INPUT_VALUE overwritten in _process_input_data leading to loss of multi-message context

[rite7sh]

Summary

SpanAttributes.INPUT_VALUE is overwritten multiple times in _process_input_data, resulting in loss of context for multi-message inputs.

In the current implementation, the final assignment reduces the input to only the first message, which breaks trace correctness for conversational inputs.

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Affected Code

In _span_io_handler.py:

if eval_input:
    eval_input_str = " \n ".join(map(str, eval_input))
    span.set_attribute(SpanAttributes.INPUT_VALUE, eval_input_str)

if eval_input and len(eval_input) > 0:
    span.set_attribute(SpanAttributes.INPUT_VALUE, eval_input[0])

[pmady]

ran into this while reviewing the codebase for #164. the issue is in _span_io_handler.py lines 55-63 -- INPUT_VALUE gets set three times in sequence:

1. line 55: full json of input_content (correct, has all messages)
2. line 61: joined eval_input strings (loses structure but keeps all messages)
3. line 63: eval_input[0] only (drops everything except the first message)

line 63 always wins and you lose multi-turn context. looks like lines 62-63 are redundant with the block at 59-61 anyway (both check if eval_input). removing 62-63 should fix it without changing behavior for the eval path.

happy to open a PR if that approach makes sense.