Skin score badges, checked before the app shows them

1. Same file. Two identical files mean nothing changed, so every metric is within noise.
2. Claim type. When the brand names the product category, a metric that category can't change is blocked. Foundation can't claim moisture.
3. Capture conditions. If the light differs between the photos, every metric is blocked.
4. Noise floor. The change must be bigger than what retaking the same photo produces.
5. Display change. The badge shows the display score, so that score must go up by at least 1 point.

On the developer's first 15 photos, all 168 pairs with a changed setup were blocked and all 42 same-light retake pairs passed; on 12 photos from a later evening, 64 of 64 changed-light pairs were blocked and 26 of 32 same-lamp pairs before and after a moisturizer passed (re-run on photos that informed the change, not held out).

Claim Guard does not make a claim compliant. It catches common ways a before/after number misleads: photos taken under different light, retake noise read as a result, and a product claiming a change it can't cause. We found no public enforcement case about a skin-analysis app itself; the cases above are about skincare ads.

Light changedSame light, foundation

9:41

Demo BrandYour skin report

Last scanToday

• Moisturehigher score = more hydrated73 → 76
• Radiancehigher score = more radiant84 → 81

Retake in the same light to see your progress

The light in this photo is different from your last scan, so the scores can't be compared yet.

Retake photo

Made-up brand app. Photos and scores are from the demo cases above.

1. Run YouCam skin analysis on the before and after photos, as you do now.
2. POST /api/v1/claim-check with both sets of scores, both photos and product_category.
3. Show a badge only where badge is not null, with badge_label next to it when present. Otherwise follow the verdict below, and log reason for your review team.

Verdict	Meaning	Suggested app copy
claimable	Raw change past the noise floor, display score moved, same light, product may claim it. A drop is real but gets no badge.	Show the badge, e.g. “Radiance +11%”, plus the appearance label for makeup.
blocked-claim-type	The product category can't make this claim.	No badge for this metric.
blocked-conditions	The two photos were taken under different light.	“Retake in the same light to see your progress.”
within-noise	The change is no bigger than retaking the photo.	“No clear change yet. Check again next week.”
no-visible-change	Raw moved, but the display score did not.	No badge for this metric.

POST /api/v1/claim-check
Content-Type: application/json

{
  "product_category": "foundation",
  "before": {
    "scores": [
      { "type": "moisture", "ui_score": 76, "raw_score": 66.841 },
      { "type": "pore", "ui_score": 73, "raw_score": 61.626 },
      { "type": "wrinkle", "ui_score": 97, "raw_score": 98.73 },
      { "type": "radiance", "ui_score": 82, "raw_score": 83.086 }
    ],
    "image_base64": "<JPEG as base64>"
  },
  "after": {
    "scores": [
      { "type": "moisture", "ui_score": 81, "raw_score": 80.561 },
      { "type": "pore", "ui_score": 71, "raw_score": 58.801 },
      { "type": "wrinkle", "ui_score": 97, "raw_score": 99.092 },
      { "type": "radiance", "ui_score": 91, "raw_score": 94.54 }
    ],
    "image_base64": "<JPEG as base64>"
  }
}

{
  "badge_allowed": true,
  "product_category": "foundation",
  "conditions": {
    "match": true,
    "reasons": []
  },
  "metrics": [
    {
      "metric": "moisture",
      "verdict": "blocked-claim-type",
      "display_change_pct": 6.58,
      "raw_delta": 13.72,
      "mdc95": 7.104,
      "badge": null,
      "claim_kind": null,
      "reason": "Foundation is makeup. A moisture claim needs a product such as a moisturizer or serum."
    },
    {
      "metric": "pore",
      "verdict": "within-noise",
      "display_change_pct": -2.74,
      "raw_delta": -2.825,
      "mdc95": 8.925,
      "badge": null,
      "claim_kind": "appearance",
      "reason": "Raw score moved −2.8. Same-light retakes stay within about ±8.9 (95% band), so this can be noise."
    },
    {
      "metric": "wrinkle",
      "verdict": "blocked-claim-type",
      "display_change_pct": 0,
      "raw_delta": 0.362,
      "mdc95": 1.511,
      "badge": null,
      "claim_kind": null,
      "reason": "Foundation is makeup. A wrinkle claim needs a product such as a serum."
    },
    {
      "metric": "radiance",
      "verdict": "claimable",
      "display_change_pct": 10.98,
      "raw_delta": 11.454,
      "mdc95": 3.829,
      "badge": "Radiance +11%",
      "claim_kind": "appearance",
      "badge_label": "Appearance with product on",
      "reason": "Raw score moved +11.5, more than the ±3.8 that same-light retakes produce. This is an appearance claim: it describes the skin with the product on."
    }
  ]
}

Accepts YouCam's output entries as returned, or a { "moisture": { "ui": 74, "raw": 59.9 } } map. product_category is optional; without it the claim-type check is skipped. Photos up to 4 MB each, JPEG or PNG; 30 requests per minute per address.

import { claimCheck } from "./claim-check"; // examples/claim-check.ts

const r = await claimCheck({
  baseUrl: "https://your-claim-guard-host",
  before: { scores: youcamBefore.output, photo: beforeJpeg },
  after: { scores: youcamAfter.output, photo: afterJpeg },
  productCategory: "moisturizer",
});
for (const m of r.metrics) {
  if (m.badge) showBadge(m.badge, m.badge_label);
  else logForReview(m.metric, m.verdict, m.reason);
}

{
  "mcpServers": {
    "youcam-beauty": {
      "command": "npx",
      "args": ["-y", "mcp-remote", "https://mcp-api-01.makeupar.com/mcp/beauty",
               "--header", "Authorization:${AUTH_HEADER}"],
      "env": { "AUTH_HEADER": "Bearer YOUR_API_KEY" }
    },
    "claim-guard": {
      "command": "node",
      "args": ["C:/path/to/youcam-claim-guard/node_modules/tsx/dist/cli.mjs",
               "C:/path/to/youcam-claim-guard/mcp/server.ts"]
    }
  }
}

npm run mcp starts a local MCP server with two tools: claim_check (scores plus two photo paths or base64, and an optional product category) and explain_thresholds. An assistant can run YouCam's skin analysis through YouCam's own MCP server, then check the claim with Claim Guard before writing a badge.