AI Code Review Best Practices Interview Prep

AI code review best practices for engineers - reviewing diffs, finding risks, checking tests, protecting architecture boundaries, and using AI responsibly.

Quick answer

AI code review best practices are the disciplines that let engineering teams use AI to accelerate diff review without reducing the rigor of judgment on correctness, security, and architectural integrity.

Code review is the enforcement point for every quality standard a team has: correctness, test coverage, security, architecture, performance, and convention compliance.

Editorial review

Written by

CompoundLearn editorial team

Wireless / RF / hardware engineering

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CompoundLearn editorial team

Wireless / RF / hardware engineering

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Key points

  • AI code review shifts reviewer attention from mechanical scanning (conventions, imports) to substantive judgment about correctness, security, and architecture — the AI handles the former, the human owns the latter.
  • The strongest use of AI is pre-screening and summarization: ask it to flag the highest-risk areas, missing test coverage, and suspicious external API calls, then read the diff against that checklist.
  • The merge decision is the boundary that must not move — never auto-approve PRs and never let an AI summary substitute for reading the diff, because AI hallucinates signatures and misses implicit state.
  • AI-generated code has characteristic failure modes to watch for: silent error swallowing, hallucinated API signatures, and reproduced insecure patterns.
  • Every behavior change needs a corresponding test change; passing CI is necessary for merge but is not a substitute for review.
  • Scope discipline matters more with AI: oversized AI-assisted PRs that are too large to review meaningfully are a direct quality risk.

What it is

AI code review best practices are the disciplines that let engineering teams use AI to accelerate diff review without reducing the rigor of judgment on correctness, security, and architectural integrity. The core shift AI makes possible is moving review attention from mechanical scanning — "does this follow our import conventions?" — to substantive judgment — "does this change correctly handle the edge case the spec describes?" AI surfaces the former class of issue quickly; engineers apply their expertise to the latter. In practical terms, the strongest use of AI in code review is as a pre-screening and summarization tool. An engineer can prompt an AI assistant with the diff and ask it to identify the highest-risk areas, flag missing test coverage, and note any external API calls that look inconsistent with the library's documented interface. This gives the reviewer a targeted starting checklist rather than a blank diff to scan from scratch. The engineer then reads the diff against that checklist, adding their own architectural and domain judgment. The boundary that must not move is the merge decision. AI assistants should not be configured to auto-approve PRs, and AI review summaries should not substitute for reading the diff. AI tools can be wrong in ways that look confident — hallucinating function signatures, missing implicit state dependencies, or failing to recognize a security pattern they were not specifically prompted to check for. The human reviewer owns the outcome of the merge, which means they must own the review.

Why interviewers ask

Code review is the enforcement point for every quality standard a team has: correctness, test coverage, security, architecture, performance, and convention compliance. Hiring managers ask about AI code review specifically because teams that adopt AI coding tools but do not update their review process end up with faster development and lower quality simultaneously — AI-generated code lands faster and with less scrutiny than it requires. Interviewers look for candidates who understand review as a risk-control mechanism, not a formality. Signals they seek include: the ability to distinguish cosmetic changes from behavior changes in a diff; knowledge of the specific failure modes common in AI-generated code (silent error swallowing, hallucinated API signatures, reproduced insecure patterns); an explicit process for checking test coverage against new logic paths; and the discipline to read the diff before reading the AI summary rather than after. For senior engineers and tech leads, the question extends to team-level process: how do you maintain review depth as AI-assisted PR volume increases? What tooling or workflow changes reduce the cognitive load of reviewing larger diffs without reducing quality? Strong candidates have concrete answers because they have worked through the tradeoffs, not just considered them abstractly.

Common mistakes

The most consequential mistake is treating the AI-generated review summary as the review itself. A summary that says "this looks correct" without the reviewer having traced the execution path through the changed code is not a review — it is a guess with extra steps. AI tools can miss context-dependent behavior, rely on stale assumptions about the codebase state, and generate confident-sounding summaries for changes that contain real defects. A second common mistake is skipping test review because the diff "looks straightforward." New code paths without tests are a deferred bug. Code review is the last gate before merge where missing test coverage can be caught without incurring the cost of a production incident. Every behavior change should have a corresponding test change — if it does not, the reviewer should comment requesting one rather than approving on the assumption the change is simple enough to skip. It also helps to read coverage the way the metrics define it: line coverage proves a statement ran, branch coverage proves each new conditional was exercised by an assertion, and mutation testing (Stryker for JS/TS, PITest for Java) proves the assertions would actually fail if the logic were wrong. A high line percentage on a new branch with no assertion is a coverage illusion. Other frequent failures include approving PRs that are too large to review meaningfully (the SmartBear/Cisco code-review study found defect discovery peaks at 200–400 lines per session and degrades beyond it — a direct consequence of AI-assisted development without scope discipline), missing security-relevant patterns such as injection (OWASP Top 10 A03:2021) that a SAST scanner like Semgrep or CodeQL would have flagged in CI because the review focused only on logic correctness, and conflating "passes CI" with "reviewed." CI passing is a necessary condition for merge, not a substitute for review. Engineers who consistently catch real defects in AI-generated code do so because they have a mental model of that code's characteristic failure modes.

