Function normalizeMessagesForAPI

src/utils/messages.ts:2008–2391

(
  messages: Message[],
  tools: Tools = [],
)

}

export function normalizeMessagesForAPI(
  messages: Message[],
  tools: Tools = [],
): (UserMessage | AssistantMessage)[] {
  // Build set of available tool names for filtering unavailable tool references
  const availableToolNames = new Set(tools.map(t => t.name))

  // First, reorder attachments to bubble up until they hit a tool result or assistant message
  // Then strip virtual messages — they're display-only (e.g. REPL inner tool
  // calls) and must never reach the API.
  const reorderedMessages = reorderAttachmentsForAPI(messages).filter(
    m => !((m.type === 'user' || m.type === 'assistant') && m.isVirtual),
  )

  // Build a map from error text → which block types to strip from the preceding user message.
  const errorToBlockTypes: Record<string, Set<string>> = {
    [getPdfTooLargeErrorMessage()]: new Set(['document']),
    [getPdfPasswordProtectedErrorMessage()]: new Set(['document']),
    [getPdfInvalidErrorMessage()]: new Set(['document']),
    [getImageTooLargeErrorMessage()]: new Set(['image']),
    [getRequestTooLargeErrorMessage()]: new Set(['document', 'image']),
  }

  // Walk the reordered messages to build a targeted strip map:
  // userMessageUUID → set of block types to strip from that message.
  const stripTargets = new Map<string, Set<string>>()
  for (let i = 0; i < reorderedMessages.length; i++) {
    const msg = reorderedMessages[i]!
    if (!isSyntheticApiErrorMessage(msg)) {
      continue
    }
    // Determine which error this is
    const errorText =
      Array.isArray(msg.message.content) &&
      msg.message.content[0]?.type === 'text'
        ? msg.message.content[0].text
        : undefined
    if (!errorText) {
      continue
    }
    const blockTypesToStrip = errorToBlockTypes[errorText]
    if (!blockTypesToStrip) {
      continue
    }
    // Walk backward to find the nearest preceding isMeta user message
    for (let j = i - 1; j >= 0; j--) {
      const candidate = reorderedMessages[j]!
      if (candidate.type === 'user' && candidate.isMeta) {
        const existing = stripTargets.get(candidate.uuid)
        if (existing) {
          for (const t of blockTypesToStrip) {
            existing.add(t)
          }
        } else {
          stripTargets.set(candidate.uuid, new Set(blockTypesToStrip))
        }
        break
      }