Engineering in the age of AI
AI makes coding easier. It also creates new requirements.
In short
- AI-assisted coding is now the norm: 90% of almost 5,000 technology professionals in the 2025 DORA study use AI at work.1
- Writing code has become easier. Producing good software has not become easier by the same amount: in a randomised trial, experienced developers took 19% longer with AI while believing they were 20% faster.6
- The bottleneck has moved from typing to specifying, reviewing, testing, securing and owning code.
- This creates seven new requirements for teams, from precise specifications to verified dependencies and clear accountability.
- AI amplifies what a team already has. Strong engineering practices turn AI speed into value; weak ones turn it into instability.2
What has really become easier
AI coding assistants have moved from curiosity to default in a remarkably short time. In Google’s 2025 DORA study of almost 5,000 technology professionals, 90% use AI at work, with a median of two hours a day, and more than 80% say it has made them more productive.1 In the Stack Overflow survey of more than 49,000 developers, 84% use or plan to use AI tools, and half of professional developers use them every day.4,5
The gains are real where the work is well defined: boilerplate, tests for existing behaviour, translation between languages and frameworks, first drafts of documentation, and exploring an unfamiliar codebase. DORA also finds that AI adoption now goes together with higher delivery throughput, a reversal of its 2024 finding.2
The same study, however, still links AI adoption with lower delivery stability.2 That combination, more output and less stability, is the signal that something else has changed.
Where the bottleneck has moved
Writing code was never the whole job. A change has to be specified, written, reviewed, tested, deployed and operated. AI compresses one of these steps dramatically. The others stay, and some grow, because there is now more code to check, and it arrives faster.
The evidence points the same way. Two thirds of developers say their top frustration is AI output that is almost right but not quite, and 45% say debugging AI-generated code takes more time.4 Trust is falling as use rises: the share of developers who distrust AI accuracy grew from 31% to 46% within a year.5
Perception is also an unreliable guide. In a randomised trial by METR, 16 experienced open-source developers worked on 246 real issues in large, mature repositories. With AI tools allowed, tasks took 19% longer. Before the study they expected a 24% speed-up; afterwards they still believed AI had made them 20% faster.6 A larger follow-up with 57 developers, published in February 2026, pointed to modest speed-ups with wide uncertainty; METR itself called the signal unreliable, partly because many developers no longer want to work without AI.7
The lesson is not that AI does not help. It is that the gain is decided outside the editor: in how clearly work is specified, how well it is checked, and how safely it reaches production.
Seven new requirements
From building and running software that operates around the clock, with AI in the daily workflow, I see seven requirements that matter more now than before. None of them is new in principle. What is new is that ignoring them has become cheaper in the short term and more expensive in the long term.
| Requirement | Why it matters more now | Practice |
|---|---|---|
| 1. Precise specification | AI implements what is asked, not what is meant. Vague intent produces plausible but wrong code at high speed. | Acceptance criteria and constraints written before code is generated |
| 2. Review as core capacity | More code arrives faster. Users of AI assistants wrote less secure code and felt more confident about it.8 | Every change reviewed by a named person; small changes |
| 3. Automated tests and fast feedback | Without them, more changes lead to more instability.2 | Tests in every change; builds and previews run automatically |
| 4. Security by default | In tests by the security vendor Veracode (80 tasks, more than 100 models), 45% of cases introduced OWASP Top 10 weaknesses.10 An earlier study found about 40% of Copilot programs vulnerable.9 | Security checks in the pipeline; threat models for sensitive parts |
| 5. Verified dependencies | Models suggest packages that do not exist: at least 5.2% for commercial and 21.7% for open-source models.11 Attackers register these names.12 | Every new dependency checked; lock files; software bill of materials |
| 6. Maintainability | According to the code-analytics firm GitClear, copy-pasted code rose from 8.3% to 12.3% of changed lines between 2021 and 2024, while refactoring fell below 10%.13 | Refactoring as planned work; duplication tracked |
| 7. Accountability and provenance | Duties fall on the product maker, however the code was written.14,15 | Clear ownership per component; record of what was generated and reviewed |
Specification becomes the new source code
When a machine writes the first draft, the quality of the instruction decides the quality of the draft. Teams that write down intent, constraints and acceptance criteria before generating code get usable output. Teams that skip this get code that compiles, passes a quick look, and fails at the edges. In practice, the most valuable senior skill has shifted from writing code to describing precisely what the code must and must not do.
Review is no longer a formality
A Stanford user study found that participants with an AI assistant wrote significantly less secure code than those without, and were more likely to believe their code was secure.8 This is the core risk of AI-assisted development: not that the machine makes mistakes, but that people check less carefully because the output looks finished. Review has to be treated as engineering work with time and responsibility attached, not as a click before merging.
