Function isThinkingBlock

src/utils/messages.ts:4771–4775

(
  block: ContentBlockParam | ContentBlock | BetaContentBlock,
)

  | BetaRedactedThinkingBlock

function isThinkingBlock(
  block: ContentBlockParam | ContentBlock | BetaContentBlock,
): block is ThinkingBlockType {
  return block.type === 'thinking' || block.type === 'redacted_thinking'
}

/**
 * Filter trailing thinking blocks from the last message if it's an assistant message.