diff --git a/scripts/load_test.js b/scripts/load_test.js
index 1500bf9..03bb486 100644
--- a/scripts/load_test.js
+++ b/scripts/load_test.js
@@ -1,29 +1,72 @@
 import http from 'k6/http';
 import { check } from 'k6';
+import { Counter } from 'k6/metrics';
+import { Trend } from 'k6/metrics';
+import exec from 'k6/execution';
+
+const API_URL = __ENV.API_URL || 'http://localhost:8000/api/v1/cdr/raw';
+const PROFILE = (__ENV.PROFILE || 'assessment').toLowerCase();
+const P95_MS = Number(__ENV.P95_MS || 50);
+
+// Assessment profile directly models the required scenario:
+// 500 records in <5s. 125 iterations/s for 4 seconds schedules exactly 500 iterations.
+const assessmentScenario = {
+  executor: 'constant-arrival-rate',
+  rate: 125,
+  timeUnit: '1s',
+  duration: '4s',
+  preAllocatedVUs: 50,
+  maxVUs: 250,
+  gracefulStop: '5s',
+};
+
+// Optional heavier capacity test. Run with PROFILE=stress.
+const stressScenario = {
+  executor: 'ramping-arrival-rate',
+  startRate: 250,
+  timeUnit: '1s',
+  preAllocatedVUs: 250,
+  maxVUs: 1000,
+  stages: [
+    { duration: '10s', target: 500 },
+    { duration: '10s', target: 1000 },
+    { duration: '30s', target: 1000 },
+    { duration: '5s', target: 0 },
+  ],
+};
 
 export const options = {
+  discardResponseBodies: true,
   scenarios: {
-    // Ramp up from 10 to 50 virtual users pushing sustained load
-    sustained_load: {
-      executor: 'ramping-vus',
-      startVUs: 10,
-      stages: [
-        { duration: '10s', target: 50 },  // Ramp up to 50 VUs
-        { duration: '30s', target: 50 },  // Stay at 50 VUs (~1,000+ req/s)
-        { duration: '5s', target: 0 },    // Ramp down
-      ],
-    },
+    ingestion: PROFILE === 'stress' ? stressScenario : assessmentScenario,
   },
   thresholds: {
-    http_req_duration: ['p(95)<50'], // 95% of API responses under 50ms
-    http_req_failed: ['rate<0.01'],  // Less than 1% failure
+    // 429 is a failure for the assessment burst. k6 also treats 4xx as failed HTTP requests.
+    http_req_failed: ['rate==0'],
+    checks: ['rate==1'],
+    dropped_iterations: ['count==0'],
+    ...(PROFILE === 'assessment' ? {
+      accepted_202: ['count==500'],
+      assessment_completion_ms: ['max<5000'],
+    } : {}),
+
+    // This is a project performance guardrail, not an assessment requirement.
+    // Override it with P95_MS=100 (etc.) if you want a different SLA.
+    http_req_duration: [`p(95)<${P95_MS}`],
   },
 };
 
+const accepted202 = new Counter('accepted_202');
+const rejected429 = new Counter('rejected_429');
+const unexpectedStatus = new Counter('unexpected_status');
+const completionTime = new Trend('assessment_completion_ms');
+
 export default function () {
-  const url = __ENV.API_URL || 'http://localhost:8000/api/v1/cdr/raw';
+  const now = Date.now();
+  const rawId = `k6-${PROFILE}-${__VU}-${__ITER}-${now}`;
+
   const payload = JSON.stringify({
-    raw_id: `load-${__VU}-${__ITER}-${Date.now()}`,
+    raw_id: rawId,
     src_ip: '10.240.1.1',
     device_id: '310410998877665',
     caller_num: '+19875551234',
@@ -33,16 +76,78 @@ export default function () {
     rat: 6,
     lac: '4021',
     ci: '8812',
-    epoch_start: 1726070000,
-    epoch_end: 1726070300,
+    epoch_start: Math.floor(now / 1000) - 300,
+    epoch_end: Math.floor(now / 1000),
   });
 
-  const params = {
+  const res = http.post(API_URL, payload, {
     headers: { 'Content-Type': 'application/json' },
-  };
+    tags: { test_profile: PROFILE },
+  });
+  completionTime.add(Date.now() - exec.scenario.startTime);
+
+  if (res.status === 202) {
+    accepted202.add(1);
+  } else if (res.status === 429) {
+    rejected429.add(1);
+  } else {
+    unexpectedStatus.add(1);
+  }
 
-  const res = http.post(url, payload, params);
   check(res, {
-    'status is 202 or 429': (r) => r.status === 202 || r.status === 429,
+    'accepted with 202': (r) => r.status === 202,
+    'not backpressured with 429': (r) => r.status !== 429,
   });
 }
+
+export function handleSummary(data) {
+  const reqs = data.metrics.http_reqs?.values?.count || 0;
+  const failedRate = data.metrics.http_req_failed?.values?.rate || 0;
+  const p95 = data.metrics.http_req_duration?.values?.['p(95)'];
+  const dropped = data.metrics.dropped_iterations?.values?.count || 0;
+  const accepted = data.metrics.accepted_202?.values?.count || 0;
+  const rejected = data.metrics.rejected_429?.values?.count || 0;
+  const unexpected = data.metrics.unexpected_status?.values?.count || 0;
+  const completionMs = data.metrics.assessment_completion_ms?.values?.max;
+
+  const lines = [
+    '',
+    '=== CDR Ingestion Load-Test Summary ===',
+    `Profile:             ${PROFILE}`,
+    `Requests attempted:  ${reqs}`,
+    `202 Accepted:        ${accepted}`,
+    `429 Backpressure:    ${rejected}`,
+    `Unexpected statuses: ${unexpected}`,
+    `Dropped iterations:  ${dropped}`,
+    `HTTP failure rate:   ${(failedRate * 100).toFixed(2)}%`,
+    `p95 latency:         ${p95 !== undefined ? p95.toFixed(2) + ' ms' : 'n/a'}`,
+  ];
+
+  if (PROFILE === 'assessment') {
+    const assessmentPass =
+      reqs === 500 &&
+      accepted === 500 &&
+      rejected === 0 &&
+      unexpected === 0 &&
+      dropped === 0 &&
+      completionMs < 5000;
+
+    lines.push(
+      'Assessment target:   500 acknowledged records in <5s, no 429, no dropped iterations',
+      `Last completion:     ${completionMs !== undefined ? completionMs.toFixed(2) + ' ms' : 'unavailable'}`,
+      `Assessment result:   ${assessmentPass ? 'PASS' : 'FAIL'}`,
+      'Note: k6 proves API-side burst handling; run generate_traffic.py',
+      '      to verify end-to-end ClickHouse/DLQ/deduplication behavior.'
+    );
+  } else {
+    lines.push(
+      'Stress target:       sustain the configured arrival rate without errors/drops.'
+    );
+  }
+
+  lines.push('=======================================', '');
+
+  return {
+    stdout: `${lines.join('\n')}\n`,
+  };
+}