diff --git a/.github/actions/detect-file-changes/action.yml b/.github/actions/detect-file-changes/action.yml
index 6d3e19bbe..9c5cb25d4 100644
--- a/.github/actions/detect-file-changes/action.yml
+++ b/.github/actions/detect-file-changes/action.yml
@@ -13,5 +13,5 @@ runs:
   using: "node20"
   main: "detect-file-changes.js"
 outputs:
-  changes_detected:
+  changed:
     description: "Returns `true` if any changed file matches the specified patterns, `false` otherwise."
diff --git a/.github/workflows/index-file-validation.yml b/.github/workflows/index-file-validation.yml
new file mode 100644
index 000000000..cea5fe7bb
--- /dev/null
+++ b/.github/workflows/index-file-validation.yml
@@ -0,0 +1,114 @@
+name: "Validate index.json files"
+
+on:
+  pull_request:
+
+jobs:
+  validate-json:
+    name: "📋 Validate changed JSON files"
+    runs-on: ubuntu-22.04
+    timeout-minutes: 10
+
+    steps:
+      - name: "☁️ Checkout repository"
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+
+      - name: "🔎 Detect relevant file changes"
+        id: filter
+        uses: ./.github/actions/detect-file-changes
+        with:
+          file-patterns: |
+            - 'metadata/index.json'
+            - 'metadata/*/*/index.json'
+            - 'tests/src/index.json'
+            - 'tests/src/*/*/*/index.json'
+
+      - name: "🔧 Setup Java"
+        if: steps.filter.outputs.changed == 'true'
+        uses: actions/setup-java@v4
+        with:
+          distribution: 'graalvm'
+          java-version: '21'
+
+      - name: "🕸️ Populate matrix"
+        id: set-matrix
+        if: steps.filter.outputs.changed == 'true'
+        run: |
+          ./gradlew generateChangedIndexFileMatrix -PbaseCommit=${{ github.event.pull_request.base.sha }} -PnewCommit=${{ github.event.pull_request.head.sha }}
+
+          echo "Matrix output:"
+          echo "${{ steps.set-matrix.outputs.matrix }}"
+
+      - name: "Setup Python"
+        if: steps.filter.outputs.changed == 'true'
+        uses: actions/setup-python@v4
+        with:
+          python-version: '3.10'
+
+      - name: "Install validation tools"
+        if: steps.filter.outputs.changed == 'true'
+        run: |
+          pip install jq check-jsonschema
+
+      - name: "Check that the changed index.json files conform to their schemas"
+        if: steps.filter.outputs.changed == 'true'
+        run: |
+          set -euo pipefail
+
+          MATRIX='${{ steps.set-matrix.outputs.matrix }}'
+          
+          # Convert matrix JSON into an array of file paths
+          FILES=($(echo "$MATRIX" | jq -r '.index_files[]'))
+
+          if [ ${#FILES[@]} -eq 0 ]; then
+            echo "No changed index.json files to validate."
