---
title: "ask: facts"
description: "a unit or a population, the date it was true, and the date we knew it, as two parameters."
section: reference
address: /reference/ask/facts
contract: 0476e35e6e275db5
---

# ask: facts

a unit or a population, the date it was true, and the date we knew it, as two parameters.

[figure: The caller sends FactsInput to /v1/ask/facts. The platform returns a card whose body is FactsAnswer.]

<span class="op-method">POST</span><span class="op-path">/v1/ask/facts</span>

Read facts as of. The call needs the strategy rung under a token with the ask grant, and it is served by either, by the size bound.

The route takes [FactsInput](/concepts/factsinput) and returns a card whose body is [FactsAnswer](/concepts/factsanswer).



## Request body
The request body is [FactsInput](/concepts/factsinput).



| field | type | required | note |
|---|---|---|---|
| `unit` | [UnitRef](/concepts/unitref) | no |  |
| `population` | [Predicate](/concepts/predicate) | no |  |
| `attributes` | `[text]` | no |  |



## Response
The route returns a card whose body is [FactsAnswer](/concepts/factsanswer). Every card ends with a foot that states the basis of each number, the scope of the call, and the time when the facts were true.

## Headers


| header | required | meaning |
|---|---|---|
| `Scale-Scope` | yes | the scope the call runs in: tenant/<id>, then /brand/<id>, then /strategy/<id> |
| `Scale-As-True-On` | no | the date the facts must have been true on; defaults to now |
| `Scale-As-Known-On` | no | the date the facts must have been known on; defaults to now |
| `Scale-Key` | no | for a change, the key made from the input; a repeat under the same key returns the unit held and writes nothing |



A caller needs the strategy rung and a token with the ask grant. The platform or the desktop app serves this route.

## Example
The example sends the smallest body that FactsInput allows. The build validates it against the schema of FactsInput.

<details class="wire"><summary>Example</summary>





```sh
curl -X POST https://api.scaleintelligence.co/v1/ask/facts \
  -H "Scale-Key: $SCALE_KEY" -H "Scale-Scope: tenant/<id>" \
  -H "content-type: application/json" \
  -d '{}'
```




```typescript
import { client } from "@scale/sdk";
const answer = await client.ask.facts({});
// answer.body is a FactsAnswer. answer.foot holds the basis, the scope and the time.
```




```python
import requests
answer = requests.post("https://api.scaleintelligence.co/v1/ask/facts",
    headers={"Scale-Key": KEY, "Scale-Scope": "tenant/<id>"},
    json={}).json()
```




```rust
let answer: Card = client.post("https://api.scaleintelligence.co/v1/ask/facts")
    .header("Scale-Key", key).header("Scale-Scope", "tenant/<id>")
    .json(&FactsInput { /* the fields of the page */ }).send().await?.json().await?;
```




</details>

## MCP tool
The MCP tool `si.ask.facts` takes the same input and returns the same card. The tool only reads data. An MCP host that renders cards draws this card from `ui://scale-intelligence/cards/FactsAnswer`. The [tool's page](/reference/tools/si-ask-facts) describes it.