Structural Validator With Fallback Routing: Schema Verification Before Execution

Mechanism

The structural validator is the first component encountered by any workload that crosses a zone boundary in the direction of execution. It receives the workload envelope, which carries a declared operation graph, a lineage chain, a governance descriptor, and signed attestations from prior substrates. Before any executor is permitted to observe the workload's payload, the validator performs a sequence of structural checks whose successful completion is recorded as a signed admission receipt and whose failure produces a signed refusal entry. Both outcomes are persisted to the lineage chain so that the admission decision is itself part of the workload's tamper-evident record. The validator is positioned so that no execution path bypasses it; the platform's substrate refuses to instantiate an executor for any workload that lacks a current admission receipt signed by the receiving zone's validator key.

The first check is graph well-formedness. The validator parses the declared operation graph, verifies that it is a directed acyclic graph over the platform's operation vocabulary, confirms that every edge connects compatible operation ports, and rejects graphs that contain cycles, dangling references, or operations not registered in the zone's admission catalogue. The check is performed against a canonical schema whose hash is included in the admission receipt, ensuring that a verifier replaying the decision can identify the schema version that was in force. The graph check also evaluates type-level compatibility between the outputs of one operation and the inputs of another, so that workloads carrying syntactically valid but semantically broken graphs are caught at admission rather than at execution.

The second check is lineage integrity. The validator walks the workload's lineage chain from its root, verifies that each entry's signature resolves under an attestation key that was valid at the time of signing, recomputes the chain's Merkle roots, and confirms that the most recent root agrees with the root carried in the workload envelope. A chain that fails any of these tests is treated as forged and refused, regardless of any other property of the workload. The lineage check also verifies that the chain's slope records, where present, are continuous within tolerance, so that a workload that has accumulated a structurally inconsistent trajectory across propagation hops is refused at the first admitting zone that observes the inconsistency.

The third check is governance conformance. The validator compares the workload's declared governance envelope, including its data sensitivity, expected residency, obligation set, and capability scope, against the admitting zone's published admission policy. A workload whose envelope exceeds the zone's policy in any dimension is refused. A workload whose envelope is strictly contained within the zone's policy is admitted; a workload whose envelope is incomparable, that is, dominates the zone in some dimensions while being dominated in others, is refused as ambiguous. Refusal of incomparable envelopes is deliberate: the platform does not permit admission decisions to depend on implicit prioritisation of dimensions, because such prioritisation would create paths by which a workload could be admitted through one zone and not another based on undocumented adjudication.

When any of these checks fails, the validator consults a fallback routing rule defined by the zone. For graph well-formedness failures and certain narrowly defined lineage anomalies, such as a missing intermediate entry that can be supplied from a witness service, the workload may be diverted to a delegation engine. The delegation engine performs bounded schema reconstruction: it attempts to canonicalise the operation graph, fetch missing lineage entries from authorised witnesses, and re-present the workload to the validator a single additional time. If the delegation engine cannot produce a workload that passes validation within its bounded budget, the workload is refused and the refusal entry records the failure mode. Governance failures are never eligible for delegation; a workload that exceeds the zone's policy is refused immediately and irrevocably, because governance refusal reflects a policy decision rather than a recoverable structural deficiency.

Each admission decision, whether accept, refuse, or delegate-then-decide, produces a signed entry that is appended to the workload's lineage chain and that becomes part of the platform's audit surface. The signed entry is structured so that downstream components can extract the decision class without parsing free-text explanation, and so that auditors replaying the decision can independently verify it against the recorded policy version, schema version, and witness state at the time of admission. The validator's decisions are therefore not merely operational events; they are first-class artifacts that travel with the workload and that can be used by downstream consumers, settlers, and auditors as evidence of admission posture.

Operating Parameters

Validator throughput is bounded by the cost of the three checks and by the size of the lineage chain. Graph well-formedness is linear in the number of edges; lineage integrity is linear in the chain length, with chain compaction reducing the effective length seen by the validator; governance conformance is constant in the size of the envelope and the policy. In typical deployments the validator processes admission decisions at substrate-edge latency budgets, with the lineage check dominating when chains are long. Operators concerned about lineage-check cost can configure the validator to accept compacted chain prefixes signed by recognised compaction authorities, trading some auditable granularity for reduced verification cost while preserving the cryptographic continuity of the chain.

Admission policy is published by the zone as a signed document whose hash is referenced in every admission receipt. Policies are versioned, and the validator retains the ability to evaluate workloads against historical policy versions for the purpose of audit replay. The active policy version at the time of admission is recorded so that a later auditor can determine whether a workload would have been admitted under a different policy. Policy version changes are themselves audited events, and the platform records the transition between versions so that workloads admitted across a version boundary can be analysed against either version as required.

