Capability and Package Map

Overview

Choose a Mississippi capability by the work your application needs to do, then use the package tables to find its contracts and implementation. A domain feature commonly spans several packages: your business rules stay in the domain model while generators connect the runtime, gateway, and client.

This reference maps all 46 projects under src/ to their consumer roles. Package identities use the Mississippi. prefix defined in Directory.Build.props; src/Directory.Build.props enables packing for source projects.

This map describes the current development source, and its GitHub source links follow main. When using a released package, compare the linked contract with that package's release tag or commit. When preparing a versioned documentation snapshot, pin its source links to the corresponding release revision so the examples and evidence stay aligned.

Choose a Capability

Your application needs to	Capability	Start with
Accept a business request only when its rules hold	Commands, handlers, and aggregate state	Write model
Keep a durable history of accepted changes	Named event streams and persisted events (Brooks)	Brooks
Reconstruct state from events	Event reducers and snapshots	Tributary
Present several views of the same business history	UX projections	Build projections
Coordinate work across aggregates	Saga steps and compensation	Build a saga
React to accepted events	Event effects and worker-grain effects	Domain Modeling
Generate HTTP endpoints, DTOs, and client actions	Inlet source generators	Inlet
Refresh subscribed UI state after server changes	Inlet projection subscriptions and Reservoir state	Read models and client sync
Make client state changes explicit and inspectable	Reservoir actions, reducers, selectors, and effects	Add a Reservoir feature
Deliver SignalR messages across gateway instances	Aqueduct backplane	Aqueduct
Compose Blazor screens from state and events	Refraction components and scenes	Refraction
Expose domain operations to an AI tool client	Generated MCP tools and metadata	Spring MCP setup
Develop a feature with an AI coding assistant	Explicit rules, generated integration, and behavioral verification	Build a feature with AI

Package Roles

Abstractions packages provide contracts and extension points. Runtime packages supply Orleans execution or server implementations. Gateway packages integrate with ASP.NET Core. Client packages provide client integration. TestHarness packages support tests of the behavior you author.

Use the SDK composition packages when following the full application pattern. Use individual packages for a focused capability, such as Reservoir state management or Aqueduct's SignalR backplane. A package's project file, linked below, is the authoritative dependency list.

Application Composition

Package	Consumer role
Mississippi.Sdk.Runtime	Composes runtime libraries and Cosmos providers for a silo project
Mississippi.Sdk.Gateway	Composes gateway libraries for an ASP.NET Core project
Mississippi.Sdk.Client	Composes client hosting, Inlet, and Reservoir libraries
Mississippi.Hosting.Abstractions	Shared host builder contracts and structured composition diagnostics
Mississippi.Hosting.Runtime.Abstractions	Runtime-role builder contracts and Orleans integration diagnostic codes
Mississippi.Hosting.Runtime	Validated terminal composition for Orleans runtime hosts
Mississippi.Hosting.Client	Provides ClientBuilder and UseMississippi() for Blazor WebAssembly client composition

Build-Time Generator References

Configure source generation in the project that consumes the domain types. SDK library references and compiler analyzer references are separate inputs. In source-based applications, Spring explicitly references both the matching Inlet generator and Inlet.Generators.Core with OutputItemType="Analyzer", ReferenceOutputAssembly="false", and PrivateAssets="all".

Consuming project	Generator project	Verified project configuration
Orleans runtime	Inlet.Runtime.Generators	Spring.Runtime.csproj
ASP.NET Core gateway	Inlet.Gateway.Generators	Spring.Gateway.csproj
Blazor client	Inlet.Client.Generators	Spring.Client.csproj

The SDK projects mark their own analyzer references private. Use the explicit consuming-project configuration above when building from source, and verify analyzer delivery separately when composing an application from NuGet packages.

See Spring host applications for the domain, runtime, gateway, and client project boundaries. For a client entry point, use Inlet getting started.

Business Behavior

Package	Consumer role
Mississippi.DomainModeling.Abstractions	Command handlers, operation results, aggregate/projection grain contracts, event effects, and saga contracts
Mississippi.DomainModeling.Runtime	Executes aggregate commands, event effects, sagas, and UX projections
Mississippi.DomainModeling.Gateway	Base classes for aggregate services/controllers and projection controllers
Mississippi.DomainModeling.TestHarness	Tests handlers, reducers, aggregate scenarios, and effects without hosting the distributed application

Start with adding an aggregate command. The same explicit command and event types give developers and AI assistants a small, named unit of behavior to implement and review.

