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Turn on the local sandbox for everyday Copilot CLI work, move to a cloud sandbox when the code or the task should never touch your laptop, and use a dev container when the team needs the same reproducible toolchain. Compared on Copilot CLI 1.0.104: what each boundary isolates, what it leaks, what it costs, and how to stack them.

EF Core never updates a key value on a tracked entity. Stop copying the key from DTOs, use a unique index instead of an alternate key, and change a real key by inserting a new row and deleting the old one. Tested on EF Core 10.0.14.

Anything you compile into a Flutter web build, including --dart-define values, ships to the browser in plain text. The only safe pattern is a small backend proxy that holds the key, authenticates the user, pins the model, and streams the Responses API SSE back. Full Dart shelf proxy and Flutter client, tested with Flutter 3.44, Dart 3.12, and http 1.6.

Enumerable.Zip allocates 144-208 bytes per call and runs about 10x slower than a plain loop. For arrays and lists, a for loop over two spans sliced to the same length is allocation-free and the fastest option; for foreach syntax, a small ref struct zip enumerator gets within 25% of it. Measured on .NET 10.0.10 and .NET 11 RC 3.

Polly.Core 8.8.1 starts the circuit breaker's background loop under ExecutionContext.SuppressFlow, so a long-lived pipeline stops pinning the AsyncLocal values of whoever built it. A 15-line repro shows the leak on 8.8.0 and the fix on 8.8.1.

Use /fleet for a one-off parallel task in your terminal, a dynamic workflow when the same multi-agent process has to run the same way twice, and GitHub Agentic Workflows when that process runs unattended on repository events. Compared on Copilot CLI 1.0.103 and gh-aw v0.93.6: who plans the split, limits, resume, permissions, write safety and billing.

The October 25, 2026 out-of-band release (.NET 8.0.33, 9.0.22, 10.0.14, 11 RC3) fixes a Brotli buffer overflow, a Linux tarball ownership flaw, and two CVEs the October 13 patches did not fully close.

Pass --output-dir once per DbContext and EF Core keeps every later migration in that folder and namespace. Why the default layout is lopsided, the CS0111 collision you get from a shared folder, how to move existing migrations, and when to split the history table.

Add a second UseStaticFiles call with a PhysicalFileProvider and a RequestPath. Why MapStaticAssets can't do it, the absolute-path and content-root traps, dot files and unknown extensions, publishing the folder, and putting it behind authorization. Tested on ASP.NET Core 10.

outputTemplate is fixed per sink, so per-level formatting needs either an ExpressionTemplate with {#if @l ...} blocks or two Logger sub-loggers with ByIncludingOnly / ByExcluding filters. Both configured purely from appsettings.json, tested on Serilog 4.4, Serilog.Settings.Configuration 10.0.1 and Serilog.Expressions 5.0.