Function mergeHookInstructions

src/services/compact/compact.ts:374–381

(
  userInstructions: string | undefined,
  hookInstructions: string | undefined,
)

 * Empty strings normalize to undefined.
 */
export function mergeHookInstructions(
  userInstructions: string | undefined,
  hookInstructions: string | undefined,
): string | undefined {
  if (!hookInstructions) return userInstructions || undefined
  if (!userInstructions) return hookInstructions
  return `${userInstructions}\n\n${hookInstructions}`
}

/**
 * Creates a compact version of a conversation by summarizing older messages