tbd

Use when a planned slice cannot ship self-complete and a mechanism is needed to keep trunk releasable, when deciding how incomplete work merges safely, or when choosing between a naturally-safe slice, a feature toggle, and branch by abstraction.

Use when checking whether a diff or planned slice is review-sized, when a PR is ballooning past budget, when deciding what counts toward PR size (generated code, lockfiles, docs, renames), or before opening any pull request on a multi-PR effort.

Use when a body of work is too big for one review-sized pull request and needs to be split into an ordered sequence of independently shippable PRs, when planning an epic's PR boundaries, or when resuming a partially finished epic that already has a decomposition map.

Use when starting work on an epic or any multi-PR feature, when the user wants trunk-based development discipline, when work looks too big for one pull request, or when the user invokes /using-tbd — establishes that work must be decomposed into small, independently shippable pull requests before implementation planning begins.