RFC-NVS-0200

Abstract

This specification defines L-Ports and the language-neutral L-ABI used to form SensOS perception, reasoning, and control pipelines. An L-Port is a self-describing runtime interface, represented by a type: port HEXT object. The protocol exposes ports to MCP-compatible clients through discovery, inspection, and invocation operations.

Layer contract

Layer	Input	Output	Responsibility
L0	raw stream	L0_RawPayload	multimodal ingestion
L1	raw payload	L1_ObservationObject	source, time, and confidence metadata
L2	observation	L2_SemanticFeature	semantic annotation
L3	semantic feature	L3_HEXTObject	canonicalization and immutable storage
L4	canonical HEXT	L4_GeometricState	distance, curvature, and velocity
L5	geometric state	L5_RiskBeliefState	belief and safety-boundary evaluation
L6	risk/belief state	L6_ControlCommand	cybernetic control decision
L7	control command	L7_ExecutionOutcome	policy application and outcome reporting

A port descriptor MUST include an identifier, layer, semantic version, input and output type/schema, capabilities, provider, and ABI version. Binding is permitted only when adjacent contracts and ABI versions are compatible and CBAC authorizes the required action.

MCP surface

The server MUST provide discover_ports, inspect_port, and invoke_port. DLNP extends this surface with negotiation and pipeline-lifecycle operations. The server MUST return only ports and operations that the caller is permitted to inspect or use.

L-ABI requirements

The native ABI uses C-compatible, versioned structures. Every extensible structure MUST begin with struct_size and abi_version. A packet contains a timestamp, serialized payload, and an optional 32-byte content_id. content_id MUST be absent or all-zero before L3 canonicalization and MUST be the SHA-256 identifier of the canonical HEXT object at L3 and later.

On successful invocation, the provider allocates the output packet. The caller MUST release it through that provider’s free_packet callback and MUST NOT free it through another allocator. Receivers MUST ignore fields beyond the recognized struct_size.

Canonicalization

Raw L2 output and canonical HEXT identity are different concepts. The L3 Canonicalizer MUST transform structured features into a defined canonical form, such as sorted keys, excluded nondeterministic fields, and specified numeric rounding, before computing content_id. Implementations MUST NOT claim independently generated model text has the same identity without this transformation.

Normative keywords

The key words MUST, MUST NOT, SHOULD, SHOULD NOT, and MAY are to be interpreted as described in RFC 2119 and RFC 8174 when written in uppercase.