Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Nitpick comments:
In `@service/convert_stream_test.go`:
- Around line 12-62: Add a regression case in
TestStreamResponseOpenAI2ClaudeParallelToolCallsHaveValidBlockLifecycle that
sends a packed final chunk or otherwise produces a delta/stop for a tool-call
index that was never opened or was already closed. Assert
StreamResponseOpenAI2Claude drops the stray events without panicking and emits
no invalid lifecycle events, while preserving the existing valid
start/delta/stop assertions.

In `@service/relayconvert/internal/oai_chat/to_claude_messages_resp.go`:
- Around line 155-180: Unify the tool-block start and guarded-delta behavior
used by the initialization and streaming loops. Extract package-level helpers
such as startToolBlockIfNeeded and emitToolDeltaIfOpen, then update both loop
paths around ClaudeConvertInfo.ToolCallOpenIndexes and claudeResponses to use
them, ensuring deltas are emitted only for open blocks and preserving existing
index handling.

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@relaykit/relayconvert/internal/oai_chat/to_claude_messages_resp_test.go`:
- Around line 256-277: Extend the event validation in the test’s event loop to
capture each content_block_delta event’s PartialJson payload by block index.
Assert that the collected values include {"city":"Tokyo"} for the expected block
and {} for the other, while preserving the existing ordering and start/stop
assertions.

In `@relaykit/relayconvert/internal/oai_chat/to_claude_messages_resp.go`:
- Around line 177-187: Update both content_block_start emission paths in
relaykit/relayconvert/internal/oai_chat/to_claude_messages_resp.go at lines
177-187 and 349-360 to require a non-empty Function.Name and an index not
already present in ToolCallOpenIndexes before emitting a start; preserve the
existing state update after emission. In
relaykit/relayconvert/internal/oai_chat/to_claude_messages_resp_test.go lines
229-277, add a replayed name for an existing index and assert that no duplicate
content_block_start is produced.
- Around line 28-35: Replace the range scan in
relaykit/relayconvert/internal/oai_chat/to_claude_messages_resp.go:28-35 with
deterministic iteration over the tracked open indexes, stopping only active
keys. In
relaykit/relayconvert/internal/oai_chat/to_claude_messages_resp.go:168-187,
validate or normalize negative and unbounded initial tool indexes before
emitting Claude blocks; apply the same validation to subsequent tool deltas in
relaykit/relayconvert/internal/oai_chat/to_claude_messages_resp.go:336-377.

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@relaykit/relayconvert/internal/oai_chat/to_claude_messages_resp_test.go`:
- Around line 324-333: Update the event validation in the test around the
content_block_start loop to collect every content_block_start event’s index,
including non-zero indexes, and assert the collected indexes exactly equal [0].
Remove the current non-zero-index filtering and starts counter while preserving
the existing replay scenario coverage.
- Around line 276-283: Strengthen the event lifecycle assertions in this test’s
content_block_stop handling to reject duplicate stops for the same block. Before
marking stopped[idx], assert that the block has not already been stopped, while
preserving the existing started-before-stop check and final started/stopped
equality assertion.