Renpy Release check — check your script free

A 28-line Ren'Py script that compiles without one complaint returns 14 findings - 10 errors and 4 warnings - the moment a solo visual novel developer running a Steam page puts a release gate over it.

Not one of those 14 is a syntax error. Ren'Py already accepted the file. That is the trap: the Ren'Py compiler checks that your script parses, and almost nothing about whether a stranger can play it.

Here is the fixture, _fixtures/dirty.rpy, trimmed to the lines that matter:

define config.developer = True
define config.version = "1.0"
define affection = 0

label start:
    "Welcome back, [ player_name]."
    "{i}Late again, she thought."
    $ affection += 1
    if persistent.seen_ending_a:
        "You have stood on this pier before."

Every one of those lines runs on your machine.

[ player_name] is the clearest one. Ren'Py reads a square bracket in dialogue as an interpolation. The space makes the name unknown, and the error does not arrive at build time - it arrives when a player reaches that line of that scene. If the line lives in chapter three, you find out from a forum post.

{i}Late again, she thought. opens an italic tag and never closes it. The scene keeps rendering, slanted, until something else closes it or the screen dies.

define affection = 0 is subtler and more expensive. In Ren'Py, define values are not written into saves and are not rolled back. A variable the player changes must be default. Ship it as define and your save files quietly disagree with your script, forever, for everyone who already bought the game.

persistent.seen_ending_a is read with no default persistent.seen_ending_a anywhere. You will never see this bug. Your persistent file has held that key since the first test build. A first-time player reads None on the first run.

And config.developer = True hands every player the console and the developer menu.

Two more findings in that fixture never appear on a single line at all. There is no config.save_directory in the project, so saves are keyed to a generated directory and the next rename orphans them. And the build rules classify game/.txt but never game/.rpy, so readable script source travels inside the distribution.

Those last two are the reason a chatbot cannot close this. A chatbot sees the snippet you paste. Whether persistent.seen_ending_a is defaulted in some other file, and whether config.save_directory exists anywhere in the project, are facts about the whole project, and they are the two findings that cost you player saves.

The gate is 14 rules, grouped by what they take from you: four that break a player's session, two that break their saves, four that ship something you did not mean to ship, four that break on a machine that is not yours.

The same 28-line fixture, gated, is _fixtures/clean.rpy: same scene, same dialogue, 0 findings. \[07:40\] escaped, {i}...{/i} closed, default affection = 0, default persistent.seen_ending_a = False, config.developer = "auto", config.save_directory set once and never touched again, build.classify('game/**.rpy', None).

The cost of getting this wrong is not abstract. Putting one title on Steam costs $100 in Steam Direct fees before a single crash report arrives, and every fix after launch is another build, another store update.

Open a .rpy file, run the check, read the line numbers. One file is free, with no key and no counter.