Function isSearchExtraToolsEnabled

src/utils/searchExtraTools.ts:296–377

(
  model: string,
  tools: Tools,
  getToolPermissionContext: () => Promise<ToolPermissionContext>,
  agents: AgentDefinition[],
  source?: string,
)

 * @returns true if tool search should be enabled for this request
 */
export async function isSearchExtraToolsEnabled(
  model: string,
  tools: Tools,
  getToolPermissionContext: () => Promise<ToolPermissionContext>,
  agents: AgentDefinition[],
  source?: string,
): Promise<boolean> {
  const mcpToolCount = count(tools, t => t.isMcp)

  // Helper to log the mode decision event
  function logModeDecision(
    enabled: boolean,
    mode: SearchExtraToolsMode,
    reason: string,
    extraProps?: Record<string, number>,
  ): void {
    logEvent('tengu_search_extra_tools_mode_decision', {
      enabled,
      mode: mode as AnalyticsMetadata_I_VERIFIED_THIS_IS_NOT_CODE_OR_FILEPATHS,
      reason:
        reason as AnalyticsMetadata_I_VERIFIED_THIS_IS_NOT_CODE_OR_FILEPATHS,
      // Log the actual model being checked, not the session's main model.
      // This is important for debugging subagent tool search decisions where
      // the subagent model (e.g., haiku) differs from the session model (e.g., opus).
      checkedModel:
        model as AnalyticsMetadata_I_VERIFIED_THIS_IS_NOT_CODE_OR_FILEPATHS,
      mcpToolCount,
      userType: (process.env.USER_TYPE ??
        'external') as AnalyticsMetadata_I_VERIFIED_THIS_IS_NOT_CODE_OR_FILEPATHS,
      ...extraProps,
    })
  }

  // Tool search is enabled uniformly regardless of provider or model.
  // All providers use self-built TF-IDF + keyword search via SearchExtraToolsTool + ExecuteExtraTool.

  // Check if SearchExtraToolsTool is available (respects disallowedTools)
  if (!isSearchExtraToolsToolAvailable(tools)) {
    logForDebugging(
      `Tool search disabled: SearchExtraToolsTool is not available (may have been disallowed via disallowedTools).`,
    )
    logModeDecision(false, 'standard', 'mcp_search_unavailable')
    return false
  }

  const mode = getSearchExtraToolsMode()

  switch (mode) {
    case 'tst':
      logModeDecision(true, mode, 'tst_enabled')
      return true

    case 'tst-auto': {
      const { enabled, debugDescription, metrics } = await checkAutoThreshold(
        tools,
        getToolPermissionContext,
        agents,
        model,