vøiddo
tool · ai / dev

@v0idd0/promptdiff.

diff two LLM prompts and visualize what actually changed.

two prompts in. structural diff out: which sections were added, reorganized, or had token-count drift. catches subtle prompt regressions.

npm i -g @v0idd0/promptdiff
github → npm mit · free forever
promptdiff icon
what it does

find out where “but the prompt is identical” isn’t.

four jobs. all in your terminal. no api call, no internet round-trip — just a plain tool that does what it says.

structural diff

$ promptdiff a.md b.md
+ section: Examples
~ section: Style (token +12)
- section: Caveats

token-count drift

$ promptdiff a.md b.md --tokens
a: 1,420t
b: 1,438t
delta: +18t (+1.3%)

live watch

$ promptdiff watch ./prompts/
system.md changed
+ 1 section, +44 tokens
(saved 14:02)

summary verdict

$ promptdiff --summary a.md b.md
minor: 2 sections drifted
+18 tokens
likely safe to ship
install

three ways. all painless.

npm

$ npm i -g @v0idd0/promptdiff

node 14+ on linux / macos / windows. updates with npm update -g.

github releases

$ curl -L github.com/voidd0/promptdiff/releases/latest

single static binary. zero runtime needed. all releases →

git clone

$ git clone github.com/voidd0/promptdiff

read the source, send a pr, fork it. mit licence, no cla. repo →

why we built it

“why is the new prompt giving worse answers?” → 2 hours later: oh, we accidentally dropped the ‘think step by step’ line. promptdiff catches that in 0.04s.

no telemetry. no signup. parses prompts as structured docs (markdown headings, xml-style tags, etc.) — not as raw byte streams. mit forever, even if vøiddo dies tomorrow.

star on github → all tools

power user?

use this daily? tools.voiddo Pro · $9 one-time

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