50 added, 11 removed. Audit A to A.
---
name: digital-twin
description: >-
Design, build, evaluate, govern, monitor, evolve, and retire digital twins
and federated twin universes for software systems, engineering processes,
agentic software factories, infrastructure, and cyber-physical operations.
Use when a task involves digital-twin architecture, digital thread, simulation,
predictive maintenance, twin health, agent authority, or dark-factory design.
Do not use for ordinary observability dashboards, static dependency graphs,
generic AI governance, or operating one named infrastructure tool without a
twin-specific representation and feedback loop.
license: MIT
---
# Digital Twin
Use this skill to design and operate a trustworthy digital twin, especially a twin of a software product, engineering process, delivery system, infrastructure estate, or agentic factory.
## Core position
A digital twin is not automatically a dashboard, 3D view, dependency graph, emulator, test fixture, or LLM wrapper. Establish the represented original, synchronization contract, models/services, intended decision, uncertainty, and action boundary before using the term.
For this skill, use these working distinctions:
- **Digital model:** representation without a required live synchronization loop.
- **Digital shadow:** observable flow from original to representation without a governed return path.
- - **Digital twin:** a versioned representation of a named entity or process, synchronized at an explicit frequency and fidelity, with models/services that support a declared decision or action.
+ - **Digital twin:** a versioned representation of a named entity or process, synchronized at an explicit frequency and fidelity, with models/services that support a declared decision or action and a governed feedback relationship to the original. If it is synchronized and useful but has no governed return path, call it a read-only twin or digital shadow rather than implying closed-loop authority.
- **Digital thread:** provenance and lifecycle linkage across systems, artifacts, decisions, and outcomes. A thread is necessary for many twins but is not itself a twin.
- **Twin universe:** a federation or composition of purpose-bounded twins with explicit identity, time, provenance, semantics, ownership, and authority boundaries.
These are operational definitions, not claims of universal standards consensus. NIST IR 8356 explicitly notes that no single definition is agreed, while allowing abstract entities and processes as twin subjects.
+ ## Choose an operating mode
+
+ | Situation | Start in | Evidence required before advancing |
+ |---|---|---|
+ | You only need inventory or explanation | Read-only | Identity, source map, freshness, provenance |
+ | You need counterfactual exploration | Simulation | Pinned snapshot/model/scenario, isolation, uncertainty, teardown |
+ | You need to compare recommendations without effects | Shadow | Independent outcome comparison, abstention, operator disagreement |
+ | You need a reversible low-impact action | Supervised or bounded | Policy, scoped credentials, preconditions, rollback, reconciliation |
+ | You need high-impact or irreversible action | Human-approved exception or do not automate | Close-to-execution approval, independent validation, emergency stop |
+
+ Do not start in a higher-authority mode merely because the model is confident or the user calls the system a dark factory.
+
+ ## Choose an entry point
+
+ | What you have now | Enter here | First question |
+ |---|---|---|
+ | A vague idea or proposed use case | Frame the use case | What original, decision, owner, and harm boundary are actually in scope? |
+ | A graph, dashboard, or event feed | Classify the representation | Is this a model, shadow, emulator, or twin, and what is missing? |
+ | A working twin with stale or conflicting state | Evaluate independently | Which health plane failed, and should authority downgrade to `hold`? |
+ | A validated shadow recommendation | Govern the action path | What exact capability, precondition, rollback, and expiry are authorized? |
+ | A retired or superseded original | Retire deliberately | Which consumers, credentials, evidence, and orphan paths remain? |
+
+ Then follow the numbered workflow and load the matching reference in its navigation table.
+
## Operating workflow
+ Load the matching reference before acting:
+
+ | Decision | Load |
+ |---|---|
+ | Architecture or federation | `references/architecture.md` |
+ | Event, identity, state, provenance, semantics, graph, model, or simulation | `references/implementation.md` |
+ | VVUQ, health, drift, SLOs, or agent evaluation | `references/evaluation.md` |
+ | Security, privacy, authority, or earned autonomy | `references/governance.md` |
+ | Change, incident recovery, or retirement | `references/lifecycle.md` |
+ | Source scope or standards comparison | `references/source-index.md` |
+
1. **Frame the use case.** Name the original, decision, desired outcome, authoritative sources, update/fidelity requirement, operating domain, owner, risk tier, forbidden actions, and simpler alternatives.
2. **Classify the representation.** Decide whether the artifact is a model, shadow, twin, emulator, simulator, or composite universe. Do not upgrade the label without evidence of synchronization, model credibility, and a governed feedback path.
3. **Design the contracts.** Define stable identities, event envelopes, timestamps, schema versions, provenance, freshness, uncertainty, validity intervals, permissions, and action semantics.
4. **Build evidence first.** Capture immutable source events and artifacts, then create replayable temporal projections. Preserve raw evidence separately from claims and disposable views.
