Architect Bot Flow 500 Error on Entity Attribute Lookup

Stumbled on a weird bug today with the Entity Lookup action in our AppFoundry bot flow. The request hits the custom API endpoint successfully, but the Architect returns a 500 Internal Server Error immediately after the HTTP request completes, despite valid JSON payload.

Error: Failed to process entity lookup. Response body is not parseable or schema mismatch detected on field 'customer_tier'.

Verified the payload matches the schema exactly. Any ideas on why the platform API rejects this post-lookup?

The documentation actually says…

  • Schema validation in Architect is stricter than standard JSON parsing. If the API returns null for a non-nullable field like customer_tier, the flow engine throws a 500 instead of a clean error. Check the raw response body during the test.
  • Rate limiting on custom endpoints can cause partial responses or timeouts that look like schema errors. Ensure your JMeter thread group doesn’t exceed the endpoint’s configured rate limit.
  • WebSocket backpressure might be dropping the response packet before Architect processes it. Increase the idle_timeout in your JMeter HTTP Request sampler to allow the full handshake to complete.
  • Verify the Content-Type header is explicitly application/json. Architect sometimes fails to parse responses if the header is missing or set to text/plain.
  • Add a retry loop in the flow with a small delay (500ms). This often masks transient 500s caused by backend scaling events during load spikes.