Playground

A deterministic, interactive Core Playground reference implementation runs locally on synthetic appointment fixtures and includes an embedded causal Trace. It is internal, uses scoped local logic rather than the current Core/Runtime/Actions package tuple, and is not included in this Portal or the private-preview download. This page and the Lumber guided tour do not launch that implementation. No hosted Playground or participant access is currently supplied.

What it adds

A scenario declares its inputs, expected lifecycle branch, fault, and bounded result before a run. It can demonstrate pre-dispatch clarification, authorization denial, provider acknowledgement without read-back, or lost-response UNKNOWN without contacting a provider. It does not prove a live integration or production behavior.

Example

A synthetic parcel-label scenario begins with two matching destination records. The correct branch asks for clarification and keeps the operation NOT_DISPATCHED. A second run crosses the synthetic dispatch boundary, loses the response, and returns UNKNOWN; the safe next step is verifier-only reconciliation, never a blind redispatch.

The fixture can prove that the declared scenario and runner behaved as designed. It cannot prove credentials, database behavior, exactly-once execution, process-loss cleanup, or production readiness. The host still supplies the real application backend, policy authority, provider adapter, authoritative system, verifier, durable action record, and operational logs.