Trace Export
Every search and generation on Mixedbread produces a structured trace: the query, the tool calls the agent issued with their arguments and results, the model turns with their token usage, and the chunks that came back. The dashboard renders these traces, and trace export pushes the same data to an observability backend you own, as OpenTelemetry spans, moments after each run finishes.
Traces land next to the rest of your LLM observability, so you can search them, score them, and alert on them with the tooling you already use.
What gets exportedLink to section
Each exported trace is one run, with a root span for the request and a child span
per recorded step: execute_tool spans for retrieval tool calls (with their
arguments and results) and chat spans for model turns (with their token usage).
Attributes follow the
OpenTelemetry GenAI semantic conventions,
so Langfuse classifies them as tool and generation observations automatically and
other OTel tooling reads them without configuration.
The export is exactly the customer-facing trace you see in the dashboard and the events API. Mixedbread's internal spans (databases, retrieval backends, inference infrastructure) are never sent.
You choose per destination which trace kinds to export:
| Trace kind | Contents | Exported by default |
|---|---|---|
| Agentic search | The agent's rounds, tool calls, and model turns | Yes |
| Chat completions | Completion and Responses turns, grouped per conversation | Yes |
| Question answering | Each Q&A request's retrieval and answer generation | Yes |
| Search | Every plain search (high volume) | No |
| Grep | Regex matches over your stores | No |
Chat completion turns in the same conversation share a session id, so a resumed chat reads as one thread in Langfuse instead of unrelated traces.
Large runs are kept deliverable rather than dropped: a trace carries up to 50 result chunks, chunk text is truncated to 2,000 characters, and any single span field is capped at 128 kB.
DestinationsLink to section
- Langfuse. Cloud or self-hosted. Takes the host and the project's public and secret key from Project settings → API keys in Langfuse.
- OpenTelemetry (OTLP). Any OTLP/HTTP collector: Phoenix, Braintrust, Traceloop, Grafana, or your own. Takes the traces endpoint and the headers it authenticates with. gRPC collectors are not supported.
SetupLink to section
In the dashboard, go to Settings → Tracing and click Connect destination. Pick the provider and paste its credentials.
Before saving, Mixedbread sends an empty, valid OTLP request to the destination. A wrong key or unreachable endpoint fails right there instead of silently dropping traces later. Credentials are stored encrypted and are never returned by the API; you can rotate them at any time.
Select the trace kinds this destination should receive. Agentic search, chat completions, and question answering are on by default; plain searches are off because of their volume.
Traces are exported as each run finishes. The destination card shows the delivery status and when the last batch arrived.
Here is an exported agentic search in Langfuse: the root span with the query and final ranking, tool spans for each retrieval call, and generations with their token usage:
DeliveryLink to section
Export is best-effort by design: a slow or failing destination never affects the request that produced the trace. Deliveries are batched and usually arrive within seconds of the run finishing.
- Status. Each destination card shows one of Delivering, Waiting for traces, Failing (with the destination's last error), or Paused.
- No duplicates. Trace and span ids are derived deterministically from the event, so a retried delivery overwrites the previous one instead of creating a duplicate trace.
- Pause and resume. Pausing stops exports without forgetting the configuration. Traces produced while paused are not backfilled.
SecurityLink to section
Traces contain your queries, retrieved content, and generated answers, so only connect backends you control. Credentials are encrypted at rest and write-only: the API returns only a non-secret hint (the Langfuse public key, or the auth header name). For organizations using Bring Your Own Bucket, customer content is blanked from exported traces, matching the events API.
TroubleshootingLink to section
A destination shows Failing: the card displays the destination's last error response. After fixing the cause (rotated keys, changed endpoint), use Update credentials on the destination; delivery resumes with the next trace and the status clears on the first success.
Traces are missing: check that the trace kind is enabled on the destination. Plain searches and grep are not exported unless you turn them on.