Langfuse

Open source LLM engineering platform. Traces, evals, prompt management and metrics to debug and improve your LLM application.

What agents can do

Create score
Attach an evaluation score to exactly one Langfuse trace, session, or dataset run, optionally narrowing a trace score to an observation.
Get annotation queue
Retrieve one Langfuse annotation queue by its ID.
Get prompt
Retrieve a Langfuse text or chat prompt by name, deployment label, or exact version, with optional dependency resolution.
List annotation queues
List annotation queues configured for human evaluation in the connected Langfuse project.
List dataset items
List dataset items, optionally scoped to a dataset, source trace or observation, or historical dataset version.
List dataset run items
List run items for a specific Langfuse dataset and run name.
List datasets
List datasets available to the connected Langfuse project.
List experiments
List Langfuse experiments active in a required time range, optionally including metadata and directly attached scores.

5 more

List models
List Langfuse-managed and project-custom model pricing definitions used for usage and cost calculation.
List observations
Search Langfuse observations such as generations, spans, events, agents, and tool calls, selecting only the field groups needed.
List scores
Search numeric, boolean, categorical, text, and correction scores with subject and annotation context.
Query metrics
Run an aggregate Langfuse metrics query over observations or numeric, boolean, or categorical scores.
Upsert llm connection
Create or update a Langfuse LLM provider connection by provider name.

You paste an API key from Langfuse on a page Composio hosts, so the key never passes through Definable.

Keep the connection to yourself or share it with your workspace. Any action that writes or sends can wait for your approval.