Canonical Knowledge Structure (CKS)

A universal, representation-independent semantic foundation for knowledge.

The Canonical Knowledge Structure (CKS) project defines a formal semantic model for representing, validating, exchanging, and evolving knowledge independently of programming languages, document formats, databases, or artificial intelligence systems.

CKS separates knowledge itself from the representations used to store or communicate it.

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Why CKS?

The same knowledge is often duplicated across many incompatible representations.

• Documents
• Databases
• JSON
• XML
• Source code
• Knowledge graphs
• APIs
• AI prompts

Each representation describes the same concepts differently.

CKS introduces a canonical semantic layer shared by all representations.

Knowledge
      │
      ▼
Canonical Knowledge Structure
      │
 ┌────┼───────────────┐
 ▼    ▼               ▼
JSON Python Database Natural Language

Representations may evolve over time.

The canonical knowledge remains unchanged.

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Design Principles

CKS is founded on four fundamental principles.

Representation Independence

Knowledge exists independently of the syntax used to describe it.

JSON, Python objects, databases, and documents are merely different representations of the same underlying semantic structure.

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Canonical Semantics

Meaning is preserved through canonical structure rather than implementation-specific syntax.

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Deterministic Behaviour

Every canonical operation produces the same observable result for identical inputs.

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Observational Purity

Canonical operations never modify their inputs.

Construction, validation, serialization, comparison, and inspection are observationally pure.

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Project Architecture

The CKS ecosystem is organised as a family of independent specifications.

CKS-000
    │
    ▼
CKS-001
    │
    ├─────────────┐
    ▼             ▼
CKS-002      CKS-003
    │             │
    └──────┬──────┘
           ▼
       CKS-004
           │
           ▼
       CKS-005
           │
           ▼
       CKS-006
           │
           ▼
       CKS-007
           │
           ▼
       CKS-008
           │
           ▼
       CKS-B001-PY

Each specification defines one canonical aspect of the ecosystem.

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Reference Implementation

This repository contains the official Python reference implementation.

Current components include:

• immutable semantic model;
• canonical serializer with format versioning;
• validator with constraint registry (including belief-revision, temporal, and layering domains);
• reference engine;
• structural evolution (Genesis/Decay/Mutation operators);
• command-line interface (CLI);
• public interface;
• conformance tests (400+ tests);
• reference corpus (valid and invalid examples);
• documentation.

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Documentation

The documentation is organised into several sections.

Section	Description
Getting Started	Installation and first steps
Concepts	Fundamental ideas and terminology
Architecture	Internal organisation of the project
API Reference	Public Python interface
Examples	Practical usage examples
Specifications	Complete formal CKS specifications

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Learning Path

New users are encouraged to explore the project in the following order.

Getting Started
       │
       ▼
Concepts
       │
       ▼
Architecture
       │
       ▼
API Reference
       │
       ▼
Examples (including CLI and Corpus)
       │
       ▼
Specifications

This progression introduces the conceptual foundations before the formal specification.

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Current Status

The CKS specifications are stable and continue to evolve through versioned releases.

The Python implementation serves as the first canonical implementation of the CKS ecosystem.

Completed milestones include:

• ✅ Core semantic model (CKS‑001)
• ✅ Canonical serialization (CKS‑003) with format versioning and migration
• ✅ Validation pipeline (CKS‑005)
• ✅ Reference Engine (CKS‑006)
• ✅ Canonical Knowledge Interface (CKS‑007)
• ✅ Structural Evolution (CKS‑004), including three-way merge and subgraph queries
• ✅ Command-Line Interface
• ✅ Reference Corpus
• ✅ Belief Revision & Reasoning Engine (ADR‑001, ADR‑002)
• ✅ Temporal Validity and Layering Rule extension constraints (ADR‑003, ADR‑004)
• ✅ Plugin architecture (constraint entry points)
• ✅ RDF‑family import/export adapters (JSON‑LD, Turtle, RDF/XML)
• ✅ MCP Server, shipped separately as cks-mcp

Future work includes:

• additional reference implementations (Rust, TypeScript);
• semantic reasoning tools beyond belief revision (pathfinding, concept similarity);
• CKS Studio (visual workspace);
• IDE integration.

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Open Source

CKS is developed as an open specification and open-source reference implementation.

Contributions are welcome.

See the following documents for additional information:

• CONTRIBUTING.md
• CODE_OF_CONDUCT.md
• SECURITY.md
• CHANGELOG.md
• ROADMAP.md

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License

The CKS reference implementation is released under the MIT License.