diff --git a/observability-pocs/poc_0_secret_manager.php b/observability-pocs/poc_0_secret_manager.php
new file mode 100644
index 000000000000..5fd2caaf3b84
--- /dev/null
+++ b/observability-pocs/poc_0_secret_manager.php
@@ -0,0 +1,123 @@
+<?php
+
+require __DIR__ . '/../vendor/autoload.php';
+
+use OpenTelemetry\API\Trace\TracerProviderInterface;
+use OpenTelemetry\API\Trace\SpanKind;
+use OpenTelemetry\API\Trace\StatusCode;
+use OpenTelemetry\SDK\Trace\TracerProviderFactory;
+use OpenTelemetry\SDK\Trace\SpanExporter\ConsoleSpanExporter;
+use OpenTelemetry\SDK\Trace\SpanProcessor\SimpleSpanProcessor;
+
+class TelemetryConfiguration {
+    public static function isTracingEnabled(?TracerProviderInterface $constructorProvider = null): bool {
+        $env = getenv('GOOGLE_CLOUD_TELEMETRY_ENABLED');
+        
+        // 1. Global Override
+        if ($env === 'false') {
+            return false;
+        }
+
+        // 2. Constructor-Based Enablement
+        if ($constructorProvider !== null) {
+            return true;
+        }
+
+        // 3. Environment-Based Enablement
+        if ($env === 'true') {
+            return true;
+        }
+
+        // 4. Default
+        return false;
+    }
+}
+
+class SecretManagerClientMock {
+    private ?TracerProviderInterface $tracerProvider;
+    private $tracer;
+
+    public function __construct(?TracerProviderInterface $tracerProvider = null) {
+        $this->tracerProvider = $tracerProvider;
+        
+        if (TelemetryConfiguration::isTracingEnabled($tracerProvider)) {
+            $provider = $this->tracerProvider ?? \OpenTelemetry\API\Globals::tracerProvider();
+            $this->tracer = $provider->getTracer('google-cloud-secretmanager', '1.0.0');
+        } else {
+            $this->tracer = null;
+        }
+    }
+
+    public function accessSecretVersion(string $name) {
+        $span = null;
+        if ($this->tracer) {
+            $span = $this->tracer->spanBuilder('SecretManagerServiceClient.access_secret_version')
+                ->setSpanKind(SpanKind::KIND_INTERNAL)
+                ->setAttribute('gcp.client.service', 'secretmanager')
+                ->startSpan();
+            $scope = $span->activate();
+        }
+
+        try {
+            if ($span) {
+                $t4 = $this->tracer->spanBuilder('GET /v1/' . $name . ':access')
+                    ->setSpanKind(SpanKind::KIND_CLIENT)
+                    ->setAttribute('rpc.system.name', 'http')
+                    ->setAttribute('http.request.method', 'GET')
+                    ->setAttribute('gcp.resource.destination.id', '//secretmanager.googleapis.com/' . $name)
+                    ->startSpan();
+                
+                $t4->setAttribute('http.response.status_code', 200);
+                $t4->end();
+            }
+
+            return "super_secret_value";
+        } finally {
+            if ($span) {
+                $span->end();
+                $scope->detach();
+            }
+        }
+    }
+}
+
+use OpenTelemetry\SDK\Trace\SpanExporter\InMemoryExporter;
+use OpenTelemetry\SDK\Trace\TracerProvider;
+
+// Setup OTel SDK for testing
+$exporter = new InMemoryExporter();
+$tracerProvider = new TracerProvider(new SimpleSpanProcessor($exporter));
+
+echo "--- Test 1: Disabled by default ---\n";
+putenv('GOOGLE_CLOUD_TELEMETRY_ENABLED'); // Unset
+$client1 = new SecretManagerClientMock();
+$client1->accessSecretVersion('projects/my-project/secrets/my-secret');
+echo "Spans generated: " . count($exporter->getSpans()) . "\n\n";
+
+echo "--- Test 2: Enabled via Constructor ---\n";
+$exporter2 = new InMemoryExporter();
+$tracerProvider2 = new TracerProvider(new SimpleSpanProcessor($exporter2));
+$client2 = new SecretManagerClientMock($tracerProvider2);
+$client2->accessSecretVersion('projects/my-project/secrets/my-secret');
+echo "Spans generated: " . count($exporter2->getSpans()) . "\n\n";
+
+echo "--- Test 3: Global Override (Disabled) ---\n";
+putenv('GOOGLE_CLOUD_TELEMETRY_ENABLED=false');
+$exporter3 = new InMemoryExporter();
+$tracerProvider3 = new TracerProvider(new SimpleSpanProcessor($exporter3));
+$client3 = new SecretManagerClientMock($tracerProvider3);
+$client3->accessSecretVersion('projects/my-project/secrets/my-secret');
+echo "Spans generated: " . count($exporter3->getSpans()) . "\n\n";
+
+echo "--- Test 4: Environment Enablement (Global Provider) ---\n";
+putenv('GOOGLE_CLOUD_TELEMETRY_ENABLED=true');
+$exporter4 = new InMemoryExporter();
+$tracerProvider4 = new TracerProvider(new SimpleSpanProcessor($exporter4));
+\OpenTelemetry\API\Globals::registerInitializer(function(\OpenTelemetry\API\Instrumentation\Configurator $configurator) use ($tracerProvider4) {
+    return $configurator->withTracerProvider($tracerProvider4);
+});
+$client4 = new SecretManagerClientMock();
+$client4->accessSecretVersion('projects/my-project/secrets/my-secret');
+echo "Spans generated: " . count($exporter4->getSpans()) . "\n";
+
+
diff --git a/observability-pocs/poc_1_pubsub_streaming.php b/observability-pocs/poc_1_pubsub_streaming.php
new file mode 100644
index 000000000000..58b7beba5f4d
--- /dev/null
+++ b/observability-pocs/poc_1_pubsub_streaming.php
@@ -0,0 +1,59 @@
+<?php
+// Mocking the Pub/Sub Streaming Pull loop to verify Span Context does not leak.
