diff --git a/php-transformer/src/Contract/ConversionReportProjection.php b/php-transformer/src/Contract/ConversionReportProjection.php
index 2c9d70fe..8bda3260 100644
--- a/php-transformer/src/Contract/ConversionReportProjection.php
+++ b/php-transformer/src/Contract/ConversionReportProjection.php
@@ -25,6 +25,7 @@ public static function fromResultParts(string $sourceFormat, array $blocks, arra
             'scope'                 => self::firstString($provenance, 'scope'),
             'source_summary'        => self::sourceSummary($sourceFormat, $blocks, $fallbacks, $sourceReports, $assets, $metrics),
             'selector_summary'      => self::selectorSummary($sourceReports, $fallbacks),
+            'conversion_classification_summary' => self::conversionClassificationSummary($sourceReports, $fallbacks),
             'fallback_diagnostics'  => self::fallbackDiagnostics($fallbacks),
             'asset_refs'            => self::assetReferences($blocks, $sourceReports),
             'navigation_candidates' => self::navigationCandidates($blocks, $sourceReports),
@@ -122,6 +123,8 @@ private static function fallbackDiagnostics(array $fallbacks): array
                     'reason'          => $fallback['reason'] ?? '',
                     'diagnostic_code' => $fallback['diagnostic_code'] ?? '',
                     'severity'        => $fallback['severity'] ?? '',
+                    'conversion_classification' => $fallback['conversion_classification'] ?? '',
+                    'preservation_strategy' => $fallback['preservation_strategy'] ?? '',
                     'runtime_requirement' => $fallback['runtime_requirement'] ?? '',
                     'recoverability'  => $fallback['recoverability'] ?? '',
                     'actionability'   => $fallback['actionability'] ?? '',
@@ -152,6 +155,41 @@ private static function fallbackDiagnostics(array $fallbacks): array
         return $diagnostics;
     }
 
+    /**
+     * @param array<string, mixed> $sourceReports
+     * @param array<int, array<string, mixed>> $fallbacks
+     * @return array<string, mixed>
+     */
+    private static function conversionClassificationSummary(array $sourceReports, array $fallbacks): array
+    {
+        $byClassification = array();
+        $byStrategy = array();
+
+        foreach ( array_merge(self::sourceProvenance($sourceReports), self::fallbackDiagnostics($fallbacks)) as $entry ) {
+            if ( ! is_array($entry) ) {
+                continue;
+            }
+
+            $classification = (string) ($entry['conversion_classification'] ?? '');
+            if ( '' !== $classification ) {
+                $byClassification[$classification] = ($byClassification[$classification] ?? 0) + 1;
+            }
+
+            $strategy = (string) ($entry['preservation_strategy'] ?? '');
+            if ( '' !== $strategy ) {
+                $byStrategy[$strategy] = ($byStrategy[$strategy] ?? 0) + 1;
+            }
+        }
+
+        return array_filter(
+            array(
+                'by_classification' => $byClassification,
+                'by_preservation_strategy' => $byStrategy,
+            ),
+            static fn (mixed $value): bool => array() !== $value
+        );
+    }
+
     /**
      * @param array<int, array<string, mixed>> $blocks
      * @param array<string, mixed> $sourceReports
@@ -383,6 +421,8 @@ private static function appendSelector(array &$selectors, array $entry, string $
                 'block_name'  => $entry['block_name'] ?? '',
                 'tag'         => $entry['tag'] ?? ($entry['element'] ?? ''),
                 'attribute'   => $entry['attribute'] ?? '',
+                'conversion_classification' => $entry['conversion_classification'] ?? '',
+                'preservation_strategy' => $entry['preservation_strategy'] ?? '',
             ),
             static fn (mixed $value): bool => '' !== $value
         );
diff --git a/php-transformer/src/HtmlToBlocks/FallbackDiagnostic.php b/php-transformer/src/HtmlToBlocks/FallbackDiagnostic.php
index da84290c..da642311 100644
--- a/php-transformer/src/HtmlToBlocks/FallbackDiagnostic.php
+++ b/php-transformer/src/HtmlToBlocks/FallbackDiagnostic.php
@@ -26,6 +26,8 @@ private static function defaults(array $fields): array
         return match ( $code ) {
             'html_form_fallback' => array(
                 'severity'              => 'warning',
+                'conversion_classification' => 'runtime_island_preserved',
+                'preservation_strategy' => 'fallback_metadata_with_readable_blocks',
                 'runtime_requirement'   => 'server_or_client_form_handler',
                 'recoverability'        => 'recoverable_with_runtime_mapping',
