# Property Graph Markdown (PGM)

> PGM maps Open Knowledge Format (OKF) Concepts and ordinary Markdown links to typed property graphs. The shipped example targets 0.4.0 Public Draft.

## Start here

- [Knowledge Catalog (JSON-LD)](https://pgm.technology/knowledge-catalog.jsonld): Structured resource types, versions, licenses, source documents, and dataset downloads.
- [Specification (Markdown)](https://raw.githubusercontent.com/property-graph-markdown/specification/main/SPEC.md): Current working draft. Main-branch documents can change; use the versioned processor archive for its matching specification and schema.

## Resources

- [Property Graph Markdown specification](https://github.com/property-graph-markdown/specification/blob/main/SPEC.md): Start here for the PGM mapping from OKF Concepts and Markdown links to typed property graphs. This is the current working draft on main; its contents can change.
- [Open Knowledge Format 0.2 specification](https://github.com/GoogleCloudPlatform/knowledge-catalog/blob/3fcbb9f828c2f23d109c855ee403c3a4c81f3a96/okf/SPEC.md): The pinned OKF foundation used by the reference processor: Knowledge Bundles, Concepts, Concept IDs, and Concept Links.
- [PGM JSON Exchange schema](https://github.com/property-graph-markdown/specification/blob/main/interop/pgm-graph.schema.json): Machine-readable schema for the canonical PGM graph exchange format, including tagged YAML values. The main-branch schema can change; the processor archive includes its matching schema.
- [PGM conformance tests and Core TCK](https://github.com/property-graph-markdown/specification/blob/main/tests/README.md): Read the test guide before using the language-neutral Core TCK. Tests on main track the working draft.
- [PGM Core TCK fixtures](https://github.com/property-graph-markdown/specification/blob/main/tests/core.yaml): Language-neutral YAML fixtures for checking Core processor behavior. Use the conformance guide to interpret expected results.
- [pgmark reference processor](https://pgm.technology/#export): Validate a PGM bundle and export deterministic JSON or Cypher. The downloadable source archive includes the matching specification, exchange schema, and canonical Ada Demo Vault; the online README tracks main.
- [PGM Viewer for Obsidian](https://github.com/property-graph-markdown/obsidian-viewer/tree/309cce16507fb149f18b4a1bafd12a61e773930f): Read-only graph and Markdown viewer. The plugin archive also includes the canonical Ada Demo Vault, licensed separately under CC BY-SA 4.0.
- [Ada Lovelace PGM Demo Vault](https://github.com/property-graph-markdown/specification/tree/main/demo-vault): A worked 0.4.0 Public Draft example with 46 Concepts and 124 relationship occurrences. Use the canonical JSON exchange for processing and the Markdown vault for source notes and attribution.

## Direct downloads

- [Canonical Ada graph JSON](https://pgm.technology/downloads/ada.graph.json): 46 nodes, 124 relationship occurrences; PGM JSON Exchange Profile v1. Tagged YAML values preserve their types.
- [Ada Markdown Demo Vault](https://pgm.technology/downloads/ada-demo-vault.zip): Source notes, citations, and attribution.
- [Reference processor 0.4.0a1](https://pgm.technology/downloads/pgm-reference-processor-0.4.0a1.zip): Python source with matching specification, schema, and Demo Vault.
- [Obsidian viewer 0.1.2](https://pgm.technology/downloads/pgm-viewer-0.1.2.zip): Plugin and Demo Vault; requires Obsidian 1.5.12 or later.

## Interpretation and reuse

The specification defines PGM semantics. This catalog describes resources; it does not redefine PGM or provide an agent execution API.

The website's /ada-graph.json is a display adapter with normalized values and text. Use /downloads/ada.graph.json for canonical exchange and the Markdown vault for source content. Repeated links are separate relationship occurrences; do not merge them when interpreting the example.

PGM specification, processor, and viewer code use MIT. Ada data and Markdown use CC BY-SA 4.0, including the vault bundled with software downloads; preserve the included attribution. Consult the pinned OKF repository for its license.

DeepDB GmbH is the publisher of PGM 0.4.0 Public Draft 1. PGM is an open, non-commercial specification project, not a DeepDB product or an HSLU project.

This llms.txt is an optional discovery aid. Agents can also discover the catalog through the homepage's structured data and links.