LangChain、OpenWiki 0.2 で OKF をコードドキュメントに導入

OpenWiki is our open source CLI for generating and maintaining documentation for codebases. It creates a wiki for your repo, connects that wiki to your coding agent, and keeps the docs up to date as your code changes. With OpenWiki 0.2, we're making it easier for developers to categorize and structure their codebase wikis.

The first OpenWiki release generated and organized Markdown documentation based on your codebase. Large codebases can require large wikis, as you might expect. When a wiki has hundreds of files, structure becomes important for discovery, updates, search, and review.

OpenWiki 0.2 adds support for OKF, a proposed standard from Google Cloud for structuring knowledge wikis. This allows for us to add better structure to the generated wiki, resulting in it being easier to navigate for coding agents. With better documentation, agents won’t need to spend as much time searching, thus reducing time and tokens spent.

What OKF adds

In OpenWiki 0.2, wikis generated or updated by OpenWiki follow the OKF format. Wiki files now include YAML front matter containing fields like title, description, tags, categories, and resource URLs.

OKF defines two conventions:

• index.md summarizes the files and subdirectories in each wiki directory.
• logs.md tracks wiki updates over time, similar to a changelog.

The changelog is especially useful for updates. Instead of needing to read the full wiki after every run, you can check logs.md to see what changed, which files were touched, and where to look if you want more detail.

OKF example

At its core, the OKF spec is very simple which makes it easy to integrate into OpenWiki. The YAML front matter just contains a few key fields which are easy to add:

type: # REQUIRED - identifying concept of the doc. E.g. "BigQuery Schema"

title:

description:

resource:

tags: [, , …] # Optional

timestamp: # Optional last-modified time

… other producer-defined key/value pairs

With this YAML front matter in each of the wiki files, you can deterministically generate the index.md files for your wiki by extracting the description field from the front matter:

Section / Group Heading

• Title 1 - description of item 1
• Title 2 - description of item 2

Another Section

• Subdirectory - description of the subdirectory

And finally, the log.md can be generated by OpenWiki at the end of a run to document its changes. Adding support for a log.md is just a matter of adding a few lines of prompting to OpenWiki instructing it to update the

log.md file once its done updating the wiki:

Directory Update Log

2026-05-22

• Update: Added new BigQuery table reference for Customer Metrics.
• Creation: Established the Dataplex Playbook.

2026-05-15

• Initialization: Created foundational directory structure.
• Update: Added progressive-disclosure guidelines to the root index.

Better retrieval for agents

OpenWiki exposes your repo wiki to coding agents through files like AGENTS.md and CLAUDE.md, allowing them to search it for relevant context.

Because OKF adds structured metadata to every document, future OpenWiki tooling can support deterministic search over tags, categories, descriptions, and other fields. For example, an agent could filter on every doc in the BigQuery tables category, or every doc tagged with billing, rather than relying entirely on open-ended agentic search.

Agentic search is useful, but it can be unnecessarily slow and expensive for simple lookups. Structured metadata gives OpenWiki a cleaner path toward faster retrieval tools.

Working with the OKF ecosystem

Because OKF is an open format, OpenWiki wikis can work with community-built viewers, renderers, linters, and other compatible tools instead of relying on one-off integrations. This article documents a few of these open-ecosystem projects which have recently popped up: https://www.owox.com/blog/articles/okf-ecosystem-tools.

That means OpenWiki users get a more standard wiki format today, plus a better foundation for the tooling we build next.

Google has published an open-source OKF wiki visualizer you can use to inspect your wiki, and view the relationships between docs. Here’s an example of what that looks like, from the OpenSWE repository:

If you already use OpenWiki, upgrading will generate and update wikis in the OKF format. If you’re new to OpenWiki, you can install it and generate a repo wiki in a few minutes.

Check out the repo here: https://github.com/langchain-ai/openwiki

And try it locally today:

npm install -g openwiki@latest

openwiki --init