> ## Documentation Index
> Fetch the complete documentation index at: https://docs.tessera.edstratumlabs.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Decisions

> Settled decisions that act as constraints on Tessera's design and build.

Tessera keeps a decision log. Accepted decisions are constraints: changing one takes a new decision that supersedes it, not an edit to the old one.

| ID    | Decision                                                                                                 | Status              |
| ----- | -------------------------------------------------------------------------------------------------------- | ------------------- |
| D-001 | "Tessera" is a working codename, not the product name                                                    | Accepted            |
| D-002 | Borrow Canvas's backbone: modules are the spine                                                          | Accepted            |
| D-003 | AI is a governed co-author and a hint-first tutor; drafts never auto-publish                             | Accepted            |
| D-004 | Personalize on evidence-based variables; no "learning styles"                                            | Accepted            |
| D-005 | Tutor modes (Off, Hints, Explain, Open) and who controls them                                            | Accepted            |
| D-006 | AI visual language: Marginalia; no stripes, sparkles, or gradients                                       | Accepted            |
| D-007 | Visual system: paper, ink, one teal accent, violet for AI; Fraunces and IBM Plex                         | Accepted            |
| D-008 | Hosting on GitHub Pages                                                                                  | Superseded by D-012 |
| D-009 | The repository is the source of truth; the design canvas mirrors it                                      | Accepted            |
| D-010 | Accessibility bar: WCAG 2.2 AA, zero automated violations, 320px reflow                                  | Accepted            |
| D-011 | Phase 2 build approach: a Vite + React component app built by Cloudflare, growing into a full-stack app  | Accepted            |
| D-012 | Hosting: Cloudflare Workers static assets, deploy on push, a preview address per branch                  | Accepted            |
| D-013 | Deploy lanes: minor changes go straight to production; big features get a full check and a preview first | Accepted            |

## The ones that shape every screen

<AccordionGroup>
  <Accordion title="D-002 · Modules are the spine">
    One course → module → lesson → block hierarchy everywhere. Grading shows the submission and rubric side by side, and a unified Today list is the entry point. AI features edit this structure and never create a parallel one.
  </Accordion>

  <Accordion title="D-003 · AI drafts, people publish">
    Every AI output is a labeled draft with its source, a diff, and Accept, Revert, and Regenerate. A person must mark it kept before learners see it. Agentic bulk actions appear as previewable change sets. The tutor gives hints and worked parallel examples, not answers, unless policy allows.
  </Accordion>

  <Accordion title="D-004 · Personalize on evidence">
    Personalize on goals, role, time, prior knowledge, language and reading level, accessibility, device, and bandwidth. Offer every format to everyone, and show every adaptation with a reason and an Undo.
  </Accordion>

  <Accordion title="D-005 · Tutor modes and control">
    Administrators set limits per program; instructors choose a mode per activity within them, and locked options say why. The answer key is never a tutor source. Instructors see per-learner summaries; full transcripts open only from a submission.
  </Accordion>

  <Accordion title="D-011 · Component app, then full stack">
    Phase 2 builds a React component app with shared design tokens and Storybook. It's designed to grow into a full-stack app on the same Cloudflare deployment. See [architecture](/build/architecture).
  </Accordion>
</AccordionGroup>