fix(server): tolerate elicitation annotation metadata

Author: mattzcarey

packages/core-internal/src/shared/elicitation.ts

@@ -82,6 +82,12 @@ function isRedundantFormatPattern(original: Record<string, unknown>, parsed: Rec
     return ZOD_REDUNDANT_FORMAT_PATTERNS.get(parsed.format)?.has(original.pattern) === true;
 }
 
+const ANNOTATION_ONLY_JSON_SCHEMA_KEYWORDS = new Set(['$comment', 'deprecated', 'examples', 'readOnly', 'writeOnly']);
+
+function isAnnotationOnlyJsonSchemaKeyword(key: string): boolean {
+    return ANNOTATION_ONLY_JSON_SCHEMA_KEYWORDS.has(key) || key.startsWith('x-');
+}
+
 function findStrippedJsonSchemaPaths(original: unknown, parsed: unknown, path = ''): string[] {
     if (Array.isArray(original) && Array.isArray(parsed)) {
         return original.flatMap((item, index) => findStrippedJsonSchemaPaths(item, parsed[index], `${path}[${index}]`));
@@ -94,7 +100,7 @@ function findStrippedJsonSchemaPaths(original: unknown, parsed: unknown, path =
     return Object.entries(original).flatMap(([key, value]) => {
         const childPath = path ? `${path}.${key}` : key;
         if (!Object.prototype.hasOwnProperty.call(parsed, key)) {
-            if (isRedundantFormatPattern(original, parsed, key)) {
+            if (isRedundantFormatPattern(original, parsed, key) || isAnnotationOnlyJsonSchemaKeyword(key)) {
                 return [];
             }
             return [childPath];

packages/core-internal/test/shared/inputRequired.test.ts

@@ -74,6 +74,35 @@ describe('inputRequired() builder', () => {
         });
     });
 
+    test('elicit drops annotation-only metadata from Standard Schema properties', () => {
+        const request = inputRequired.elicit({
+            message: 'Name?',
+            requestedSchema: z.object({
+                name: z.string().meta({
+                    title: 'Name',
+                    examples: ['Ada Lovelace'],
+                    deprecated: false,
+                    readOnly: true,
+                    'x-ui-order': 1
+                })
+            })
+        });
+
+        expect(request).toEqual({
+            method: 'elicitation/create',
+            params: {
+                mode: 'form',
+                message: 'Name?',
+                requestedSchema: {
+                    $schema: 'https://json-schema.org/draft/2020-12/schema',
+                    type: 'object',
+                    properties: { name: { type: 'string', title: 'Name' } },
+                    required: ['name']
+                }
+            }
+        });
+    });
+
     test('elicit rejects non-object Standard Schema roots as invalid elicitation params', () => {
         expect(() =>
             inputRequired.elicit({

packages/server/src/server/server.ts

@@ -1136,6 +1136,18 @@ export class Server extends Protocol<ServerContext> {
         params: ElicitInputFormParams<Schema>,
         options?: RequestOptions
     ): Promise<ElicitInputResult<Schema>>;
+    /**
+     * Creates an elicitation request for the given parameters.
+     * For backwards compatibility, `mode` may be omitted for form requests and will default to `"form"`.
+     * @param params The parameters for the elicitation request.
+     * @param options Optional request options.
+     * @returns The result of the elicitation request.
+     *
+     * @deprecated Throws on a 2026-07-28-era request — use {@link index.inputRequired | inputRequired} (multi-round-trip)
+     * instead. The 2025 push-style server-to-client request model is replaced by input_required
+     * results in the 2026-07-28 protocol. If your factory serves both eras, this only works on the
+     * legacy path.
+     */
     async elicitInput(params: ElicitRequestFormParams | ElicitRequestURLParams, options?: RequestOptions): Promise<ElicitResult>;
     async elicitInput(
         params: ElicitRequestFormParams | ElicitRequestURLParams | ElicitInputFormParams<StandardSchemaWithJSON>,