Event History, State, and Storage

Package	Consumer role
Mississippi.Brooks.Abstractions	Brook identity, event envelopes, storage-name attributes, and read/write grain contracts
Mississippi.Brooks.Runtime	Brook readers, writers, and cursor tracking
Mississippi.Brooks.Runtime.Storage.Abstractions	Event storage provider, reader, and writer contracts
Mississippi.Brooks.Runtime.Storage.Cosmos	Cosmos event storage with Azure Blob lease locking
Mississippi.Brooks.Serialization.Abstractions	Serialization provider, reader, and writer contracts
Mississippi.Brooks.Serialization.Json	JSON event serialization
Mississippi.Tributary.Abstractions	Event reducer, snapshot, and snapshot-key contracts
Mississippi.Tributary.Runtime	Composes reducers and reconstructs, caches, and persists snapshots
Mississippi.Tributary.Runtime.Storage.Abstractions	Snapshot storage provider, reader, and writer contracts
Mississippi.Tributary.Runtime.Storage.Cosmos	Cosmos snapshot storage
Mississippi.Common.Runtime.Storage.Abstractions	Shared retry-policy contract for storage implementations
Mississippi.Common.Runtime.Storage.Cosmos	Cosmos retry policy for transient storage failures

Use Brooks storage providers and Tributary storage providers for the event and snapshot provider boundaries. Keep the persisted event history distinct from the derived state that reducers reconstruct.

Generated Interfaces and Client Synchronization

Package	Consumer role
Mississippi.Inlet.Abstractions	Shared projection-path metadata
Mississippi.Inlet.Generators.Abstractions	Attributes for generated endpoints, commands, sagas, DTO customization, authorization, and MCP tools
Mississippi.Inlet.Generators.Core	Shared analysis and generation support used by the target-specific generators
Mississippi.Inlet.Runtime.Abstractions	Projection discovery, subscription, and authorization metadata contracts
Mississippi.Inlet.Runtime	Runtime projection registration and subscription handling
Mississippi.Inlet.Runtime.Generators	Generates domain, aggregate, projection, and saga silo registrations and saga status reducers
Mississippi.Inlet.Gateway.Abstractions	Server projection notification contracts and in-process notifier integration
Mississippi.Inlet.Gateway	Inlet SignalR hub, gateway registration, and subscription authorization options
Mississippi.Inlet.Gateway.Generators	Generates HTTP controllers, server DTOs, MCP tools, and gateway registrations
Mississippi.Inlet.Client.Abstractions	Projection state, subscription actions, selectors, and client contracts
Mississippi.Inlet.Client	Fetches projections, manages SignalR integration, and exposes projection-aware Blazor components
Mississippi.Inlet.Client.Generators	Generates client DTOs, mappers, command/saga actions, effects, state, reducers, and registrations

Generation operates on attributed domain types. Application code still supplies business rules, host configuration, and UI composition. See Inlet reference for the current client builder entry points.

Client State and Blazor UI

Package	Consumer role
Mississippi.Reservoir.Abstractions	Store, feature state, action, reducer, effect, middleware, and builder contracts
Mississippi.Reservoir.Core	Store execution, feature registration, reducer/effect composition, and memoized selectors
Mississippi.Reservoir.Client	Blazor store components, navigation/lifecycle features, and Redux DevTools integration
Mississippi.Reservoir.TestHarness	Given/When/Then scenarios for feature reducers, effects, emitted actions, and resulting state
Mississippi.Refraction.Abstractions	Theme, focus, and motion preference contracts
Mississippi.Refraction.Client	Blazor components, state/event contracts, and design tokens
Mississippi.Refraction.Client.StateManagement	Reservoir-connected scenes that pass state to Refraction components and handle their events

For state management alone, start with Reservoir getting started. Use Refraction for component composition on top of that state.

Distributed SignalR and Shared Mapping

Package	Consumer role
Mississippi.Aqueduct.Abstractions	Backplane grain contracts, messages, keys, and options
Mississippi.Aqueduct.Gateway	SignalR lifetime manager, local connection handling, and Orleans stream integration
Mississippi.Aqueduct.Runtime	Orleans grains for connection routing, groups, users, and server tracking
Mississippi.Common.Abstractions	Mapper contracts, collection mapping, and mapping registration

Summary

Packages define installation and extension boundaries. Commands, events, reducers, projections, and actions define the application behavior that you and your team work on.

Next Steps

• Build a feature with AI for a repeatable development workflow.
• Add an aggregate command for a concrete domain example.
• Reservoir getting started for client state management.