ValidationException: messages: text content blocks must be non-empty

[volkanunsal]

Bedrock Anthropic API is complaining because the client is sending an empty string to it:

   at process.processTicksAndRejections (node:internal/process/task_queues:105:5)
cause:
  name: ValidationException
  $fault: client
  $metadata:
    requestId: ""
    extendedRequestId: ""
    cfId: ""
  message: "messages: text content blocks must be non-empty"
  stack: >-
    ValidationException: messages: text content blocks must be non-empty

Here is the last few log entries before the error:

genaiscript:anthropic:msg { type: 'content_block_stop', index: 1 } +0ms
genaiscript:anthropic message_delta +0ms
genaiscript:anthropic:msg {
genaiscript:anthropic:msg   type: 'message_delta',
genaiscript:anthropic:msg   delta: { stop_reason: 'tool_use', stop_sequence: null },
genaiscript:anthropic:msg   usage: { output_tokens: 553 }
genaiscript:anthropic:msg } +0ms
genaiscript:anthropic message_stop +0ms
genaiscript:anthropic:msg {
genaiscript:anthropic:msg   type: 'message_stop',
genaiscript:anthropic:msg   'amazon-bedrock-invocationMetrics': {
genaiscript:anthropic:msg     inputTokenCount: 2842,
genaiscript:anthropic:msg     outputTokenCount: 491,
genaiscript:anthropic:msg     invocationLatency: 12235,
genaiscript:anthropic:msg     firstByteLatency: 1118
genaiscript:anthropic:msg   }
genaiscript:anthropic:msg } +0ms

[volkanunsal]

Related: #1388

[pelikhan]

Try 1.138.1. More checks and more logging.