1/ 80 days until Article 12 of the EU AI Act becomes applicable. If you operate a high-risk AI system in the EU, this is your deadline. Penalty cap: 15 million euros or 3% of global turnover.

2/ We have been running Article 12 logging in production for 14 months across a multi-provider setup. A few things that turned out to matter more than the text suggests.

3/ Per-vote logging in multi-provider setups. If you log only the final outcome you cannot reconstruct decisions in an audit. Log every voter, every gate, every threshold separately, linked to a decision_id.

4/ Hash chains plus Ed25519 signatures per batch. The text says "automatic recording" but regulators expect tamper-evidence in any non-trivial audit. Append-only storage is not negotiable in practice.

5/ Retention is a sliding scale with sectoral overlays. Article 12 baseline ends up overlaid by MDR (medical), NIS2 (critical infrastructure), Law Enforcement Directive, sector finance law. The matrix matters more than the headline number.

6/ GDPR cross-compliance does more of the work than the AI Act text alone. Articles 5(1)(c), 17, 30, 32 and 35 force specific implementation choices that cloud-native logging does not handle by default.

7/ Operator interventions are logged events under Article 12, not just inference. Human overrides, manual approvals, training-data injections — all in scope. Easy to forget until the first practice audit.

8/ The five pillars in my mental model (identifiability, integrity, completeness, availability, proportionality) do not appear in the text but match every audit checklist I have seen. Useful organising framework.

9/ Multi-tenancy means each tenant's high-risk system is a separate compliance object under the AI Act, in addition to GDPR Article 32 isolation. Per-tenant DEKs, RLS at the database, cross-tenant query alerts.

10/ Common pitfall: storing raw PII alongside log records. Hash the inputs, store raw payloads encrypted separately with tighter retention. Erasure events become separate log entries documenting what was deleted.

11/ I wrote the patterns up into a bilingual (DE/EN) practitioner toolkit with PDF, Excel templates, checklists and JSON schemas. Launch price 29 euros for the first 100 buyers with code LAUNCH50.

12/ https://yoendem.gumroad.com/l/eu-ai-act-article-12-toolkit