fly mcp list fails parsing zed settings

[ananthb]

Describe the bug
Briefly, describe what broke and provide the following details:
Running fly mcp list fails to parse zed settings with an error indicating
that it is unable to parse comments.

Here's the error:

Error: failed to parse /Users/ananth/.config/zed/settings.json: invalid character '/' looking for beginning of value

And sure enough my zed settings file starts with some comments.

• Operating system: MacOS
• fly version: fly v0.3.140 darwin/arm64 Commit: 4ffd0f7 BuildDate: 2025-06-04T23:06:05Z

** Command output: **

Error: failed to parse /Users/ananth/.config/zed/settings.json: invalid character '/' looking for beginning of value

[vky5]

Hi @rubys 👋

I'd like to work on this issue. I’ve identified that the problem is happening in:

decoder := json.NewDecoder(file)
if err := decoder.Decode(&data); err != nil {
    return fmt.Errorf("failed to parse %s: %w", configPath.Path, err)
}

The file (like Zed’s settings.json) might contain comments, which the standard encoding/json parser can't handle. I’d like to add a small helper to strip // or # comment lines before parsing, which should fix the issue cleanly without introducing new dependencies.

Let me know if you're okay with this approach. I’ll open a PR right after if approved.

[ananthb]

My 2 cents: you should use a JSONC parser like hujson.

[vky5]

@rubys Can you review my pr and suggest changes?

[rubys]

My apologies, I missed that there was a PR. There was a minor lint error which I have fixed.

This looks like it will indeed fix mcp list, but doesn't that meant that we will just get to the next problem? Other commands attempt to modify that file, and will stumble when they encounter comments.

[vky5]

Yes, since encoding/json can’t handle JSON with comments, any attempt to modify or parse such files using it will lead to errors.

Do you think it would make sense to use hujson in place of encoding/json wherever we're dealing with files? Would that be a good long-term solution, or should we only apply it in specific cases like this one?

[rubys]

I don't know how hard it would be to preserve comments when modifying, but overall:

• I'm willing to merge this change as it allows you to continue; you may have several AI tools and if you don't modify zed's configuration, this pull request helps.
• My default assumption would be that most tools can't handle comments in JSON (as they are disallowed by the spec). Any attempt to output JSON with comments should only be done after confirming that the tool in question can handle it (this list obviously would include Zed, but may not include any other tools).

[vky5]

Thanks, @rubys, that makes total sense.

I’ll keep this fix scoped just to reading Zed’s settings, where comments are expected and supported. I understand that while hujson allows reading and writing JSON with comments, we should be careful not to adopt it as the default, since many tools (both internal and external) likely depend on standard JSON parsing and could fail if they encounter comments.

For now, I won’t modify any files using hujson, and I’ll make sure it’s only used in places where we’re certain comments are supported like with Zed’s config. Let me know if there’s anything else I should adjust here.