                 'actionability'         => 'map_form_action_controls_and_submission_handler',
@@ -34,6 +36,8 @@ private static function defaults(array $fields): array
             ),
             'html_script_fallback' => array(
                 'severity'              => 'warning',
+                'conversion_classification' => 'runtime_island_preserved',
+                'preservation_strategy' => 'scoped_runtime_metadata',
                 'runtime_requirement'   => 'client_script_execution',
                 'recoverability'        => 'recoverable_with_script_enqueue_or_component_runtime',
                 'actionability'         => 'review_script_source_and_enqueue_or_rebuild_behavior',
@@ -42,6 +46,8 @@ private static function defaults(array $fields): array
             ),
             'html_inline_svg_fallback' => array(
                 'severity'              => 'info',
+                'conversion_classification' => 'editable_approximation',
+                'preservation_strategy' => 'sanitized_static_markup_or_image',
                 'runtime_requirement'   => 'none',
                 'recoverability'        => 'recoverable_as_static_markup_or_image_asset',
                 'actionability'         => 'review_sanitized_svg_and_materialize_as_image_or_html',
@@ -50,6 +56,8 @@ private static function defaults(array $fields): array
             ),
             'html_unsafe_inline_svg' => array(
                 'severity'              => 'warning',
+                'conversion_classification' => 'unsupported_loss',
+                'preservation_strategy' => 'diagnostic_only_until_security_review',
                 'runtime_requirement'   => 'sanitization_review',
                 'recoverability'        => 'recoverable_after_security_review',
                 'actionability'         => 'remove_scriptable_svg_content_or_replace_with_safe_asset',
@@ -58,6 +66,8 @@ private static function defaults(array $fields): array
             ),
             'html_iframe_embed_fallback' => array(
                 'severity'              => 'warning',
+                'conversion_classification' => 'runtime_island_preserved',
+                'preservation_strategy' => 'sanitized_embed_markup',
                 'runtime_requirement'   => 'third_party_embed_runtime',
                 'recoverability'        => 'recoverable_with_embed_provider_or_html_preservation',
                 'actionability'         => 'map_iframe_src_to_supported_embed_provider_or_preserve_html',
@@ -66,6 +76,8 @@ private static function defaults(array $fields): array
             ),
             'html_canvas_runtime_fallback' => array(
                 'severity'              => 'warning',
+                'conversion_classification' => 'runtime_island_preserved',
+                'preservation_strategy' => 'bounded_raw_html_runtime_island',
                 'runtime_requirement'   => 'canvas_element_and_client_script_execution',
                 'recoverability'        => 'recoverable_with_canvas_markup_preservation_or_rebuilt_interactive_block',
                 'actionability'         => 'preserve_canvas_markup_with_matching_script_runtime_or_rebuild_canvas_behavior',
@@ -74,6 +86,8 @@ private static function defaults(array $fields): array
             ),
             'html_unsupported_element' => array(
                 'severity'              => 'info',
+                'conversion_classification' => 'unsupported_loss',
+                'preservation_strategy' => 'diagnostic_only',
                 'runtime_requirement'   => 'unknown',
                 'recoverability'        => 'recoverable_with_manual_mapping',
                 'actionability'         => 'map_element_to_supported_block_or_preserve_html',
@@ -82,6 +96,8 @@ private static function defaults(array $fields): array
             ),
             default => array(
                 'severity'              => 'warning',
+                'conversion_classification' => 'unsupported_loss',
+                'preservation_strategy' => 'diagnostic_only',
                 'runtime_requirement'   => 'unknown',
                 'recoverability'        => 'unknown',
                 'actionability'         => 'review_fallback_metadata',
diff --git a/php-transformer/src/HtmlToBlocks/HtmlTransformer.php b/php-transformer/src/HtmlToBlocks/HtmlTransformer.php
index cdaf7ddb..78cf1552 100644
--- a/php-transformer/src/HtmlToBlocks/HtmlTransformer.php
+++ b/php-transformer/src/HtmlToBlocks/HtmlTransformer.php
@@ -216,6 +216,8 @@ public function transform(string $html, array $options = array()): TransformerRe
                     'source'              => self::class,
                     'reason'              => $fallback['reason'] ?? null,
