Function startRelevantMemoryPrefetch

src/utils/attachments.ts:2361–2424

(
  messages: ReadonlyArray<Message>,
  toolUseContext: ToolUseContext,
)

 * handle with settlement tracking. Bound with `using` in query.ts.
 */
export function startRelevantMemoryPrefetch(
  messages: ReadonlyArray<Message>,
  toolUseContext: ToolUseContext,
): MemoryPrefetch | undefined {
  if (
    !isAutoMemoryEnabled() ||
    !getFeatureValue_CACHED_MAY_BE_STALE('tengu_moth_copse', false)
  ) {
    return undefined
  }

  const lastUserMessage = messages.findLast(m => m.type === 'user' && !m.isMeta)
  if (!lastUserMessage) {
    return undefined
  }

  const input = getUserMessageText(lastUserMessage)
  // Single-word prompts lack enough context for meaningful term extraction
  if (!input || !/\s/.test(input.trim())) {
    return undefined
  }

  const surfaced = collectSurfacedMemories(messages)
  if (surfaced.totalBytes >= RELEVANT_MEMORIES_CONFIG.MAX_SESSION_BYTES) {
    return undefined
  }

  // Chained to the turn-level abort so user Escape cancels the sideQuery
  // immediately, not just on [Symbol.dispose] when queryLoop exits.
  const controller = createChildAbortController(toolUseContext.abortController)
  const firedAt = Date.now()
  const promise = getRelevantMemoryAttachments(
    input,
    toolUseContext.options.agentDefinitions.activeAgents,
    toolUseContext.readFileState,
    collectRecentSuccessfulTools(messages, lastUserMessage),
    controller.signal,
    surfaced.paths,
  ).catch(e => {
    if (!isAbortError(e)) {
      logError(e)
    }
    return []
  })

  const handle: MemoryPrefetch = {
    promise,
    settledAt: null,
    consumedOnIteration: -1,
    [Symbol.dispose]() {
      controller.abort()
      logEvent('tengu_memdir_prefetch_collected', {
        hidden_by_first_iteration:
          handle.settledAt !== null && handle.consumedOnIteration === 0,
        consumed_on_iteration: handle.consumedOnIteration,
        latency_ms: (handle.settledAt ?? Date.now()) - firedAt,
      })
    },