# What you can do

> Recalculate a project plan under dependencies and capacity, preview it before it is written, see the critical path and who is overloaded, and build a shift roster that covers demand

Source: https://aipril.dev/docs/scheduling/what-you-can-do

## Recalculate a project plan

One button on the project's Gantt chart. The solver takes the task network as it stands and finds
dates that satisfy all of it at once:

- **Dependencies of all four kinds** - finish-to-start, start-to-start, finish-to-finish and
  start-to-finish.
- **People's capacity** - nobody is booked beyond what they have, counted in tasks, in hours or as a
  share of a working week.
- **Earliest starts** - a task that cannot begin before a delivery arrives does not.
- **Hard finishes** - a date the task must end by.
- **Deadlines** - a target the plan tries to meet and reports when it cannot.

A task can need more than one person, and the plan respects each of them.

## Change as little as possible

A recalculated plan that moves everything is as useless as one that moves nothing. Two rules keep it
steady:

- **Started work is pinned.** Tasks in progress or done stay where they are. The switch is on by
  default and can be turned off for a full replan.
- **Tasks with slack stay put.** If a task does not have to move, it does not, so the new plan reads
  as a list of real changes rather than a new plan.

What the plan optimises for is an organisation setting: finish as early as possible, or disturb the
current plan as little as possible.

## See it before it changes

- **Preview.** The new dates are shown next to the current ones. Nothing is written yet.
- **Apply.** The plan is written into the project's tasks. If anybody changed the project while the
  preview was open, apply refuses instead of overwriting their change with a plan built without it.
- **Undo.** A whole run is reversed in one step.

## Understand why

- **When no plan is possible, you get the reason**, not an error: the rules that could not be met,
  heaviest first, with the resource, the day and the amount. The plan is not written.
- **The critical path** is drawn over the Gantt chart: the chain of tasks where any delay moves the
  finish.
- **Resource load** shows each person's booking over time as a heatmap, with the tasks behind every
  cell, so overload is visible weeks before it happens.
- **A baseline** keeps the approved plan to compare against as the real one moves.

## Reassign work on the timeline

In the team view each person is a row and each task a block. Drag a block along the row to move it
in time; drag it onto another person to reassign it. The change is written to the project directly.

## Build a shift roster

The same engine plans people instead of tasks:

- **Coverage requirements** - how many people with which skill are needed, when.
- **Skills** - who is qualified for what.
- **Unavailability** - holidays, sick leave, training.

Generate the roster, check it against the requirements, adjust it by hand - drag a shift to another
day or another person, edit its hours in place - and publish it. After the week, the timesheet
records what was actually worked next to what was planned.

## One widget, two modes

The roster is one widget for [pages and portals](https://aipril.dev/docs/cms.md) with a mode switch: shifts, or a
project's people and tasks. The same screen serves the store manager planning next week and the
project manager balancing a team, and it can be placed in any application.

## Through the assistant

The recalculation is also a tool the assistant can run for you in chat: "recalculate the schedule
for this project and tell me what moved". It acts as you, with your access, and the answer includes
the explanation when a plan is not feasible.

It is deliberately a tool for a person, not for an
[AI employee](https://aipril.dev/docs/ai-organisation.md) working on its own: moving a whole project's dates is a
decision somebody should own. See [Under the hood](https://aipril.dev/docs/scheduling/under-the-hood.md).

## Next

[Under the hood](https://aipril.dev/docs/scheduling/under-the-hood.md) - the solver, the preview-and-apply contract, and
who is allowed to recalculate.