+require __DIR__ . '/../vendor/autoload.php';
+
+use OpenTelemetry\API\Trace\SpanKind;
+use OpenTelemetry\SDK\Trace\TracerProvider;
+use OpenTelemetry\SDK\Trace\SpanProcessor\SimpleSpanProcessor;
+use OpenTelemetry\SDK\Trace\SpanExporter\InMemoryExporter;
+
+$exporter = new InMemoryExporter();
+$tracerProvider = new TracerProvider(new SimpleSpanProcessor($exporter));
+$tracer = $tracerProvider->getTracer('google-cloud-pubsub-mock', '1.0.0');
+
+// Mock Streaming Pull Loop
+echo "Starting Pub/Sub Streaming Pull PoC...\n";
+
+// The overall subscriber span (T2)
+$subscriberSpan = $tracer->spanBuilder('Subscriber.StreamingPull')
+    ->setSpanKind(SpanKind::KIND_CLIENT)
+    ->startSpan();
+$subscriberScope = $subscriberSpan->activate();
+
+try {
+    for ($i = 1; $i <= 3; $i++) {
+        // T3: Process individual message
+        $messageSpan = $tracer->spanBuilder("ProcessMessage $i")
+            ->setSpanKind(SpanKind::KIND_INTERNAL)
+            ->startSpan();
+        
+        $messageScope = $messageSpan->activate();
+        try {
+            // Simulate user callback executing
+            echo "Processing message $i in trace " . $messageSpan->getContext()->getTraceId() . "\n";
+            
+            // T4: Simulated network call inside the user callback (e.g. acking the message)
+            $ackSpan = $tracer->spanBuilder("POST /v1/projects/p/subscriptions/s:acknowledge")
+                ->setSpanKind(SpanKind::KIND_CLIENT)
+                ->startSpan();
+            $ackScope = $ackSpan->activate();
+            try {
+                // Network delay
+            } finally {
+                $ackSpan->end();
+                $ackScope->detach();
+            }
+        } finally {
+            $messageSpan->end();
+            $messageScope->detach(); // CRITICAL: Detaching prevents context leak to next message loop
+        }
+    }
+} finally {
+    $subscriberSpan->end();
+    $subscriberScope->detach();
+}
+
+echo "\nTotal Spans Exported: " . count($exporter->getSpans()) . "\n";
+foreach ($exporter->getSpans() as $span) {
+    echo "- Span: " . $span->getName() . " | Parent ID: " . $span->getParentContext()->getSpanId() . "\n";
+}
diff --git a/observability-pocs/poc_2_gapic_resource_name.php b/observability-pocs/poc_2_gapic_resource_name.php
new file mode 100644
index 000000000000..2e26fceb0066
--- /dev/null
+++ b/observability-pocs/poc_2_gapic_resource_name.php
@@ -0,0 +1,66 @@
+<?php
+// Mocking the GAPIC generator dynamic path parsing heuristic
+
+$tests = [
+    [
+        'api_domain' => 'pubsub.googleapis.com',
+        'http_annotation' => 'v1/{name=projects/*/topics/*}',
+        'runtime_path' => 'v1/projects/my-project/topics/my-topic'
+    ],
+    [
+        'api_domain' => 'spanner.googleapis.com',
+        'http_annotation' => 'v1/{session=projects/*/instances/*/databases/*/sessions/*}:commit',
+        'runtime_path' => 'v1/projects/p/instances/i/databases/d/sessions/s:commit'
+    ],
+    [
+        'api_domain' => 'storage.googleapis.com',
+        'http_annotation' => 'b/{bucket}/o/{object}',
+        'runtime_path' => 'b/my-bucket/o/my-file.txt'
+    ]
+];
+
+echo "Starting GAPIC Resource Name Parser PoC...\n\n";
+
+foreach ($tests as $test) {
+    echo "Testing annotation: " . $test['http_annotation'] . "\n";
+    
+    // In gapic-generator-php, this regex generation would happen at compile-time.
