Open knowledge format

Open Knowledge Format (OKF) — v0.1

Google Cloud published the Open Knowledge Format v0.1 on June 12, 2026 — an open specification that formalizes the LLM-wiki pattern into a portable, vendor-neutral format for AI agent knowledge.

The design is intentionally minimal: a directory of markdown files with YAML frontmatter. No schema registry, no central authority, no required tooling.

"If you can cat a file, you can read OKF; if you can git clone a repo, you can ship it."

Core Concepts

Concept	Definition
Knowledge Bundle	A self-contained directory tree of markdown files. The unit of distribution.
Concept	A single unit of knowledge — one markdown file. May describe a table, a metric, a playbook, an API, or any idea.
Concept ID	The file path with .md stripped (e.g. tables/users.md has ID tables/users).
Frontmatter	YAML block at the top of each file with structured metadata.
Body	Standard markdown content after the frontmatter.
Link	A markdown link from one concept to another — expresses relationships.

Reference Files

Reference	Load when	File
Spec summary	You need the full OKF v0.1 specification, conformance criteria, and field definitions	references/spec-summary.md
Bundle architecture	You're creating or structuring an OKF bundle — directory layout, index files, cross-linking conventions	references/bundle-architecture.md
Use cases	You need real-world examples, third-party implementations, and adoption patterns	references/use-cases.md

Scripts

Script	Purpose	Load when
okf-bundle-validate.py	Validate an OKF bundle directory — checks frontmatter, required fields, reserved filenames, and cross-link integrity	You've created or modified an OKF bundle and want to verify conformance

Assets

Asset	Purpose	Path
Concept template	A template markdown file with all recommended frontmatter fields and body sections	assets/concept-template.md
Example bundle	A minimal but complete OKF bundle showing directory structure, index files, and cross-linked concepts	assets/example-bundle/

Bundle Structure

path/to/bundle/
├── index.md                      # Optional. Directory listing for progressive disclosure.
├── log.md                        # Optional. Chronological update history.
├── <concept>.md                  # A concept at the bundle root.
└── <subdirectory>/               # Subdirectories organize concepts into groups.
    ├── index.md
    ├── <concept>.md
    └── <subdirectory>/
        └── …

Files named index.md and log.md are reserved — they have defined semantics and must not be used for concept documents.

Frontmatter Fields

---
type: <Type name>                  # REQUIRED
title: <Optional display name>
description: <Optional one-line summary>
resource: <Optional canonical URI for the underlying asset>
tags: [<tag>, <tag>, …]            # Optional
timestamp: <ISO 8601 datetime>     # Optional last-modified time
# … other producer-defined key/value pairs
---

Required: type — a short string identifying the kind of concept. Types are NOT registered centrally. Producers pick descriptive values; consumers tolerate unknown types gracefully.

Conventional body sections:

Heading	Purpose
# Schema	Structured description of an asset's columns/fields
# Examples	Concrete usage examples, often as code blocks
# Citations	External sources backing claims in the body

Cross-linking

Concepts link to each other via standard markdown links:

• Absolute (bundle-relative): Begin with /, relative to bundle root. Recommended — stable when documents move.
• Relative: Standard markdown relative paths.

A link from concept A to concept B asserts a relationship. The specific kind (references, depends-on, joins-with) is conveyed by the surrounding prose, not by the link syntax.

Consumers MUST tolerate broken links — a link whose target doesn't exist is not malformed; it may represent not-yet-written knowledge.

Conformance

A bundle is conformant with OKF v0.1 if:

1. Every non-reserved .md file contains parseable YAML frontmatter
2. Every frontmatter block contains a non-empty type field
3. Reserved filenames (index.md, log.md) follow their defined structure

Consumers MUST NOT reject a bundle for: missing optional frontmatter fields, unknown type values, unknown frontmatter keys, broken cross-links, or missing index.md files.

Relationship to Other Formats

Format	How OKF Differs
Karpathy's LLM Wiki	OKF specifies the interoperability surface — required fields, reserved filenames, conformance criteria
Obsidian / Notion vaults	OKF is format-only — no tooling, no runtime, no UI. Any editor works
AGENTS.md / CLAUDE.md	OKF is multi-file, hierarchical, cross-linked — not a single convention file
Metadata-as-code repos	OKF standardizes the file format so different producers and consumers interoperate
Domain schemas (Avro, Protobuf, OpenAPI)	OKF references them — it does not subsume or replace them

Quick Start

# 1. Create a bundle directory
mkdir my-knowledge && cd my-knowledge

# 2. Create a concept file
cat > datasets/sales.md << 'EOF'
---
type: BigQuery Dataset
title: Sales
description: All sales-related tables for the retail business.
tags: [sales]
timestamp: 2026-06-18T00:00:00Z
---
The sales dataset contains [orders](/tables/orders.md) and [customers](/tables/customers.md).
EOF

# 3. Add an index for navigation
cat > index.md << 'EOF'
# Knowledge Bundle

* Sales Dataset (`datasets/sales.md`) - Retail sales data in an example OKF bundle
EOF

# 4. Validate your bundle
python3 scripts/okf-bundle-validate.py .

Gotchas

• Type values are not registered centrally. Pick descriptive types (BigQuery Table, Playbook, Metric). Consumers should handle unknown types gracefully.
• File path is the identity. Renaming a file changes its concept ID. Use stable paths or add redirects in documentation.
• index.md uses no frontmatter (except optionally at the bundle root for okf_version). The body is a markdown list with links.
• log.md date headings must be ISO 8601 (YYYY-MM-DD).
• Cross-links are untyped. The relationship semantics live in the prose, not in the link syntax. Graph builders treat all links as directed edges.
• OKF does not specify a tag-browsing format. Producers that want tag aggregation should synthesize it at consumption time by scanning frontmatter.
• OKF v0.1 is a draft. The spec will evolve. Minor bumps add backward-compatible features; major bumps may break required fields. Consumers should do best-effort consumption on unknown versions.