+            exit 0
+          fi
+          
+          # Track failures
+          FAILURES=()
+          
+          for FILE in "${FILES[@]}"; do
+          
+            # Determine schema for each file
+            if [[ "$FILE" == "metadata/index.json" ]]; then
+              SCHEMA="schemas/metadata-root-index-schema-v1.0.0.json"
+            elif [[ "$FILE" == metadata/*/*/index.json ]]; then
+              SCHEMA="schemas/metadata-library-index-schema-v1.0.0.json"
+            elif [[ "$FILE" == "tests/src/index.json" ]]; then
+              SCHEMA="schemas/tests-root-index-schema-v1.0.0.json"
+            elif [[ "$FILE" == tests/src/*/*/*/index.json ]]; then
+              SCHEMA="schemas/tests-project-index-schema-v1.0.0.json"
+            else
+              echo "ℹ️ Skipping: $FILE (no schema mapping)"
+              continue
+            fi
+          
+            echo "🔍 Validating $FILE using $SCHEMA"
+          
+            # Step 1: Check JSON well-formedness
+            if ! jq -e . "$FILE" >/dev/null; then
+              echo "❌ $FILE is not valid JSON"
+              FAILURES+=("$FILE (invalid JSON)")
+              continue
+            fi
+          
+            # Step 2: Validate against schema
+            if ! check-jsonschema --schemafile "$SCHEMA" "$FILE"; then
+              FAILURES+=("$FILE (schema failure)")
+              continue
+            fi
+          
+            echo "✅ $FILE validated successfully"
+          done
+          
+          # Fail at the end if any errors occurred
+          if [ ${#FAILURES[@]} -ne 0 ]; then
+            echo "::error ::Some files failed validation:"
+          for f in "${FAILURES[@]}"; do
+            echo "::error ::  $f"
+          done
+            exit 1
+          fi
diff --git a/.github/workflows/library-and-framework-list-validation.yml b/.github/workflows/library-and-framework-list-validation.yml
index 70343b417..703d5764e 100644
--- a/.github/workflows/library-and-framework-list-validation.yml
+++ b/.github/workflows/library-and-framework-list-validation.yml
@@ -17,7 +17,8 @@ jobs:
         uses: ./.github/actions/detect-file-changes
         with:
           file-patterns: |
-            - 'library-and-framework-list*.json'
+            - 'library-and-framework-list.json'
+            - 'schemas/library-and-framework-list-schema*.json'
 
       - uses: actions/setup-python@v4
         with:
@@ -43,4 +44,4 @@ jobs:
         if: steps.filter.outputs.changed == 'true'
         run: |
           pip install check-jsonschema
-          check-jsonschema --schemafile library-and-framework-list-schema.json library-and-framework-list.json
+          check-jsonschema --schemafile schemas/library-and-framework-list-schema-v1.0.0.json library-and-framework-list.json
diff --git a/build.gradle b/build.gradle
index abd10a873..c2fc5b6b8 100644
--- a/build.gradle
+++ b/build.gradle
@@ -99,10 +99,17 @@ tasks.register('package', Zip) { task ->
     task.destinationDirectory = layout.buildDirectory
 
     from(tck.metadataRoot)
-    // library-and-framework-list.json is used by Native Build Tools to provide additional
-    // information on library and framework support to the native image Build Report
+
     from(project.rootDir) {
+        // library-and-framework-list.json is used by Native Build Tools to provide additional
+        // information on library and framework support to the native image Build Report
         include("library-and-framework-list.json")
+
+        // Schemas are included in the ZIP root to allow Native Build Tools to verify
+        // structural compatibility with this release of GraalVM Reachability Metadata
+        include("schemas/metadata-root-index-schema-v1.0.0.json")
+        include("schemas/metadata-library-index-schema-v1.0.0.json")
+        include("schemas/library-and-framework-list-schema-v1.0.0.json")
     }
 }
 
diff --git a/ci.json b/ci.json
index 24aad6e87..8a7c2d905 100644
--- a/ci.json
+++ b/ci.json
@@ -15,5 +15,9 @@
   "generateMatrixMatchingCoordinates": {
     "java": ["25","latest-ea"],
     "os": ["ubuntu-latest"]
+  },
+  "generateChangedIndexFileMatrix": {
+    "java": ["latest-ea"],
+    "os": ["ubuntu-latest"]
   }
 }
diff --git a/docs/CONTRIBUTING.md b/docs/CONTRIBUTING.md
index f52b8d6b0..c803a4afe 100644
--- a/docs/CONTRIBUTING.md
+++ b/docs/CONTRIBUTING.md
@@ -344,4 +344,4 @@ Where:
 
 **Note:** To pass format and style checks, please run `sorted="$(jq -s '.[] | sort_by(.artifact)' library-and-framework-list.json)" && echo -E "${sorted}" > library-and-framework-list.json` before submitting a PR.
