The Missing Identity Layer- A Minimal Ontology for Live and Exploratory Modeling

Model-driven engineering (MDE) treats identity as an implicit property of files, repositories, and tool-specific identifiers. This assumption fails under live and exploratory modeling, where models evolve interactively, spawn parallel variants, and migrate across execution environments. Version control tracks syntactic change; identity explains continuity. This paper introduces SEBA—a minimal, four-layer ontology of identity continuity: Substrate, Execution, Behavior, Attestation. SEBA was originally developed for autonomous AI agents (Ecker-Fils, 2026a–2026e) and is here generalized to persistent synthetic artifacts such as software models. We identify five structural failure modes arising from implicit identity: · Fork collision ambiguity· Silent restoration (implicit version reset)· Infrastructure-bound identity reset· Design space amnesia· Attestation and provenance gap We map SEBA to MDE, showing that: · Substrate ensures identity is tool- and repository-independent· Execution binds runtime traces to model versions· Behavior defines invariants whose violation signals identity-relevant drift· Attestation provides cryptographically verifiable provenance We demonstrate that SEBA resolves the core challenges of live and exploratory modeling: bidirectional consistency becomes a matter of distinguishing continuity from fork; design space exploration becomes reconstructable because variants are persistent identities; feedback becomes attributable because execution traces are bound to identity. Implications are outlined for tool architecture, MDE research, and alignment with emerging standards (SLSA, SBOM, W3C DIDs, NIST AI RMF). Appendices provide a glossary, a detailed scenario (automotive braking system), and a systematic comparison with existing versioning systems (Git, EMF Compare, CDO). Key Contributions 1. Structural gap identification: MDE has versioning but no identity semantics. The paper formalizes five failure classes as expressions of this deficit.2. SEBA ontology for MDE: A minimal (four-layer) and complete ontology of identity continuity, mapped to modeling concepts.3. Resolution of live/exploratory modeling challenges: Demonstrates how SEBA addresses bidirectional consistency, design space reconstruction, attribution, tool migration, and safety-critical provenance.4. Implications for tools, research, and standards: Provides a roadmap for adoption, including assurance levels, partial adoption strategies, and integration with SLSA, SBOM, W3C DIDs, and Eclipse EMF. Keywords model-driven engineering; MDE; identity continuity; live modeling; exploratory modeling; software provenance; SEBA; substrate; execution; behavior; attestation; fork; merge; termination; versioning; traceability; safety-critical systems; software supply chain; SLSA; SBOM; W3C DIDs; NIST AI RMF; autonomous agents; digital twins; cyber-physical systems Related Works (SEBA Corpus) This paper builds on the SEBA corpus (Ecker-Fils, 2026): · Execution-Rooted Identity: A Formal System for Identity, Collapse, and Governance (2026a)· Axioms for Identity Preservation in Organized Systems (2026b)· Identity Collapse Taxonomy (2026c)· Substrate-Rooted Identity as an Architectural Construct for Engineered Systems (2026d)· Substrate-Rooted Attestation: Execution-Realized Identity as the Missing Layer Between PUFs and AI Governance (2026e)· The Four-Layer Identity Decomposition: A Substrate-Rooted Ontology for Execution-Realized Identity (2026f)· Priority Statement for Substrate-Rooted Identity, Interpretive Geometry, and Collapse Theory (2026g) Audience · Researchers in model-driven engineering, software language engineering, and software provenance· Practitioners in safety-critical systems (automotive, aerospace, medical) and digital twins· Standards bodies (NIST, W3C, OMG, ISO) working on identity, traceability, and AI governance· Tool developers (Eclipse EMF, Simulink, Papyrus) seeking to implement identity continuity