Function getAttachments

src/utils/attachments.ts:743–1003

(
  input: string | null,
  toolUseContext: ToolUseContext,
  ideSelection: IDESelection | null,
  queuedCommands: QueuedCommand[],
  messages?: Message[],
  querySource?: QuerySource,
  options?: { skipSkillDiscovery?: boolean },
)

 * TODO: Generate attachments when we create messages
 */
export async function getAttachments(
  input: string | null,
  toolUseContext: ToolUseContext,
  ideSelection: IDESelection | null,
  queuedCommands: QueuedCommand[],
  messages?: Message[],
  querySource?: QuerySource,
  options?: { skipSkillDiscovery?: boolean },
): Promise<Attachment[]> {
  if (
    isEnvTruthy(process.env.CLAUDE_CODE_DISABLE_ATTACHMENTS) ||
    isEnvTruthy(process.env.CLAUDE_CODE_SIMPLE)
  ) {
    // query.ts:removeFromQueue dequeues these unconditionally after
    // getAttachmentMessages runs — returning [] here silently drops them.
    // Coworker runs with --bare and depends on task-notification for
    // mid-tool-call notifications from Local*Task/Remote*Task.
    return getQueuedCommandAttachments(queuedCommands)
  }

  // This will slow down submissions
  // TODO: Compute attachments as the user types, not here (though we use this
  // function for slash command prompts too)
  const abortController = createAbortController()
  const timeoutId = setTimeout(ac => ac.abort(), 1000, abortController)
  const context = { ...toolUseContext, abortController }

  const isMainThread = !toolUseContext.agentId

  // Attachments which are added in response to on user input
  const userInputAttachments = input
    ? [
        maybe('at_mentioned_files', () =>
          processAtMentionedFiles(input, context),
        ),
        maybe('mcp_resources', () =>
          processMcpResourceAttachments(input, context),
        ),
        maybe('agent_mentions', () =>
          Promise.resolve(
            processAgentMentions(
              input,
              toolUseContext.options.agentDefinitions.activeAgents,
            ),
          ),
        ),
        // Skill discovery on turn 0 (user input as signal). Inter-turn
        // discovery runs via startSkillDiscoveryPrefetch in query.ts,
        // gated on write-pivot detection — see skillSearch/prefetch.ts.
        // feature() here lets DCE drop the 'skill_discovery' string (and the
        // function it calls) from external builds.
        //
        // skipSkillDiscovery gates out the SKILL.md-expansion path
        // (getMessagesForPromptSlashCommand). When a skill is invoked, its
        // SKILL.md content is passed as `input` here to extract @-mentions —
        // but that content is NOT user intent and must not trigger discovery.
        // Without this gate, a 110KB SKILL.md fires ~3.3s of chunked AKI
        // queries on every skill invocation (session 13a9afae).