# Collegica

> A learning companion to the Mechatronics3D newsletter: software development, AI, finance, and aging well. The site at collegica.org is written for people. The same knowledge is available to agents as an Open Knowledge Format (OKF v0.2) bundle — plain markdown with provenance, trust and lifecycle frontmatter — regenerated from the source tree on every deploy.

Start at the bundle index. Every concept declares a `type`; articles carry `sources` with per-claim ids, `generated` and `verified` actors, and a `stale_after` instant where a fact has a shelf life. Attested computations ship with an executor and a deterministic attester, so a number can be re-derived rather than quoted.

The bundle root is https://www.collegica.org/okf/ — links and `resource` paths that begin with `/` are bundle-relative (OKF §6.1) and resolve against that root, not against the site root. So `/references/computations/mortgage.js` means https://www.collegica.org/okf/references/computations/mortgage.js. The same tree is in the repository under `okf/`, so `git clone` works too.

## Knowledge bundle

- [Bundle index](https://www.collegica.org/okf/index.md): every concept by type, with descriptions, for progressive disclosure
- [Bundle log](https://www.collegica.org/okf/log.md): what changed, newest first
- [How this bundle is made](https://www.collegica.org/okf/about.md): the design, the decisions, and what the generator deliberately does not do
- [OKF specification](https://github.com/GoogleCloudPlatform/knowledge-catalog/blob/main/okf/SPEC.md): the format this bundle follows

## Skill for Claude Code

- [Collegica skill](https://www.collegica.org/okf/references/skills/collegica/SKILL.md): teaches a session to walk this bundle, name the trust tier with every answer, refuse stale figures, and run the attested computations rather than quote them. Install: `mkdir -p ~/.claude/skills/collegica && curl -sSL https://www.collegica.org/okf/references/skills/collegica/SKILL.md -o ~/.claude/skills/collegica/SKILL.md`, then restart Claude Code and type `/collegica`.

## Finance

- [Fixed or Variable](https://www.collegica.org/okf/finance/fixed-or-variable.md): two Canadian mortgages replayed against the real rate path, human-reviewed, with a dated snapshot that goes stale on the next Bank of Canada announcement
- [The mortgage computation](https://www.collegica.org/okf/finance/computations/mortgage.md): an attested computation — run it with a signing month and a term instead of reading numbers off the page
- [Research notes](https://www.collegica.org/okf/finance/research/index.md): each opens with what was read in full, what is snippet-only, and what could not be verified

## Human site

- [collegica.org](https://www.collegica.org/): the rendered site
- [Source repository](https://github.com/Collegica/collegica): Quarto sources, research notes, and the `okf/` bundle, all in one tree

## Optional

- [Mechatronics3D newsletter](https://mechatronics3d.substack.com/): where new writing appears first