oraios/serena · error · ValueError

symbol_info_budget cannot be negative, got: {symbol_info_bud

Error message

symbol_info_budget cannot be negative, got: {symbol_info_budget}

What it means

SerenaConfig._from_dict validates the optional symbol_info_budget setting from serena_config.yml. The raw value is parsed to float, and a negative number is rejected because a budget of symbols sent to the LLM cannot be below zero. This is a defensive config-validation error raised at config-parse time.

Source

Thrown at src/serena/config/serena_config.py:615

        # Validate activation_command_timeout
        activation_command_timeout_raw = data.get("activation_command_timeout", 180.0)
        try:
            activation_command_timeout = float(activation_command_timeout_raw)
        except (TypeError, ValueError) as e:
            raise ValueError(f"activation_command_timeout must be a number, got: {activation_command_timeout_raw}") from e
        if activation_command_timeout <= 0:
            raise ValueError(f"activation_command_timeout must be positive, got: {activation_command_timeout}")

        # Validate symbol_info_budget
        symbol_info_budget_raw = data["symbol_info_budget"]
        symbol_info_budget = symbol_info_budget_raw
        if symbol_info_budget is not None:
            try:
                symbol_info_budget = float(symbol_info_budget_raw)
            except (TypeError, ValueError) as e:
                raise ValueError(f"symbol_info_budget must be a number or null, got: {symbol_info_budget_raw}") from e
            if symbol_info_budget < 0:
                raise ValueError(f"symbol_info_budget cannot be negative, got: {symbol_info_budget}")

        language_backend_value = data.get("language_backend")
        language_backend = LanguageBackend.from_str(language_backend_value) if language_backend_value else None

        line_ending_value = data.get("line_ending")
        line_ending = LineEnding.from_str(line_ending_value) if line_ending_value else None

        # gracefully handle user errors: incorrect use of None/empty where a list is required
        ignored_paths = data["ignored_paths"] or []
        fixed_tools = data["fixed_tools"] or []
        excluded_tools = data["excluded_tools"] or []
        included_optional_tools = data["included_optional_tools"] or []
        additional_workspace_folders = data.get("ls_additional_workspace_folders") or []

        if "base_modes" in data and data["base_modes"] is not None:
            log.warning("The base_modes setting in project.yml is deprecated and will be ignored.")

        return cls(

View on GitHub (pinned to 7fcbca7e62)

Solutions

Open serena_config.yml and set symbol_info_budget to a non-negative number (e.g. 5000) or remove/null the key to use the default.
If building a dict programmatically, clamp or validate the value: max(0, value) before calling _from_dict.
Check for locale/formatted strings that parse as negative after float() conversion.

Example fix

// before (serena_config.yml)
symbol_info_budget: -1
// after
symbol_info_budget: 5000

Defensive patterns

Strategy: validation

Validate before calling

def ensure_valid_budget(cfg: dict) -> None:
    raw = cfg.get('symbol_info_budget')
    if raw is not None:
        v = float(raw)
        if v < 0:
            raise ValueError(f'symbol_info_budget must be >= 0, got {v}')

Type guard

def has_valid_budget(cfg: dict) -> bool:
    raw = cfg.get('symbol_info_budget')
    return raw is None or (isinstance(raw, (int, float)) and not isinstance(raw, bool) and raw >= 0)

Try / catch

try:
    config = SerenaConfig.load()
except ValueError as e:
    if 'symbol_info_budget' in str(e):
        fix_budget_in_yml(); config = SerenaConfig.load()
    else:
        raise

Prevention

Never hand-write negative placeholder values in serena_config.yml
Validate the yml with a schema check before loading
Clamp numeric config values programmatically when generating configs

When it happens

Trigger: Calling SerenaConfig.load(), SerenaConfig.autogenerate(), or ProjectConfig._from_dict() when the symbol_info_budget key in serena_config.yml (or a dict passed to _from_dict) parses to a negative float, e.g. 'symbol_info_budget: -1'.

Common situations: Hand-editing serena_config.yml and typoing the value (e.g. '-1' as a placeholder, or a locale-style decimal like '-0,5' misinterpreted); test fixtures passing dicts with negative budgets; pasting config from an old version where the field meant something else.

Related errors

AI-assisted analysis of oraios/serena@7fcbca7e62 (2026-08-29). Data as JSON: /api/errors/5182668ae9c45864. Report an issue: GitHub.