 
-**Note:** The entries you add will be validated against [library-and-framework-list-schema.json](https://github.com/oracle/graalvm-reachability-metadata/blob/master/library-and-framework-list-schema.json)
+**Note:** The entries you add will be validated against [library-and-framework-list-schema-v1.0.0.json](https://github.com/oracle/graalvm-reachability-metadata/blob/master/schemas/library-and-framework-list-schema-v1.0.0.json)
diff --git a/library-and-framework-list-schema.json b/schemas/library-and-framework-list-schema-v1.0.0.json
similarity index 100%
rename from library-and-framework-list-schema.json
rename to schemas/library-and-framework-list-schema-v1.0.0.json
diff --git a/schemas/metadata-library-index-schema-v1.0.0.json b/schemas/metadata-library-index-schema-v1.0.0.json
new file mode 100644
index 000000000..1e09a68f2
--- /dev/null
+++ b/schemas/metadata-library-index-schema-v1.0.0.json
@@ -0,0 +1,100 @@
+{
+  "$id": "https://github.com/oracle/graalvm-reachability-metadata/schemas/metadata-library-index.schema.json",
+  "$schema": "https://json-schema.org/draft/2020-12/schema",
+  "description": "Schema for metadata/<groupId>/<artifactId>/index.json. Each entry describes a metadata bundle for a range of library versions.",
+  "type": "array",
+  "minItems": 1,
+  "items": {
+    "type": "object",
+    "additionalProperties": false,
+    "required": [
+      "module",
+      "metadata-version",
+      "tested-versions"
+    ],
+    "properties": {
+      "module": {
+        "$ref": "#/$defs/moduleCoordinate",
+        "description": "Maven coordinates in the form '<groupId>:<artifactId>'."
+      },
+      "metadata-version": {
+        "type": "string",
+        "minLength": 1,
+        "description": "Subdirectory name where the metadata files for this entry reside, e.g. '7.1.0.Final'."
+      },
+      "tested-versions": {
+        "type": "array",
+        "description": "Explicitly tested upstream library versions that this metadata is known to support.",
+        "minItems": 1,
+        "uniqueItems": true,
+        "items": {
+          "type": "string",
+          "minLength": 1
+        }
+      },
+      "latest": {
+        "type": "boolean",
+        "description": "Marks this entry as the latest/default metadata for currently supported versions."
+      },
+      "default-for": {
+        "type": "string",
+        "description": "Java regular expression describing the version range for which this entry should be used by default (e.g. '7\\\\.1\\\\..*')."
+      },
+      "override": {
+        "type": "boolean",
+        "description": "When true, expresses the intent to exclude outdated built-in metadata shipped with Native Image for the matched versions."
+      },
+      "skipped-versions": {
+        "type": "array",
+        "description": "Versions explicitly excluded from support, each with a reason.",
+        "minItems": 1,
+        "items": {
+          "type": "object",
+          "additionalProperties": false,
+          "required": [ "version", "reason" ],
+          "properties": {
+            "version": {
+              "type": "string",
+              "minLength": 1
+            },
+            "reason": {
+              "type": "string",
+              "minLength": 1
+            }
+          }
+        }
+      }
+    }
+  },
+  "$defs": {
+    "moduleCoordinate": {
+      "type": "string",
+      "pattern": "^[^:]+:[^:]+$"
+    }
+  },
+  "examples": [
+    [
+      {
+        "metadata-version": "0.0.1",
+        "module": "org.example:library",
+        "tested-versions": [ "0.0.1", "0.0.2" ],
+        "default-for": "0\\.0\\..*"
+      },
+      {
+        "latest": true,
+        "metadata-version": "1.0.0",
+        "module": "org.example:library",
+        "tested-versions": [ "1.0.0", "1.1.0-M1", "1.1.0" ]
+      },
+      {
+        "metadata-version": "1.19.0",
+        "module": "io.opentelemetry:opentelemetry-exporter-logging",
+        "tested-versions": [ "1.19.0" ],
+        "override": true,
+        "skipped-versions": [
