> ## Documentation Index
> Fetch the complete documentation index at: https://docs.usefusion.ai/llms.txt
> Use this file to discover all available pages before exploring further.
# Question Guards
> Server-side validation rules that screen participants for eligibility before they can join a quest.
Question guards (also called consent gates or validation rules) are **server-side validation rules** on onboarding questions. They determine whether a participant is eligible to join a quest based on their answers.
## How They Work
1. Participant fills out onboarding questions
2. Answers are sent to the server: `POST /quest/validate-onboarding`
3. Every question with a guard is evaluated
4. If **any** guard fails → participant is blocked with rejection messages
5. If **all** guards pass → participant can proceed to join
Guard validation is **server-side** — it cannot be bypassed by participants.
## Guard Configuration
Each guard has three fields:
| Field | Type | Description |
| --------------------- | ------ | ------------------------------------------------------------------------------------------------------------------------------- |
| **Operator** | string | The comparison operator (see table below) |
| **Value** | string | The expected value. Single value for `eq/neq/gt/gte/lt/lte`. Comma-separated for `in/not_in`. |
| **Rejection Message** | string | Custom message shown to the participant if they fail. Default: *"Your response does not meet the requirements for this study."* |
## Available Operators
Which operators are available depends on the question's response type:
| Response Type | Available Operators |
| --------------- | ------------------------------------------------------------------------------------------------------------- |
| `text` | `eq` (Equals), `neq` (Not equals) |
| `yesno` | `eq` (Equals), `neq` (Not equals) |
| `number` | `eq`, `neq`, `gt` (Greater than), `gte` (Greater than or equal), `lt` (Less than), `lte` (Less than or equal) |
| `numberRange` | `eq`, `neq`, `gt`, `gte`, `lt`, `lte` |
| `customOptions` | `eq` (Equals), `neq` (Not equals), `in` (Is one of), `not_in` (Is not one of) |
### Operator Details
| Operator | Label | Behavior |
| -------- | --------------------- | -------------------------------------------------------------------- |
| `eq` | Equals | Case-insensitive exact match |
| `neq` | Not equals | Case-insensitive non-match |
| `gt` | Greater than | Parses as float: answer > value |
| `gte` | Greater than or equal | Parses as float: answer ≥ value |
| `lt` | Less than | Parses as float: answer \< value |
| `lte` | Less than or equal | Parses as float: answer ≤ value |
| `in` | Is one of | Value is comma-separated. Answer (lowercased) must be in the set |
| `not_in` | Is not one of | Value is comma-separated. Answer (lowercased) must NOT be in the set |
When you change a question's response type, the operator resets to the first valid option if the current operator is no longer available for the new type.
## Rejection Behavior
When a participant fails validation:
* **Per-question**: Each failed question shows its rejection message in a **red inline box** below the question
* **Global**: A **yellow warning banner** appears: *"You do not meet the eligibility criteria for this quest."*
* The participant **cannot proceed** and cannot join the quest
## Adding a Guard
1. Open a quest and navigate to the onboarding section
2. Click on an onboarding question (or add a new one)
3. Check **"Add validation rule (consent gate)"**
4. Select an **operator** from the dropdown
5. Enter the expected **value**
6. Optionally customize the **rejection message**
## Worked Examples
### Must Be 18 or Older
| Field | Value |
| ----------------- | ----------------------------------------------------------------- |
| Question | "How old are you?" |
| Response type | `number` |
| Operator | `gte` |
| Value | `18` |
| Rejection message | "You must be at least 18 years old to participate in this study." |
**Behavior**: If a participant enters 17, they see the rejection message and cannot join.
### Must Consent to Data Collection
| Field | Value |
| ----------------- | ----------------------------------------------------------------------------- |
| Question | "Do you consent to your data being collected and used for research purposes?" |
| Response type | `yesno` |
| Operator | `eq` |
| Value | `Yes` |
| Rejection message | "Consent is required to participate in this study." |
**Behavior**: If a participant selects "No", they see the rejection message and cannot join.
### Must Be in Target Demographic
| Field | Value |
| ----------------- | ---------------------------------------------------------------- |
| Question | "What is your occupation?" |
| Response type | `customOptions` |
| Options | Student, Professional, Retired, Other |
| Operator | `in` |
| Value | `Student,Professional` |
| Rejection message | "This study is only open to students and working professionals." |
**Behavior**: If a participant selects "Retired" or "Other", they see the rejection message and cannot join.
### Exclude a Specific Condition
| Field | Value |
| ----------------- | -------------------------------------------------------------------------------------------------------------------- |
| Question | "Do you have a history of epilepsy?" |
| Response type | `yesno` |
| Operator | `eq` |
| Value | `No` |
| Rejection message | "Due to the nature of the visual stimuli in this study, participants with a history of epilepsy cannot participate." |
**Behavior**: If a participant selects "Yes", they see the rejection message and cannot join.