edit_file tool fails with PowerShell expressions containing dollar signs

[DannyJanmaat]

Describe the bug The edit_file tool fails with "Cannot convert undefined or null to object" when newText parameter contains PowerShell expressions with dollar signs and parentheses, specifically $($null -eq $toolObject.Config). To Reproduce Steps to reproduce the behavior:

Use edit_file tool with newText containing PowerShell expression: $($null -eq $toolObject.Config) Tool attempts to parse JSON parameter Error occurs: "Cannot convert undefined or null to object"

Expected behavior The edit_file tool should handle PowerShell code with dollar signs and complex expressions without JSON parsing errors, or provide clear documentation about required escaping. Logs Error executing code: Cannot convert undefined or null to object Additional context The error occurs during JSON parameter parsing in the MCP filesystem server's edit_file function when PowerShell variables and expressions are used in newText strings. Dollar signs in PowerShell code appear to interfere with JSON processing.