Function sanitizeErrorToolResultContent

src/utils/messages.ts:1884–1907

* Strip non-text blocks from is_error tool_results — the API rejects the * combination with "all content must be type text if is_error is true". * * Read-side guard for transcripts persisted before smooshIntoToolResult * learned to filter on is_error. Without this a resumed session with one * o

(
  messages: (UserMessage | AssistantMessage)[],
)

 * text left behind by a stripped image is re-merged.
 */
function sanitizeErrorToolResultContent(
  messages: (UserMessage | AssistantMessage)[],
): (UserMessage | AssistantMessage)[] {
  return messages.map(msg => {
    if (msg.type !== 'user') return msg
    const content = msg.message.content
    if (!Array.isArray(content)) return msg

    let changed = false
    const newContent = content.map(b => {
      if (b.type !== 'tool_result' || !b.is_error) return b
      const trContent = b.content
      if (!Array.isArray(trContent)) return b
      if (trContent.every(c => c.type === 'text')) return b
      changed = true
      const texts = trContent.filter(c => c.type === 'text').map(c => c.text)
      const textOnly: TextBlockParam[] =
        texts.length > 0 ? [{ type: 'text', text: texts.join('\n\n') }] : []
      return { ...b, content: textOnly }
    })
    if (!changed) return msg
    return { ...msg, message: { ...msg.message, content: newContent } }
  })
}

/**
 * Move text-block siblings off user messages that contain tool_reference.