Trails

Understand what this notebook is and how to read it.

Read and write the core C# constructs that everything else is built on.

Choose between a class, a struct, an interface and a record, and know what each does when it is copied or compared.

Use the modern C# features that cut boilerplate and null bugs.

Explain the four pillars of OOP in C#, and choose between an interface and an abstract class.

Apply the five SOLID principles to C# code, and spot when one is being broken.

Recognize the common design patterns in C# code, and use one only when it solves a real problem.

Pick the right C# collection for the job, and judge its cost with Big O.

Write LINQ queries, and know when and where they run.

Write async code that does not block threads, and know where it goes wrong.

Explain what .NET is made of, and how a project becomes running code.

Explain how .NET frees memory, and release resources the right way.

Explain how cores, threads and the thread pool serve a .NET app, and how a single request moves across them.

Choose between concurrency and parallelism in .NET, and avoid the common failures.

Explain how an ASP.NET Core application starts, handles a request, and gets its services and settings.

Design, version and document a web API in ASP.NET Core.

Query and change data with EF Core, and keep it fast.

Explain what event-driven architecture is, and choose between queues, topics and streams for a message.

Build publishers and consumers that stay correct when messages are duplicated, late, out of order or failing.

Choose between thin and fat events, coordinate a workflow across services with a saga, and decide when CQRS, event sourcing or event-driven design is worth its cost.

Build event-driven features in .NET, from an in-process queue to a broker with a framework or Dapr, and trace an event across services.

Explain what makes a model an agent, and build the core loops of tool use, planning, ReAct and reflection.

Decide what goes into an agent's context window on every call, and trim, order and scope it when it grows.

Explain how RAG puts fresh and private data in front of a model, and choose between RAG, long context and agentic retrieval.

Choose between a router, a handoff, a group chat and a swarm, and say what each one costs.

Say which protocol connects an agent to a tool, to another agent, and to a user, and what one MCP tool call looks like on the wire.

Name the risks of an agent that reads text and calls tools, and put the right control in front of each one.

Test an agent before release, watch it after, and follow the lifecycle that connects the two.