                     'severity'            => $fallback['severity'] ?? null,
+                    'conversion_classification' => $fallback['conversion_classification'] ?? null,
+                    'preservation_strategy' => $fallback['preservation_strategy'] ?? null,
                     'runtime_requirement' => $fallback['runtime_requirement'] ?? null,
                     'tag'                 => $fallback['tag'] ?? null,
                     'selector'            => $fallback['selector'] ?? null,
@@ -1496,13 +1498,47 @@ private function resolveSourceProvenancePaths(array &$blocks, string $path, arra
      */
     private function sourceProvenanceEntry(string $blockName, DOMElement $element): array
     {
-        return array(
+        return array_merge(array(
             'block_name'        => $blockName,
             'tag'               => strtolower($element->tagName),
             'selector'          => $this->elementSelector($element),
             'source_attributes' => $this->safeSourceAttributes($element),
             'source_fragment'   => $this->safeSourceFragment($element),
             'context'           => $this->sourceContext($element),
+        ), $this->sourceConversionMetadata($blockName, $element));
+    }
+
+    /**
+     * @return array{conversion_classification: string, preservation_strategy: string}
+     */
+    private function sourceConversionMetadata(string $blockName, DOMElement $element): array
+    {
+        $tagName = strtolower($element->tagName);
+
+        if ( 'core/html' === $blockName ) {
+            return array(
+                'conversion_classification' => 'runtime_island_preserved',
+                'preservation_strategy'     => 'bounded_raw_html_runtime_island',
+            );
+        }
+
+        if ( $this->isRuntimeDomTarget($element) ) {
+            return array(
+                'conversion_classification' => 'runtime_island_preserved',
+                'preservation_strategy'     => 'core_block_shell_with_runtime_target',
+            );
+        }
+
+        if ( in_array($tagName, array('form', 'input', 'select', 'textarea'), true) && 'core/search' !== $blockName ) {
+            return array(
+                'conversion_classification' => 'editable_approximation',
+                'preservation_strategy'     => 'readable_static_block_approximation',
+            );
+        }
+
+        return array(
+            'conversion_classification' => 'native_block_conversion',
+            'preservation_strategy'     => 'core_block',
         );
     }
 
diff --git a/php-transformer/tests/contract/run.php b/php-transformer/tests/contract/run.php
index 75ffc3c8..22634bbe 100644
--- a/php-transformer/tests/contract/run.php
+++ b/php-transformer/tests/contract/run.php
@@ -108,9 +108,13 @@ function serialize_blocks(array $blocks): string
 $assert('image' === ($imageReferenceReports['image_references'][5]['element'] ?? ''), 'image reference analysis reports SVG image href elements');
 $assert('assets/vector.png' === ($imageReferenceReports['image_references'][5]['asset_path'] ?? ''), 'image reference analysis resolves SVG image href paths relative to the HTML document');
 
-$assertNormalizedFallbackDiagnostic = static function (array $diagnostic, string $code, string $severity, string $runtimeRequirement, string $suggestedPrimitive) use ($assert): void {
+$assertNormalizedFallbackDiagnostic = static function (array $diagnostic, string $code, string $severity, string $runtimeRequirement, string $suggestedPrimitive, string $conversionClassification = '') use ($assert): void {
     $assert($code === ($diagnostic['diagnostic_code'] ?? ''), "conversion report exposes {$code} diagnostic code");
     $assert($severity === ($diagnostic['severity'] ?? ''), "conversion report exposes {$code} severity");
+    if ( '' !== $conversionClassification ) {
+        $assert($conversionClassification === ($diagnostic['conversion_classification'] ?? ''), "conversion report exposes {$code} conversion classification");
+        $assert(isset($diagnostic['preservation_strategy']) && '' !== $diagnostic['preservation_strategy'], "conversion report exposes {$code} preservation strategy");
+    }
     $assert($runtimeRequirement === ($diagnostic['runtime_requirement'] ?? ''), "conversion report exposes {$code} runtime requirement");
     $assert(isset($diagnostic['recoverability']) && '' !== $diagnostic['recoverability'], "conversion report exposes {$code} recoverability");
     $assert(isset($diagnostic['actionability']) && '' !== $diagnostic['actionability'], "conversion report exposes {$code} actionability");
@@ -560,7 +564,7 @@ public function match(DOMElement $element, PatternContext $context): ?array
 }
