{"mode":"preview","message":"This endpoint is POST-only with payment. The example_response below shows what a successful POST returns.","example_response":{"pqs_version":"2.0","injection_detected":true,"injection_confidence":0.97,"injection_pattern":"instruction_override","matched_signals":["regex:ignore_previous_instructions","regex:reveal_system_prompt"],"sanitized_prompt":"[redacted: instruction-override fragment]","detector":"heuristic","powered_by":"PQS - promptqualityscore.com"},"upgrade":"POST /api/fix-injection with x402 payment ($0.025 USDC on Base) and body { prompt } to detect prompt-injection attempts and receive a sanitized prompt. Or use Authorization: Bearer PQS_... with an API key from promptqualityscore.com/api-key.","try_free":"POST /api/score/free with body { prompt, vertical } for unauthenticated 5/min real scoring.","powered_by":"PQS - promptqualityscore.com"}