feat: add sanitize command to remove extensions and clean OpenAPI specs

.github/workflows/ci.yaml

@@ -166,6 +166,10 @@ jobs:
           timeout 300 go test -coverprofile=main-coverage.out -covermode=atomic ./... > /dev/null 2>&1 || echo "Main branch tests failed or timed out"
 
           if [ -f main-coverage.out ]; then
+            # Filter out cmd and tests folders from main branch coverage (same as current branch)
+            grep -v -E '/cmd/|/tests/' main-coverage.out > main-coverage.filtered.out || true
+            mv main-coverage.filtered.out main-coverage.out
+
             MAIN_COVERAGE=$(go tool cover -func=main-coverage.out | grep total | awk '{print $3}' || echo "0.0%")
             echo "main-coverage=$MAIN_COVERAGE" >> $GITHUB_OUTPUT
             echo "Main branch coverage: $MAIN_COVERAGE"

marshaller/coremodel.go

@@ -24,13 +24,16 @@ type CoreModeler interface {
 	SetConfig(config *yml.Config)
 	GetConfig() *yml.Config
 	Marshal(ctx context.Context, w io.Writer) error
+	SetUnknownProperties(props []string)
+	GetUnknownProperties() []string
 }
 
 type CoreModel struct {
-	RootNode  *yaml.Node  // RootNode is the node that was unmarshaled into this model
-	Valid     bool        // Valid indicates whether the model passed validation, ie all its required fields were present and ValidYaml is true
-	ValidYaml bool        // ValidYaml indicates whether the model's underlying YAML representation is valid, for example a mapping node was received for a model
-	Config    *yml.Config // Generally only set on the top-level model that was unmarshaled
+	RootNode          *yaml.Node  // RootNode is the node that was unmarshaled into this model
+	Valid             bool        // Valid indicates whether the model passed validation, ie all its required fields were present and ValidYaml is true
+	ValidYaml         bool        // ValidYaml indicates whether the model's underlying YAML representation is valid, for example a mapping node was received for a model
+	Config            *yml.Config // Generally only set on the top-level model that was unmarshaled
+	UnknownProperties []string    // UnknownProperties lists property keys that were present in the YAML but not defined in the model (excludes extensions which start with "x-")
 }
 
 var _ CoreModeler = (*CoreModel)(nil)
@@ -86,6 +89,18 @@ func (c *CoreModel) GetConfig() *yml.Config {
 	return c.Config
 }
 
+func (c *CoreModel) SetUnknownProperties(props []string) {
+	c.UnknownProperties = props
+}
+
+func (c *CoreModel) GetUnknownProperties() []string {
+	if c.UnknownProperties == nil {
+		return []string{}
+	}
+
+	return c.UnknownProperties
+}
+
 // GetJSONPointer returns the JSON pointer path from the topLevelRootNode to this CoreModel's RootNode.
 // Returns an empty string if the node is not found or if either node is nil.
 // The returned pointer follows RFC6901 format (e.g., "/path/to/node").

marshaller/unmarshaller.go

@@ -347,6 +347,10 @@ func unmarshalModel(ctx context.Context, parentName string, node *yaml.Node, str
 
 	jobValidationErrs := make([][]error, numJobs)
 
+	// Track unknown properties (non-extension, non-field, non-embedded map properties)
+	var unknownPropertiesMutex sync.Mutex
+	var unknownProperties []string
+
 	// Mutex to protect concurrent access to extensionsField
 	var extensionsMutex sync.Mutex
 
@@ -363,15 +367,16 @@ func unmarshalModel(ctx context.Context, parentName string, node *yaml.Node, str
 			// Direct field index lookup (eliminates map[string]Field allocation)
 			fieldIndex, ok := fieldMap.FieldIndexes[key]
 			if !ok {
-				if strings.HasPrefix(key, "x-") && extensionsField != nil {
+				switch {
+				case strings.HasPrefix(key, "x-") && extensionsField != nil:
 					// Lock access to extensionsField to prevent concurrent modification
 					extensionsMutex.Lock()
 					defer extensionsMutex.Unlock()
 					err := UnmarshalExtension(keyNode, valueNode, *extensionsField)
 					if err != nil {
 						return err
 					}
-				} else if embeddedMap != nil {
+				case embeddedMap != nil:
 					// Skip alias definitions - these are nodes where:
 					// 1. The value node has an anchor (e.g., &keyAlias)
 					// 2. The key is not an alias reference (doesn't start with *)
@@ -381,6 +386,11 @@ func unmarshalModel(ctx context.Context, parentName string, node *yaml.Node, str
 						return nil
 					}
 					jobMapContent[i/2] = append(jobMapContent[i/2], keyNode, valueNode)
+				default:
+					// This is an unknown property (not a recognized field, not an extension, not in embedded map)
+					unknownPropertiesMutex.Lock()
+					unknownProperties = append(unknownProperties, key)
+					unknownPropertiesMutex.Unlock()
 				}
 			} else {
 				// Get field info from cache and field value directly
@@ -438,6 +448,11 @@ func unmarshalModel(ctx context.Context, parentName string, node *yaml.Node, str
 		validationErrs = append(validationErrs, embeddedMapValidationErrs...)
 	}
 
