Agent: creating a JSON file shows [object Object] instead of its contents #13362

Relevant environment info

• OS: macOS
• Continue version: 2.0.0 (also checked on main at 5522c6f)
• IDE version: VS Code 1.141.0
• Model: Qwen3.6-Coder 35B, served locally through an OpenAI-compatible API (provider openai)

Description

In Agent mode, when the model creates a .json file (for example package.json or tsconfig.json) and sends its contents as a JSON value rather than a string, the tool call in the chat shows:

[object Object]

instead of the file contents. Qwen models do this often for JSON files.

Cause: the GUI parses the tool call arguments deeply, so parsedArgs.contents is an object. FunctionSpecificToolCallDiv passes it to CreateFile, which puts it in a template string (gui/src/pages/gui/ToolCallDiv/FunctionSpecificToolCallDiv.tsx, fileContents={args?.contents ?? ""}).

To reproduce

A test that renders FunctionSpecificToolCallDiv for create_new_file with parsedArgs = { filepath: "app/package.json", contents: { name: "app", version: "1.0.0" } }: the preview source is [object Object].

Log output

No response