Evidence packs

An evidence pack is a portable, offline-verifiable snapshot of what your AI system did during a period. Built for auditors, DPOs, lawyers, and regulators.

When to create one

Monthly as a routine — for your DPA archive.
During an incident — the period around a suspicious event.
For a regulator request — exactly the window they ask for.
For due diligence — a prospective customer or investor asks for proof.

Create

Via dashboard: AI → Evidence packs → New pack.

Via API:

curl -X POST https://api.monsys.ai/api/v1/ai/evidence-packs \
  -b cookies.txt \
  -H "Content-Type: application/json" \
  -d '{
    "period_start": "2026-04-01T00:00:00Z",
    "period_end":   "2026-04-30T23:59:59Z",
    "app_id":       42,         // optional, otherwise all apps for the tenant
    "include_blobs": true       // bundle redacted content
  }'

Response:

{
  "pack_id": "7",
  "trace_count": 14233,
  "span_count":  37501,
  "blob_count":  12044,
  "total_cost_micro_eur": 89412300,
  "manifest_sha256": "3abb09…",
  "signing_public_hex": "d2f60e21…",
  "download_url": "/api/v1/ai/evidence-packs/7/download",
  "verify_with": "Use tools/evidence-pack-verify.py — manifest is Ed25519-signed by the hub."
}

Bundle layout

pack-7.tar.gz
├── manifest.json
├── manifest.sig          ← Ed25519 signature over manifest.json bytes (base64)
├── traces.jsonl          ← one line per trace
├── spans.jsonl           ← one line per span
└── blobs/
    ├── 1bd2ea92….txt     ← redacted content per hash
    ├── 8a48cdca….txt
    └── ...

`manifest.json` keys

Key	Type	Description
`schema_version`	int	Pack format version (starts at 1)
`pack_id`	string	Numeric ID
`tenant_id`	uuid	The owner
`app_id`	int/null	One app or all apps of the tenant
`period_start/_end`	RFC3339	The window
`trace_count`	int	Number of traces in the pack
`span_count`	int	Number of spans
`blob_count`	int	Number of unique content blobs
`traces_sha256`	hex	SHA256 of traces.jsonl bytes
`spans_sha256`	hex	SHA256 of spans.jsonl bytes
`blob_index[]`	array	`{hash, sha256}` per blob — recompute & check
`signing_public_hex`	hex	Ed25519 public key — cross-verify with monsys
`created_at`	RFC3339	Pack generation timestamp

Offline verification

pip install cryptography
python3 evidence-pack-verify.py pack-7.tar.gz \
    --expected-pubkey <pinned fingerprint from monsys.ai/security/keys>
# Quiet mode, exit-code only:
python3 evidence-pack-verify.py --quiet pack-7.tar.gz --expected-pubkey …

Example output:

pack_id      : 7
tenant_id    : 77198636-a5fe-484e-93fe-98b11a55ca84
period       : 2026-04-01T00:00:00Z → 2026-04-30T23:59:59Z
traces       : 14233
spans        : 37501
blobs        : 12044
signing key  : d2f60e21e0d496252b92bb308310e1a1dd1d5010f8fcaabbe169bdae1e2b7173
✓ signature valid
✓ traces.jsonl hash matches (3abb0918cda7…)
✓ spans.jsonl hash matches  (b517235df141…)
✓ all 12044 content blobs hash-matched

RESULT: OK

Exit codes:

0 — everything matches
1 — at least one hash or the signature does not match — pack has been altered

What does the auditor do with the public key?

The manifest contains a signing_public_hex. But who says that’s the right key?

Two options:

Cross-verify against monsys.ai/security/keys (the public page where we publish our Ed25519 fingerprints).
Request a printed certificate at onboarding — we send you a PDF with the fingerprint that you keep in your archive.

This lets the auditor independently confirm that the signature wasn’t made by someone with a spoofed key.

Guarantees

Tamper-evident: one byte changed in a blob → verifier raises.
Period-bound: the manifest pins which window the pack covers — you cannot retroactively add “extra” data without re-signing.
Reproducible: same period + same data → byte-identical manifest_sha256 (deterministic serialisation).
No monsys account needed to verify.

Retention

We keep evidence packs on disk for at least 12 months. For longer retention export to your own object store; monsys.ai does not guarantee long-term archival (NIS2 requires you to keep the evidence anyway).