# Methods — Crovia Continuity Observatory

## Architecture in one paragraph

The Continuity Observatory is an append-only Ed25519-signed JSONL ledger of observations about public AI artifacts. Each observation is hashed (SHA-256), placed as a leaf in a Merkle tree, and the tree root is anchored to the Bitcoin blockchain via OpenTimestamps (`.ots` proof) once per day. Three classes of collectors (Wayback, direct HTTP, co-attestation) feed observations. A retrofit job periodically re-checks old absences and emits an `AX.ABS` (Axiom of Absence) record when the silence threshold is crossed. All artifacts are deterministically rebuildable from the ledger.

## The AX.ABS primitive

Most disclosure systems certify *presence*: "vendor V has published artifact A". `AX.ABS` certifies *absence*: "for target T, with respect to disclosure class C, no public update has been observed in the interval \[t₀, t₁\]". An `AX.ABS` record is itself a signed observation in the ledger.

```
AX.ABS (target=t, class=c, t0=…, t1=…, evidence_set=E, sig=σ)
```

The evidence set `E` is the multiset of negative observations (no new content fingerprint, no new commit, no new card section) collected during \[t₀, t₁\]. The signature σ binds the claim to the observer.

The *Axiom of Echo* (`AX.ECHO`) is a contemplated extension that asserts temporal consistency between a past observation at t₀ and a present observation at t₁ for a given target and field. It is not yet emitted in production but the schema is reserved.

## Daily operations

- 00:05–07:00 UTC: collectors run (wayback, arxiv, robots, spider-vendor-press, etc.)
- 02:13 (Mon) UTC: weekly leaderboard publishes to GitHub Contents API
- 03:00 UTC: OpenTimestamps stamp of the daily Merkle root
- 04:00 UTC: OpenTimestamps upgrade attempt (await Bitcoin confirmation)
- 04:30 UTC: wayback Save Page Now co-attestation (≤ 150 targets/day)
- 07:00 UTC: `observation_daily.sh` (discover + compliance + bridge + forensic + TPA + lineage)
- every minute: `home_pulse.py` aggregator
- every 5 minutes: observatory feed regeneration
- every 30 minutes: silence index rebuild

## Independence guarantees

1. **Two-witness rule.** For every target, Crovia *and* Internet Archive maintain independent snapshots. A vendor cannot rewrite history at one source without diverging from the other.
2. **OpenTimestamps anchor.** No party (including Crovia) can backdate observations: each daily Merkle root is committed to a Bitcoin block.
3. **Append-only ledger.** No deletion, only amendment. Every state of the ledger is reachable from earlier states.
4. **Public verifiability.** All signatures use Ed25519 with the public key published at <https://croviatrust.com/keys/>.

## Limitations

- Wayback coverage is uneven. Long-tail targets may have only one capture per quarter.
- A `presence` observation does *not* attest to truthfulness of the disclosure; it attests only to publication.
- The collectors run from a single Hetzner location; geo-regional access controls (e.g., from CN-blocked IPs) are not detected as such.
- Single-observer deployment today: the federation protocol (Continuity Signature Mesh) is on the roadmap, not yet operational.