# Condition (/workflows/blocks/condition)





The **Condition block** checks branches in order and follows the first true expression. It makes no model call. Use a [Router](/workflows/blocks/router) when the decision depends on understanding intent or unstructured text.

<BlockPreview type="condition" />

## Route by priority [#route-by-priority]

<WorkflowPreview workflow="CONDITION_ROUTE_WORKFLOW" />

Check `<start.priority> === 'high'` in the **if** branch. Connect that port to escalation and **else** to a standard reply.

## Configuration [#configuration]

**Conditions** contains an **if** branch, optional **else if** branches, and **else**. Each expression uses JavaScript operators and methods and connects to its own path. Put specific checks before general ones: the first match wins.

```javascript
<agent.score> > 75
<ticket.subject>.toLowerCase().includes('urgent')
<user.email>.endsWith('@company.com') && <user.plan> === 'pro'
```

Comparisons, logical operators, string/array methods, math, and Date comparisons work in expressions. Move lengthy logic to a [Function](/workflows/blocks/function) and branch on its result.

[Environment variables](/workflows/variables#environment-variables) use `{{KEY}}`:

```javascript
{{MAX_RETRIES}} === 3
{{FEATURE_ON}} === true
{{TIER}} === 'pro'
```

Numbers, booleans, and `null` compare as literals here. Other environment values are bound as strings, so quotes or newlines inside a secret cannot become expression code. This differs from [Function placeholders](/workflows/blocks/function#placeholders-are-always-strings), which always remain strings.

## Outputs [#outputs]

| Reference | Value |
| - | - |
| `<condition.conditionResult>` | `true` for a matching expression; `false` when else is selected or no branch matches |
| `<condition.selectedOption>` | Selected branch ID, or `null` if none |
| `<condition.selectedPath>` | Destination object containing `blockId`, `blockType`, and `blockTitle`, or `null` when no destination is connected |

Only the chosen path runs. A reference to a known block on a skipped path has no output.

## Errors and unmatched input [#errors-and-unmatched-input]

Connect **else** to handle input that matches no expression. An unconnected else path ends without an error. A final `true` expression is another catch-all when you deliberately omit else.

<Callout type="warn">
  An expression that throws fails the block. Guard missing values with optional chaining (`?.`) or a null check, and connect the error port when the workflow should recover.
</Callout>

## Gate on a model score [#gate-on-a-model-score]

<WorkflowPreview workflow="CONDITION_MODERATE_WORKFLOW" />

Give the Agent a Response Format containing numeric `toxicity`, then check `<moderate.toxicity> > 0.7`. The high-score branch blocks the content; else sends it to the publishing endpoint. The same pattern can route accounts by a structured `tier` field.

## Related docs [#related-docs]

* [Router](/workflows/blocks/router)
* [Function](/workflows/blocks/function)
* [Connections](/workflows/connections)