# Langfuse

Langfuse LLM observability — трейсы, генерации, скоры, сессии, промпты, датасеты

## Scenarios

### Trace review for the last 24 hours
The agent goes through a day of traces and shows where generations failed and which steps lost the most time.

### Answer quality drop
The agent matches scores to sessions and names the conversations where answer quality fell the most.

### Observability digest
The agent sends a digest on schedule: how many traces there were, what share of them failed and how scores moved over the chosen period.

### Prompts and datasets
The agent pulls the prompt versions and dataset items of the project so you can tie a prompt edit to a change in scores.

## How to connect

### Sign in to Langfuse in your region
EU is https://cloud.langfuse.com, US is https://us.cloud.langfuse.com, Japan is https://jp.cloud.langfuse.com. Keys are scoped to a single project, so open the exact project whose data the agent needs.

### Open Settings → "API Keys" in the project
Inside the project go to Settings → "API Keys". You need the Owner or Admin role: Member and Viewer cannot configure the project, so the keys section stays out of reach.

### Create a new key pair and copy both values
A pair is a public key prefixed pk-lf- and a secret key prefixed sk-lf-. Copy both right after creation — you need the full secret key, the shortened preview in the list is not enough.

### Write down your host address
If the project is not in the EU region, you also need the host address: https://us.cloud.langfuse.com, https://jp.cloud.langfuse.com, https://hipaa.cloud.langfuse.com, or the domain of your self-hosted instance.

## FAQ

### How do I connect Langfuse?
With a project key pair: open the project, go to Settings, then API Keys, and create a pair. The public key starts with pk-lf-, the secret one with sk-lf-. If the project is not in the EU region, set host: for example, https://us.cloud.langfuse.com or the domain of your own installation.

### What does the agent see in Langfuse?
Traces and generations, scores, sessions, prompt versions and datasets of one project: keys are issued per project, not for the whole organisation.

### Does the agent write to Langfuse?
By default the agent reads observability data and reports in chat: it sends no traces of its own and does not change prompts without your request.

### Is a separate role required?
Only a project Owner or Admin can create a key pair — Member and Viewer cannot open the settings section. The agent itself only needs a key pair that already exists.

[Open Langfuse](https://cloud.langfuse.com)