diff --git a/src/main/java/com/seleniumboot/ai/AiFailureAnalyzer.java b/src/main/java/com/seleniumboot/ai/AiFailureAnalyzer.java
index 3ae99d1..faf297c 100644
--- a/src/main/java/com/seleniumboot/ai/AiFailureAnalyzer.java
+++ b/src/main/java/com/seleniumboot/ai/AiFailureAnalyzer.java
@@ -73,8 +73,12 @@ static void resetCache() {
      * @param pageTitle current page title (may be null)
      */
     public static void analyze(String testId, String pageUrl, String pageTitle) {
+        analyze(config(), testId, pageUrl, pageTitle);
+    }
+
+    /** Test seam: same as {@link #analyze(String, String, String)} with the AI config supplied. */
+    static void analyze(SeleniumBootConfig.Ai aiCfg, String testId, String pageUrl, String pageTitle) {
         try {
-            SeleniumBootConfig.Ai aiCfg = config();
             if (aiCfg == null || !aiCfg.isFailureAnalysis()) return;
 
             String apiKey = resolveApiKey(aiCfg.getApiKey());
diff --git a/src/test/java/com/seleniumboot/ai/AiFailureAnalyzerSameCauseTest.java b/src/test/java/com/seleniumboot/ai/AiFailureAnalyzerSameCauseTest.java
new file mode 100644
index 0000000..f7e4495
--- /dev/null
+++ b/src/test/java/com/seleniumboot/ai/AiFailureAnalyzerSameCauseTest.java
@@ -0,0 +1,138 @@
+package com.seleniumboot.ai;
+
+import com.seleniumboot.config.SeleniumBootConfig;
+import com.seleniumboot.metrics.ExecutionMetrics;
+import com.sun.net.httpserver.HttpServer;
+import org.testng.annotations.AfterMethod;
+import org.testng.annotations.BeforeMethod;
+import org.testng.annotations.Test;
+
+import java.net.InetSocketAddress;
+import java.nio.charset.StandardCharsets;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicInteger;
+
+import static org.testng.Assert.*;
+
+/** One AI call per distinct failure cause, against a local fake provider. */
+public class AiFailureAnalyzerSameCauseTest {
+
+    private HttpServer server;
+    private final AtomicInteger calls = new AtomicInteger();
+    private volatile int status;
+    private volatile long delayMs;
+
+    @BeforeMethod
+    public void start() throws Exception {
+        calls.set(0);
+        status = 200;
+        delayMs = 0;
+        AiFailureAnalyzer.resetCache();
+        ExecutionMetrics.reset();
+        server = HttpServer.create(new InetSocketAddress("127.0.0.1", 0), 0);
+        server.createContext("/", ex -> {
+            calls.incrementAndGet();
+            ex.getRequestBody().readAllBytes();
+            try { Thread.sleep(delayMs); } catch (InterruptedException ignored) { }
+            byte[] out = "{\"content\":[{\"type\":\"text\",\"text\":\"Root cause: login API down\"}]}"
+                    .getBytes(StandardCharsets.UTF_8);
+            ex.sendResponseHeaders(status, out.length);
+            ex.getResponseBody().write(out);
+            ex.close();
+        });
+        server.start();
+    }
+
+    @AfterMethod
+    public void stop() {
+        server.stop(0);
+        AiFailureAnalyzer.resetCache();
+        ExecutionMetrics.reset();
+    }
+
+    private SeleniumBootConfig.Ai cfg() {
+        SeleniumBootConfig.Ai ai = new SeleniumBootConfig.Ai();
+        ai.setFailureAnalysis(true);
+        ai.setApiKey("k");
+        ai.setBaseUrl("http://127.0.0.1:" + server.getAddress().getPort() + "/api");
+        ai.setTimeoutSeconds(5);
+        return ai;
+    }
+
+    private static void failed(String id, String message) {
+        ExecutionMetrics.recordBrowser(id, "chrome");
+        ExecutionMetrics.recordError(id, new AssertionError(message));
+    }
+
+    @Test
+    public void sameCauseFailures_shareOneCall_andEachGetTheAnalysis() {
+        failed("a.One.run", "login API returned 500");
+        failed("a.Two.run", "login API returned 503");
+        failed("a.Three.run", "login API returned 502");
+
+        for (String id : new String[]{"a.One.run", "a.Two.run", "a.Three.run"}) {
+            AiFailureAnalyzer.analyze(cfg(), id, null, null);
+        }
+
+        assertEquals(calls.get(), 1, "numbers normalise, so one cause costs one call");
+        for (String id : new String[]{"a.One.run", "a.Two.run", "a.Three.run"}) {
+            assertEquals(ExecutionMetrics.getTiming(id).getAiAnalysis(), "Root cause: login API down", id);
+        }
+    }
+
+    @Test
+    public void differentCauses_getTheirOwnCall() {
+        failed("a.One.run", "login API returned 500");
+        failed("a.Other.run", "cart badge missing");
+
+        AiFailureAnalyzer.analyze(cfg(), "a.One.run", null, null);
+        AiFailureAnalyzer.analyze(cfg(), "a.Other.run", null, null);
+
+        assertEquals(calls.get(), 2);
+    }
+
+    @Test
+    public void concurrentSameCauseFailures_waitForTheFirstCall() throws Exception {
+        delayMs = 300;
+        int n = 4;
+        for (int i = 0; i < n; i++) failed("a.T" + i + ".run", "login API returned 500");
+
+        ExecutorService pool = Executors.newFixedThreadPool(n);
+        CountDownLatch go = new CountDownLatch(1);
+        for (int i = 0; i < n; i++) {
+            String id = "a.T" + i + ".run";
+            pool.submit(() -> {
+                go.await();
+                AiFailureAnalyzer.analyze(cfg(), id, null, null);
+                return null;
+            });
+        }
+        go.countDown();
+        pool.shutdown();
+        assertTrue(pool.awaitTermination(15, TimeUnit.SECONDS));
+
+        assertEquals(calls.get(), 1, "concurrent same-cause failures share the in-flight call");
+        for (int i = 0; i < n; i++) {
+            assertNotNull(ExecutionMetrics.getTiming("a.T" + i + ".run").getAiAnalysis());
+        }
+    }
+
+    @Test
+    public void failedCall_isNotCached_soTheNextSameCauseFailureRetries() {
+        failed("a.One.run", "login API returned 500");
+        failed("a.Two.run", "login API returned 500");
+
+        status = 500;
+        AiFailureAnalyzer.analyze(cfg(), "a.One.run", null, null);
+        assertNull(ExecutionMetrics.getTiming("a.One.run").getAiAnalysis());
+
+        status = 200;
+        AiFailureAnalyzer.analyze(cfg(), "a.Two.run", null, null);
+
+        assertEquals(calls.get(), 2, "an error must not poison the cause");
+        assertNotNull(ExecutionMetrics.getTiming("a.Two.run").getAiAnalysis());
+    }
+}