Devlog: 2026-03-17 — BestEx Engine Implementation

What Happened

Implemented the full BestEx (Best Execution) engine in the PowerSeller.SaaS.Modules.BestEx project, using parallel AI developer agents for independent workstreams after establishing the entity foundation.

Implementation Strategy

1. Sequential foundation: 19 entity classes + EF Core configuration with composite keys
2. Parallel agents (3 concurrent):
   • Agent A: Profile management service + 13 CRUD endpoints
   • Agent B: 24-step analysis pipeline + pricing calculator + feature adjustments + ranking
   • Agent C: Analysis run orchestration + results/errors/loans endpoints
3. Sequential integration: Wire up BestExModule.cs, fix build errors, verify

What Was Built

Domain Entities (19 files)

Entity	Table	Purpose
BestExProfile	rmcat_bx_profile_names	Analysis profile definition
ProfileStrategy	rmcat_bx_profile_strategies	Buy-up/buy-down/excess strategies
ProfileParameters	rmcat_bx_setup_parameters	Profile configuration flags and filters
ProfileInstrumentMapping	rmcat_bx_setup_instr_inv	Instrument/investor associations
ProfileLockWindow	rmcat_bx_setup_lock_windows	Lock window configuration
ProfileStatus	rmcat_bx_setup_statuses	Eligible loan statuses
AnalysisResult	rmcat_bestex_analysis	67-column analysis output
AnalysisError	rmcat_bestex_analysis_error	Per-loan error tracking
Loan	loan	Loan pipeline (key columns)
Instrument	pscat_instruments	Instrument configuration
TodaysPrice	rmcat_todays_prices	Current validated prices
TodaysParRate	rmcat_todays_par_rates	Computed par rates
PriceAdjustment	rmcat_price_adjustments	Adjustment rules with SQL syntax
PriceAdjustmentValue	rmcat_price_adjustment_values	Adjustment values per investor
PriceAdjustmentGroup	rmcat_price_adjustment_groups	Adjustment group definitions
ProfitMargin	rmcat_profit_margin	Profit margin configuration
InvestorDeliveryWindow	pscat_rm_inv_delivery_win	Delivery window configuration
Zone	pscat_rm_zones	Investor zones
ZoneState	pscat_rm_zone_states	Zone-to-state mappings

Services (6 files)

Service	Lines	Purpose
ProfileService	~200	Full CRUD for profiles and configuration
AnalysisPipelineService	~470	24-step analysis engine
PricingCalculator	~130	Pure math: par rate interpolation, DPCs, total price formula
FeatureAdjustmentService	~170	Adjustment rule evaluation with simplified syntax parser
RankingService	~60	SQL RANK() window function for scenario ranking
AnalysisRunService	~170	Orchestration, results pagination, summaries, history

Endpoints (3 files)

Endpoint Group	Count	Path
Profile endpoints	13	/api/bestex/profiles/*
Analysis endpoints	5	/api/bestex/analysis/*
Loan endpoints	3	/api/bestex/loans/*

Infrastructure

• TenantDbContext updated with module-based entity registration (RegisterEntityAssembly)
• BestExEntityConfiguration defines all composite keys via IEntityTypeConfiguration
• BestExModule.cs wires up all DI registrations and endpoint mappings

Pipeline Implementation Status

Phase	Steps	Status
1: Setup	1-4	Fully implemented
2: Pricing Windows	5-8	Implemented (pool check simplified)
3: Rate Optimization	9-10	Servicing defaults to "sell" (TODO)
4: Value Components	11-13	Price lookup + interpolation done; guarantee_fee from instrument config
5: Income and Cost	14-17	Simplified to 0 (TODOs for warehouse rate, finance cost, early delivery)
6: Final Calculations	18-21	Total price + profit calculated; cost basis = 100 (TODO)
7: Ranking and Output	22-24	Bulk insert + SQL RANK() done; report/archive are no-ops

12 TODO comments mark simplified steps referencing spec rule numbers.

Build Verification

• Build: 0 warnings, 0 errors across all 6 projects
• Tests: 1 passed, 0 failed
• Solution builds cleanly in Docker container

Issues Encountered

• AnalysisRunResult record defined in two files by parallel agents -- removed duplicate
• Entity property naming mismatch (PriceAdjustmentGroupName vs PriceAdjustmentGroup) between entity classes and EF Core configuration -- fixed
• Nullable value type pattern match needed for TreatWarningsAsErrors compliance
• Api.Tests project missing using Xunit;

Technical Debt

• 12 pipeline steps are simplified (income/cost components set to 0, cost basis hardcoded to 100, no archive)
• Feature adjustment syntax evaluator handles only simple single-column comparisons -- no AND/OR/NOT/IN/BETWEEN
• No integration tests against the local SQL Server yet
• The AnalysisError entity is keyless (HasNoKey()) -- works for read/insert but can't be tracked by EF Core change tracker

What's Next

1. Start Docker containers with --profile dev and verify API responds with all 21+ endpoints in Swagger
2. Add PricingCalculator unit tests (par rate formula, total price formula)
3. Fill in simplified pipeline steps as individual work items
4. Connect to local SQL Server and test end-to-end with synthetic data