🐛 JSON and JSONC formatting with VS Code extension: "Extension 'Biome' is configured as formatter but it cannot format 'JSON with Comments'-files"

[epicwhale]

VS Code version

1.108.0-insider (Universal)

Extension version

2025.11.271431

Biome version

2.2.4 installed in frontend/nodule_modules directory

Operating system

• Windows
• macOS
• Linux

Description

I am struggling to use Biome to format any JSON or JSONC in my vscode with the extension

In my project's settings.json, I have also configured:

    "[json]": {
        "editor.defaultFormatter": "biomejs.biome"
    },
    "[jsonc]": {
        "editor.defaultFormatter": "biomejs.biome"
    },

"Extension 'Biome' is configured as formatter but it cannot format 'JSON with Comments'-files"

or I select the "Format Document" option for any json file in the project

Steps to reproduce

Try formatting any json with Biome extension installed

Expected behavior

Work as a formatter like Prettier VSCode did.

Does this issue occur when using the CLI directly?

Not sure / Not applicable

Link to a minimal reproduction

No response

Logs

[kornerc]

I can also reproduce this issue:

[github-actions]

Hello @epicwhale, please provide a minimal reproduction. You can use one of the following options:

• Provide a link to our playground, if it's applicable.
• Provide a link to a GitHub repository. To easily create a reproduction, you can use our interactive CLI via npm create @biomejs/biome-reproduction

Issues marked with Needs reproduction will be closed if they have no activity within 3 days.

[epicwhale]

Unsure how the repro can be provided more than I already have!

[kornerc]

Unsure how the repro can be provided more than I already have!

I can try to create a mini repo for reproduction.

[kornerc]

I have here an minimal example using a devcontainer: biome-vs-code-cannot-format-json.zip

Use VS Code to open the repo in a devcontainer (extension Dev Containers is needed):

Open the file test.json and execute Format Document (Shift + Alt + F)

I can also reproduce the issue directly without devcontainer natively under Windows.

Also changing in .vscode/settings.json from

{
  "[json]": {
    "editor.defaultFormatter": "biomejs.biome"
  }
}

to

{
  "editor.defaultFormatter": "biomejs.biome"
}

makes no difference.

PS if needed I can also create a GitHub repo instead of attaching a .zip archive.

[kornerc]

When I change biome.lsp.trace.server to verbose I get this issue:

2026-01-14 22:20:03.806 [info] 🔒 Started listening for lockfile changes.
2026-01-14 22:20:03.806 [info] ⚙️ Started listening for extension settings changes.
2026-01-14 22:20:03.806 [warning] 🔍 Could not find global Node Modules path for npm
2026-01-14 22:20:03.806 [error] Unable to find the Biome binary

[kornerc]

And installing biome solves this issue 🙃

npm i -D -E @biomejs/biome

I thought the extension ships with Biome but apparently it needs to be installed.

Is it mandatory to install Biome in order to be able to use the extension (I am using Biome in a non-JavaScript repo where I plan to use it to format .json files)?

[ematipico]

I thought the extension ships with Biome but apparently it needs to be installed

Where did you get this information? No, we don't ship binaries inside the extension anymore

[kornerc]

Where did you get this information? No, we don't ship binaries inside the extension anymore

It was a misconception from my side.
I looked at the Biome docs and description at the Visual Studio Marketplace for the VS Code extension.
Under installation it is just stated that the extension needs to be installed.
The VS Code extension for ruff (a Python linter and formatter) ships the binary and I wrongly assumed that Biome does the same.