Connect Langfuse tracing
Optional third-party observability for jobs and evaluation runs — off by default, and inert without your own keys.
Langfuse is an optional third-party dashboard for AI traces. RoughCut ships with tracing off, and the client is completely inert unless the toggle is on and both keys are present — nothing is sent until you deliberately turn it on. To connect it, create a Langfuse account and project, copy that project's public and secret keys, then in Settings → Full → Evals paste both, check that Langfuse base URL matches your region or self-hosted instance, and switch Langfuse tracing on. Both keys are stored in the macOS Keychain. What leaves your Mac is run metadata and aggregate numeric scores only — no media, no transcript text, and no API keys. If you would rather send nothing at all, leave the toggle off, which is the default and the safe choice.
On this page
Advanced and entirely optional. Langfuse is a third-party service. Turning tracing on means sending data about your runs to a company that is not Apple and not RoughCut. The safe default is the shipped default: off. Nothing is sent whileLangfuse tracingis off, and nothing is sent even with the toggle on unless both keys are present. To return to the default at any time, switchLangfuse tracingoff and clickSave Configuration; to go further, remove both keys.
Prerequisites
- A reason to want it. Tracing is useful if you run many evaluations and want their history, timings and scores collected in one dashboard over time. For a handful of runs, the summary files in your golden set are enough.
- A Langfuse account and a project in it. Langfuse is not affiliated with RoughCut.
- Comfort with the data listed under What is sent below. Read that section before you turn the toggle on.
Steps
- Create an account at Langfuse and create a project in it.
- In that project's settings, create an API key pair and copy both halves: the public key (it begins
pk-) and the secret key (it beginssk-). The secret is typically shown once — copy it before you close the page. - In RoughCut, open
Settings, choose theFulltab, and scroll to theEvalsgroup. - Paste the public key into
Langfuse public keyand click itsSavebutton. The field switches to a saved state with the value masked. - Paste the secret key into
Langfuse secret keyand save it the same way. - Check
Langfuse base URL. The default ishttps://cloud.langfuse.com; change it if your project lives on a different regional endpoint or on a self-hosted instance. - Switch
Langfuse tracingon. - Click
Save Configuration. - Run something — an ordinary job, or a smoke evaluation from
Evaluation. - Open your Langfuse project and confirm the trace appears.
Expected result
A trace for the run shows up in your Langfuse project, tagged with the environment you configured. An evaluation run arrives named for its mode, carrying the run identifier, the mode, the clip count, the transcription source, the counts of scored, skipped and failed clips, whether the run was flagged as a regression, and the run's mean Word-F1 as a numeric score.
Nothing appears until a run happens after you enabled tracing. Enabling the toggle does not backfill anything.
What is sent
This is the part that matters, so it is explicit.
Sent: run metadata and aggregate numeric scores. For an evaluation run that means the run identifier, the mode, how many clips were involved, whether transcription was on-device or cloud, how many clips scored, were skipped and failed, whether a regression was flagged, and the aggregate Word-F1 mean. Traces carry an environment tag and short descriptive tags.
Not sent: your media, your transcript text, and your API keys. None of them are part of a trace.
Requests go directly from your Mac to the base URL you configured, authenticated with your own Langfuse key pair. There is no RoughCut server in the path.
If a trace request fails, it is logged and ignored. Tracing never fails a job or an evaluation.
For the complete picture of what leaves your Mac across the whole app, see Privacy and data flow.
The environment tag
Langfuse environment is a plain string attached to every trace, and it exists to keep unrelated runs apart inside one Langfuse project. If you trace from more than one machine or want to separate a period of experimentation from your normal runs, change the tag rather than creating another project. Traces from a previous tag are unaffected — the tag is applied when the trace is created.
Where the keys live
Both Langfuse keys are stored in the macOS Keychain, encrypted by the system, exactly like your AI provider keys. They are never written into RoughCut's configuration file and never included in an exported configuration. Once saved, the stored value is not displayed back to you; you can Replace… it or Remove it.
Treat the secret key like a password. See Settings overview.
If privacy is your priority, leave it off
Tracing is the only feature in RoughCut whose entire purpose is to send information about your work to a third party you chose. If you are unsure whether you want that, the answer is to leave Langfuse tracing off. Everything else in the app — including the whole evaluation system — works identically without it, and the summary files written into your golden set already hold the same numbers locally.
Troubleshooting
| Symptom | Cause | Fix |
|---|---|---|
| No traces at all | Langfuse tracing is off | Turn it on and click Save Configuration |
| No traces at all | One of the two keys is missing | Both are required. The client stays inert with only one |
| No traces at all | No run has happened since you enabled it | Run a job or a smoke evaluation. Nothing is backfilled |
| Traces missing but the toggle is on | The keys belong to different projects, or the public key was pasted into the secret field | Re-copy both halves from the same project's key pair and save them again |
| Nothing arrives, everything looks correct | Langfuse base URL points at the wrong region or a stale self-hosted address | Check the exact base URL for your project and correct the field |
| Nothing arrives on a restricted network | Outbound access to your Langfuse host is blocked | Allow the host, or accept that tracing will not work there |
| Traces appear in the wrong place | The environment tag differs from the one you are filtering on | Match Langfuse environment to the filter you use in Langfuse |
| You want it to stop | — | Switch Langfuse tracing off, save, and remove both keys |
Common mistakes
- Expecting tracing to affect the cut. It does not. It observes runs; it never changes them.
- Turning the toggle on without saving. Configuration changes need
Save Configuration. Keys, by contrast, save immediately when you click their ownSave. - Pasting an organisation-level key. Use the project's own key pair.
- Assuming a failed trace means a failed run. Trace failures are logged and ignored by design.
A note on the Langfuse product
Langfuse is developed independently of RoughCut. Its interface, its terminology, where its keys live in its settings, and its regional endpoints can all change without notice. Where this page and the Langfuse documentation disagree about anything on the Langfuse side, their documentation is authoritative. What is fixed on RoughCut's side is what this page describes: two keys, one base URL, one toggle, one environment tag, and traces that carry run metadata and scores only.