 $assertNormalizedFallbackDiagnostic($diagnosticsByCode['html_unsafe_inline_svg'] ?? array(), 'html_unsafe_inline_svg', 'warning', 'sanitization_review', 'image_asset');
 $assertNormalizedFallbackDiagnostic($diagnosticsByCode['html_script_fallback'] ?? array(), 'html_script_fallback', 'warning', 'client_script_execution', 'script_asset');
-$assertNormalizedFallbackDiagnostic($diagnosticsByCode['html_canvas_runtime_fallback'] ?? array(), 'html_canvas_runtime_fallback', 'warning', 'canvas_element_and_client_script_execution', 'runtime_canvas');
+$assertNormalizedFallbackDiagnostic($diagnosticsByCode['html_canvas_runtime_fallback'] ?? array(), 'html_canvas_runtime_fallback', 'warning', 'canvas_element_and_client_script_execution', 'runtime_canvas', 'runtime_island_preserved');
 $assertNormalizedFallbackDiagnostic($diagnosticsByCode['html_iframe_embed_fallback'] ?? array(), 'html_iframe_embed_fallback', 'warning', 'third_party_embed_runtime', 'embed');
 $assert(! isset($diagnosticsByCode['html_inline_svg_fallback']), 'safe inline SVGs convert to image blocks instead of fallback diagnostics');
 
@@ -568,7 +572,7 @@ public function match(DOMElement $element, PatternContext $context): ?array
     '<main><canvas id="bonsai" class="stage" width="640" height="360">Fallback</canvas><script src="/js/script.js"></script></main>'
 )->toArray();
 $canvasDiagnostic = $canvasFallback['source_reports']['conversion_report']['fallback_diagnostics'][0] ?? array();
-$assertNormalizedFallbackDiagnostic($canvasDiagnostic, 'html_canvas_runtime_fallback', 'warning', 'canvas_element_and_client_script_execution', 'runtime_canvas');
+$assertNormalizedFallbackDiagnostic($canvasDiagnostic, 'html_canvas_runtime_fallback', 'warning', 'canvas_element_and_client_script_execution', 'runtime_canvas', 'runtime_island_preserved');
 $assert('canvas_requires_runtime' === ($canvasDiagnostic['reason'] ?? ''), 'canvas fallback exposes runtime-specific reason');
 $assert('bonsai' === ($canvasFallback['fallbacks'][0]['attributes']['id'] ?? ''), 'canvas fallback preserves id for runtime mapping');
 $assert(str_contains((string) ($canvasFallback['fallbacks'][0]['html'] ?? ''), '<canvas id="bonsai"'), 'canvas fallback preserves bounded safe canvas markup');
@@ -576,6 +580,30 @@ public function match(DOMElement $element, PatternContext $context): ?array
 $assert(! str_contains((string) ($canvasFallback['serialized_blocks'] ?? ''), '<!-- wp:html'), 'canvas fallback does not emit core/html');
 $assert(! str_contains((string) ($canvasFallback['serialized_blocks'] ?? ''), '<canvas'), 'canvas fallback does not smuggle raw canvas markup into generated core blocks');
 
+$runtimePreserved = ( new HtmlTransformer() )->transform(
+    '<main><canvas id="stage" aria-hidden="true"></canvas><input id="amount" value="10"></main>',
+    array(
+        'runtime_canvas_selectors' => array('#stage'),
+        'runtime_dom_selectors'    => array('#amount'),
+    )
+)->toArray();
+$runtimeSelectors = $runtimePreserved['source_reports']['conversion_report']['selector_summary']['selectors'] ?? array();
+$runtimeClassifications = array();
+foreach ( $runtimeSelectors as $selector ) {
+    if ( 'block' === ($selector['kind'] ?? '') && 'core/html' === ($selector['block_name'] ?? '') ) {
+        $runtimeClassifications[$selector['tag'] ?? ''] = $selector['conversion_classification'] ?? '';
+    }
+}
+$assert('runtime_island_preserved' === ($runtimeClassifications['canvas'] ?? ''), 'runtime-preserved canvas core/html block is classified as runtime island preservation');
+$assert('runtime_island_preserved' === ($runtimeClassifications['input'] ?? ''), 'runtime-preserved control core/html block is classified as runtime island preservation');
+$runtimeSummary = $runtimePreserved['source_reports']['conversion_report']['conversion_classification_summary']['by_classification'] ?? array();
+$assert(2 <= ($runtimeSummary['runtime_island_preserved'] ?? 0), 'conversion report summarizes runtime island preservation counts');
+
+$unsupportedLoss = ( new HtmlTransformer() )->transform('<main><applet code="clock.class"></applet></main>')->toArray();
+$unsupportedDiagnostic = $unsupportedLoss['source_reports']['conversion_report']['fallback_diagnostics'][0] ?? array();
+$assert('html_unsupported_element' === ($unsupportedDiagnostic['diagnostic_code'] ?? ''), 'unsupported element emits fallback diagnostic');
+$assert('unsupported_loss' === ($unsupportedDiagnostic['conversion_classification'] ?? ''), 'true unsupported fallback is classified as unsupported loss');
+
 $decorativeCanvas = ( new HtmlTransformer() )->transform(
     '<main><section class="hero"><canvas id="stars" aria-hidden="true"></canvas><h1>Stars</h1></section></main>',
     array(