---
phase: 01-architecture-foundation
plan: 01
subsystem: infra
tags: [dotnet, blazor-wasm, webapi, solution-scaffold, net9]

# Dependency graph
requires: []
provides:
  - Three-project .NET 9 solution (Client, Api, Shared)
  - Predictable dev ports (Client: 5200, API: 7100)
  - Shared project reference wiring
  - API base URL configuration in client
affects: [01-02, 02, 03, 04, 05]

# Tech tracking
tech-stack:
  added: [".NET 9 SDK 9.0.312", "Blazor WebAssembly Standalone", "ASP.NET Core Web API", "Class Library"]
  patterns: ["Three-project solution with shared library", "Predictable port assignment", "global.json SDK pinning"]

key-files:
  created:
    - ChatAgent.sln
    - global.json
    - src/ChatAgent.Client/ChatAgent.Client.csproj
    - src/ChatAgent.Api/ChatAgent.Api.csproj
    - src/ChatAgent.Shared/ChatAgent.Shared.csproj
    - src/ChatAgent.Client/wwwroot/appsettings.json
  modified:
    - .gitignore
    - src/ChatAgent.Client/Properties/launchSettings.json
    - src/ChatAgent.Api/Properties/launchSettings.json

key-decisions:
  - "Pinned .NET 9 via global.json since .NET 10 is installed as default"
  - "Kept inspectUri in Client launchSettings for Blazor WASM debugging support"

patterns-established:
  - "SDK pinning: global.json at repo root locks .NET version"
  - "Port convention: Client HTTPS=5200, API HTTPS=7100"
  - "Client config: wwwroot/appsettings.json for public settings (ApiBaseUrl)"

requirements-completed: [CODE-02]

# Metrics
duration: 2min
completed: 2026-03-27
---

# Phase 01 Plan 01: Solution Scaffold Summary

**Three-project .NET 9 solution with Blazor WASM client, ASP.NET Core Web API, and shared class library at predictable dev ports**

## Performance

- **Duration:** 2 min
- **Started:** 2026-03-27T22:50:21Z
- **Completed:** 2026-03-27T22:52:42Z
- **Tasks:** 2
- **Files modified:** 26

## Accomplishments
- Created ChatAgent.sln with three projects targeting net9.0
- Wired ChatAgent.Shared as ProjectReference in both Client and Api
- Configured predictable ports (Client: 5200, API: 7100) and API base URL
- Removed template boilerplate (WeatherForecast, Class1)
- Pinned .NET 9 SDK via global.json

## Task Commits

Each task was committed atomically:

1. **Task 1: Create solution and three projects with references** - `eeaa9de` (feat)
2. **Task 2: Configure predictable dev ports and clean up template defaults** - `c6f1225` (feat)

## Files Created/Modified
- `ChatAgent.sln` - Solution file at repo root with 3 projects
- `global.json` - Pins .NET SDK to 9.0.312
- `src/ChatAgent.Client/ChatAgent.Client.csproj` - Blazor WASM client with Shared reference
- `src/ChatAgent.Api/ChatAgent.Api.csproj` - Web API with Shared reference
- `src/ChatAgent.Shared/ChatAgent.Shared.csproj` - Shared class library
- `src/ChatAgent.Client/Properties/launchSettings.json` - Client ports 5200/5100
- `src/ChatAgent.Api/Properties/launchSettings.json` - API ports 7100/7000
- `src/ChatAgent.Client/wwwroot/appsettings.json` - ApiBaseUrl pointing to API
- `.gitignore` - Added .NET-specific ignore patterns

## Decisions Made
- Pinned .NET 9 via global.json since machine default is .NET 10 (10.0.201) -- required to match CLAUDE.md constraint
- Kept inspectUri in Client launchSettings profiles for Blazor WASM debugging support

## Deviations from Plan

### Auto-fixed Issues

**1. [Rule 3 - Blocking] Added global.json to pin .NET 9 SDK**
- **Found during:** Task 1 (before project creation)
- **Issue:** Machine has .NET 10 as default SDK; `dotnet new` would target net10.0 without intervention
- **Fix:** Created global.json with version 9.0.312 and rollForward: latestPatch
- **Files modified:** global.json
- **Verification:** `dotnet --version` returns 9.0.312
- **Committed in:** eeaa9de (Task 1 commit)

---

**Total deviations:** 1 auto-fixed (1 blocking)
**Impact on plan:** Essential for correctness -- without SDK pinning, all projects would target wrong framework version.

## Issues Encountered
None

## User Setup Required
None - no external service configuration required.

## Next Phase Readiness
- Solution scaffold is complete and builds with zero errors
- Ready for Plan 02: CORS configuration, health endpoint, HttpClient setup, and tutorial comments
- All three projects have proper references and port alignment

---
*Phase: 01-architecture-foundation*
*Completed: 2026-03-27*