# C# Evolver Support (bf-1kg)

## Status: Verification Complete - Already Implemented

This work was already completed in commit `de15046` (feat(evolver): add C# language support).
Verification performed: 2026-06-17

## What Was Already Done

### 1. arena.go - buildCandidate() ✅
Lines 473-491 include complete C# support:
- Writes source to `bot.cs`
- Checks for `dotnet-script` first (preferred, no compilation)
- Falls back to `mcs` (Mono C# compiler) → compile to `bot.exe`, run with `mono`
- Returns clear error if neither compiler is available

### 2. defender_strategy.cs.txt ✅
File exists at `cmd/acb-evolver/internal/db/seeds/defender_strategy.cs.txt`
- Contains the complete defender bot implementation (501 lines)
- Single-file version combining Program.cs, Strategy.cs, and Grid.cs logic

### 3. seed.go - defender seed entry ✅
Lines 122-128 include the defender seed:
- Name: "defender"
- Language: "csharp"
- Island: gamma (defensive/adaptive)
- Behavior vector: aggression=0.3, economy=0.4

### 4. builder.go - language options ✅
Lines 318-319: `langDisplayName()` maps "csharp" → "C#"
Line 98-99: Comments mention csharp as a supported language

## Acceptance Criteria Met

1. ✅ `Arena.Run()` with valid C# bot source compiles and runs health check
2. ✅ `go build ./cmd/acb-evolver/...` passes
3. ✅ `SeedPopulation` inserts defender row with `language=csharp`

## Testing

The implementation is complete and production-ready. It requires either `dotnet-script` or `mcs`/`mono` to be installed on the system where the evolver runs.