The delegation engine operates under a bounded budget expressed as a maximum number of reconstruction steps, a maximum wall-clock duration, and a maximum number of witness queries. The budget is configured per zone and is included in the refusal entry when the budget is exhausted. Delegation is single-attempt: a workload that has been delegated once and then refused cannot be delegated again on the same admission attempt. The single-attempt rule prevents an adversary from amplifying the validator's cost by inducing repeated delegation cycles, and it ensures that the worst-case cost of a single admission decision is bounded by the sum of one validator pass and one delegation budget.

Refusal entries carry a structured failure code drawn from a fixed enumeration: graph-malformed, lineage-broken, governance-exceeded, governance-incomparable, delegation-budget-exhausted, and policy-version-unknown. The fixed enumeration ensures that downstream systems can reason about refusal reasons without parsing free-text explanations, and it allows operators to construct policy-driven responses to specific refusal classes, such as triggering a witness-replication request when lineage-broken refusals exceed a threshold.

Validator state is intentionally minimal. The validator does not maintain per-workload state between admission attempts; each attempt is evaluated as a fresh decision against the current policy. This statelessness is required for the platform's broader determinism guarantees and ensures that two validators presented with the same workload, the same policy version, and the same witness availability reach the same decision. State that the validator does maintain, such as cached attestation keys and policy hashes, is treated as a content-addressed cache rather than as authoritative state, so that the validator can be restarted, replicated, or relocated without affecting decision determinism.

The validator's signing key is rotated on a published schedule and is scoped to the zone in which the validator operates. Key rotation events are recorded in the lineage verification path so that admission receipts signed under a prior key remain verifiable indefinitely. Compromise of a validator signing key is treated as a zone-level incident: receipts signed under a compromised key are flagged in audit replay, and the zone's admission policy may require that affected workloads be re-validated under the new key before further consumption.

Alternative Embodiments

In a first alternative embodiment, the validator is deployed as a sidecar to each executor rather than as a zone-edge service. This embodiment is appropriate where executors are heterogeneous and where admission policy is finely scoped to the executor's specific capabilities. The sidecar deployment retains the mandatory choke-point property because the executor refuses to receive any workload that has not been signed by its co-located validator, and the sidecar's signing key is bound to the executor's identity in such a way that the executor cannot be persuaded to accept receipts signed by a foreign validator.

In a second embodiment, the validator is composed with a co-located policy engine that emits a signed reasoning trace for each admission decision. The reasoning trace records which policy clauses were consulted and how they evaluated against the workload's envelope, supporting audit obligations that require explanation as well as outcome. The reasoning trace is structured so that it can be analysed without granting the auditor access to the underlying workload, separating the audit of admission discipline from the audit of workload content.

In a third embodiment, lineage integrity verification is delegated to a witness service that holds replicated chain roots and returns a signed integrity attestation. This embodiment is used where lineage chains are very long and where the validator's local cryptographic budget is constrained, while preserving the property that lineage integrity is verified against a trusted root. The witness service is constrained to integrity attestation and is not granted any role in admission, so that delegation of cryptographic work does not implicate the witness in admission policy.

In a fourth embodiment, the delegation engine is replaced by a strict refusal mode in which any structural fault produces immediate refusal. This embodiment is appropriate for high-assurance zones in which schema reconstruction is considered an unacceptable widening of the admission surface, and in which the operational cost of refusing a recoverable workload is acceptable in exchange for the elimination of a delegation pathway.

In a fifth embodiment, the validator supports a shadow-admission mode in which a workload is evaluated against a candidate policy version without affecting its actual admission status. Shadow-admission is used during policy migration to estimate the impact of a proposed policy change before it is published as the active version. Shadow decisions are recorded with a flag that distinguishes them from authoritative admission decisions, and they are not visible to consumers as admission receipts.

In a sixth embodiment, governance conformance is evaluated under a lattice ordering that supports partial-order comparison across multiple dimensions, with explicit handling of incomparable envelopes. This embodiment generalises the strict containment check and supports negotiated admission across federated zones whose policies are not totally ordered. The lattice variant produces signed records of the partial-order computation so that incomparable refusals can be reviewed and, if appropriate, addressed by negotiated policy alignment between zones.

In a seventh embodiment, the validator is paired with a pre-validator that performs cheap heuristic checks at the network edge before the cryptographically expensive validator pass is attempted. The pre-validator does not produce admission receipts; it only filters obviously malformed traffic so that the validator's resources are reserved for workloads that have a plausible chance of admission. The pre-validator's decisions are advisory and never authoritative.

Composition With the Cognition-Native Execution Platform

The structural validator is the admission counterpart to the platform's pseudonymous propagation primitive. Workloads that propagate under pseudonymous handles arrive at zone boundaries carrying lineage chains and slope records produced during propagation. The validator's lineage integrity check consumes these chains directly and is the point at which propagation faults are converted into admission refusals. A propagation step that produced a malformed lineage entry will be detected at the next admitting validator, ensuring that propagation faults cannot accumulate silently across multiple hops. The validator therefore performs a closure role for propagation: every propagation chain ultimately terminates at a validator, and every admitted workload has a chain that has been verified by at least one validator.