The supply chain is now part of the code
Package hallucination turns a model’s mistake into an attack surface. In an analysis of 576,000 generated code samples from 16 models, researchers found more than 200,000 unique names of packages that do not exist.11 OWASP lists this pattern explicitly and recommends cross-checking and human oversight.12 At the same time, regulation is raising the bar: since 11 September 2026, manufacturers of products with digital elements sold in the EU must send an early warning about actively exploited vulnerabilities and severe incidents within 24 hours, followed by a notification within 72 hours, under the Cyber Resilience Act; the main obligations apply from 11 December 2027.14 The Act also requires a software bill of materials in the technical documentation.15 A team that does not know what is in its software cannot meet these duties, however the code was written.
Ownership cannot be generated
Legal questions follow the same logic. In the United States, the Copyright Office has stated that AI output is protected only where a human has determined sufficient expressive elements; prompts alone are not enough.16 Whatever the jurisdiction, the practical answer is the same: someone in the team must understand, own and be able to explain every component that ships.
From a tool to a team practice
DORA’s most useful finding is a simple one: AI is an amplifier. It makes strong teams more efficient and intensifies the problems of struggling ones. Loosely coupled architectures benefit; tightly coupled ones see little gain.2 DORA has since described seven capabilities that turn AI adoption into results.3
- A clear and communicated AI stance
- Healthy data ecosystems
- AI-accessible internal data
- Strong version control practices
- Working in small batches
- A user-centric focus
- Quality internal platforms
In the systems I build and run, this translates into one rule: every AI-written change goes through exactly the same gate as a human one. It lives on its own branch, is built and tested automatically, is deployed to a preview, and is approved by a named person before it reaches production. Changes are kept small, so that review stays meaningful. The AI is fast; the gate keeps it safe. This costs a little speed on each change and saves a great deal of it over the life of a system.
For leaders, the implication is that investment in AI coding tools should come with investment in the practices around them: an explicit AI policy, review capacity, automated testing and a clear map of dependencies. Without these, the tool accelerates the accumulation of problems rather than the delivery of value.
What the evidence cannot yet say
The research base is young and moves quickly. Surveys capture perception, which the METR trial shows can differ sharply from measured effect.6 Controlled studies are small (the Stanford security study analysed 47 participants8) and hard to repeat, and the latest METR update calls its own signal unreliable.7 Security studies test individual samples, not complete systems with review and testing in place. And the tools improve from one quarter to the next.
What does hold across the evidence is the direction: the cost of producing code has fallen, and the value of judgement, verification and responsibility has risen. Teams that plan for that shift get the speed of AI without paying for it later.
Frequently asked questions
Does AI-assisted coding make software teams faster?
It makes writing code faster. Whether a team delivers better software faster depends on its review, testing and delivery practices. Surveys show high perceived gains, while a controlled trial with experienced developers measured a slowdown, and later measurements were inconclusive.
Is AI-generated code less secure?
Studies repeatedly find security weaknesses in a large share of AI-generated code samples, and one user study found that developers with an AI assistant wrote less secure code while feeling more confident. AI code needs the same or stricter security review as human code.
What is package hallucination?
AI models sometimes suggest software packages that do not exist. Attackers can register such names and publish malicious packages under them. Every new dependency should be checked before it is installed.
Who is responsible for code written by AI?
The team and the company that ship the software. Regulations such as the EU Cyber Resilience Act place duties on the manufacturer of a product, regardless of how the code was written.
What should a team change first?
Agree on a clear AI policy, keep changes small, make automated tests and review mandatory for every change, and verify every new dependency.
Sources
- Google: How are developers using AI? Inside our 2025 DORA report (23 Sep 2025)
- Google Cloud: Announcing the 2025 DORA Report, State of AI-Assisted Software Development (23 Sep 2025)
- Google Cloud: From adoption to impact, putting the DORA AI Capabilities Model to work (9 Dec 2025)
- Stack Overflow Developer Survey 2025: AI
- Stack Overflow: 2025 Developer Survey reveals trust in AI at an all time low (29 Jul 2025)
- METR: Measuring the impact of early-2025 AI on experienced open-source developer productivity (10 Jul 2025)
- METR: We are changing our developer productivity experiment design (24 Feb 2026)
- Perry, Srivastava, Kumar, Boneh: Do users write more insecure code with AI assistants? ACM CCS 2023
- Pearce et al.: Asleep at the keyboard? Assessing the security of GitHub Copilot’s code contributions
- Veracode: AI-generated code poses major security risks in nearly half of all development tasks (30 Jul 2025)
- Spracklen et al.: We have a package for you! A comprehensive analysis of package hallucinations by code generating LLMs
- OWASP GenAI Security Project: LLM09:2025 Misinformation
- GitClear: AI Copilot code quality, 2025 look back at 12 months of data
- European Commission: Safer and more secure digital products (11 Sep 2026)
- ENISA: SBOM adoption state of play 2026 (June 2026)
- Library of Congress, Copyright blog: Inside the Copyright Office’s report on Copyright and AI, Part 2: Copyrightability (6 Feb 2025)