Public registry

Publish audits as a static site where every visitor can recompute the hashes and check the signature in the browser.

modeldiffr registry build audits --out registry_site --key acme=keys/acme.pub
python -m http.server --directory registry_site 8000

wrote registry_site with 11 audits
preview: python -m http.server --directory registry_site 8000

The site has no server code and no build step. Put the folder on any static host.

What the build does

1. Finds every report.json under the given folders (skipping _controls).
2. Runs modeldiffr verify on each, with the publisher key when one is given. A report that fails any check is left out and listed in skipped, and the command exits with 4. --allow-failed lists it anyway.
3. Copies the report, its HTML page, signatures, timestamps and bills of materials into audits/<first 16 hex of the audit id>/.
4. Writes registry.json with a summary of each audit and the publisher keys, and the pages that read it.

What a visitor's browser checks

Opening an audit downloads its report.json and recomputes, in plain JavaScript with no server help:

Check	How
audit_id	RFC 8785 canonical JSON of the manifest, then SHA 256
manifest_consistency	Settings and model entries rebuilt from the report
results_root	RFC 6962 Merkle tree over every per item result
verdict	Rebuilt from the significance and minimum effect flags
*_weights_leaves	Merkle root over the per tensor hashes
statement	SHA 256 over every claim
signature	Ed25519 signature on report.dsse.json with the listed keys, through Web Crypto, and its binding to this report

The canonical JSON, Merkle and signature code is tested against the Python implementation on every commit, including awkward numbers and Unicode keys. Two checks are left to modeldiffr verify: recomputing bootstrap intervals, which needs the same random number generator, and Sigstore bundles, which need the Sigstore trust root. The page says so instead of claiming them.

Deploy on Netlify

Keep the registry in its own repository, or in a folder of this one, and build it in CI:

```toml netlify.toml [build] command = "pip install modeldiffr[proof] && modeldiffr registry build audits --out registry_site --key acme=keys/acme.pub" publish = "registry_site"

[build.environment] PYTHON_VERSION = "3.12"

Commit `audits/` (reports are small) and the public key, never the private key. Each push rebuilds the site; the generated `_headers` file lets other sites fetch `registry.json` and reports across origins.

GitHub Pages, Cloudflare Pages and S3 work the same way: upload the folder.

## registry.json

```json
{
  "schema": "modeldiffr.registry/1",
  "title": "Modeldiffr audit registry",
  "generated_at": "2026-10-22T10:31:02+00:00",
  "keys": [{"name": "acme", "path": "keys/acme.pub", "pem": "-----BEGIN PUBLIC KEY-----..."}],
  "audits": [
    {
      "id": "71e1c0a4b2d39f10",
      "audit_id": "mdr1:71e1...",
      "base": "Qwen/Qwen2.5-1.5B-Instruct",
      "derivative": "Qwen/Qwen2.5-1.5B-Instruct-GGUF:qwen2.5-1.5b-instruct-q4_k_m.gguf",
      "suite": "lite",
      "verdict": {"any_change": true, "changed": ["gsm8k_accuracy"], "negligible": []},
      "signed": true,
      "anchored": false,
      "files": ["report.json", "report.html", "report.dsse.json"]
    }
  ],
  "skipped": []
}

Other tools can read it to show audits next to model listings.