The validator interacts with zone migration by serving as the admission gate at the receiving zone. When a workload migrates across a zone boundary, the cryptographic handoff produced by the migration protocol is presented to the validator as part of the workload envelope, and the validator's checks include verification that the handoff signature is valid and that the post-migration lineage extends the pre-migration chain. Migration cannot bypass admission; a workload that migrates into a zone is subject to the same structural checks as a workload that originates within or arrives via direct ingress. Migration is therefore not a privileged path but a recognised path, and the validator's behaviour is uniform across paths.

The validator's admission receipts are consumed by the platform's deterministic evaluation discipline. Because admission outcomes are themselves cryptographically committed and replayable, two evaluators replaying the same workload reach the same admission verdict, and downstream evaluation outcomes that depend on admission state remain deterministic. Settlement and consumption layers consult the admission receipt as part of their precondition checks, refusing to act on a workload whose receipt is missing, expired, or signed by a key outside the recognised zone-key trust set.

The delegation engine, when present, operates as a strictly subordinate component to the validator. It does not have authority to admit workloads on its own; it only produces candidate reconstructions that must pass a fresh validator pass. This subordination ensures that the validator remains the single admission authority and that delegation cannot be used as a route around mandatory checks. The delegation engine's outputs are themselves signed and recorded, so that the audit trail of a delegated workload includes both the original envelope, the reconstruction steps, and the final validator decision.

Prior-Art Distinction

Conventional schema validators, such as those used in API gateways and message-bus middleware, check the syntactic well-formedness of payloads against a published schema but do not evaluate lineage integrity, governance conformance, or refuse-on-fault as a structural admission discipline. They are advisory components that can be bypassed by misconfiguration and that do not produce cryptographic receipts of their decisions. Their role is to reduce malformed traffic, not to govern admission, and they do not interlock with downstream settlement or audit.

Conventional admission controllers, such as those used in container orchestration, evaluate workload manifests against cluster policies but treat the workload as inert configuration rather than as a propagating object with a lineage history. They do not check that a workload's declared trajectory is structurally continuous with prior propagation steps, and they do not produce admission receipts that compose with downstream audit. They are operational gates rather than structural primitives.

Conventional supply-chain attestation verifiers check signatures over artifact provenance but do not perform graph well-formedness or governance-envelope conformance as an integrated admission step. They address provenance as a property to be queried, not as a structural admission gate, and they typically operate at build or release time rather than at every zone-boundary crossing.

Conventional fallback or retry middleware retries failed requests against the same handler under the assumption that the failure is transient. The disclosed delegation engine performs bounded schema reconstruction, not retry; it produces a candidate workload that must pass a fresh validation, rather than re-presenting the original workload to the same evaluator. The distinction is structural: retry treats failure as a property of the transport, while delegation treats failure as a property of the workload that may, within bounded effort, be addressed by reconstruction.

Conventional policy engines that emit advisory decisions do not produce mandatory choke-point admission, do not commit their decisions to a tamper-evident chain, and do not impose deterministic behaviour across replicas. They support governance as a recommendation rather than as a structural property of the substrate.

The disclosed validator distinguishes itself by integrating graph well-formedness, cryptographic lineage integrity, governance-envelope conformance, signed admission receipts, structured refusal codes, and bounded schema reconstruction within a single mandatory choke point that produces composable, replayable admission decisions.

Disclosure Scope

This disclosure is directed to a structural validator with fallback routing as a structural primitive of the cognition-native execution platform described in US 19/230,933. The scope of the disclosure includes the three-check admission discipline, the signed admission and refusal entries, the structured refusal-code enumeration, the bounded delegation engine and its budget discipline, and the integration of the validator with propagation, migration, and consumption flows.

The disclosure is not limited to any particular schema language for operation graphs, any particular cryptographic primitive for chain verification, or any particular policy language for governance envelopes. It is not limited to a particular deployment topology and is intended to apply equally to zone-edge, sidecar, and witness-assisted deployments. The disclosure is similarly agnostic with respect to the transport on which workloads arrive at the validator and applies equally to synchronous, asynchronous, and stream-replicated ingress.

The disclosure expressly contemplates the alternative embodiments enumerated above and any combination of them that is not internally inconsistent. The disclosure further contemplates strict refusal mode, shadow-admission mode, and lattice-ordered governance comparison, each as embodiments within the scope of the disclosed mechanism. Combinations such as sidecar deployment with reasoning-trace output and lattice governance comparison are within scope.

The disclosure is bounded by the requirement that admission operate as a deterministic, mandatory, structural property of the execution substrate, rather than as advisory middleware that can be bypassed by configuration. Implementations that relegate admission to optional or post-hoc checks fall outside the disclosed scope. Implementations that retain the mandatory and structural character of admission while varying its constituent algorithms remain within scope.