Anuken/Mindustry · error · IllegalArgumentException

Unknown team: ${data.asString()}. Team must either be a stri

Error message

Unknown team: ${data.asString()}. Team must either be a string or a number.

What it means

Thrown by the Team parser when data is neither a string nor a number (e.g. an object, array, or boolean). Teams can only be addressed by base-team name or numeric ID.

Source

Thrown at core/src/mindustry/mod/ContentParser.java:397

        put(ConsumeLiquidBase.class, (type, data) -> {
            var oc = resolve(data.getString("type", ""), ConsumeLiquidBase.class);
            data.remove("type");
            var consume = make(oc);
            readFields(consume, data);
            return consume;
        });
        put(Team.class, (type, data) -> {
            if(data.isString()){
                Team out = Structs.find(Team.baseTeams, t -> t.name.equals(data.asString()));
                if(out == null) throw new IllegalArgumentException("Unknown team: " + data.asString());
                return out;
            }else if(data.isNumber()){
                if(data.asInt() >= Team.all.length || data.asInt() < 0){
                    throw new IllegalArgumentException("Unknown team: " + data.asString());
                }
                return Team.get(data.asInt());
            }else{
                throw new IllegalArgumentException("Unknown team: " + data.asString() + ". Team must either be a string or a number.");
            }
        });
    }};
    /** Stores things that need to be parsed fully, e.g. reading fields of content.
     * This is done to accommodate binding of content names first.*/
    private Seq<Runnable> reads = new Seq<>();
    private Seq<Runnable> postreads = new Seq<>();
    private ObjectSet<Object> toBeParsed = new ObjectSet<>();

    @Nullable LoadedMod currentMod;
    @Nullable Content currentContent;
    @Nullable Fi currentFile;

    private Json parser = new Json(){
        @Override
        protected <T> Class<T> resolveClass(String className){
            if(allowClassResolution){
                return super.resolveClass(className);

View on GitHub (pinned to f695ad7e60)

Solutions

1. Provide the team as a string base-team name.
2. Or provide the team as a numeric ID.

Example fix

// before
"team": { "name": "crux" }
// after
"team": "crux"

// Guard: team value must be a string or number.
boolean isTeamRef(JsonValue v) { return v.isString() || v.isNumber(); }

When it happens

Trigger: A mod JSON team field is an object or other non-scalar JSON value.

Common situations: Misformatted team value, e.g. wrapping the team in an object or passing a boolean.

Related errors

• Unknown team:
• Unknown team: ${data.asString()}
• Team field missing.
• Attribute definitions must be objects, e.g. {heat: 10}
• Unknown status effect: '

AI-assisted analysis of Anuken/Mindustry@f695ad7e60 (2026-08-14). Data as JSON: /api/errors/7b71dd530d8318c2. Report an issue: GitHub.