResult JSON against TradeItem schema locally (required fields present, correct types, breakclause is Y or N)
• 3.5 Inject typed HttpClients into ExtractionPlugin via constructor. Register ExtractionPlugin in DI with its dependencies.
• 3.6 Add error handling in each tool method — catch HttpRequestException, return structured error JSON instead of throwing

4. Update Controller

• 4.1 Update ChatController.Post() — no changes needed, DI resolution via GetRequiredService works with scoped registration to use the new ExtractionPlugin constructor (pass DI-resolved instance with HttpClients)

5. Update Tests

• 5.1 Remove or rewrite tests referencing old ExtractedFields schema
• 5.2 Add unit tests for ValidateSchema method against TradeItem (valid, missing fields, wrong types)
• 5.3 Add unit tests for ExtractionPlugin tool methods with mocked HttpClients (success, error, multi-candidate responses)

6. Build and Verify

• 6.1 Build the solution (dotnet build) and confirm no compilation errors
• 6.2 Run all tests (dotnet test) and confirm they pass