AI-assisted code review — division of labor

Review concernAI handles wellHuman must own
Conventions, style, importsYes — fast mechanical scanSpot-check only
Diff summary and risk triageYes — focuses attentionRead the diff against it, never instead of it
Correctness vs spec/intentPartial — can guess plausiblyOwns — trace the changed paths against the requirement
Security patterns (injection, secrets, weak crypto)Flags some when prompted; SAST (Semgrep, CodeQL) catches the mechanical casesOwns — explicit scan; models reproduce these from training data
Test adequacy for new branchesFlags missing coverageOwns — judge whether the tests actually prove the behavior
Merge decisionNo — must not auto-approveOwns — the boundary that never moves

Sample interview questions

  1. An AI assistant reviews a 200-line PR and returns "No issues found; changes look correct and well-tested." What is the correct way to use that output before merging?
    • A. Approve and merge — the assistant scanned the whole diff, which a human skim would not.
    • B. Treat the summary as a triage starting point, then read the diff yourself and trace the changed execution paths against the spec before deciding.
    • C. Re-run the assistant two more times and merge if all three runs agree.
    • D. Merge if CI is green, since the assistant plus CI together cover correctness and tests.

    Option B is correct. An AI summary is a hypothesis and a triage aid, not a verdict. The merge decision requires human-traced verification because models produce confident "looks correct" summaries for diffs that contain real defects — missed implicit state, stale assumptions about the codebase, an edge case the spec calls out. The discipline is to read the diff before the summary, not after, so the summary cannot anchor your judgment. Option A is wrong. Scanning every line is not the same as judging it; a confident "no issues" is precisely the failure mode that invites rubber-stamping. Option C is wrong. Re-running the same model on the same diff produces correlated guesses, not independent verification — a systematic blind spot repeats. Option D is wrong. Green CI is necessary but not sufficient: tests can pass while the change is wrong, under-tested, or out of scope. Production reality: "no issues found" is the highest-risk summary to receive, because it is the one most likely to be accepted without the reviewer doing the work.

  2. Reviewing AI-generated code you find: try { result = await fetchConfig(); } catch (e) { result = {}; }. Why is this a review flag even though it "handles" the error?
    • A. try/catch is deprecated in modern async code.
    • B. It silently swallows the failure — a fetch error becomes an empty config, so the system proceeds on wrong data and the root cause is hidden from logs and callers.
    • C. Returning an object literal from a catch block is a type error.
    • D. It is fine — defensive defaults are always good practice.

    Option B is correct. Swallowing the exception and substituting an empty default converts a loud, diagnosable failure into a silent one that corrupts everything downstream. AI-generated code reproduces this pattern often because it optimizes for "does not throw." The fix is to let it throw, or log and rethrow, or fail closed with an explicit surfaced error — never to mask the failure with a default on a load-bearing path. Option A is wrong. try/catch is not deprecated; the construct is fine, the handling is not. Option C is wrong. Assigning an object literal is valid; there is no type error. Option D is wrong. A default that hides a real failure is the opposite of good practice — defensive defaults are appropriate only when the absence of data is itself a valid, expected state. Production reality: silent fallback on an I/O path is one of the most common ways AI-assisted code passes review and tests yet fails in production with no trace, so scan every catch block for a swallowed error. See /topics/ai-native-debugging-best-practices.

  3. An AI-completed data-access function builds a query as db.query('SELECT * FROM users WHERE id = ' + req.params.id). The PR's tests pass. What is the right review action?
    • A. Approve — the model produced working code and the query returns the right row in tests.
    • B. Block it: untrusted input is concatenated into SQL (injection). Require a parameterized/prepared query plus input validation.
    • C. Ask the author to add a comment explaining the query.
    • D. Approve, but add a TODO to parameterize it in a later PR.

