Function buildEffectiveSystemPrompt

src/utils/systemPrompt.ts:41–123

({
  mainThreadAgentDefinition,
  toolUseContext,
  customSystemPrompt,
  defaultSystemPrompt,
  appendSystemPrompt,
  overrideSystemPrompt,
}: {
  mainThreadAgentDefinition: AgentDefinition | undefined
  toolUseContext: Pick<ToolUseContext, 'options'>
  customSystemPrompt: string | undefined
  defaultSystemPrompt: string[]
  appendSystemPrompt: string | undefined
  overrideSystemPrompt?: string | null
})

 * Plus appendSystemPrompt is always added at the end if specified (except when override is set).
 */
export function buildEffectiveSystemPrompt({
  mainThreadAgentDefinition,
  toolUseContext,
  customSystemPrompt,
  defaultSystemPrompt,
  appendSystemPrompt,
  overrideSystemPrompt,
}: {
  mainThreadAgentDefinition: AgentDefinition | undefined
  toolUseContext: Pick<ToolUseContext, 'options'>
  customSystemPrompt: string | undefined
  defaultSystemPrompt: string[]
  appendSystemPrompt: string | undefined
  overrideSystemPrompt?: string | null
}): SystemPrompt {
  if (overrideSystemPrompt) {
    return asSystemPrompt([overrideSystemPrompt])
  }
  // Coordinator mode: use coordinator prompt instead of default
  // Use inline env check instead of coordinatorModule to avoid circular
  // dependency issues during test module loading.
  if (
    feature('COORDINATOR_MODE') &&
    isEnvTruthy(process.env.CLAUDE_CODE_COORDINATOR_MODE) &&
    !mainThreadAgentDefinition
  ) {
    // Lazy require to avoid circular dependency at module load time
    const { getCoordinatorSystemPrompt } =
      // eslint-disable-next-line @typescript-eslint/no-require-imports
      require('../coordinator/coordinatorMode.js') as typeof import('../coordinator/coordinatorMode.js')
    return asSystemPrompt([
      getCoordinatorSystemPrompt(),
      ...(appendSystemPrompt ? [appendSystemPrompt] : []),
    ])
  }

  const agentSystemPrompt = mainThreadAgentDefinition
    ? isBuiltInAgent(mainThreadAgentDefinition)
      ? mainThreadAgentDefinition.getSystemPrompt({
          toolUseContext: { options: toolUseContext.options },
        })
      : mainThreadAgentDefinition.getSystemPrompt()
    : undefined

  // Log agent memory loaded event for main loop agents
  if (mainThreadAgentDefinition?.memory) {
    logEvent('tengu_agent_memory_loaded', {
      ...(process.env.USER_TYPE === 'ant' && {
        agent_type:
          mainThreadAgentDefinition.agentType as AnalyticsMetadata_I_VERIFIED_THIS_IS_NOT_CODE_OR_FILEPATHS,
      }),
      scope:
        mainThreadAgentDefinition.memory as AnalyticsMetadata_I_VERIFIED_THIS_IS_NOT_CODE_OR_FILEPATHS,
      source:
        'main-thread' as AnalyticsMetadata_I_VERIFIED_THIS_IS_NOT_CODE_OR_FILEPATHS,
    })
  }