Open Knowledge Format · v0.2 · by Google Cloud

Knowledge your agents can account for

OKF is an open specification from Google Cloud for knowledge that agents write and people rely on. It's a folder of markdown files, and each file says where its claims came from, who checked them and when they expire. Knowtarium is built on it.

The bundle

A folder of markdown. Nothing else.

An OKF bundle is a directory of markdown files with YAML frontmatter. There's no database, no schema registry and no required tool: if you can open a text file, you can read it, and if you can copy a folder or clone a repo, you can share it.

Each file is one concept: a metric, a policy, a customer interview, a runbook. The only required field is type. Folders group concepts however suits the team, and two filenames are reserved: index.md lists what a folder holds, and log.md records what changed.

bundle
~/kb/
index.md # what's in this folder (optional)
log.md # what changed, newest first (optional)
company/
mission.md
glossary.md
metrics/
revenue.md # one concept per file
churn.md
computations/
quarterly-revenue.md # an attested computation
customers/
segments.md
interviews/
northwind-traders.md

Inside a document

Four questions, answered in the frontmatter.

When agents write most of a knowledge base, a reader needs more than the text. OKF v0.2 adds a few optional field families that make every document answer the same questions. They're all optional: a document with just a type is still valid, and a missing family simply means the answer is unknown.

Claims in the body cite sources with footnotes keyed by id, like [^billing-export], so the link survives when an agent reorders the list.

metrics/revenue.md
---
type: Metric
title: Quarterly revenue
tags: [finance, revenue]
status: stable
generated: { by: claude-code/2.1, at: 2026-09-26T07:42:00Z }
verified:
- { by: human:maya, at: 2026-09-26T10:05:00Z }
stale_after: 2026-12-31T00:00:00Z
sources:
- id: billing-export
resource: exports/billing/2026-09.csv
author: process:billing-sync
owner: human:maya # your own keys are kept as written
---
Q3 revenue was €112,400, up 12% on Q2.[^billing-export]

provenance

Where did this come from?

Each claim cites a source by id. Sources carry who wrote them, how often they're used and when they changed.

sources · usage_window

trust

Who checked it?

Who wrote the document, and every person or process that confirmed it since, with the time.

generated · verified

lifecycle

Is it still current?

A draft, stable or deprecated status, and the moment the document stops being safe to quote.

status · stale_after

attestation

Was this number computed the approved way?

A computation lives in its own document. Agents fill in the parameters; a deterministic check confirms the approved query is what ran.

runtime · parameters · executor · attester

Trust tiers

Derived, never declared.

No document gets to call itself trustworthy. A reader works out the tier from who is listed under verified, and staleness from stale_after. Knowtarium colours every document by these rules and nothing else.

unverifiedNo verified entries at all.
machine-confirmedVerified only by agents or processes, such as process:ci.
human-reviewedVerified by at least one person, such as human:maya.
staleThe current time is past stale_after, whatever the tier.

Who did it

Every by field names an actor in one of three forms. The human: prefix is what makes a verification count as a person's review.

claude-code/2.1
An agent or tool, with its version
human:maya
A person
process:finance-nightly
An automated process

Knowtarium and OKF

What the app reads and writes.

Knowtarium is a reader and reviewer for OKF bundles. It follows the spec closely, so a bundle you review in Knowtarium stays a bundle every other OKF tool can use.

It reads any bundle

Missing fields, unknown types, unknown keys and broken links never make a document unreadable. Knowtarium shows what's there.

Approving writes one entry

When you approve a change, Knowtarium adds you to verified with the time. That's the only field it writes when you review.

Your own keys stay put

Custom frontmatter keys, comments and formatting are kept exactly as written, as the spec asks.

Every change is checked from both sides

An agent's change waits for your approval. Your own edit is marked as yours, and an agent checks it against every connected document.

Broken links are ghosts

A link to a document nobody wrote yet isn't an error in OKF. Knowtarium draws it as a dashed ghost: a to-do for your agents.

History stays out of your documents

Review history and comments live in a separate folder next to the bundle, so the documents themselves stay clean OKF.

Coming from Obsidian

Your vault is most of the way there.

An Obsidian vault is already a folder of markdown with frontmatter. Our free migration skill lets your agent add the OKF fields, turn wikilinks into markdown links and write an index, without touching your writing.

OKF is an open format published by Google Cloud in the open-knowledge-format repository on GitHub. Knowtarium is an independent app, not affiliated with or endorsed by Google.