[FEATURE] Add a new tool to the VS Code extension to let Claude Code trigger format on save on a file

Preflight Checklist

• [x] I have searched existing requests and this feature hasn't been requested yet
• [x] This is a single feature request (not multiple features)

Problem Statement

Claude can write files directly, but it can't run the save participants in VS Code. The current VS Code extension exposes these tools for CC:

• mcp__ide__getDiagnostics - get language diagnostics
• mcp__ide__executeCode - execute code in Jupyter kernel

Proposed Solution

I propose adding a new tool for saving a file _via the VS Code extension API_ so that save participants run on save. This will apply Prettier (even when used with the implicit config provided by the VS Code Prettier extension which is different from the config Prettier uses when run using bunx) etc.

Alternative Solutions

I don't see an alternative, ignoring the save participants when I am using Claude Code in the VS Code integrated terminal and have the VS Code extension is just bad product design.

Priority

High - Significant impact on productivity

Feature Category

MCP server integration

Use Case Example

See above

Additional Context

_No response_