You support a large service with a well-defined Service Level Objective (SLO). The development team deploys new releases of the service multiple times a week. If a major incident causes the service to

An error budget policy, collaboratively developed with all service stakeholders, defines the acceptable level of unreliability and dictates actions to be taken when the budget is consumed, such as halting feature development to focus on reliability work. Establishing this policy proactively ensures there is an agreed-upon mechanism and consequence for missing SLOs, aligning the team's incentives towards reliability.

Negotiating to always prioritize reliability over features is an unrealistic and inflexible approach that can stifle innovation and product growth, and doesn't provide a clear, measurable trigger for when such a shift should occur.

Negotiating to reduce release frequency doesn't directly address the mechanism for shifting focus to reliability when SLOs are missed; it's a separate concern regarding deployment practices.

Adding a Jenkins plugin to prevent new releases when out of budget is an implementation detail of an error budget policy, not the policy itself, and cannot be done without first defining the policy and its triggers.