yuzu-block (working title)

An open-source public site and auth-free MCP server that render anonymous, aggregate-only data from a voice journal built on ElevenLabs Scribe transcription as a 3D block sculpture, maintained by STUDIO CON. This repo is independent from the voice journal's own codebase; it consumes aggregate numbers only.

What it shows / what it never shows

Shows weekly aggregate rings:

• record count → block height

• silence-day ratio → gaps in the ring

• words-per-record → a second block color

The sculpture itself carries no text, numbers, or labels. Page chrome around it is limited to the YUZU logo (linking to yuzu.style), a two-line lead, and a footer; no metrics — record counts, per-user data, consecutive-day counts — are displayed anywhere. No counters, no congratulatory effect, no light or sound cue. The sculpture never exceeds the server snapshot it started from — see "Rendering" for what it does show while a visitor watches. Weeks whose cohort is below the anonymity threshold render as empty rings.

Related MCP server: oura-mcp

Concept

Open the material, never the interpretation.

Annual rings: layers are cut by time passing, not by effort. Numbers are counted, not praised.

Setup

npm install
npm run dev

Open /. The MCP endpoint is at /api/mcp.

npm run check
npm run build

Requires Node 20+.

MCP server

No authentication. Streamable HTTP at /api/mcp. One tool: get_ring_data.

Input:

{ "year": 2026 }

Trimmed example output (RingAggregate, buckets truncated):

{
  "year": 2026,
  "unit": "week",
  "minCohort": 50,
  "generatedAt": "2026-09-12T00:00:00.000Z",
  "buckets": [
    {
      "index": 0,
      "start": "2025-12-29",
      "sufficient": true,
      "recordCount": 214,
      "wordCount": 18904,
      "silenceDayRatio": 0.412
    },
    {
      "index": 1,
      "start": "2026-01-05",
      "sufficient": false,
      "recordCount": null,
      "wordCount": null,
      "silenceDayRatio": null
    },
    {
      "index": 2,
      "start": "2026-01-12",
      "sufficient": true,
      "recordCount": 233,
      "wordCount": 21172,
      "silenceDayRatio": 0.388
    }
  ]
}

Custom connector

Add as a custom connector using the URL only:

https://<your-deployment>/api/mcp

curl example

Initialize:

curl -s http://localhost:3000/api/mcp \
  -H "Content-Type: application/json" \
  -H "Accept: application/json, text/event-stream" \
  -d '{
    "jsonrpc": "2.0",
    "id": 1,
    "method": "initialize",
    "params": {
      "protocolVersion": "2024-11-05",
      "capabilities": {},
      "clientInfo": { "name": "curl", "version": "0.0.1" }
    }
  }'

Call the tool:

curl -s http://localhost:3000/api/mcp \
  -H "Content-Type: application/json" \
  -H "Accept: application/json, text/event-stream" \
  -d '{
    "jsonrpc": "2.0",
    "id": 2,
    "method": "tools/call",
    "params": { "name": "get_ring_data", "arguments": { "year": 2026 } }
  }'

Data contract

export interface WeekBucket {
  index: number;
  /** ISO date, YYYY-MM-DD, Monday of the bucket's week. */
  start: string;
  /** False when the cohort for this bucket is below the anonymity threshold. */
  sufficient: boolean;
  recordCount: number | null;
  wordCount: number | null;
  /** 0..1 — days with zero records / days in the bucket. */
  silenceDayRatio: number | null;
}

export interface RingAggregate {
  year: number;
  unit: "week";
  minCohort: number;
  generatedAt: string;
  buckets: WeekBucket[];
}

Buckets are ISO weeks: Monday-start, week 1 is the week containing January 4, and a year has 52 or 53 of them. The reference upstream computes these boundaries in Asia/Tokyo.

Anonymization policy: week-level granularity only. Buckets whose cohort falls below minCohort are returned with every numeric field set to null and sufficient: false. No per-user field exists anywhere in this shape, by construction.

The data source is selected by the DATA_SOURCE_URL environment variable (lib/data-source.ts):

• Unset: a deterministic mock (lib/mock-aggregate.ts), seeded by year and date.

• Set (e.g. DATA_SOURCE_URL=https://app.yuzu.style/api/public/weekly): GET {DATA_SOURCE_URL}?year=YYYY, expected to return JSON matching RingAggregate exactly (52 or 53 WeekBuckets, unit: "week", nulls agreeing with sufficient). The response is validated against that shape; any failure — network error, non-2xx, timeout, or invalid shape — falls back to the mock and logs one line server-side. The upstream is expected to set long CDN cache headers; no auth is sent or required.

When a validated upstream payload has no week above the anonymity threshold at all, the site and MCP tool fall back to the mock as well and report source: "mock".

The MCP tool's JSON output carries a top-level source field ("upstream" or "mock") alongside the aggregate, so a caller can see which one produced a given response. The page never renders this field.

wordCount's unit is defined by whichever source produced it. For the reference upstream (the voice journal above), it is transcribed characters, not words.

Rendering

The scene is a snapshot: SceneSpec is generated server-side on every request and handed to the client once. A slow, continuous camera orbit runs throughout. On top of the snapshot, the client holds back about 10% of its blocks at first paint and reveals them one at a time on a bounded schedule, and independently re-colors whole cell columns between the two tokens while holding the overall color balance close to the snapshot's — the sculpture reads as continuously carved, but it converges to the snapshot and never adds anything beyond it. prefers-reduced-motion renders the finished snapshot with no camera motion and no carving. Blocks are unlit, per-face tints of the two block tokens defined in lib/palette.ts — side faces are fixed, darker multiples of the same top-face color, not a separate token or a lighting effect. Colors actually rendered:

• YUZU_YELLOW #F5D84A

• YUZU_ZEST #E8A020

• YUZU_WHITE #FAFAF5 (background)

ElevenLabs

The words that become blocks are transcribed by ElevenLabs Scribe in the upstream journal. This repo is intended for submission to the ElevenLabs Grant / Showcase as a standalone, free, open-source demo.

Deploy

Vercel, zero configuration (next build). To use a real upstream instead of the mock, set DATA_SOURCE_URL in the Vercel project's environment variables (see .env.local.example).

License

MIT © 2026 STUDIO CON.