+          { "version": "1.0.5", "reason": "Known incompatible API change." }
+        ]
+      }
+    ]
+  ]
+}
diff --git a/schemas/metadata-root-index-schema-v1.0.0.json b/schemas/metadata-root-index-schema-v1.0.0.json
new file mode 100644
index 000000000..0a5703ec3
--- /dev/null
+++ b/schemas/metadata-root-index-schema-v1.0.0.json
@@ -0,0 +1,67 @@
+{
+  "$id": "https://github.com/oracle/graalvm-reachability-metadata/schemas/metadata-root-index.schema.json",
+  "$schema": "https://json-schema.org/draft/2020-12/schema",
+  "description": "Schema for metadata/index.json. This file lists modules known to the repository and optionally the directory where their metadata is stored, the allowed package prefixes for metadata, and inter-module requirements. See docs/CONTRIBUTING.md (Metadata structure).",
+  "type": "array",
+  "items": {
+    "type": "object",
+    "additionalProperties": false,
+    "required": ["module"],
+    "properties": {
+      "module": {
+        "$ref": "#/$defs/moduleCoordinate",
+        "description": "Maven coordinates for the module in the form '<groupId>:<artifactId>'."
+      },
+      "directory": {
+        "type": "string",
+        "minLength": 1,
+        "pattern": "^[^\\s].*$",
+        "description": "Repository-relative path under 'metadata/' containing this module's metadata (e.g. 'org.example/library'). If omitted, the entry may reference requirements only."
+      },
+      "allowed-packages": {
+        "type": "array",
+        "description": "List of package (or fully-qualified name) prefixes considered valid sources of metadata entries for this module. Used to filter-in relevant JSON entries.",
+        "minItems": 1,
+        "uniqueItems": true,
+        "items": {
+          "type": "string",
+          "minLength": 1
+        }
+      },
+      "requires": {
+        "type": "array",
+        "description": "Optional list of module coordinates this module depends on. Each item is '<groupId>:<artifactId>'.",
+        "minItems": 1,
+        "uniqueItems": true,
+        "items": {
+          "$ref": "#/$defs/moduleCoordinate"
+        }
+      }
+    }
+  },
+  "$defs": {
+    "moduleCoordinate": {
+      "type": "string",
+      "pattern": "^[^:]+:[^:]+$"
+    }
+  },
+  "examples": [
+    [
+      {
+        "directory": "org.example/library",
+        "module": "org.example:library"
+      },
+      {
+        "allowed-packages": ["org.package.name"],
+        "module": "org.example:dependant-library",
+        "requires": ["org.example:library"]
+      },
+      {
+        "allowed-packages" : [ "org.hibernate", "jakarta" ],
+        "directory" : "org.hibernate.orm/hibernate-envers",
+        "module" : "org.hibernate.orm:hibernate-envers",
+        "requires" : [ "org.hibernate.orm:hibernate-core" ]
+      }
+    ]
+  ]
+}
diff --git a/schemas/tests-project-index-schema-v1.0.0.json b/schemas/tests-project-index-schema-v1.0.0.json
new file mode 100644
index 000000000..089ec5720
--- /dev/null
+++ b/schemas/tests-project-index-schema-v1.0.0.json
@@ -0,0 +1,30 @@
+{
+  "$id": "https://github.com/oracle/graalvm-reachability-metadata/docs/schemas/tests-project-index-schema-v1.0.0.json",
+  "$schema": "https://json-schema.org/draft/2020-12/schema",
+  "title": "Test Project Index",
+  "description": "Schema for tests/src/<groupId>/<artifactId>/<version>/index.json. This file optionally customizes the test invocation via 'test-command'. If omitted or if the property is not present, a default command will be used (gradlew nativeTest with environment overrides) per TestInvocationTask.",
+  "type": "object",
+  "additionalProperties": false,
+  "properties": {
+    "test-command": {
+      "type": "array",
+      "description": "Command line to run for this test project. Supports template parameters: <metadata_dir>, <group_id>, <artifact_id>, <version>.",
+      "minItems": 1,
+      "items": {
+        "type": "string",
+        "minLength": 1,
+        "description": "Part of the command line. May include template parameters like <metadata_dir>, <group_id>, <artifact_id>, <version>."
