Function evaluate_tool_program 

pub fn evaluate_tool_program(
    source: &str,
    limits: ToolProgramLimits,
) -> Result<Vec<ToolProgramCall>>

Evaluate a pure Starlark expression that returns a JSON string.

The source’s final expression must be a zero-argument function. Calling it must return a JSON array of { "tool": ..., "arguments": {...} } values. Starlark is deliberately given only its standard pure globals and no loader.