Problem

Users installing autogen-ext v0.6.4 encounter an ImportError when trying to import MCP tools:

from autogen_ext.tools.mcp import SseMcpToolAdapter, SseServerParams

This fails with:

ImportError: cannot import name 'trace_tool_span' from 'autogen_core'

The issue occurs because trace_tool_span was not available in the released autogen-core v0.6.4, but the MCP workbench code attempts to import it unconditionally.

Solution

Made the trace_tool_span import conditional to maintain backward compatibility with older autogen-core versions while preserving full functionality when the function is available.

Key changes in _workbench.py:

1. Conditional import with graceful fallback:

# Import trace_tool_span conditionally for backward compatibility
try:
    from autogen_core import trace_tool_span
except ImportError:
    # If trace_tool_span is not available (older autogen-core versions),
    # use a no-op context manager
    trace_tool_span = None

2. Context creation that works with both scenarios:

# Use trace_tool_span if available, otherwise use nullcontext for no-op
tracing_context = (
    trace_tool_span(
        tool_name=name,
        tool_call_id=call_id,
    )
    if trace_tool_span is not None
    else nullcontext()
)

Benefits

• ✅ Backward compatibility: Works with autogen-core v0.6.4 and earlier
• ✅ Forward compatibility: Preserves full tracing when trace_tool_span is available
• ✅ Minimal changes: Only 21 lines modified in a single file
• ✅ No functionality loss: Telemetry/tracing works normally when available
• ✅ Graceful degradation: No-op context when tracing unavailable

Testing

Validated the fix handles both scenarios correctly:

• With trace_tool_span available: Full tracing functionality preserved
• Without trace_tool_span: Graceful fallback to no-op context manager
• Original user import scenario now works without errors

Fixes #6791.

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