+      }
+    }
+  },
+  "examples": [
+    {
+      "test-command": [
+        "gradle",
+        "nativeTest",
+        "-Pmetadata.dir=<metadata_dir>",
+        "-Plibrary.version=<version>"
+      ]
+    }
+  ]
+}
diff --git a/schemas/tests-root-index-schema-v1.0.0.json b/schemas/tests-root-index-schema-v1.0.0.json
new file mode 100644
index 000000000..8e6050987
--- /dev/null
+++ b/schemas/tests-root-index-schema-v1.0.0.json
@@ -0,0 +1,74 @@
+{
+  "$id": "https://github.com/oracle/graalvm-reachability-metadata/docs/schemas/tests-root-index-schema-v1.0.0.json",
+  "$schema": "https://json-schema.org/draft/2020-12/schema",
+  "title": "Tests Root Index",
+  "description": "Schema for tests/src/index.json mapping test projects to libraries and versions (see docs/CONTRIBUTING.md).",
+  "type": "array",
+  "minItems": 1,
+  "items": {
+    "type": "object",
+    "additionalProperties": false,
+    "required": [ "test-project-path", "libraries" ],
+    "properties": {
+      "test-project-path": {
+        "type": "string",
+        "minLength": 1,
+        "pattern": "^[^\\s/]+/[^\\s/]+/[^\\s/]+$",
+        "description": "Path under tests/src: <groupId>/<artifactId>/<version> (e.g. 'org.hibernate.orm/hibernate-core/7.1.0.Final')."
+      },
+      "libraries": {
+        "type": "array",
+        "minItems": 1,
+        "items": {
+          "type": "object",
+          "additionalProperties": false,
+          "required": [ "name", "versions" ],
+          "properties": {
+            "name": {
+              "type": "string",
+              "pattern": "^[^:]+:[^:]+$",
+              "description": "Library coordinates in the form '<groupId>:<artifactId>' (e.g. 'org.hibernate.orm:hibernate-core')."
+            },
+            "versions": {
+              "type": "array",
+              "minItems": 1,
+              "uniqueItems": true,
+              "items": {
+                "type": "string",
+                "minLength": 1
+              },
+              "description": "List of library versions covered by this test project (strings as published upstream, e.g. '1.1.0', '7.1.0.Final')."
+            }
+          }
+        },
+        "description": "Libraries covered by this test project path with the versions to run."
