Langfuse - Veryfront

At a glance

Availability: Experimental (how to enable).
Auth: Basic auth.
Connection: HTTP Basic auth with LANGFUSE_PUBLIC_KEY as the username and LANGFUSE_SECRET_KEY as the password.
Docs: https://langfuse.com/docs/api-and-data-platform/features/public-api

Set these per environment. See Connect an integration.

Variable	Required	Description
`LANGFUSE_PUBLIC_KEY`	Yes	Langfuse project public key (starts with pk-lf-), used as the HTTP Basic username Docs.
`LANGFUSE_SECRET_KEY`	Yes	Langfuse project secret key (starts with sk-lf-), used as the HTTP Basic password Docs.

Create a Langfuse account: Sign up at https://cloud.langfuse.com (EU) or https://us.cloud.langfuse.com (US) - the free Hobby plan is enough for testing. Self-hosting is also supported.
Create project API keys: In your Langfuse project, open Settings → API Keys and create a key pair. You get a public key (pk-lf-…) and a secret key (sk-lf-…).
Store the keys: Add LANGFUSE_PUBLIC_KEY=pk-lf-… and LANGFUSE_SECRET_KEY=sk-lf-… to your .env file. The API uses HTTP Basic auth with the public key as username and secret key as password.
Verify access: Run the List Traces tool. If your project is in the US region, pass host us.cloud.langfuse.com; EU projects use the default cloud.langfuse.com.

API keys are project-scoped - create separate keys per project/environment
All tools take a ‘host’ parameter (default cloud.langfuse.com for EU); US cloud is us.cloud.langfuse.com and self-hosted deployments use their own domain

Tool	Access	Description
List Traces	Read	List traces in the Langfuse project with optional filters
Get Trace	Read	Get a single trace with its full observation tree and scores
List Observations	Read	List observations (spans, generations, events) with optional filters
Create Score	Write	Attach a score (evaluation result) to a trace or observation

List my most recent Langfuse traces and summarize latency, errors, and usage patterns.
Look up a Langfuse trace I specify and attach an accuracy score with a short comment.