LykosAI/StabilityMatrix · error · InvalidOperationException

Expected numeric weight value.

Error message

Expected numeric weight value.

What it means

Thrown by ParseParenthesized when, after consuming the ':' separator inside a weighted group, the next token is missing or does not carry the textmate scope 'constant.numeric'. The library requires the weight after ':' to be tokenized as a number. It surfaces as an InvalidOperationException naming the missing numeric weight.

Solutions

1. Add a valid numeric weight after the colon, e.g. '(text:1.1)'
2. Remove the ':' if no weight is intended, using plain '(text)' grouping
3. Check for stray characters (spaces are fine, commas are not) between ':' and the number
4. Catch InvalidOperationException and report the malformed weight to the user

Example fix

// before
var prompt = "(highly detailed:)";
// after
var prompt = "(highly detailed:1.3)";

var ok = System.Text.RegularExpressions.Regex.IsMatch(prompt, "\([^()]*:[0-9]+(\.[0-9]+)?\)"); // each '(text:w)' group has a numeric weight

null

try { var node = builder.Parse(prompt); } catch (InvalidOperationException ex) when (ex.Message.Contains("weight")) { // prompt user to fix the weight after ':' }

When it happens

Trigger: Parsing input like '(text:)' with an empty weight, or '(text:abc)' where the text after ':' is not tokenized as numeric, or input ending immediately after ':'.

Common situations: Hand-edited prompts where the weight number was deleted or replaced by text ('strong'); locales/tools writing weights with non-ASCII digits or commas ('1,2') that fail to tokenize as numeric.

Understand the failure class

Background: "Invalid ... format", "must be in format X", "does not look like a ..." — invalid argument format errors across CLI tools and libraries — this error's family across 17 libraries.

Related errors

• Expected network weight.
• Unexpected end of input.
• Expected closing parenthesis.
• Expected opening bracket.
• Expected network type.

AI-assisted analysis of LykosAI/StabilityMatrix@af93d6ef57 (2026-09-12). Data as JSON: /api/errors/5d8f30313d1fb7f5. Report an issue: GitHub.

Appendix: source

Thrown at StabilityMatrix.Core/Models/PromptSyntax/PromptSyntaxBuilder.cs:202

            // Check if no more tokens to consume.
            if (PeekToken() is not { } nextToken)
            {
                // Ensure we have length set
                if (node.Span.Length == 0)
                    throw new InvalidOperationException("Unexpected end of input.");
                break;
            }

            if (nextToken.Scopes.Contains("punctuation.separator.weight.prompt"))
            {
                // Parse the weight.
                ConsumeToken(); // Consume the ':'

                // Check the weight value token.
                var weightToken = PeekToken();
                if (weightToken is null || !weightToken.Scopes.Contains("constant.numeric"))
                {
                    throw new InvalidOperationException("Expected numeric weight value.");
                }

                // Consume the weight token.
                node.Weight = ParseNumber();
            }
            // We're supposed to check `punctuation.definition.array.end.prompt` here, textmate is not parsing it
            // separately always with current tmLanguage grammar, so ALSO use `meta.structure.weight.prompt` for now
            // We check this AFTER `punctuation.separator.weight.prompt` to avoid consuming the ':'
            else if (
                nextToken.Scopes.Contains("punctuation.definition.array.end.prompt")
                || nextToken.Scopes.Contains("meta.structure.weight.prompt")
            )
            {
                // Verify contents
                if (GetTextSubstring(nextToken) != ")")
                    throw new InvalidOperationException("Expected closing parenthesis.");

                ConsumeToken(); // Consume the ')'

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