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POST/api/v1/firewall/ground

Run the grounding / hallucination guardrail against an answer

Live grounding rail: checks a model answer against its retrieved sources under the tenant's grounding policy, then STRIPs / regrounds / blocks the ungrounded spans and signs every non-clean event into the crypto evidence-ledger. Per-request enforcement overrides (onFailAction, thresholds, failMode) apply to THIS check only.

Authentication

Send Authorization: Bearer YOUR_API_KEY on every request. Generate API keys at /dashboard/api-keys.

Request body required

Example

{
  "question": "<The user query the answer responds to.>",
  "sources": [],
  "answer": "<The model answer to check / strip / regr>",
  "orgId": "00000000-0000-0000-0000-000000000000",
  "projectId": "00000000-0000-0000-0000-000000000000",
  "onFailAction": "strip_ungrounded",
  "minGroundedFraction": 0,
  "riskThreshold": 0,
  "failMode": "open"
}
Schema
{
  "application/json": {
    "schema": {
      "type": "object",
      "properties": {
        "question": {
          "type": "string",
          "minLength": 1,
          "maxLength": 100000,
          "description": "The user query the answer responds to."
        },
        "sources": {
          "minItems": 1,
          "maxItems": 200,
          "type": "array",
          "items": {
            "anyOf": [
              {
                "type": "string",
                "minLength": 1,
                "maxLength": 100000
              },
              {
                "type": "object",
                "properties": {
                  "id": {
                    "type": "string",
                    "maxLength": 200
                  },
                  "text": {
                    "type": "string",
                    "minLength": 1,
                    "maxLength": 100000
                  }
                },
                "required": [
                  "text"
                ],
                "additionalProperties": false
              }
            ]
          },
          "description": "Retrieved context the answer must be grounded in (>=1 passage)."
        },
        "answer": {
          "type": "string",
          "minLength": 1,
          "maxLength": 100000,
          "description": "The model answer to check / strip / reground / block."
        },
        "orgId": {
          "type": "string",
          "format": "uuid",
          "pattern": "^([0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[1-8][0-9a-fA-F]{3}-[89abAB][0-9a-fA-F]{3}-[0-9a-fA-F]{12}|00000000-0000-0000-0000-000000000000|ffffffff-ffff-ffff-ffff-ffffffffffff)$",
          "description": "Optional — tenant resolution / telemetry (membership verified by the API handler)."
        },
        "projectId": {
          "type": "string",
          "format": "uuid",
          "pattern": "^([0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[1-8][0-9a-fA-F]{3}-[89abAB][0-9a-fA-F]{3}-[0-9a-fA-F]{12}|00000000-0000-0000-0000-000000000000|ffffffff-ffff-ffff-ffff-ffffffffffff)$",
          "description": "Optional — tenant resolution / telemetry (membership verified by the API handler)."
        },
        "onFailAction": {
          "type": "string",
          "enum": [
            "strip_ungrounded",
            "reground",
            "block",
            "warn",
            "allow"
          ],
          "description": "Per-request enforcement override (wins over the tenant policy for this check only)."
        },
        "minGroundedFraction": {
          "type": "number",
          "minimum": 0,
          "maximum": 1
        },
        "riskThreshold": {
          "type": "number",
          "minimum": 0,
          "maximum": 1
        },
        "failMode": {
          "type": "string",
          "enum": [
            "open",
            "closed"
          ]
        }
      },
      "required": [
        "question",
        "sources",
        "answer"
      ],
      "additionalProperties": false
    }
  }
}

Response

200 example

{
  "success": true
}

All status codes

200Grounding verdict (decision, groundedFraction, riskScore, strippedOutput, blocked, incidentId).
400(no description)
401(no description)
429(no description)

Code samples

cURL

curl -X POST \
  https://evalguard.ai/api/v1/firewall/ground \
  -H "Authorization: Bearer $EVALGUARD_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{ "question": "<The user query the answer responds to.>", "sources": [], "answer": "<The model answer to check / strip / regr>", "orgId": "00000000-0000-0000-0000-000000000000", "projectId": "00000000-0000-0000-0000-000000000000", "onFailAction": "strip_ungrounded", "minGroundedFraction": 0, "riskThreshold": 0, "failMode": "open" }'

TypeScript

import { EvalGuard } from "@evalguard/sdk";

const client = new EvalGuard({ apiKey: process.env.EVALGUARD_API_KEY });

const response = await client.request({
  method: "POST",
  path: "/api/v1/firewall/ground",
  body: {
    "question": "<The user query the answer responds to.>",
    "sources": [],
    "answer": "<The model answer to check / strip / regr>",
    "orgId": "00000000-0000-0000-0000-000000000000",
    "projectId": "00000000-0000-0000-0000-000000000000",
    "onFailAction": "strip_ungrounded",
    "minGroundedFraction": 0,
    "riskThreshold": 0,
    "failMode": "open"
  },
});
console.log(response);

Python

from evalguard import EvalGuard
import os

client = EvalGuard(api_key=os.environ["EVALGUARD_API_KEY"])

response = client.request(
    method="POST",
    path="/api/v1/firewall/ground",
    body={
    "question": "<The user query the answer responds to.>",
    "sources": [],
    "answer": "<The model answer to check / strip / regr>",
    "orgId": "00000000-0000-0000-0000-000000000000",
    "projectId": "00000000-0000-0000-0000-000000000000",
    "onFailAction": "strip_ungrounded",
    "minGroundedFraction": 0,
    "riskThreshold": 0,
    "failMode": "open"
},
)
print(response)

Go

package main

import (
	"context"
	"fmt"
	"net/http"
	"os"
	"strings"
)

func main() {
	body := strings.NewReader(`{"question":"<The user query the answer responds to.>","sources":[],"answer":"<The model answer to check / strip / regr>","orgId":"00000000-0000-0000-0000-000000000000","projectId":"00000000-0000-0000-0000-000000000000","onFailAction":"strip_ungrounded","minGroundedFraction":0,"riskThreshold":0,"failMode":"open"}`)
	req, _ := http.NewRequestWithContext(context.Background(), "POST", "https://evalguard.ai/api/v1/firewall/ground", body)
	req.Header.Set("Authorization", "Bearer "+os.Getenv("EVALGUARD_API_KEY"))
	req.Header.Set("Content-Type", "application/json")
	resp, err := http.DefaultClient.Do(req)
	if err != nil { panic(err) }
	defer resp.Body.Close()
	fmt.Println(resp.Status)
}

Errors

400401429

Other Firewall endpoints