War-game a shared infra budget before headroom claims, kill-switch gaps, and rollback steps harden into what every capacity review will quote.
Shared infra budgets fail when the runbook invents headroom the cluster never had, when cost centers dual-count the same pool as reserved and as spare, when money routes still lack a named freeze owner, and when ops cannot show who owns the decision after a partial spend misfire. A neat budget PDF is not evidence.
Freeze the budget
One sentence for why the shared pool exists, which surfaces and tenant classes it covers, who owns spend classes, logging, and rollback, and the abort trigger if spend or latency ages past a named threshold. Attach the draft allocation, sample cost exports, reservation map, and the measured path from alert to restored headroom. If platform, finance, and product disagree on which surfaces are truly covered, stop and reconcile first.
Name the decision you will make if the war game finds nothing new, and the delay criteria if any money path still lacks a named rollback owner or a verified canary.
Who speaks
Platform ops should say where headroom invents coverage or hides shared rules across surfaces. Finance should say where bypasses still leave the pool and become standing exceptions. Product should say which customer decision breaks first when spare capacity disappears. Support should show how status language trails the customer-visible incident rate. A skeptic should pick the claim that looks strongest and is least evidenced by prior budget drills.
Give every seat the same source pack. Secret reservations for favorite tenants only create fake calm. Require a canary surface with a measured open-and-reconcile pass before any money path joins the shared pool. If the canary still depends on a verbal reservation, keep the change in hold.
Private loop
Feed Pingpong the draft budget, canary notes, and open risk list. Early passes steelman the design. Later passes attack from platform, finance, product, support, and skeptic seats. End with a pass that turns surviving objections into clearer owners, a timed canary, or a hold. Delete invented "we already have headroom" claims and dual-counted spare rates.
Ask for a month-after narrative: what happens if a partner quotes a retired reservation, if a billing path starts failing latency checks, or if an operator widens a reservation under launch pressure. If those stories outrun the mitigation plan, fix the package before you ship the budget.
Pair with the platform ops lead seat, a tenant isolation rule review, a quota burst policy stress test, a capacity plan review, and the war-game decisions hub.