Be the first to get access to new connectors. Get early access →
ConnectorBay Early access

Langfuse (BYOK) — connector documentation

  • MCP endpoint: https://byok-langfuse.connectorbay.com/mcp
  • REST API: POST https://byok-langfuse.connectorbay.com/v1/tools/{tool_name}, described by the OpenAPI 3.1 spec at https://byok-langfuse.connectorbay.com/openapi.json
  • Transport: Streamable HTTP, stateless, MCP specification 2025-06-18 or later
  • Authentication: your own Langfuse Langfuse public key (starts with pk-lf-), sent in the X-Upstream-Key header and the Langfuse secret key (starts with sk-lf-) in X-Upstream-Key-2 of every request (never stored, logged or cached)
  • Health: https://byok-langfuse.connectorbay.com/health · Tool schemas: https://byok-langfuse.connectorbay.com/tools.json
  • Publisher: Unify Dynamics LLC · connectorbay.com/byok-langfuse · agent@connectorbay.com

What Langfuse (BYOK) is for

Langfuse (BYOK) lets an AI assistant read your own Langfuse data through the Langfuse API with a key you supply (Langfuse public key (starts with pk-lf-)). Read-only: 12 tools (get_project, list_observations, list_scores, list_models, get_model, list_prompts, get_prompt, list_datasets, list_dataset_items, list_score_configs, list_experiments, query_metrics). The BYOK key travels with each request, is used for that one call only and is never stored, logged or cached; it is only ever sent to cloud.langfuse.com. Unofficial connector by Unify Dynamics LLC: not affiliated with, endorsed by or sponsored by Langfuse. Langfuse and its logos are trademarks of their owners and are used only to say which service the connector works with.

Ask your assistant things like:

  • "Which Langfuse project do my keys belong to?"
  • "Show the most expensive Langfuse generations from the last day"
  • "What evaluation scores named 'helpfulness' were recorded in Langfuse?"
  • "What model prices does my Langfuse project use?"
  • "Show the Langfuse model definition clm1abc"
  • "Which prompts are labelled production in Langfuse?"

What it does

  • get_project: Show the Langfuse project the keys belong to: id, name, organization and data retention days.
  • list_observations: List observations (generations, spans, events) newest first with type, name, model, latency, token usage, cost and trace id. Page with the cursor from meta.cursor of the previous answer.
  • list_scores: List scores (evaluations and user feedback) with name, value, source, data type and the trace, observation or session they belong to. Page with the cursor in meta.cursor.
  • list_models: List the models Langfuse knows for cost calculation with match pattern, unit and input, output and total price.
  • get_model: Get one model definition by id with its prices and pricing tiers.
  • list_prompts: List prompts with type, versions, labels, tags and last update. Filter by name, label or tag.
  • get_prompt: Get one prompt version: its text or chat messages, config, labels, tags and commit message. Defaults to the version labelled production.
  • list_datasets: List datasets with description, schemas and creation and update times.
  • list_dataset_items: List dataset items with input, expected output, status and the trace they came from. Filter by dataset name.
  • list_score_configs: List score configurations with name, data type, value range, categories and archived state.
  • list_experiments: List experiments (dataset runs) that had events since a start time, with item count, dataset and time range.
  • query_metrics: Aggregate observation or score data with Langfuse's metrics query, for example cost by model per day. query is a JSON string with view (observations, scores-numeric, scores-boolean or scores-categorical), metrics, optional dimensions and filters, fromTimestamp and toTimestamp.

BYOK key

You bring your own Langfuse Langfuse public key (starts with pk-lf-) (https://cloud.langfuse.com). Your assistant sends it in the X-Upstream-Key header with each request. ConnectorBay uses it for that one call only: it is never stored, logged or cached, never shown in an answer, and it is only sent to cloud.langfuse.com over https, with no redirects followed. Create a key with the fewest permissions the tools need (read-only if the provider offers it), and revoke it at the provider whenever you like.

Data sources

Live from the Langfuse API (cloud.langfuse.com) with a BYOK key; documentation: https://cloud.langfuse.com/generated/api/openapi.yml. Endpoints checked against that documentation on 2026-10-16.

What it is not

Unofficial connector by Unify Dynamics LLC: not affiliated with, endorsed by or sponsored by Langfuse. Langfuse and its logos are trademarks of their owners and are used only to say which service the connector works with. It is read-only: it never creates, changes, sends or deletes anything in your Langfuse account.

Built for: Worldwide. Languages: English.