> ## Documentation Index > Fetch the complete documentation index at: https://docs.leapter.com/llms.txt > Use this file to discover all available pages before exploring further. # Decision Tables > Express first-match business rules as a grid of inputs and outcomes — clearer and easier to review than a long chain of nested decisions. A **decision table** captures a set of rules as a grid: a few input columns, one or more output columns, and one row per rule. When some inputs match a row, that row's outputs are produced. It is the natural way to express a lookup — "these inputs lead to this outcome" — where a long chain of [Decision](/fundamentals/leapter-canvas/controlling-the-flow#decision) branches would hide the structure. Because the rules sit in a table, the inputs, the outcomes, and the order they are checked are all visible at a glance — which makes a decision table much easier for a reviewer to read and verify than nested IF/ELSE logic. ## Where decision tables appear A decision table is a type of element inside a Blueprint, shown as a grid with a table icon. You see it in both places you work with a Blueprint: * In the **[Diagram view](/fundamentals/leapter-canvas/diagram-view)**, as a grid element in the flow. * In the **[Specification view](/fundamentals/leapter-canvas/specification-view)**, as a table in the document. A decision table element in a Blueprint — a grid mapping the riskCategory and hasCleanCreditHistory input columns to a reviewAction output column, with an arrow marker between them ## How to read a decision table | Part | Meaning | | :----------------- | :------------------------------------------------------------------------ | | **Input columns** | The values a rule looks at (left of the arrow marker) | | **Output columns** | The values a matching rule produces (right of the arrow marker `→`) | | **Rows** | One rule each, checked from top to bottom | | **`any`** | A wildcard cell — this rule does not care about that input's value | | **First-match** | The **first** row whose inputs all match wins; no later row is considered | The **first-match** badge on the table is a reminder that order matters: rules are evaluated top to bottom, and evaluation stops at the first row that matches. A row full of `any` at the bottom is a common way to provide a catch-all default. An input cell matches when the input **equals** the cell's value (an enum option or a boolean), or when the cell is **`any`**. Output cells are expressions, so an outcome can be a fixed value or a small calculation. ## Creating a decision table The quickest way to add a decision table is to ask the **[Lab Agent](/fundamentals/change-your-blueprint/lab-agent)**. Describe the rule as a mapping — for example *"map each score band and binding flag to a legal consequence"* — and the agent builds the table for you. When a rule is a straightforward lookup, the agent now prefers a decision table over a chain of decisions. Decision tables are also part of the underlying Blueprint logic, so they are created and regenerated whenever your logic is generated or edited with AI. ## Editing cells To change a decision table by hand, **maximize** it first: click its maximize icon to open the full-width view, which shows the table's name, its first-match policy, and the complete grid. A maximized decision table showing the name, the first-match policy, and the full grid of rules On the maximized table you can: * **Edit a value cell** — click a cell and type a new value. * **Toggle a wildcard** — switch a cell to or from **`any`**. Edits go through the same save path as any other change, so they appear in the [Timeline](/fundamentals/track-changes/timeline), can be undone, and show up in review just like edits to any other element. Editing the compact grid in the flow, and adding or removing whole columns, are not available yet — maximize the table to edit its cells, and use the Lab Agent to change its shape. ## Running a decision table When you [run your Blueprint](/fundamentals/test-your-blueprint), the row that fired lights up in the table, so you can see exactly which rule applied for a given set of inputs. This makes it easy to confirm that the right rule won — especially useful when several rows could plausibly match and first-match order decides between them. ## What to do next * **[Controlling the Flow](/fundamentals/leapter-canvas/controlling-the-flow)** — the other elements that make up a Blueprint * **[Lab Agent](/fundamentals/change-your-blueprint/lab-agent)** — build and edit decision tables by describing the rules * **[Test your Blueprint](/fundamentals/test-your-blueprint)** — run your logic and see which row fires