[Bug]: Response not received when URL guardrail is added to response flow

Please select the area the issue is related to

Area/Management (Management API or Management Portal UI), Area/AIGateway (AI Gateway runtime/control plane)

Please select the aspect the issue is related to

Aspect/AI (AI/LLM integration, MCP, AI readiness)

Description

The LLM response fails when the URL guardrail is enabled for the response flow. This happens only when invoked through Postman

{"time":"2026-03-24T03:46:42.144732595Z","level":"DEBUG","msg":"URLGuardrail: Error extracting value from JSONPath","jsonPath":"$.choices[0].message.content","error":"invalid character '\\x1b' looking for beginning of value","isResponse":true}

It seems postman sends Accept-Encoding: gzip, deflate, br which causes most of the payload processing in our guardrails to fail

Steps to Reproduce

Add the URL guardrail with the response flow enabled to an LLM provider and deploy it in the gateway. Try out a request through postman.

Severity Level of the Issue

Severity/Minor (Non-critical functionality. Can be fixed in future releases)

Environment Details (with versions)

No response

Reproduce the response-flow failure through Postman with Accept-Encoding: gzip, deflate, br, then trace the URL guardrail handling of the response payload and JSONPath $.choices[0].message.content. Done means the LLM response is received and URL guardrail processing succeeds when invoked through Postman.