Factorio provides a Debug Adapter for compatible tools in single-session mode on stdin/stdout when launched with the --dap command line argument.

The Debug Adapter supports a Launch request with the following arguments:

• factorioArgs :: array[string]? : Command line arguments for the debug session

• followSymlinks :: boolean? : Follow symlinks when emitting locations (stack traces, etc) (default: true)

• tags :: Any? : Extra debug session tags, see also tags

Metatable methods may be used to customize debug views:

• __tostring(self) -> string : Called when the object appears as a value.

• __debugcounts(self) -> indexedVariables :: int32 , namedVariables :: int32 : Called when the object appears in a parent object's listing, to estimate the size of this object's listing, and enabled paged listing for large indexed objects.

• __debugchildren(self, filters :: DebugVariablesFilter) -> array(DebugVariable) : Called when the object itself is opened for a debug listing. If __debugcounts was implemented, the client may choose to fetch Indexed and Named children separately, and Indexed children in pages as-needed for display. See also describe_field.

This class also provides debug session APIs, as the global object debugadapter in all stages.