Runtime
Runtime is the moment of actual user pursuit, when someone is using the product, working toward what they came for, and putting the pieces together as they go. The contrast is the time beforehand, when the team builds the product, theorizes about who'll use it, and decides what to put in front of users. The team's preparation sets up what's available; the user produces the progress at runtime, and preparation can't do that work in advance.
Definition
The moment of user pursuit — when intent is detected, affordances get integrated, hopscotch happens, and efficacy is produced — as distinct from construction time, when the team builds affordances and externalizes route expertise.
What happens at runtime
Runtime is when the user is actually pursuing their transition. They arrive carrying some intent (often without explicitly knowing what it is), encounter the offering, evaluate affordances against their moment-specific needs, hopscotch from one affordance to the next, and produce route efficacy through that activity. Everything that turns a built-out offering into actual user value happens here.
The user is the only party present at runtime. The provider isn't in the room. Whatever the team built is what the user has to work with, and the user can't ask the team to reconsider a design choice mid-traversal. This is what makes runtime structurally different from construction time: runtime is user-produced activity.
How construction time and runtime split the work
Construction time is when the team builds the offering — theorizing intent categories, designing affordances, externalizing route-expertise into the path. Runtime is when the user integrates those affordances into their actual traversal. The two halves are conserved: what the team externalizes at construction time, users access at runtime; what the team doesn't externalize, users have to figure out themselves at runtime.
Construction time work prepares affordances for runtime integration. It doesn't substitute for runtime activity. Designs that try to engineer outcomes entirely at construction time — railroaded wizards built on construction time intent-guesses, manufactured comprehension or motivation, visual polish standing in for trust moments — fail because the work is runtime-shaped. The user has moment-knowledge the team can't access from construction time, and only the user can do the integrating.
Example
A team builds a five-step "set up your workspace" wizard around what new users typically need to configure. At runtime, a user arrives evaluating the product against a specific use case — they want to skip past the generic setup and see whether one particular feature works for their situation. They click through the wizard with their attention fixed on getting past it. The construction time work prepared affordances for an intent the user didn't bring; the misfit is only visible at runtime, and only the user can route around it.