+    // We convert the annotation to a regex pattern capturing the dynamic parts.
+    // Simplified regex generation for PoC:
+    $pattern = preg_replace('/\{([a-zA-Z0-9_]+)=([^\}]+)\}/', '(?P<$1>$2)', $test['http_annotation']);
+    // Handle simple {bucket} cases without explicit wildcards
+    $pattern = preg_replace('/\{([a-zA-Z0-9_]+)\}/', '(?P<$1>[^/:]+)', $pattern);
+    
+    // Replace * with regex wildcard for the generated pattern
+    $pattern = str_replace('*', '[^/:]+', $pattern);
+    $pattern = '#^' . $pattern . '$#';
+    
+    echo "  Generated Regex: $pattern\n";
+    
+    // At runtime in the client library, we apply the regex to the actual path.
+    if (preg_match($pattern, $test['runtime_path'], $matches)) {
+        // Find the named capturing group that matches a valid GCP resource structure
+        // (For simplicity in PoC, we just take the first named match that contains a slash)
+        $extractedResource = null;
+        foreach ($matches as $key => $value) {
+            if (is_string($key) && strpos($value, '/') !== false) {
+                $extractedResource = $value;
+                break;
+            }
+        }
+        
+        if (!$extractedResource && isset($matches[1])) {
+             // Fallback for simple non-slashed variables (like bucket name)
+             $extractedResource = $matches['bucket'] ?? null;
+        }
+
+        if ($extractedResource) {
+            $formattedId = '//' . $test['api_domain'] . '/' . $extractedResource;
+            echo "  Extracted Resource ID: " . $formattedId . "\n\n";
+        } else {
+            echo "  FAILED to extract resource.\n\n";
+        }
+    } else {
+        echo "  FAILED to match runtime path.\n\n";
+    }
+}
diff --git a/observability-pocs/poc_3_metric_exemplars.php b/observability-pocs/poc_3_metric_exemplars.php
new file mode 100644
index 000000000000..83c8dd5aeaf6
--- /dev/null
+++ b/observability-pocs/poc_3_metric_exemplars.php
@@ -0,0 +1,61 @@
+<?php
+// Mocking Metric Exemplars with OpenTelemetry PHP SDK
+require __DIR__ . '/../vendor/autoload.php';
+
+use OpenTelemetry\API\Trace\SpanKind;
+use OpenTelemetry\SDK\Trace\TracerProvider;
+use OpenTelemetry\SDK\Trace\SpanProcessor\SimpleSpanProcessor;
+use OpenTelemetry\SDK\Trace\SpanExporter\InMemoryExporter as InMemoryTraceExporter;
+use OpenTelemetry\SDK\Metrics\MeterProvider;
+use OpenTelemetry\SDK\Metrics\MetricExporter\InMemoryExporter as InMemoryMetricExporter;
+use OpenTelemetry\SDK\Metrics\MetricReader\ExportingReader;
+
+$traceExporter = new InMemoryTraceExporter();
+$tracerProvider = new TracerProvider(new SimpleSpanProcessor($traceExporter));
+$tracer = $tracerProvider->getTracer('poc-tracer');
+
+$metricExporter = new InMemoryMetricExporter();
+$meterProvider = OpenTelemetry\SDK\Metrics\MeterProvider::builder()
+    ->addReader(new ExportingReader($metricExporter))
+    ->build();
+$meter = $meterProvider->getMeter('poc-meter');
+
+$histogram = $meter->createHistogram(
+    'gcp.client.request.duration',
+    'ms',
+    'Duration of client request'
+);
+
+echo "Starting Metric Exemplars PoC...\n";
+
+// Start a trace
+$span = $tracer->spanBuilder('Storage.Upload')->setSpanKind(SpanKind::KIND_CLIENT)->startSpan();
+$scope = $span->activate();
+
+try {
+    echo "Active Trace ID: " . $span->getContext()->getTraceId() . "\n";
+    echo "Active Span ID:  " . $span->getContext()->getSpanId() . "\n";
+    
+    // Simulate workload
+    usleep(150000); // 150ms
+    
+    // Record the metric WHILE the trace context is active. 
+    // The OTel SDK should automatically attach the active trace as an exemplar.
+    $histogram->record(150.5, ['gcp.client.service' => 'storage']);
+    echo "Recorded metric: 150.5 ms\n";
+} finally {
+    $span->end();
+    $scope->detach();
+}
+
+// Force flush the metrics reader to the memory exporter
+$meterProvider->shutdown();
+
+echo "\nVerifying Metric Export for Exemplars:\n";
+$metrics = $metricExporter->collect();
+
+foreach ($metrics as $metric) {
+    if ($metric->name === 'gcp.client.request.duration') {
+        echo print_r($metric->data, true);
+    }
+}