Reads the current meter snapshot from the Phantom Studio plugin running in your DAW: loudness, true peak, stereo correlation, band energy, and meter verdicts. This gives your assistant the numbers on your meters at the moment you’re listening, not the numbers from a file analysis.
Warning
Phantom Studio hasn’t shipped yet. The read_live_metrics tool is in the MCP server today,
but it reads a snapshot written by the Phantom Studio plugin, and that plugin is still in
development. Without it running there is no snapshot to read and the tool returns an error. Join
the waitlist if you want to know when it lands. File analysis works without Studio.
Processing, matching, and separation still require their optional extras.
Parameters
| Parameter | Type | Default | Description |
|---|---|---|---|
| instance_id | string | most recent instance | Plugin instance ID (the metrics file stem). Omit to read the most recently written snapshot of any running instance. |
Example Output
Illustrative summary; MCP responses use structured JSON.
$ read_live_metrics
What the Numbers Mean
-
instance_id — The plugin instance the snapshot came from. When multiple Phantom Studio instances are running, pass the ID of the instance you care about; when omitted, the most recently written snapshot wins.
-
age_seconds / stale — The plugin publishes a fresh snapshot roughly every half second while it runs and removes its file when the instance closes. A snapshot older than about 10 seconds is flagged
stale— usually a crashed host or frozen DAW — and you should treat its numbers with caution. -
instance_count — How many plugin instances have snapshots available right now.
-
snapshot — The current meter state: loudness (integrated, short-term, momentary LUFS), true peak in dBTP per channel, stereo correlation and width, per-band energy, and meter verdicts. These are the numbers that would be moving on the plugin’s meters while you listen.
The snapshot object above is illustrative. The reader returns the producer’s JSON object without enforcing a meter schema. In 1.6.0 it rejects invalid JSON, non-finite numbers, non-object payloads, and files larger than 1,000,000 bytes.
Requirements
- The Phantom Studio plugin must be loaded on a track and playing (or otherwise producing a snapshot).
- When no snapshot is available, the tool fails with a message explaining that the plugin needs to be running — it doesn’t measure silence by itself.
- The Windows path is part of the snapshot contract, not Windows support for the Phantom Python package. Snapshot files live in
PHANTOM_METRICS_DIRwhen set, otherwise the platform default:~/Library/PhantomStudio/metricson macOS,%APPDATA%\PhantomStudio\metricson Windows,~/.config/PhantomStudio/metricson Linux.
Example Prompts
Stereo check while listening
Read the live metrics — is the stereo image collapsing in the chorus?
Loudness on the meters
Read the live loudness while I play this section — is it around -14 LUFS?
Related Tools
- analyze_loudness — File-based loudness measurement (EBU R128)
- analyze_stereo — File-based stereo field analysis
- full_diagnostic — Run all six analysis types on a file at once
Pro tip
Live metrics reflect the moment, file analysis reflects the whole file. Use read_live_metrics while you audition a change, then confirm the result with a file-based analysis once you render.