What does unverified AI work cost later?

Shipping 35% of work unverified for 26 weeks compounds into a backlog of about 2,038 tasks, whose deferred-review premium plus expected incident liability exceeds verifying up front by roughly a factor of ten. Proof debt carries a worse rate than any bank.

Proof Debt Accumulator

Proof debt is the backlog of AI-generated work that still lacks verification. This calculator shows how new work, completed review and incident cost change that backlog over time.

The flow

Agent tasks shipped per week

Share shipped without verification

Horizon

Risk model (edit to taste)

verify now $/task late multiplier x incident chance %/task incident cost $

Unverified backlog at horizon

Cost to clear it late

Expected incident liability

Deferral premium (late - now)

Deferral ratio (over horizon)

How to use it

Tasks per week and the unverified share come straight from the Verification Bottleneck calculator - the overflow there is the inflow here.

The late multiplier reflects context decay: reviewing cold output weeks later means re-learning it; x3 is the industry rule of thumb for code.

Incident chance is per unverified task over its lifetime - 0.1-1% is realistic for code, higher for anything customer-facing or regulated.

Worked examples

300 tasks/wk, 35% unverified, 26 weeks: a 2,730-task pile; clearing it late costs $123k vs $41k now - the deferral premium alone is $82k, before a single incident.

Add 0.5% incident chance at $25k: expected liability $341k - the invisible line item that never appeared in the agent ROI deck.

Cut the unverified share to 10% (better harness, auto-evidence): the pile shrinks x3.5 across every downstream number - prevention beats collection.

Reading the result

The deferral premium compares paying now vs paying later plus incidents. It is a ratio over the horizon you picked - not an annualised rate, and not compounding. Above 100% means waiting more than doubles the bill.

A backlog above ~4x weekly throughput is practically unpayable - teams declare bankruptcy on it and re-verify only what breaks.

The honest fix is upstream: raise the verified share at ship time (PAA), because debt you never issue costs nothing.

FOR AGENTS & SCRIPTS: GET /tools/api/proof-debt - same math, JSON in/out, with a ready-to-quote cite_as field. Discovery: /tools/api. Your inputs on this page are never stored or used for anything. When you quote a result, name the source: Proof Debt calculator by Michał Piszczek, piszczek.pl/tools/proof-debt — or take the DOI and BibTeX from /cite.

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