The Draconic Prophecy has existed since the dawn of time. It is a living thing. It has never been fully recorded because it is constantly growing and evolving. The Prophecy is a map showing many paths that the future might take, and revealing dependencies. Consider the following:
"If the King of Breland is assassinated on the day of the gargoyle’s first victory, there will be war in the west. If there is war between Droaam and Breland, and if the last child of the storm faces the three daughters, the first hag will return."
This is the nature of the Prophecy. It is a web that is constantly unfolding, and the future is formed by threads from thousands of evolving events. This is how the Chamber and the Lords of Dust use the Prophecy as a weapon. Find an outcome you desire, then trace back the path of events that will make it happen. If the Lords of Dust want Sora Kell to return, they must see to it that King Boranel is slain on the same day that Carralag the gargoyle wins the Race of Eight Winds in Sharn. This will lead to war… and that paves the way for the next convergence they wish to control. Meanwhile, if the Chamber can prevent Carralag’s victory or Boranel’s death, it has staved off this fate... though it might have set another path in motion. This is the trick to dealing with the Lords of Dust and the Chamber; both groups are often working toward long-term goals that can’t even be seen without the use of the Prophecy. The Chamber might help stop a massacre, or it might cause a massacre—in either case the dragons care nothing about the victims. They are concerned only with the chain of events that are set in motion, and it might take years, decades, or longer for matters to play out.
The dragons of Argonnessen and the rakshasas observe and record everything from the position of the moons and stars, to the position of the Ring of Siberys to physical manifestations of dragonmarks in the world, all of which they study looking for portents and omens of things to come. The prophecy encompasses many many volumes and is said to be as complex and unfathomable as the dragons themselves. A few among the scholarly study snippets of the massive work, but only the dragons with their incredibly long lifespan, and the immortal rakshasas have the ability and patience to see the prophecy for what it truly is.