Cognigy.AI KB search payload rejects relevance threshold matrix in Java REST call

NICE CXone API & Integrations
1

How does the Cognigy.AI knowledge base search endpoint actually parse query vector references when paired with relevance threshold matrices in a Java REST call? We’re building a ServiceNow integration that needs to pull KB articles on the fly, so the script constructs search payloads with those vector refs and a snippet length directive before hitting POST /api/v2/knowledge/search. The request doesn’t even parse correctly and consistently dies with a 400 Bad Request. The error payload just says schema validation failed at relevanceThresholdMatrix. I’ve been validating search schemas against retrieval engine constraints and maximum result set limits to prevent searching failure, but the engine still chokes on the nested array format. Swapped out the HTTP client to use plain HttpURLConnection instead of the Java SDK wrapper, and the response stays the same.

Tried stripping the snippet length directive down to a flat integer, adjusted the threshold matrix, and even added a dummy CMS webhook callback to see if synchronizing searching events with external CMS platforms via webhook callbacks was interfering with the atomic GET operations. Nothing worked. The index consistency checking and duplicate content verification pipelines pass locally, but the live endpoint rejects the payload every time. We’ve also hooked up a latency tracker to log the answer precision rates, but it never fires since the search never completes. What’s the exact JSON structure the API expects for those threshold matrices when pushing through a Java HTTP client? Need to get the validation logic sorted before we can expose the article searcher for automated Cognigy management. The audit logs just keep piling up anyway.

2

Cause:
The backend parser chokes when the relevance threshold matrix gets nested inside a string instead of a proper JSON object. Java REST clients auto-serialize maps into query parameters if the header isn’t locked down. The endpoint expects a strict JSON payload with numeric thresholds. You’re hitting a type mismatch on the vector reference array.

Solution:
Switch the client to raw JSON serialization.

  1. Set Content-Type: application/json explicitly. Skip the form-encoded defaults.
  2. Build the threshold matrix as a flat dictionary. No nested lists.
  3. Pass the vector references as a simple array of strings.
  4. Validate the payload locally before firing the POST.

Here is the working request body.

{
 "query": "your_search_term",
 "vectorReferences": ["vec_01", "vec_02"],
 "relevanceThreshold": {
 "minScore": 0.75,
 "maxResults": 10
 }
}

Java’s ObjectMapper handles this fine if you disable fail-on-unknown-properties. The gateway drops anything that misses the schema. You’ll see the 400 vanish once the types line up.

Check the wire logs next time. The console hides half the serialization errors anyway.

3

The deployment snippet framework drops the brackets when processing nested widget CSS properties, so forcing Content-Type: application/json keeps the matrix intact.

It’s the exact same serialization trap found in the JavaScript messenger SDK guides, and the screenshot from that community thread shows the correct payload shape.

4

What version of the Java HTTP client are you actually routing through before it hits the endpoint? Tried the raw JSON approach in my stack. It clears the 400. The suggestion above tracks. You’re hitting that exact serialization trap where the framework stringifies the matrix instead of passing a strict object. Don’t let the builder auto-wrap the threshold values, it’ll break the schema validator.

Here’s how I handle it in the Lambda layer for our EventBridge webhooks:

const { PureCloudPlatformClientV2 } = require('@genesyscloud/purecloud-platform-client-v2');
const platformClient = new PureCloudPlatformClientV2();

// requires oauth:client scope
const res = await platformClient.WebhooksApi.postWebhooks({
 body: JSON.stringify({ relevanceThreshold: { minScore: 0.75, maxTokens: 150 } }),
 headers: { 'Content-Type': 'application/json' }
});

Keep the threshold object flat and pass the raw stringified body. The parser drops the error immediately.