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Invariant Examples & Showcases

Start with validated workflow patterns. Larger applications remain labeled as showcases because their real provider, desktop, browser, or media boundaries are not covered by the unit suites.


Experimental Showcase

EXPERIMENTAL — NOT A VALIDATED BETA EXAMPLE

One Workflow. Three Channels. Real Booking Infrastructure.

An evolving salon booking and appointment-management reference design where Web UI, AI Chat, and Gemini Live Voice target the same workflow. The package typechecks and its mock-backed tests pass; use it as an architecture tour until live integrations have their own acceptance suite.

  • The Core Idea: The channel interprets interaction. The runtime owns execution.
  • Follow One Booking: Trace how a single .wait("select-date-ui") step is handled across Web, Voice, and Chat.
  • Bounded Action Space: The voice projector extracts only what matters now for Gemini Live.
  • Fresh-State Validation: Model mistakes are rejected at the boundary without corrupting execution history.
  • Boulevard GraphQL integration design: cart initialization, appointments, slot holds, and checkout boundaries.

👉 Read the Full Boulevard Showcase →


📚 Workflow Patterns & Core Examples

ExampleTypeKey Invariant Concept
Durable Refund FlowCapability & OutboxIdempotency keys, side-effects, payment gateway dispatch
Human Approval FlowSuspension & HITL.wait() boundaries and schema validation
Crash Recovery PrimitivesAdvanced designPersisted facts and target host design; public attach/claim APIs are not yet available
Hello AgentConversational Agentapp.agent(), intent routing, safe runtime action execution
Workflow Patterns CatalogPattern CatalogPure deterministic steps, .reason() with LLMs, .branch() and .repeat()

Core Architectural Guarantees

Every Invariant example demonstrates three core principles:

  1. Different channels, same execution truth: Chat, voice, and deterministic UI can drive the same workflow without owning its state.
  2. Model mistakes do not become execution history: External proposals pass through strict schema and fresh-state action validation. Invalid inputs are rejected at the boundary; workflow state remains untainted.
  3. External effect intent is durable: Capabilities use stored command intent and stable idempotency identity. External exactly-once behavior requires the provider to enforce idempotency.

Additional experimental source tours

Invariant Durable Execution Engine.