    Option B is correct. Concatenating request input into a SQL string is a classic injection vulnerability (CWE-89, under OWASP Top 10 A03:2021-Injection), and models reproduce it because the pattern is abundant in training data. The fix is a parameterized query or prepared statement plus validation of the input — never hand-rolled escaping. This exact shape is what SAST scanners like Semgrep and CodeQL flag automatically, so a CI gate would have caught it before review. Option A is wrong. The passing tests exercise benign input; correctness on a valid id says nothing about a malicious one like 1 OR 1=1. Option C is wrong. A comment documents the vulnerability without removing it. Option D is wrong. Shipping a known injection behind a TODO is an unacceptable transfer of risk to production. Production reality: AI output routinely passes style and unit checks while carrying injection, hardcoded secrets, and weak-crypto defaults inherited from the corpus, so reviews must scan for these patterns explicitly rather than assume the model avoided them. See /topics/llm-guardrails-and-safety.

  4. A PR adds a new branch — if (user.tier === 'enterprise') — with distinct behavior, but the test diff is unchanged. CI is green. What should the reviewer do?
    • A. Approve — existing tests still pass, so green CI means coverage is fine.
    • B. Request a test that exercises the new enterprise branch; an untested new code path is a deferred bug and review is the last cheap place to catch it.
    • C. Approve and open a separate ticket to add tests next sprint.
    • D. Rewrite the branch yourself so it no longer needs a dedicated test.

    Option B is correct. Every new behavior branch needs a corresponding test. Passing existing tests only proves the old paths still work; it says nothing about whether the new enterprise path is correct. Requesting the test now, before merge, is far cheaper than a production incident later. Option A is wrong. Green CI on unchanged tests is silent about new logic — it cannot fail on a path it never executes. Option C is wrong. Deferring coverage on already-merged logic is exactly how untested paths accumulate; the cheapest catch point is this review. Option D is wrong. A reviewer rewriting the author's code sidesteps the process, and the coverage gap still exists. Production reality: coverage tools report a line percentage, but line coverage only proves a statement ran. Confirming each new conditional is actually exercised by an assertion — not merely touched during an unrelated test — is branch coverage, the metric that matters for a new behavior branch. Stronger still is mutation testing (Stryker for JS/TS, PITest for Java), which injects faults into the code and checks whether the tests fail; surviving mutants reveal assertions that execute a line without verifying its behavior. See /topics/test-driven-ai-coding.

  5. After adopting AI coding tools, PR volume triples and reviewers begin approving faster to keep up; quality is slipping. What is the correct structural fix?
    • A. Reduce review depth per PR to match the higher throughput.
    • B. Hold review depth constant and reduce PR size — cap logic diffs to a reviewable size and use AI to pre-screen, so human attention stays on architecture, security, and correctness.
    • C. Require two approvals on every PR regardless of size.
    • D. Pause AI tool adoption until review capacity catches up.

    Option B is correct. The lever is PR scope, not review depth. Small, single-purpose diffs stay reviewable, and AI pre-screening offloads the mechanical triage so the human spends attention on substantive judgment. Volume rising is healthy; the diff size per PR is what must stay bounded. Option A is wrong. Cutting depth to match volume is the exact mechanism by which AI adoption produces faster and worse at the same time. Option C is wrong. Adding approvers to oversized PRs multiplies cost without restoring reviewability — two skims of an unreviewable diff are not one real review. Option D is wrong. Abandoning the tooling discards real velocity to solve a process problem that has a cheaper fix. Production reality: a healthy signature of an AI-assisted team is more, smaller PRs — not the same large PRs arriving faster. The SmartBear/Cisco code-review study puts the effective ceiling at 200–400 lines per review session, beyond which defect-discovery rates fall off. See /topics/avoid-spaghetti-code-ai-coding.

  6. AI-generated code calls client.batchWrite(items, { retries: 3 }), a signature you do not recognize. The tests mock client and pass. What is the right review step?
    • A. Trust it — the model has seen this library and the tests pass.
    • B. Verify the method and its options against the library's current documentation or type definitions; a mock cannot catch a hallucinated signature or an unsupported option.
    • C. Remove the retries option to be safe.
    • D. Approve and rely on a runtime error to surface a wrong signature.

    Option B is correct. Models hallucinate plausible-but-nonexistent methods and parameters, and a hand-written mock that mirrors the AI's assumption will pass happily. The only reliable check is the real API surface — the installed version's docs or its type definitions. Option A is wrong. Training exposure does not guarantee the current API; libraries add, rename, and remove methods across versions. Option C is wrong. Blindly deleting an option may break intended behavior; the action is to verify, not to guess. Option D is wrong. Deferring to runtime ships a likely defect and burns a production or CI cycle to discover what a docs check would have caught in seconds. Production reality: hallucinated signatures are a signature AI failure mode — pin them at review by checking calls against the installed package's types, never against memory. See /topics/context-engineering-for-coding-agents.