+	// Store unknown properties in the core model if any were found
+	if len(unknownProperties) > 0 {
+		unmarshallable.SetUnknownProperties(unknownProperties)
+	}
+
 	// Use the errors to determine the validity of the model
 	unmarshallable.DetermineValidity(validationErrs)
 

mise-tasks/test-cli

@@ -26,6 +26,7 @@ $CLI spec validate --help > /dev/null
 $CLI spec upgrade --help > /dev/null
 $CLI spec inline --help > /dev/null
 $CLI spec clean --help > /dev/null
+$CLI spec sanitize --help > /dev/null
 $CLI spec bundle --help > /dev/null
 $CLI spec join --help > /dev/null
 $CLI spec bootstrap --help > /dev/null
@@ -122,6 +123,23 @@ if ! diff -q dist/test/test-cleaned-empty.yaml openapi/testdata/clean/clean_empt
     exit 1
 fi
 
+# Test sanitize command with known test files
+echo "  ✓ Testing sanitize command..."
+$CLI spec sanitize openapi/testdata/sanitize/sanitize_input.yaml dist/test/test-sanitized.yaml > /dev/null
+$CLI spec sanitize --config openapi/testdata/sanitize/sanitize_pattern_config.yaml openapi/testdata/sanitize/sanitize_pattern_input.yaml dist/test/test-sanitized-pattern.yaml > /dev/null
+
+# Compare sanitize outputs with expected
+echo "  ✓ Comparing sanitize outputs with expected..."
+if ! diff -q dist/test/test-sanitized.yaml openapi/testdata/sanitize/sanitize_expected.yaml > /dev/null; then
+    echo "    ❌ Sanitize output differs from expected"
+    exit 1
+fi
+
+if ! diff -q dist/test/test-sanitized-pattern.yaml openapi/testdata/sanitize/sanitize_pattern_expected.yaml > /dev/null; then
+    echo "    ❌ Sanitize pattern output differs from expected"
+    exit 1
+fi
+
 # Test join command with known test files
 echo "  ✓ Testing join command..."
 $CLI spec join openapi/testdata/join/main.yaml openapi/testdata/join/subdir/second.yaml openapi/testdata/join/third.yaml dist/test/test-joined-counter.yaml > /dev/null
@@ -161,6 +179,8 @@ $CLI spec validate dist/test/test-joined-counter.yaml > /dev/null
 $CLI spec validate dist/test/test-joined-filepath.yaml > /dev/null
 $CLI spec validate dist/test/test-cleaned.yaml > /dev/null
 $CLI spec validate dist/test/test-cleaned-empty.yaml > /dev/null
+$CLI spec validate dist/test/test-sanitized.yaml > /dev/null
+$CLI spec validate dist/test/test-sanitized-pattern.yaml > /dev/null
 $CLI spec validate dist/test/test-joined-conflicts.yaml > /dev/null
 
 # Test arazzo validation with known test files
@@ -232,7 +252,7 @@ echo "✅ All CLI integration tests passed!"
 echo "📊 Test summary:"
 echo "   - Tested all command help outputs"
 echo "   - Validated known good and bad files"
-echo "   - Tested bootstrap, upgrade, inline, clean, bundle, join commands"
+echo "   - Tested bootstrap, upgrade, inline, clean, sanitize, bundle, join commands"
 echo "   - Compared outputs with expected results"
 echo "   - Tested arazzo validation"
 echo "   - Tested overlay validation, apply, and compare"

mise-tasks/test-coverage

@@ -7,6 +7,14 @@ if ! gotestsum --format testname -- -race -coverprofile=coverage.out -covermode=
     exit 1
 fi
 
+# Filter out cmd and tests folders from coverage report
+if [ -f coverage.out ]; then
+    echo "🔧 Filtering cmd and tests folders from coverage report..."
+    grep -v -E '/cmd/|/tests/' coverage.out > coverage.filtered.out || true
+    # Keep original for reference, use filtered for reporting
+    mv coverage.filtered.out coverage.out
+fi
+
 echo ""
 echo "## 📊 Test Coverage Report"
 echo ""

