## Purpose

Document the technology stack decisions for Chat Agent WebApp.
## Requirements
### Requirement: Core technology stack

The stack spec SHALL document the recommended core technologies with version, purpose, and rationale for each.

#### Scenario: Core stack documented

- **WHEN** a developer needs to add or update a dependency
- **THEN** the stack spec provides the authoritative record of: .NET 9 SDK, Blazor WebAssembly Standalone, ASP.NET Core Web API, C# 13, OpenAI SDK 2.9.1, Markdig 1.1.1, MudBlazor 9.2.0, and System.Text.Json

### Requirement: Supporting libraries and tools

The stack spec SHALL document supporting libraries, development tools, and installation notes.

#### Scenario: Supporting libraries referenced

- **WHEN** a developer evaluates adding a new dependency
- **THEN** the stack spec lists supporting libraries with guidance on when to use them (e.g., Microsoft.Extensions.AI — skip for v1)

### Requirement: Alternatives and exclusions

The stack spec SHALL document considered alternatives and explicitly excluded technologies with rationale.

#### Scenario: Alternative considered

- **WHEN** a developer proposes an alternative package or approach
- **THEN** the stack spec provides a record of alternatives already evaluated and why the current choice was made

#### Scenario: Excluded technology referenced

- **WHEN** a developer considers using a technology on the exclusion list
- **THEN** the stack spec explains why it was excluded and what to use instead

### Requirement: Stack patterns

The stack spec SHALL document implementation patterns that govern how stack technologies are used together (streaming, storage, markdown rendering).

#### Scenario: Pattern referenced during implementation

- **WHEN** a developer implements streaming, storage, or markdown rendering
- **THEN** the stack spec provides the canonical pattern to follow

### Requirement: Version compatibility matrix

The stack spec SHALL maintain a compatibility matrix and list of authoritative sources for version decisions.

#### Scenario: Compatibility check

- **WHEN** a package version is being upgraded
- **THEN** the stack spec provides the compatibility matrix to verify cross-package compatibility