fix(streaming): handle tool use metadata in contentBlockDelta for non-standard models

[Zelys-DFKH]

Problem

When Kimi K2.5 (moonshotai.kimi-k2.5) is used via the Amazon Bedrock Converse streaming API, tool calls on the second cycle crash with a KeyError. The streaming parser in handle_content_block_delta only reads input from contentBlockDelta.delta.toolUse, ignoring toolUseId and name. When a model provides those fields in the delta rather than in contentBlockStart (a non-standard but valid variation), current_tool_use reaches handle_content_block_stop without toolUseId or name, causing a crash.

A secondary gap: if delta.toolUse has no input key, the direct dict access raises KeyError instead of treating it as an empty string.

Solution

In handle_content_block_delta, capture toolUseId and name from the delta when they are present and not already set from a prior contentBlockStart. Use .get("input", "") to handle deltas with no input key.

In handle_content_block_stop, replace the direct current_tool_use["toolUseId"] and current_tool_use["name"] accesses with .get() calls, and log a warning and skip the block if either field is still missing after processing all events.

Testing

• Added test_handle_content_block_delta_captures_tool_use_id_and_name_from_delta: delta with all three fields populates current_tool_use correctly.
• Added test_handle_content_block_delta_does_not_override_existing_tool_use_id_and_name: fields set by contentBlockStart are not overwritten by a later delta.
• Added test_handle_content_block_delta_tool_use_without_input_key: delta missing input does not raise.
• Added test_handle_content_block_stop_skips_incomplete_tool_use_missing_id / _missing_name: warning logged and block skipped when fields are absent.
• Added test_process_stream_tool_use_info_in_delta: end-to-end check simulating a model that sends all tool use metadata in the delta.
• All 111 existing event loop tests pass. Lint clean.

Fixes #1646

Documentation PR

N/A

Type of Change

Bug fix

Checklist

• I have read the CONTRIBUTING document
• I have added any necessary tests that prove my fix is effective or my feature works
• I have updated the documentation accordingly
• My changes generate no new warnings
• Any dependent changes have been merged and published

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