Chronicle and Arc used to derive database names and connect with one credential. Now they can ask. This post shows how the question and the answer work, and wires one example through a Chronicle kernel, an Arc application and a plain client with no Arc in it.
Chronicle's own documentation says it isn't a DCB event store. So why do I keep using the term? A proposal to drop the acronym and name what we actually want from it: freedom in how events are modeled, one owner for every event, and rules that live with the command.
A walkthrough of how Cratis Studio is built: the services and what each one owns, the edge and the lobby in front of them, four event stores that talk in facts, and the infrastructure underneath. Studio is built with the platform it's meant to help you use.
Give each stage of an entity its own read model and let Chronicle move it from one to the next. No Status column, no pile of nullable fields, nothing to index just to find the backlog. How projection variants work, model-bound and fluent.
Model-bound projections put the mapping on the read model. Fluent projections keep it beside the model, in IProjectionFor
Sign-in, tenant, identity and invitations are the same chores in every service. AuthProxy is a container you configure at the ingress, in front of services written in anything, so they can assume the request is already authenticated, tenant-scoped and enriched. Here's how it works, what it buys you in security, and where Arc and Ante fit.
Arc generates the commands and queries. Cratis Components is the layer that turns them into dialogs, forms and tables, without tying you to a UI library. Here's why it exists, how it works, and what 'agnostic' honestly covers.
Most of a form isn't the fields. A command form links a form to a command by its type, so you write the fields and Arc handles the state, the validation and the errors. And because it's all typed, the compiler guards the way for you, and for your AI assistant.
The classic way to enforce uniqueness in an event-sourced system, check a read model and then append, loses races by design. Chronicle constraints move the check into the kernel, and in doing so put the Dynamic Consistency Boundary to work.
A projection describes a read model. A reactor does something about the outside world. A reducer is the one in between: you write the code that decides what the read model looks like, and Chronicle keeps the storage consistent.
The JVM has bytecode and .NET has IL. Over the last couple of weeks Screenplay became that for the business: one .play model that people, AI assistants, Studio and your C# code all write, and that VS Code, your MCP host, your running Arc application and the Cratis CLI all draw as the same event model board.
The zero-to-first-projection walkthrough again — same store, same domain, same destination — but this time Claude Code does the typing, using the official .NET templates and the Cratis AI cratis/application/csharp profile installed with the Cratis CLI, with Arc commands carrying the full loop.
