ship-mlp-core is the portable contract and validation engine that operationalizes NBM4 inside a Git repository. It replaces ad-hoc document sprawl with JSON Schema Draft 2020-12 contracts, immutable artifact identities, and deterministic Continuous Integration guards.

Two-Root Repository Taxonomy (ADR-0060)

Every governed workspace separates method instance artifacts from reusable schemas and validators:

Root Path	Ownership & Role	Key Contents
.0-mlp/	NBM4 Specification & Instance Root	Numbered stage branches (1_idea/, 2_customer/, 3_product/, 4_growth/) plus docs/learn/ for voyage lessons learned. Only the four top-level stages use taxonomy numbers because their sequence represents stable method semantics.
.0-ship-mlp/	Reusable Contract & Validator Root	Versioned discovery registry (schema/registry.jsonc v3.7.0), modular JSON Schema Draft 2020-12 definitions (foundation/, methods/nbm4/, horizontal/), generated catalogs (artifact-catalog.md), and the merge-compatible CI Guard Office (governance/government/executive/guard-office/).

Canonical Metadata Envelope & Provenance

Every governed artifact in .0-mlp/ carries a machine-verifiable metadata envelope bound by .0-ship-mlp/schema/foundation/artifact-metadata.schema.json:

• artifact_uuid: Immutable UUIDv7 generated at creation (UUIDv4 accepted for imported historical artifacts).
• artifact_id: Stable human-readable typed identifier (for example NOTE-0247, ADR-0060, RFC-0016).
• type & artefact_type_id: Lowercase kebab-case discriminator (research, spec) paired with the registered uppercase contract ID (NBM4-CUSTOMER-RESEARCH, NBM4-PRODUCT-SPEC).
• schema_version & version: Semantic contract version (4.0.0) and monotonic integer instance revision (1, 2, ...).
• authority_refs & supersedes: Explicit upstream authorization set and lineage pointers.
• content_digest: Deterministic sha256:... digest computed under the ship-mlp-c14n-json profile (Unicode NFC, code-point key ordering, RFC 8785 number serialization).
• path_history: Ordered provenance log allowing files to move across folders without losing identity.

L1–L4 Method Topology (28 NBM4 Contracts)

The ship-mlp-core v3.7.0 registry organizes product work into four hierarchy levels:

• L1 Foundation (foundation:ship-mlp@1.0.0)
• L2 Method (method:nbm4@1.0.0)
• L3 Stages (stage:nbm4:idea, stage:nbm4:customer, stage:nbm4:product, stage:nbm4:growth)
• L4 Artifact Contracts (28 authoring-current NBM4 types)

L3 Stage	Count	L4 Governed Artifact Contracts (v3.7.0)
01 Idea (1_idea)	7	Note (v5.0.0), Napkin (v1.0.0), Feature Request Capture (v1.0.0), Request for Change (RFC) (v2.0.0), Chat Session (v2.0.0), Chat Source (v1.0.0), Chat Extraction (v1.0.0)
02 Customer (2_customer)	5	Research (v2.0.0), ICP Definition (v2.0.0), Persona (v2.0.0), Customer Journey Map (v2.0.0), Customer Journey Stage (v2.0.0)
03 Product (3_product)	15	Product Vision (v1.0.0), Product Hypothesis (v1.0.0), Strategy Window (v2.0.0), Release Requirements Document (RRD) (v1.0.0), Product Requirements Document (v1.0.0), Product Document (v1.0.0), Architecture Decision (ADR) (v2.0.0), Architecture Review Record (ARV) (v1.0.0), SPEC (v4.0.0), SPEC Graph (v3.0.0), Test Matrix (v2.0.0), Request for Bug-fix (RFB) (v2.0.0), Change Package (CPK) (v2.0.0), Validation Evidence (v2.0.0), Pull Request Candidate (v2.0.0)
04 Growth (4_growth)	1	Strategy Cycle (v4.0.0)

H1 Horizontal Packs (13 Cross-Cutting Contracts)

Cross-method engineering, Git, and graph contracts live outside the NBM4 method vocabulary in three H1 Horizontal Packs:

1. Repository Governance (horizontal-pack:repository@1.0.0): API Contract, Configuration, Executable Script, Generated Artifact, Imported Package, Repository Control, Source Module, Test Module, UI Component.
2. Source Control (horizontal-pack:source-control@1.0.0): Commit (ship-mlp:commit@1.0.0), Pull Request (ship-mlp:pull-request@1.0.0).
3. Traceability (horizontal-pack:traceability@1.0.0): Artifact Traceability (ship-mlp:artifact-traceability@1.0.0), Graph Companion (ship-mlp:graph-companion@1.0.0).

Continuous Integration Guard Office

Rather than relying on manual process policing, ship-mlp-core enforces contract integrity at the commit and pull-request boundary through numbered CI Guards in .0-ship-mlp/governance/government/executive/guard-office/:

• Schema & Envelope Validation: Verifies every Markdown frontmatter and JSON artifact against its pinned Draft 2020-12 schema.
• Identity & Timestamp Parity: Ensures filenames, created_date prefixes, artifact_id patterns, and artefact_type_id registrations agree.
• Fixture & Digest Integrity: Protects canonical market fixtures and verifies sha256 content digests.