Agno traces keep the full message history on tool-heavy runs

Agno's setup_tracing(), which AgentOS(tracing=True) also calls, now builds its tracer provider with SpanLimits(max_span_attributes=1024). OpenInference stores each input message on the model span as several attributes, so a run with dozens of tool calls blew past OpenTelemetry's default of 128 and lost its oldest messages first, starting with the user's prompt.

Setting OTEL_SPAN_ATTRIBUTE_COUNT_LIMIT or OTEL_ATTRIBUTE_COUNT_LIMIT hands the limit back to OpenTelemetry. A TracerProvider your app installed itself stays untouched.

We traced an agent driven by a scripted stand-in model that calls a lookup tool 40 times, with an in-memory span exporter swapped in for the database exporter, and counted attributes on the final model span:

setup_tracing(db=db)
Agent(model=ScriptedModel(), tools=[lookup]).run("Look up 40 records.")

# Before (real output)
attributes on the final model span: 128
input messages on it: 34 of 81
user prompt kept: False
 
# Now (real output)
attributes on the final model span: 293
input messages on it: 81 of 81
user prompt kept: True
 
# Now, with OTEL_SPAN_ATTRIBUTE_COUNT_LIMIT=200 (real output)
attributes on the final model span: 200
input messages on it: 55 of 81
user prompt kept: False

See the cookbook, and learn more about setting up tracing in the documentation.