Open Knowledge Format for Crossplane v2

This repository provides a structured knowledge catalog for the Crossplane v2 ecosystem using Open Knowledge Format v0.2.

The goal is to make Crossplane concepts, APIs, providers, composition functions, documentation, and practical examples easier to discover and understand. The catalog is designed for both humans and knowledge-aware tools.

Installation

Warning

The public MCP server is a temporary early-access service for early adopters. Its availability is not guaranteed, and it may change or be removed without notice. It is intended to bridge the current tooling gap until the OKF ecosystem provides practical, end-user-friendly solutions that run locally. For reliable or production use, self-host the included container.

Install the companion skill and hosted OKF-aware MCP server together as a plugin for every detected supported agent:

npx plugins add jkroepke/okf-crossplane-v2

Pass --target codex to install only in Codex. Restart the selected agents after installation.

Alternatively, install the hosted OKF-aware MCP server globally:

npx add-mcp \
  https://crossplane.mcp.jkroepke.de/mcp \
  --name crossplane-v2-okf \
  --global

Then install the companion skill so the agent prefers this bundle over generic documentation providers for Crossplane v2 questions:

npx skills add jkroepke/okf-crossplane-v2 \
  --skill crossplane-v2-okf \
  --global

Both standalone installers detect supported agents and ask where the integration should be installed. Restart the selected agent after installation.

The public MCP health endpoint is available at https://crossplane.mcp.jkroepke.de/healthz.

Self-hosting the MCP server

The included container fetches this repository, ingests catalog/ into a DuckDB catalog, and serves the okf-mcp tools over Streamable HTTP.

docker compose up --build --detach

To authenticate the server's GitHub requests, export GITHUB_TOKEN before starting the container. The token is optional.

The local MCP endpoint is http://127.0.0.1:8000/mcp. Put it behind a TLS reverse proxy for crossplane.mcp.jkroepke.de.

The catalog is refreshed at container startup. If fetching or ingestion fails and a previous catalog exists in the volume, the server continues with that last successful catalog.

The MCP tools are read-only, but the public endpoint has no application-level authentication. Apply request limits and access controls at the reverse proxy when required.

Crossplane package tools

The server adds these tools backed by OSS GitHub repositories:

• get_versions(name) resolves an OSS provider or function repository and returns its canonical repository name, versions.latest, a compact list of recent stable versions, and tag counts. Pass the returned provider name to the CRD tools.
• provider_crd_search(provider_name, provider_version, crd_search_term) searches CRDs in one explicit provider package version. The search term supports case-insensitive shell-style wildcards.
• provider_crd_get_definition(provider_name, provider_version, crd_name, path?) returns the complete CRD definition as token-efficient YAML. Use a dotted path such as .spec or .spec.versions[0] to return only a subtree.
• provider_crd_get_examples(provider_name, provider_version, crd_name) returns GitHub repository paths for generated and handwritten examples. Without an API version, it selects the latest served CRD API version, for example examples-generated/namespaced/ec2/v1beta2/route.yaml.
• provider_crd_get_terraform_docs(provider_name, provider_version, crd_name) returns the Terraform provider repository, version, and documentation path. It reads the Crossplane provider Makefile and the generated controller mapping instead of inferring the Terraform resource name.

crd_name accepts a Kind, group/Kind, group/version/Kind, or a YAML fragment containing apiVersion and kind.

Use an OSS GitHub repository name such as crossplane-contrib/provider-upjet-aws or crossplane-contrib/function-go-templating. A small set of historical package aliases is mapped to their known OSS source repositories; unmapped upbound/... names are rejected rather than guessed.

The CRD tools require an explicit provider version. The value latest is also supported and selects the highest stable semantic-version Git tag. Self-hosted deployments need outbound HTTPS access to GITHUB_API_URL and GITHUB_RAW_URL.

Successful remote fetches are cached in memory. Git tag listings use the configurable short FETCH_CACHE_TTL_SECONDS (default: 300 seconds); CRDs, definitions, examples, and Terraform metadata resolved at immutable Git tags are cached for 30 days. FETCH_CACHE_MAX_ENTRIES (default: 512) bounds memory use.

Why this repository exists

Crossplane knowledge is distributed across many repositories and kinds of sources:

• Go API types and runtime implementations
• CustomResourceDefinitions and OpenAPI schemas
• package metadata
• tests and executable examples
• official Crossplane documentation
• community implementations and real-world composition examples

Upjet-based providers add another layer. Their Crossplane managed resources are generated from Terraform provider resources, while the Terraform documentation often contains more details about the underlying cloud APIs and configuration fields.

This repository connects these sources in one versioned catalog without replacing the original documentation.

Knowledge structure

Knowledge is stored as small Markdown documents under catalog/. Each document represents an independently useful concept and includes OKF metadata, provenance in sources, keyed claim footnotes, and relationships to related concepts.

Repository validation pins okf-ingest 0.11.0, which adds OKF v0.2 core support, including generated.at freshness fallback and preservation of the new frontmatter families (upstream support commit).

If the task is to build a Crossplane v2 Composition, start with the Composition developer route. It routes agents through separate API/provider, pipeline/security, and testing/packaging concepts without pretending that provider-specific schemas or credentials are universal.

The catalog is intended to be:

• Source-backed: important statements link to source code, schemas, tests, examples, or official documentation.
• Version-aware: sources are tied to specific repository revisions.
• Navigable: overview documents connect related concepts without requiring readers to know the source repository layout.
• Incremental: providers, functions, services, documentation areas, and example repositories can be added in focused batches.

License

This project is licensed under the Apache License 2.0.