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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.