Logging

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ctx.logger.debug('Fetched page', pageNumber);
ctx.logger.info('Sync complete.');
ctx.logger.warn('Rate limited, backing off.');
ctx.logger.error('Sync failed.', error);

const sync = ctx.logger.scoped('sync');   // logs as `my-plugin:sync`

Every line goes to three places:

The browser console, at the matching level (console.debug / info / warn / error).
An in-memory ring buffer (2000 records), shared with the host’s own output.
The VRCNext Bridge, which appends every record to its plugins.log on disk — so logs survive a VRCNext restart without the page storing anything.

ctx.logger needs no permission: it can only produce text the user reads.

The Logs panel

Plugins → Logs is a live viewer for plugin, host and bridge output:

Live tail, auto-scrolling unless you have scrolled up to read history.
Filter by level and by scope — a plugin id, host, or bridge for the daemon’s own lines, which come back over the socket.
Copy the filtered log to the clipboard.
Download it as a timestamped .log file.
Clear the in-page buffer.

This exists so you can follow what plugins are doing without opening devtools.

Why it does not write to VRCNext’s log file

VRCNext appends to ~/.config/VRCNext/Logs/ inside AppShell.SendToJS — the C#→page direction. There is no page→C# action that logs arbitrary text, and the page has no filesystem access. So a plugin cannot write into VRCNext’s activity log, and neither can this host.

The Download button is the closest real equivalent: it writes an actual file to your Downloads folder, containing the same formatted lines.

If you genuinely need plugin output interleaved into VRCNext’s own log file, that requires patching VRCNext itself — for example a Harmony hook on AppShell.SendToJS in a locally-built VRCNext. That is outside this project’s scope, which is explicitly “never modify VRCNext”.

Format

11:42:07.318 INFO  [kitchen-sink] Game log backlog: 412 entries.
11:42:09.004 WARN  [kitchen-sink:sync] Rate limited, backing off.

Extra arguments are stringified at capture, so an object mutated later cannot rewrite history. Error values render as Name: message; circular structures fall back to String().

Guidance

Never log secrets — tokens, auth headers, message content. This output is user-visible and gets pasted into bug reports.
Use debug for anything per-event. onParam can fire dozens of times a second; logging each one at info makes the panel useless.
Prefer ctx.logger over console.log — console output alone does not reach the panel, the bridge’s plugins.log, or the downloadable file.

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