+      }
+    }
+  },
+  "examples": [
+    [
+      {
+        "test-project-path": "org.example/library/0.0.1",
+        "libraries": [
+          {
+            "name": "org.example:library",
+            "versions": [
+              "0.0.1"
+            ]
+          }
+        ]
+      },
+      {
+        "test-project-path" : "org.hibernate.orm/hibernate-core/7.1.0.Final",
+        "libraries" : [
+          {
+            "name" : "org.hibernate.orm:hibernate-core",
+            "versions" : [
+              "7.1.0.Final"
+            ]
+          }
+        ]
+      }
+    ]
+  ]
+}
diff --git a/tests/tck-build-logic/src/main/groovy/org.graalvm.internal.tck-harness.gradle b/tests/tck-build-logic/src/main/groovy/org.graalvm.internal.tck-harness.gradle
index 05a9eaaf9..513d6144e 100644
--- a/tests/tck-build-logic/src/main/groovy/org.graalvm.internal.tck-harness.gradle
+++ b/tests/tck-build-logic/src/main/groovy/org.graalvm.internal.tck-harness.gradle
@@ -150,6 +150,13 @@ if (project.hasProperty("baseCommit")) {
     }
 }
 
+List<String> diffIndexFiles = new ArrayList<>()
+if (project.hasProperty("baseCommit")) {
+    String baseCommit = project.findProperty("baseCommit")
+    String newCommit = Objects.requireNonNullElse(project.findProperty("newCommit"), "HEAD")
+    diffIndexFiles.addAll(tck.diffIndexFiles(baseCommit, newCommit))
+}
+
 Map<String, Object> loadCi() {
     File f = project.file("ci.json")
     if (!f.exists()) {
@@ -223,6 +230,32 @@ Provider<Task> generateChangedCoordinatesMatrix = tasks.register("generateChange
     }
 }
 
+// gradle generateChangedIndexFileMatrix -PbaseCommit=<base-commit> -PnewCommit=<new-commit>
+Provider<Task> generateChangedIndexFileMatrix = tasks.register("generateChangedIndexFileMatrix", DefaultTask) { task ->
+    task.setDescription("Returns matrix definition populated with changed index.json files")
+    task.setGroup(METADATA_GROUP)
+
+    task.doFirst {
+        if (!project.hasProperty("baseCommit")) {
+            throw new GradleException("Missing 'baseCommit' property! Rerun Gradle with '-PbaseCommit=<commit-hash>'")
+        }
+
+        boolean noneFound = diffIndexFiles.isEmpty()
+
+        def matrix = [
+                "index_files": noneFound ? [] : diffIndexFiles
+        ]
+        matrix.putAll(matrixDefaultsFor("generateChangedIndexFileMatrix"))
+
+        if (noneFound) {
+            println "No changed index.json files were found!"
+        }
+
+        writeGithubOutput("matrix", JsonOutput.toJson(matrix))
+        writeGithubOutput("none-found", noneFound.toString())
+    }
+}
+
 // gradle generateInfrastructureChangedCoordinatesMatrix -PbaseCommit=<base-commit> -PnewCommit=<new-commit>
 Provider<Task> generateInfrastructureChangedCoordinatesMatrix = tasks.register("generateInfrastructureChangedCoordinatesMatrix", DefaultTask) { task ->
     task.setDescription("Returns matrix definition populated with pre-selected coordinates when test infrastructure has changed")
diff --git a/tests/tck-build-logic/src/main/groovy/org/graalvm/internal/tck/harness/TckExtension.java b/tests/tck-build-logic/src/main/groovy/org/graalvm/internal/tck/harness/TckExtension.java
index c62423971..cb34d8c1e 100644
--- a/tests/tck-build-logic/src/main/groovy/org/graalvm/internal/tck/harness/TckExtension.java
+++ b/tests/tck-build-logic/src/main/groovy/org/graalvm/internal/tck/harness/TckExtension.java
@@ -184,6 +184,28 @@ List<String> diffCoordinates(String baseCommit, String newCommit) {
         return changedCoordinates;
     }
 
+    /**
+     * Returns a list of changed index.json files between baseCommit and newCommit.
+     *
+     * @return List of index.json files
+     */
+    public List<String> diffIndexFiles(String baseCommit, String newCommit) {
+        ByteArrayOutputStream baos = new ByteArrayOutputStream();
+        getExecOperations().exec(spec -> {
+            spec.setStandardOutput(baos);
+            spec.commandLine("git", "diff", "--name-only", "--diff-filter=ACMRT",
+                    baseCommit, newCommit);
+        });
+
+        String output = baos.toString(StandardCharsets.UTF_8);
+        List<String> diffFiles = Arrays.asList(output.split("\\r?\\n"));
+
+        return diffFiles.stream()
+                .filter(f -> f.endsWith("index.json"))
+                .distinct()
+                .collect(Collectors.toList());
+    }
+
     private boolean metadataIndexContainsChangedEntries(Set<String> changedCoordinates, List<String> changedEntries) {
         boolean containsAll = true;
         for (var n : changedEntries) {