Frequently asked questions

What are AI code review best practices?
AI code review best practices are the disciplines that let engineers use AI to accelerate diff review without reducing the quality of human judgment on correctness, security, and architecture. The key practices are: use AI to generate a focused summary and a risk checklist, then read the diff yourself against that checklist; never approve based on the AI summary alone; check test coverage for every new branch added; and verify that the change matches the spec or ticket before merging.
Can AI replace human code review?
No. AI can summarize what changed, flag probable defects, and identify conventions violations faster than a human skimming the diff. But the engineer still owns the merge decision, the architectural judgment, the security threat model, and the determination of whether the change actually satisfies the requirement. AI review assists by surfacing candidates for human attention — it does not evaluate whether those candidates are acceptable.
What should AI look for in a code review?
Scope creep (the PR touches files outside its stated purpose), missing or broken tests for changed logic, unsafe API usage or deprecated function calls, missing error handling on I/O paths, duplicated logic that should use an existing utility, changes that violate import-direction conventions, and any mutation of shared state that could produce race conditions or unexpected side effects in concurrent execution paths.
What is the best AI-assisted code review workflow?
Start by asking AI to summarize the diff and list the highest-risk areas. Then read the diff yourself, using the AI summary as a starting checklist rather than a final verdict. Check that every new code path has test coverage — and specifically branch coverage (each new conditional exercised by an assertion), not just the line percentage. Compare the behavior change against the spec or ticket. Run CI and verify that all checks pass. Only then make the merge decision. The workflow saves time on triage while keeping the human in the loop on every substantive judgment.
How do I review AI-generated code more effectively than hand-written code?
AI-generated code tends to have characteristic failure modes: hallucinated function signatures, overly generous error swallowing, unnecessary abstraction layers, and confident reproduction of insecure patterns from training data. In addition to standard review, check all external API calls against live documentation, look for try/catch blocks that silently discard errors, and inspect any new utility function to verify it does not duplicate something already in the codebase. AI-generated code often passes style checks while containing these subtler issues.
What security risks should reviewers check in AI-generated code?
Injection vulnerabilities (SQL — CWE-89, shell/OS-command — CWE-78, both under OWASP Top 10 A03:2021-Injection) where AI has concatenated user input into a query or command; path traversal (CWE-22, OWASP Top 10 A01:2021-Broken Access Control) from unsanitized file paths; hardcoded credentials or tokens that slipped in because the AI was completing a pattern; insecure cryptographic defaults (MD5, ECB mode, fixed IVs); overly permissive CORS or authorization conditions; and missing input validation on externally supplied data. These patterns appear in AI output because they exist in the training corpus — reviews should explicitly scan for them rather than assuming the model avoided them. Most of these are exactly what static analysis (SAST) scanners such as Semgrep and CodeQL detect automatically, so wiring a SAST gate into CI catches the mechanical cases before human review and frees the reviewer to judge the cases a scanner cannot.
How do you keep review quality high as PR volume increases with AI coding tools?
Reduce PR size, not review depth. AI-assisted development tends to increase PR frequency — which is healthy — but reviewers sometimes respond to higher volume by approving faster. The correct response is to keep PRs under a reviewable diff size — the SmartBear/Cisco code-review study found defect discovery is highest at 200–400 lines reviewed in a 60–90 minute session (roughly 70–90% of defects found), and drops sharply on larger diffs — and use AI tooling to pre-screen for obvious defects so reviewer attention stays on architecture, behavior correctness, and security. Review depth per PR should not decrease; PR scope should.

Related topics

Essential AI-Native Skills for AI Code Review Best Practices

Modern engineering work increasingly uses AI tools for design and code review, debugging, documentation, test and testbench generation, and workflow automation. The goal is not to let AI replace engineering judgment — it is to move faster while keeping verification discipline.

  • Use AI to explain unfamiliar code, logs, waveforms, datasheets, or test failures.
  • Break large problems into small, reviewable steps you can verify independently.
  • Ask AI for hypotheses, then validate them against tests, measurements, simulations, or lab data.
  • Version-control your analysis scripts, testbenches, and configs — keep changes small and reviewable.
  • Document your assumptions, design tradeoffs, and debugging decisions.
  • Verify AI output before trusting it: run the checks that fit the domain — unit tests, linters, simulations, or bench/lab measurements.
  • Review AI output for correctness, edge cases, and real-world consequences.

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