The alliance began as a work-sharing agreement after a rain-swollen slope destroyed a freight path and trapped workers above the canyon. Its first success was a stepped route cut into stable granite, allowing grain and iron braces to reach the farms before the season turned. The Compact grew as quarry camps asked for the same arrangement: contribute labor, tools, or stone, then share the road and its protection. Its watershed moment came roughly 60 years ago, when an upper basin diverted meltwater to protect its own grain stores and sent a destructive surge through lower terraces. The Compact's crews braced a damaged stair-road and opened a relief channel under pressure, saving the route and enabling evacuation. The Valley Stewards subsequently asserted broader authority over shared water and land use. The Compact accepted joint emergency rules but resisted permanent Steward control of its quarries and roads. Since then, it has become both a construction consortium and a political bloc. It has repaired roads after repeated slides, established regular cargo movement between Third Survey Hold and First Rain Market, and helped frontier settlements withstand beast attacks. Its reputation has suffered from disputes over timber, quarry boundaries, and the occasional blast that reveals something better left undisturbed.

The Mason's Anvil is the local name for the broad stone shelf at the center of Third Survey Hold, where a captured thermal vent warms the forge floor. The Compact keeps its records and contract table in a low granite hall adjoining the workshops. The air smells of hot iron, wet wool, and stone dust; hammer blows travel through the floor before they reach the ear.