Agent rules for FortressGD projects

Rules for AI coding agents (and humans) working in a Godot project that ships through FortressGD. Production exports may mangle GDScript identifiers when [production].mangle_scripts is true.

Use Callables, not string call / rpc

Do not write call("name"), rpc("name"), or other string-dispatched method names. After mangling, those strings still name the old identifier and the packed game breaks.

Use a Callable instead:

my_attack()
my_attack.call()
do_thing.bind(arg)
rpc_id.rpc()  # typed rpc via Callable, not rpc("do_thing")

If a third-party API truly requires a string method name, mark that usage:

## fortressgd:keep
call("public_mod_hook")

Unmarked call("…") / rpc("…") / set("…") fail the export with file:line.

No secrets under res://

Never put the project secret, aes_key, API tokens, or other credentials in anything Godot packs (res://, scenes, scripts, export_presets.cfg). The 32-byte FortressGD secret lives in .fortressgd.secret (gitignored) or FORTRESSGD_SECRET. Source maps (*.fortressgd.map.json) are written to .fortressgd/maps/ in the project, never packed and never next to the export. Do not copy them into a build folder or commit them: a map reverses all mangling.

Prefer direct access over string set / get

Prefer assigning the property, or a setter method as a Callable, over set("prop", value) / get("prop"). Unmarked set("…") still fails the export.

Member names written as string literals anywhere in the project’s scripts are left unmangled automatically, so emit_signal("hit"), get("hp"), has_method("go"), Callable(self, "go"), &"go", ^".:hp" and "speed:x" keep working. The mangler keeps every identifier-shaped piece of a string (split on :, / and .) out of the rename map.

Names built at runtime cannot be seen: call("on_" + event) or get(prefix + "_hp") still break after mangling. Mark the declaration of each such member with ## fortressgd:keep so it is not renamed:

## fortressgd:keep
func on_jump() -> void:
  pass

Names scenes and autoloads use are kept

Names that scenes and resources refer to are left unmangled automatically: @export vars, methods connected in the editor, AnimationPlayer method and property tracks, and autoload names. The mangler keeps every identifier that appears in a .tscn, .tres or project.godot out of the rename map. Binary .scn / .res files cannot be scanned: export prints a warning for each. Save scenes and resources as text (.tscn / .tres) when mangling is on.

See what stays readable

Run fortressgd mangle-report (no secret needed) to list the names mangling leaves alone and why. Most come from scenes, @export vars, obj.member access and names in strings. To get a name renamed, stop referring to it that way: use a Callable instead of a method name in a string, keep internal helpers off @export, and reach members through typed references to scripts in the project rather than untyped obj.member.