PhiGraph Core 4.0: A Shadow-First Evidence Ledger and Policy-Gated Runtime for Software-Agent Operations

PhiGraph Core 4.0.0 is a model-agnostic governance system for software-agent and AI operations. The paper describes its typed claim-evidence-policy-action protocol, scope-tagged tamper-evident ledger, policy-gated runtime, shadow-first deployment boundary, Python implementation, software verification, and an initial external anomaly-ranking experiment on CIC-IDS2017. It also describes PhiGraph HAV v0.2, a fail-closed extension that verifies agent-generated textual claims against an explicitly supplied authoritative state and records the result through the same protocol and ledger. Results are interpreted conservatively and include explicit implementation gaps and threats to validity.