Duplicated Code Check — Are Identical Blocks Pasted Across Your Codebase?
DevMeth checks the 48 known AI-code failure patterns — not a penetration test or a security guarantee.
What the issue is
When the same block of code exists in two or more places, every future change happens twice — and usually only once. A bug fixed in one copy stays alive in the other, which is how regressions survive unnoticed.
Why AI tools generate it
Agents copy working answer patterns from one prompt to the next. Pasting and adjusting is faster than extracting a shared function, so identical twins accumulate with every iteration round.
How DevMeth detects it
The scan normalizes every source file (trimming, collapsing whitespace, dropping comments) and hashes sliding windows of 10 lines. Any window that appears in two distinct locations is reported, with boilerplate import lines excluded.
Large identical blocks of code are copy-pasted in more than one place
WHAT WE FOUND
lib/csv-a.ts + lib/csv-b.ts — 12 identical lines in both files
The fix, in three steps
Extract the shared behavior into one function, pass the differences as parameters, and replace every copy with a call. No new copies allowed.
Run a free scan and each finding carries a paste-ready fix prompt you can act on.
Maintainability findings ship in the Rescue Report — bundled with the Launch Pack or available on its own.
Try a free scanFAQ
Why is duplication more than just ugly?
Every copy multiplies the cost of change. One fix, one feature, or one bug lands in only some copies — and the diverged ones become the next incident.
Does this flag a copy-paste of just a few lines?
No. The scan only fires on runs of 10 or more identical lines with real logic in them, so a one-line helper or repeated boilerplate does not produce a finding.
What counts as a real fix?
Extracting one shared function and calling it from every site. Pasting the extracted code into a third file does not count — the re-scan still sees two identical blocks.
DevMeth checks the 48 known AI-code failure patterns — not a penetration test or a security guarantee. A clear result means each known pattern was checked and found clear or not applicable for your app; it is not a guarantee of security.