openapi/cmd/README.md

@@ -12,6 +12,7 @@ OpenAPI specifications define REST APIs in a standard format. These commands hel
   - [`upgrade`](#upgrade)
   - [`inline`](#inline)
   - [`clean`](#clean)
+  - [`sanitize`](#sanitize)
   - [`bundle`](#bundle)
     - [Bundle vs Inline](#bundle-vs-inline)
   - [`join`](#join)
@@ -216,6 +217,166 @@ components:
 - You're preparing a specification for publication or distribution
 - You want to reduce document size and complexity
 - You're maintaining a large specification with many components
+
+### `sanitize`
+
+Remove unwanted elements from an OpenAPI specification to create clean, standards-compliant documents.
+
+```bash
+# Default sanitization (remove all extensions and unused components)
+openapi spec sanitize ./spec.yaml
+
+# Sanitize and write to new file
+openapi spec sanitize ./spec.yaml ./clean-spec.yaml
+
+# Sanitize in-place
+openapi spec sanitize -w ./spec.yaml
+
+# Use config file for selective sanitization
+openapi spec sanitize --config sanitize-config.yaml ./spec.yaml
+```
+
+**Default Behavior (no config):**
+
+By default, sanitize performs aggressive cleanup:
+
+- Removes ALL x-* vendor extensions throughout the document
+- Removes unused components (schemas, responses, parameters, etc.)
+- Removes unknown properties not defined in the OpenAPI specification
+
+**Configuration File Support:**
+
+Create a YAML configuration file to control sanitization behavior:
+
+```yaml
+# sanitize-config.yaml
+
+# Remove only specific extension patterns (if not set, removes ALL extensions)
+extensionPatterns:
+  - "x-go-*"
+  - "x-internal-*"
+
+# Keep unused components (default: false, removes them)
+keepUnusedComponents: true
+
+# Keep unknown properties (default: false, removes them)
+keepUnknownProperties: true
+```
+
+**What gets sanitized:**
+
+- **Extensions**: All x-* vendor extensions (info, paths, operations, schemas, etc.)
+- **Unused Components**: Schemas, responses, parameters, examples, request bodies, headers, security schemes, links, callbacks, and path items that aren't referenced
+- **Unknown Properties**: Properties not defined in the OpenAPI specification
+
+**Before sanitization:**
+
+```yaml
+openapi: 3.1.0
+info:
+  title: My API
+  version: 1.0.0
+  x-api-id: internal-123
+  x-go-package: myapi
+paths:
+  /users:
+    get:
+      operationId: listUsers
+      x-go-name: ListUsers
+      x-rate-limit: 100
+      responses:
+        '200':
+          description: Success
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/User'
+components:
+  schemas:
+    User:
+      type: object
+      x-go-type: User
+      properties:
+        id:
+          type: string
+    UnusedSchema:
+      type: object
+      description: Not referenced anywhere
+```
+
+**After sanitization (default):**
+
+```yaml
+openapi: 3.1.0
+info:
+  title: My API
+  version: 1.0.0
+paths:
+  /users:
+    get:
+      operationId: listUsers
+      responses:
+        '200':
+          description: Success
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/User'
+components:
+  schemas:
+    User:
+      type: object
+      properties:
+        id:
+          type: string
+```
+
+**After sanitization (with pattern config):**
+
+Using config with `extensionPatterns: ["x-go-*"]`:
+
+```yaml
+openapi: 3.1.0
+info:
+  title: My API
+  version: 1.0.0
+  x-api-id: internal-123  # kept (doesn't match x-go-*)
+paths:
+  /users:
+    get:
+      operationId: listUsers
+      x-rate-limit: 100  # kept (doesn't match x-go-*)
+      responses:
+        '200':
+          description: Success
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/User'
+components:
+  schemas:
+    User:
+      type: object
+      properties:
+        id:
+          type: string
+```
+
+**Benefits of sanitization:**
+
+- **Standards compliance**: Remove vendor-specific extensions for clean, standard specs
+- **Clean distribution**: Prepare specifications for public sharing or publishing
+- **Reduced size**: Remove unnecessary extensions and unused components
+- **Selective cleanup**: Use patterns to target specific extension families
+- **Flexible control**: Config file allows fine-grained control over what to keep
+
+**Use Sanitize when:**
+
+- You want to remove all vendor extensions before publishing
+- You're preparing specifications for standards-compliant distribution
+- You need to clean up internal annotations before sharing externally
+- You want to remove specific extension families (e.g., x-go-*, x-internal-*)
+- You're combining extension removal with component cleanup in one operation
 
 ### `bundle`
 

openapi/cmd/root.go

@@ -8,6 +8,7 @@ func Apply(rootCmd *cobra.Command) {
 	rootCmd.AddCommand(upgradeCmd)
 	rootCmd.AddCommand(inlineCmd)
 	rootCmd.AddCommand(cleanCmd)
+	rootCmd.AddCommand(sanitizeCmd)
 	rootCmd.AddCommand(bundleCmd)
 	rootCmd.AddCommand(joinCmd)
 	rootCmd.AddCommand(bootstrapCmd)