5. **Add models and scenarios.** Register model purpose, assumptions, domain, parameters, version, calibration, uncertainty, tests, and prohibited use. Pin scenario inputs, model digests, seeds, clocks, fixtures, and outputs.
6. **Run read-only and shadow modes.** Compare reconstructed state and recommendations with independently captured reality before allowing side effects. Treat missing, stale, contradictory, or unauthenticated evidence as `unknown` or `hold`, not pass.
7. **Govern the action path.** Separate observe, simulate, recommend, approve, execute, rollback, and stop. Put authorization in deterministic policy enforcement, not model prose. Require idempotency, scoped credentials, preconditions, expiry, rollback, and reconciliation.
8. **Evaluate independently.** Keep represented-system health, synchronization/data health, model credibility, platform health, and agent/action quality as separate planes. The twin must not grade itself.
9. **Operate and evolve.** Monitor freshness, loss, ordering, schema/topology drift, residuals, calibration, uncertainty, scenario gaps, platform SLOs, agent trajectories, authority, and outcome value. Revalidate after material changes.
10. **Retire deliberately.** Revoke action authority, drain and migrate consumers, preserve required lineage, remove secrets and sensitive data under policy, mark endpoints retired, detect orphan calls, and verify no live workflow still depends on the twin.
- ## Choose the right reference
+ ## Reference loading
- | Need | Read |
- |---|---|
- | Architecture and federation | `references/architecture.md` |
- | Data, identity, event, graph, model, and simulation implementation | `references/implementation.md` |
- | VVUQ, health planes, SLOs, drift, agent evaluation, and chaos tests | `references/evaluation.md` |
- | Security, privacy, decision rights, and earned autonomy | `references/governance.md` |
- | Growth, change, incident recovery, and decommissioning | `references/lifecycle.md` |
- | Standards, source boundaries, and further reading | `references/source-index.md` |
+ The **Operating workflow** navigation table is canonical: load the matching reference there before acting. The same references remain directly addressable for deep dives: architecture, implementation, evaluation, governance, lifecycle, and source-index.
## Agentic software factory boundary
A software factory analogue maps repositories, revisions, requirements, builds, artifacts, dependencies, services, environments, deployments, incidents, humans, agents, policies, and runtime observations to twin entities and events. Executable repository environments, service emulators, traffic mirrors, IaC sandboxes, and learned world models are useful components, but each has a simulator-reality boundary. Real execution remains the release oracle for consequential code and infrastructure changes.
A dark factory is an authority state, not a twin type. More automation requires stronger independent validation, provenance, staged rollout, rollback, and accountable escalation. Do not equate high model confidence with authority.
+ ## Choose the artifact
+
+ | User needs | Produce | Template/reference |
+ |---|---|---|
+ | Define a twin and its authority | Twin manifest | `templates/twin-manifest.yaml` + `references/architecture.md` |
+ | Test fidelity, synchronization, or agent behavior | Evaluation plan | `templates/evaluation-plan.md` + `references/evaluation.md` |
+ | Decide whether to grant or expand authority | Release evidence packet | `templates/release-evidence.md` + `references/governance.md` |
+ | Change, recover, or retire a twin | Lifecycle record | `references/lifecycle.md` |
+
+ Use the smallest artifact that answers the decision; do not create a twin universe when a bounded model, shadow, emulator, or ordinary observability record is sufficient.
+
## Minimum release packet
- Before granting non-read-only authority, preserve:
+ Before granting any authority beyond read-only, preserve the following evidence packet. It is the release gate, not a suggestion:
- intended-use, risk, and authority contract;
- source and identity map;
- event/schema/provenance contract;
- assumptions, validity limits, and uncertainty budget;
- verification and independent validation results;
- synchronization/data-quality benchmark;
- scenario and replay manifest;
- agent task and trajectory evaluation;
- security, privacy, and supply-chain review;
- shadow/canary and rollback evidence;
- health SLOs and alert ownership;
- signed `approve`, `conditional approve`, `hold`, or `block` decision.
## When not to use
Do not load this skill for ordinary dashboard construction, static asset inventory, generic dependency mapping, generic AI governance, generic DevOps design, or routine operation of a named tool. Route those tasks to the relevant observability, AI-governance, platform, data, or tool-specific skill. In this repository, use `agent-evals-and-observability` for generic agent eval/telemetry, `ai-governance` for organization-wide AI governance, `data-architect` for general data-platform design, and the relevant tool skill for operating a named platform. Load this skill when the representation itself, its synchronization, simulation/prediction, composition, authority, or lifecycle is the problem.
## Exit criteria
Stop when the requested twin design or decision artifact exists, claims are separated into evidence and inference, the relevant evaluation/governance gates are explicit, and unresolved gaps have owners or bounded escalation. Never claim a twin is trustworthy, autonomous, production-ready, or safe solely because its schema, graph, dashboard, or component tests pass.