ln-770-crosscutting-setup Skill

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ln-770-crosscutting-setup

Type: L2 Domain Coordinator Category: 7XX Project Bootstrap Parent: ln-700-project-bootstrap

Coordinates cross-cutting concerns configuration for .NET and Python projects.

Overview

| Aspect | Details | |--------|---------| | Input | Project root directory | | Output | Configured logging, error handling, CORS, health checks, API docs | | Workers | ln-771 to ln-775 | | Stacks | .NET (ASP.NET Core), Python (FastAPI) |

Phase 1: Detect Project Stack

Determine the technology stack by scanning project files.

Detection Rules:

| File Pattern | Stack | Framework | |--------------|-------|-----------| | *.csproj | .NET | ASP.NET Core | | pyproject.toml or requirements.txt + FastAPI | Python | FastAPI |

Actions:

Glob for *.csproj files
If not found, Glob for pyproject.toml or requirements.txt
If Python, check for FastAPI in dependencies
Store detected stack in Context Store

Context Store Initial:

{
  "STACK": ".NET" | "Python",
  "FRAMEWORK": "ASP.NET Core" | "FastAPI",
  "PROJECT_ROOT": "/path/to/project",
  "FRAMEWORK_VERSION": "8.0" | "0.109.0"
}

Phase 2: Check Existing Configuration

Scan for already configured cross-cutting concerns.

Detection Patterns:

| Concern | .NET Pattern | Python Pattern | |---------|--------------|----------------| | Logging | Serilog in *.csproj, UseSerilog in Program.cs | structlog in requirements, logging config | | Error Handling | GlobalExceptionMiddleware, UseExceptionHandler | @app.exception_handler, exception_handlers.py | | CORS | AddCors, UseCors | CORSMiddleware | | Health Checks | AddHealthChecks, MapHealthChecks | /health routes | | API Docs | AddSwaggerGen, UseSwagger | FastAPI auto-generates |

Actions:

Grep for each pattern
Mark configured concerns as skip: true
Update Context Store with findings

Context Store Updated:

{
  "concerns": {
    "logging": { "configured": false },
    "errorHandling": { "configured": false },
    "cors": { "configured": true, "skip": true },
    "healthChecks": { "configured": false },
    "apiDocs": { "configured": false }
  }
}

Phase 3: Invoke Workers (Conditional)

Delegate to workers only for unconfigured concerns.

Worker Invocation Order:

| Order | Worker | Condition | Skill Call | |-------|--------|-----------|------------| | 1 | ln-771-logging-configurator | logging.configured == false | /skill ln-771-logging-configurator | | 2 | ln-772-error-handler-setup | errorHandling.configured == false | /skill ln-772-error-handler-setup | | 3 | ln-773-cors-configurator | cors.configured == false | /skill ln-773-cors-configurator | | 4 | ln-774-healthcheck-setup | healthChecks.configured == false | /skill ln-774-healthcheck-setup | | 5 | ln-775-api-docs-generator | apiDocs.configured == false | /skill ln-775-api-docs-generator |

Pass Context Store to each worker.

Worker Response Format:

{
  "status": "success" | "skipped" | "error",
  "files_created": ["path/to/file.cs"],
  "packages_added": ["Serilog.AspNetCore"],
  "message": "Configured structured logging with Serilog"
}

Phase 4: Generate Aggregation File

Create a single entry point for all cross-cutting services.

.NET: Extensions/ServiceExtensions.cs

Generate based on configured workers:

// Structure only - actual code generated via MCP ref
public static class ServiceExtensions
{
    public static IServiceCollection AddCrosscuttingServices(
        this IServiceCollection services,
        IConfiguration configuration)
    {
        // Calls added based on configured workers:
        // services.AddLogging(configuration);      // if ln-771 ran
        // services.AddCorsPolicy(configuration);   // if ln-773 ran
        // services.AddHealthChecks();              // if ln-774 ran
        // services.AddSwaggerServices();           // if ln-775 ran
        return services;
    }
}

Python: middleware/init.py

Generate based on configured workers:

# Structure only - actual code generated via MCP ref
def configure_middleware(app):
    # Middleware added based on configured workers:
    # configure_logging(app)        # if ln-771 ran
    # configure_error_handlers(app) # if ln-772 ran
    # configure_cors(app)           # if ln-773 ran
    # configure_health_routes(app)  # if ln-774 ran
    pass

Phase 5: Summary Report

Display summary of all configured concerns.

Output Format:

Cross-cutting Setup Complete
============================
Stack: .NET (ASP.NET Core 8.0)

Configured:
  ✓ Logging (Serilog) - Extensions/LoggingExtensions.cs
  ✓ Error Handling - Middleware/GlobalExceptionMiddleware.cs
  ✓ CORS - Extensions/CorsExtensions.cs
  ✓ Health Checks - Extensions/HealthCheckExtensions.cs
  ✓ API Docs (Swagger) - Extensions/SwaggerExtensions.cs

Skipped (already configured):
  - None

Entry Point: Extensions/ServiceExtensions.cs
  Add to Program.cs: builder.Services.AddCrosscuttingServices(builder.Configuration);

Packages to Install:
  dotnet add package Serilog.AspNetCore
  dotnet add package Swashbuckle.AspNetCore

Workers

| Worker | Purpose | Stacks | |--------|---------|--------| | ln-771-logging-configurator | Structured logging | .NET (Serilog), Python (structlog) | | ln-772-error-handler-setup | Global exception middleware | .NET, Python | | ln-773-cors-configurator | CORS policy configuration | .NET, Python | | ln-774-healthcheck-setup | /health endpoints | .NET, Python | | ln-775-api-docs-generator | Swagger/OpenAPI | .NET (Swashbuckle), Python (FastAPI built-in) |

Context Store Interface

Workers receive and return via Context Store:

Input to Workers:

{
  "STACK": ".NET",
  "FRAMEWORK": "ASP.NET Core",
  "FRAMEWORK_VERSION": "8.0",
  "PROJECT_ROOT": "/path/to/project",
  "ENVIRONMENT": "Development"
}

Output from Workers:

{
  "status": "success",
  "files_created": [],
  "packages_added": [],
  "registration_code": "services.AddLogging(configuration);"
}

Idempotency

This skill is idempotent:

Phase 2 detects existing configuration
Workers skip if already configured
Aggregation file preserves existing entries

Critical Rules

Skip already configured concerns — Phase 2 detection must gate worker invocation (set skip: true)
Pass Context Store to every worker — workers depend on STACK, FRAMEWORK, PROJECT_ROOT
Generate aggregation file only for workers that ran — do not add registration calls for skipped concerns
Support only .NET and Python — detect via *.csproj or pyproject.toml/requirements.txt + FastAPI
Idempotent execution — re-running must not duplicate configs or break existing setup

Definition of Done

Project stack detected and stored in Context Store
Existing configurations detected (Phase 2 complete)
All unconfigured concerns delegated to workers (ln-771 through ln-775)
Aggregation entry point generated (ServiceExtensions.cs or middleware/__init__.py)
Summary report displayed with configured/skipped concerns and package install commands

Reference Files

Worker skills: ln-771-logging-configurator/SKILL.md through ln-775-api-docs-generator/SKILL.md

Version: 2.0.0 Last Updated: 2026-01-10

Agent Skills: ln-770-crosscutting-setup

Install this agent skill to your local

Skill Files