Why AI can increase technical debt

The hidden risks of adopting AI without review, testing and engineering guardrails — and the five guardrails that prevent it.

Here is the uncomfortable mechanism behind most disappointing AI adoptions: AI makes generating code dramatically cheaper, but it does not make verifying code cheaper at anything like the same rate. When production speeds up and verification doesn't, unverified work accumulates. In software, accumulated unverified work has a name — technical debt.

This is not an argument against AI coding tools. It is an argument that adoption without an operating model converts a productivity opportunity into a deferred cost. Below is how that happens, in the order teams usually experience it.

1. The generation–verification asymmetry

A developer with an AI assistant can produce in an afternoon what used to take days. But someone still has to confirm the code is correct, secure, consistent with the codebase and maintainable — and that work has barely accelerated. The result is a growing queue of plausible-looking changes waiting for scarce verification capacity. Whatever slips through under time pressure becomes debt.

2. Review burden migrates to your most expensive people

The people qualified to catch subtle problems in AI-generated code are senior engineers. As volume grows, they spend a rising share of their week reviewing rather than building — and when they are saturated, reviews get shallower. Shallow review of high-volume output is the single fastest debt-creation machine we see in client teams.

3. Pattern inconsistency compounds

AI tools generate locally reasonable code that is globally inconsistent: three ways of handling errors, duplicated logic that almost matches, new dependencies nobody chose deliberately. Each instance is small. Six months of instances is a codebase that is harder to change — which is the practical definition of technical debt.

4. Tests that demonstrate less than they appear to

Generated tests are genuinely useful — and dangerously reassuring. A test suite written by the same tool that wrote the code will often encode the same misunderstanding of the requirement. Coverage goes up; confidence goes up; correctness may not. Validation has to be designed, not just generated.

5. Knowledge debt: shipping code nobody understands

The quietest form of debt: changes merged by developers who could not explain them line by line. The system works today, but the team's mental model of it decays. The cost appears later, as longer incident resolution, slower onboarding and fear-driven "don't touch that module" zones.

The five guardrails that prevent it

None of the mechanisms above is inevitable. Each one maps to a guardrail — an explicit standard your team applies inside its normal workflow:

AI usage policy and approved workflows — which tools, for which tasks, with which data. Removes improvised private workflows.
An AI Definition of Done — what "done" means when AI contributed: understood, consistent with repo standards, explainable by its author.
Review standards for AI-assisted PRs — what reviewers check and at what depth, sized so seniors don't become the bottleneck.
Testing and validation standards — correctness demonstrated independently of the tool that generated the code.
Security, privacy and data boundaries — what may leave your environment, decided once, explicitly.

Wrapped around all five: measurement against a baseline. Rework rate, review time per change and delivery predictability tell you whether AI is compounding value or compounding debt. Without the baseline, you find out from the P&L — a year late.

We cover the full framework, and what these artefacts look like inside a real repo, on the AI engineering guardrails page.

The takeaway

AI doesn't create technical debt. Unverified speed creates technical debt — and AI is the cheapest unverified speed the industry has ever had. Teams that pair the acceleration with explicit standards capture the value. Teams that don't, borrow it.

Nicolás Espinosa — Founder, Optimum Agile. Former Director of Product at PikPok and Senior Delivery Manager at Trade Me; postgraduate specialisation in AI Product Management (Duke University). Based in Auckland, working with NZ and Australian software teams.

See the guardrails framework Take the Scorecard