Architecture

DotnetTokenKiller follows a clean architecture pattern with four layers, each in its own project.

Project Structure

src/
├── DotnetTokenKiller.Domain/           Core abstractions
├── DotnetTokenKiller.Application/      Use cases and filters
├── DotnetTokenKiller.Infrastructure/   External integrations
└── DotnetTokenKiller.Cli/              CLI entry point

Layer Diagram

graph TD
    CLI["CLI<br/><small>Spectre.Console — Commands, Settings, DI setup</small>"]
    APP["Application<br/><small>Use cases, Output filters</small>"]
    INFRA["Infrastructure<br/><small>SQLite, JSON config, Process</small>"]
    DOM["Domain<br/><small>Interfaces, Models, Value objects</small>"]

    CLI --> APP
    CLI --> INFRA
    APP --> DOM
    INFRA --> DOM

Dependencies flow inward: CLI → Application → Domain, and Infrastructure → Domain. The CLI layer wires everything together via dependency injection.

Domain

The innermost layer defines core abstractions with no external dependencies.

Folder	Contents
Configuration/	DtkConfig (configuration model), IConfigProvider (config loading interface)
Execution/	CommandResult (return value from running a command), ICommandRunner (process execution interface)
Filters/	IOutputFilter (contract for transforming raw output to filtered output)
Tracking/	CommandRecord, CommandGainDetail, GainSummary (tracking models), ITracker (persistence interface)
Tee/	ITeeService (raw output logging interface)

Application

Contains the business logic — use cases and per-command output filters.

Use Cases

Class	Purpose
FilteredRunUseCase	Runs a dotnet command, filters its output, tracks token usage, and optionally tees the raw output
GainReportUseCase	Aggregates tracking data and produces the savings report
ResetTrackingUseCase	Clears all stored tracking records

Filters

Each supported dotnet subcommand has a dedicated filter implementing IOutputFilter:

Filter	Command
DotnetBuildFilter	dotnet build
DotnetTestFilter	dotnet test
DotnetRestoreFilter	dotnet restore
DotnetCleanFilter	dotnet clean
DotnetFormatFilter	dotnet format

These filters parse the raw dotnet output and produce compact, LLM-friendly summaries — stripping MSBuild noise, adapter banners, absolute paths, and duplicate information.

Infrastructure

Implements domain interfaces with concrete external integrations.

Class	Implements	Description
ProcessCommandRunner	ICommandRunner	Spawns dotnet as a child process and captures output
SqliteTracker	ITracker	Persists command records and token counts in SQLite
JsonConfigProvider	IConfigProvider	Reads and deserializes ~/.config/dtk/config.json

CLI

The entry point, built with Spectre.Console.Cli.

Component	Purpose
Program.cs	Registers services, configures commands, handles passthrough for unknown subcommands
Commands/	One command class per CLI verb (DotnetBuildCommand, DotnetTestCommand, GainCommand, ResetCommand, etc.)
Infrastructure/	Spectre.Console DI integration (TypeRegistrar, TypeResolver)

Key Dependencies

Package	Purpose
Spectre.Console	Rich terminal output (tables, colors, emoji)
Spectre.Console.Cli	CLI command framework
Microsoft.ML.Tokenizers	BPE token counting (cl100k_base, o200k_base, etc.)
Microsoft.Data.Sqlite	Tracking data persistence
Microsoft.Extensions.DependencyInjection	Service container

Target Framework

• .NET 10 (net10.0)
• C# 14 with nullable reference types enabled
• Analyzers: Roslynator, SonarAnalyzer, Microsoft.CodeAnalysis.NetAnalyzers
• TreatWarningsAsErrors enabled