One tool execution. Maps to an execute_tool OTel span.
arguments and result use the JSONString annotation:
callers can assign a dict / list / scalar and the SDK JSON-encodes
it at construction or assignment. The stored value is always a
string, matching the wire format per GenAI semconv.
Tool is a Pydantic model. Set any field below as a keyword argument when you construct it.
Tool is a context manager and can be used in a with statement.
Fields
Methods
end
start
Start this span once; context-manager entry uses the same path.
record_error
Record a failure without ending the span; call end() when ready.
set_attributes
Stamp arbitrary OTel attributes on this span.
Pass a dict whether you have one key or many; single-key callers
use span.set_attributes({"weave.tag": "value"}). Mirrors OTel’s
Span.set_attributes.
Must be called after a start_* factory, start(), or with
starts the span, and before it ends. Outside that window the call is a
no-op and logs a warning. For batch ingest, populate the object’s declared fields
directly and pass it to log_turn / log_conversation. Last modified on September 30, 2026
