In reading order.
Trill's Stories service is four projects with a dependency-free domain at the bottom. Its Users service is two projects with everything in one assembly - same author, same week, same estate, opposite answers to what a layer is.
Trill extracts story-text validation into an IStoryTextFactory and leaves the value object's constructor public - plus an implicit conversion from string, so any assignment builds an unvalidated StoryText in one keystroke.
StoryDocument.ToEntity passes the body where the title goes and the title where the body goes. It compiles because of one implicit conversion operator, and it has survived since the first commit because the only code path that would notice is dead.
Trill's last commit built a complete domain-event pipeline - dispatcher, mapper, handlers - and migrated one of the two command handlers onto it. The other still constructs its aggregate directly, so one domain event is never raised and a reputation gate can never fire.
Trill wraps every command handler in logging, metrics, tracing and an outbox using Scrutor's TryDecorate - and the whole arrangement only works because a single attribute keeps the decorators out of the assembly scan that registers handlers.
Trill creates one compound index on its ratings collection, keyed userId then storyId, and every read query in the service filters on storyId alone - so the only index that exists cannot serve the only queries that run.
Trill's browse endpoint loads every rating document for every story on the page into process memory and sums them in LINQ - while the same codebase already has a server-side SumAsync that returns the number without moving a single document.
Trill's User constructor stores the name trimmed but not lower-cased, and the repository looks it up lower-cased. Any account with a capital letter in its name can never be found, which means it can never sign in - and the test fixture is all lowercase.
Trill's Stories service ships a complete caller-identity abstraction - context, factory, claims, an IsAdmin flag - registers it in the container, and injects it into nothing, while every endpoint reads the user id out of the request body instead.
The same .NET format specifier means thirty-two hex digits on a Guid and a grouped decimal on a long - and Trill's timeline writes its sorted-set members one way then reads them the other, so every non-empty timeline throws.
Trill's Timeline service stores each story body once and fans out only the identifier into every follower's sorted set - the right hybrid design, executed as a sequential foreach with one Redis round trip per follower and no batching anywhere.
Trill's entire ranking engine is thirty-nine lines of OrderByDescending().Take(10) over counters that only ever increase - no time window, no decay, no visibility filter - so once the top ten stabilises it can never change again.
Trill's entire advertising product resolves to one boolean on somebody else's entity - a published ad is a Stories-service story with Highlighted set true - and the flag is priced at a hundred units a day while the same field is free on the public endpoint.
Trill's Blazor WebAssembly client has twenty Razor components, thirty-seven inline style attributes, two authored class names and one stylesheet containing a single rule - and the thinness is not an oversight, it is the most precise measurement of what a teaching repository is.
An honest retrospective on Trill's five services and its client - twelve xunit scaffolds with no test files and no project references, a green test script over nothing, and a defect list where almost every entry would have died to a four-line assertion.