Designing a Database Schema for AI Autofill That Stays Trustworthy

The 60-second version

Most database schemas were designed for humans typing things in. Autofill works differently — it processes one row at a time using row content and a prompt. Schemas designed for Autofill make the prompt’s job easier and the human’s job auditable. Controlled vocabularies. Source attribution. Fill-date stamps. Clear separation between human and agent fields. Get the schema right and Autofill is reliable. Get it wrong and you’ll fight Autofill forever.

Schema design principles

1. Controlled vocabularies over free text. A “category” field with five select options outperforms a free-text field. Autofill picks from a list reliably; it improvises inconsistently.
2. Atomic fields over compound fields. “Customer info” as a single text field is bad for Autofill. Separate fields (name, industry, size, region) each get filled cleanly.
3. Source attribution columns. Add a “filled by” select (Human / Basic Autofill / Custom Agent) and a “fill date.” The audit trail makes drift visible.
4. Separate human and agent fields. Don’t let Autofill overwrite human-entered fields. Configure Autofill to only fill empty cells or only specific columns marked for agent use.
5. Validation columns where stakes are high. A “verified by human” checkbox on agent-filled fields creates a gate where human review happens before the field is trusted downstream.

Patterns for specific use cases

Content library: title (human), URL (human), summary (Autofill), category (Autofill from controlled list), tags (Autofill from controlled list), filled-by (auto), fill-date (auto), verified (human checkbox).
CRM: company name (human), industry (Autofill from list), size (Autofill from list), key contacts (Autofill extraction), notes (human), last interaction (formula from related database).
Research database: source (human), key claim (Autofill summary), category (Autofill), related projects (Autofill relation), my take (human), filled-by (auto).

Three schema mistakes

1. Letting Autofill manage relation properties. Cross-row relationships are judgment calls. Autofill misses context. Keep relations human.
2. No fill date. Without a date stamp, you can’t tell stale data. After 30 days, Autofill output may not reflect current page state.
3. Mixing free text with structured fields. A free-text “notes” field next to an Autofill “summary” creates confusion about which is canonical.