StraitjacketWhy duplication is compiled in
Copy-paste is a loud LLM tell, so Straitjacket detects clones in-process with no external tool.
Copy-paste is one of the loudest LLM tells: models clone-and-tweak instead of factoring out a shared helper. So Straitjacket ships duplication detection in the box.
Compiled in, no external tool
The duplication rule is compiled into Straitjacket — it uses
cpd-finder, the Rust engine behind
jscpd 5, as a library. Nothing to install,
no Node, no separate binary; Straitjacket walks and tokenizes the tree (Rust,
TS/JS, Python, and more) in-process.
The policy: a structure may appear only once
This matches Straitjacket's max-by-default stance. Any clone of ≥ 50 tokens is an error:
src/util.rs:42:1 [duplication] 9 lines, 71 tokens
duplicated code — this block also appears at src/helpers.rs:88.
LLMs clone-and-tweak; factor out a shared helper.The finding points at both locations so you can see the pair and decide where the shared helper belongs.
Tuning
Raise the floor with --dup-min-tokens N to only flag larger duplicated blocks,
or turn it off entirely with --skip duplication. The default of 50 tokens is
deliberately low — it catches the small clone-and-tweak blocks that accumulate
fastest.
How slop-prose works
The density model behind detecting AI-written prose — machine artifacts, style tells, the sliding window, and why it's a nudge rather than proof.
The React rules
Why Straitjacket enforces one component per file and keeps effects out of component files — and how the AST analysis works.