JSON Contracts, AI Workflows, and Query Plans
A varied .NET roundup covering Swagger polymorphism, ASP.NET Core claims, RAG and MCP choices, PostgreSQL plans, and C# fundamentals.
Jasen's top three picks
- 1 Is Any() Really Better Than Count() > 0?
medium.com
A sensible performance question with the right answer: measure the source, provider, and intent before declaring a LINQ winner.
- 2 System.Text.Json Polymorphism with Swagger in .NET 7
medium.com
Serialization support alone is not an API contract; OpenAPI consumers need the discriminator story too.
- 3 Operators & Control Flow in C#: What .NET Interviews Actually Ask
medium.com
Useful interview preparation for revisiting the C# mechanics developers use every day.
Editor's note
I pulled together a deliberately broad mix today, from language fundamentals to AI workflow design and database diagnostics. The System.Text.Json and Swagger piece matters because API contracts need to remain coherent beyond serialization. Milan Jovanović’s PostgreSQL index example is a useful reminder to verify query plans rather than assuming another index helps.
Today's articles
Is Any() Really Better Than Count() > 0?
medium.com
Like everything else in life, it depends.
Topics: C# Performance
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System.Text.Json Polymorphism with Swagger in .NET 7
medium.com
Polymorphic JSON is not finished when System.Text.Json can serialize a derived type. The same discriminator contract must survive OpenAPI…
Topics: C# System.Text.Json Web API
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Operators & Control Flow in C#: What .NET Interviews Actually Ask
medium.com
Value types vs reference types usually opens a .NET interview — operators and control flow is often where it continues. Most of it looks…
Topics: C#
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CommandFlow — version 2.0
medium.com
A few weeks ago, I presented CommandFlow, the alternative to CQRS and MediatR. The goal of the framework was to provide a simple but…
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Microsoft Agent Framework: Human In The Loop
jesseliberty.com
tl;dr If you’re building automated workflows that sometimes must pause for human judgment (approvals, moderation, triage), Microsoft Agent Framework provides first‑class HITL primitives: typed Request...
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Authentication in ASP.NET Core
medium.com
A deep-dive walkthrough of authentication in ASP.NET Core — covering the ClaimsPrincipal/ClaimsIdentity model everything else builds on…
Topics: ASP.NET Core Authentication
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How can I remove the Close button from my window caption?
devblogs.microsoft.com
Occasionally, somebody wants to create a window without a Close button. The only way to get rid of the Close button is not to have a System menu at all: Remove the WS_SYSMENU style from the window. B...
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Building a RAG Application with .NET 10 and OpenAI
medium.com
A practical, step-by-step introduction to embeddings, vector similarity, retrieval, and grounded LLM responses using C# and .NET 10.
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Adding an Index Made This Query Slower
milanjovanovic.tech
A query already had a usable index. Adding another index made Postgres choose a plan that discarded almost half a million rows to return ten.
Topics: Performance PostgreSQL
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What if an agent could refactor your agent?
youtube.com
https://aka.ms/foundry-portal https://aka.ms/InsideMicrosoftFoundryPlaylist Your cupcake agent works. But is it still using the current Microsoft Foundry pattern? Would you notice if the SDK changed? ...
Topics: Azure
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Value Types vs Reference Types in C#: What .NET Interviews Actually Ask
medium.com
If there’s one C# fundamentals topic that shows up in almost every .NET interview, it’s this one. It sounds simple on the surface — “value…
Topics: C#
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8 Modern C# Features That Make Everyday Code Shorter and Safer
medium.com
C# has changed a lot since the C# 7 days, and most of the additions are not exotic language-designer toys.
Topics: C#
Read articleWhen (Not) to Use MCP in .NET: A Practical Guide
topuzas.medium.com
I built a working MCP server in C#, hit every production gotcha the tutorials skip, and then had to ask myself if any of it was necessary
Topics: C#
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I Built a Finite-State Transducer in C# Because a Dictionary Wasn’t Enough
jordansrowles.medium.com
There are not many situations in normal C# development where you start with
Topics: C# Design Patterns
Read articleWhy didn't ReadDirectoryChangesW provide a way to correlate the two sides of a rename operation?
devblogs.microsoft.com
Brian Dellisanti asked why ReadDirectoryChangesW didn't provide a way to correlate the two sides of a rename operation. I wasn't there, but I can guess. My guess is that the implementation alwa
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