fix(packaging): drop root validator provider declarations

Author: morluto

.changeset/root-validator-declarations.md

@@ -0,0 +1,6 @@
+---
+'@modelcontextprotocol/server': patch
+'@modelcontextprotocol/client': patch
+---
+
+Remove subpath-only JSON Schema validator provider classes from the root declaration barrels. `AjvJsonSchemaValidator`, `CfWorkerJsonSchemaValidator`, and `CfWorkerSchemaDraft` remain available from the explicit `validators/ajv` and `validators/cf-worker` subpaths, matching the runtime export surface and avoiding CJS declarations that compile and then resolve to `undefined` at runtime.

packages/client/test/client/barrelClean.test.ts

@@ -10,6 +10,7 @@ const distDir = join(pkgDir, 'dist');
 const NODE_ONLY = /\b(child_process|cross-spawn|node:stream|node:child_process)\b/;
 // Anchored at start-of-line so JSDoc-example `from 'ajv'` strings in vendored chunks don't match.
 const VALIDATOR_BACKEND_IMPORT = /^import[^\n]*?from\s+["'](?:ajv|ajv-formats|@cfworker\/json-schema)["']/m;
+const ROOT_VALIDATOR_PROVIDER_EXPORTS = /\b(?:AjvJsonSchemaValidator|CfWorkerJsonSchemaValidator|CfWorkerSchemaDraft)\b/;
 
 function chunkImportsOf(entryPath: string): string[] {
     const visited = new Set<string>();
@@ -67,4 +68,10 @@ describe('@modelcontextprotocol/client root entry is browser-safe', () => {
             }
         }
     });
+
+    test('root declarations do not advertise subpath-only validator providers', () => {
+        for (const declaration of ['index.d.mts', 'index.d.cts']) {
+            expect(readFileSync(join(distDir, declaration), 'utf8')).not.toMatch(ROOT_VALIDATOR_PROVIDER_EXPORTS);
+        }
+    });
 });

packages/core-internal/src/exports/public/index.ts

@@ -131,10 +131,8 @@ export {
 export type { SpecTypeName, SpecTypes } from '../../types/specTypeSchema';
 export { isSpecType, specTypeSchemas } from '../../types/specTypeSchema';
 export type { StandardSchemaV1, StandardSchemaV1Sync, StandardSchemaWithJSON } from '../../util/standardSchema';
-// Validator providers are type-only here — import the runtime classes from the explicit
-// `@modelcontextprotocol/{client,server}/validators/{ajv,cf-worker}` subpaths to customise.
-export type { AjvJsonSchemaValidator } from '../../validators/ajvProvider';
-export type { CfWorkerJsonSchemaValidator, CfWorkerSchemaDraft } from '../../validators/cfWorkerProvider';
+// Validator provider classes are subpath-only so root entries stay runtime-neutral.
+// Import them from `@modelcontextprotocol/{client,server}/validators/{ajv,cf-worker}`.
 // fromJsonSchema is intentionally NOT exported here — the server and client packages
 // provide runtime-aware wrappers that default to the appropriate validator via _shims.
 export type { JsonSchemaType, JsonSchemaValidator, jsonSchemaValidator, JsonSchemaValidatorResult } from '../../validators/types';

packages/server/test/server/barrelClean.test.ts

@@ -10,6 +10,7 @@ const distDir = join(pkgDir, 'dist');
 const NODE_ONLY = /\b(child_process|cross-spawn|node:stream|node:child_process)\b/;
 // Anchored at start-of-line so JSDoc-example `from 'ajv'` strings in vendored chunks don't match.
 const VALIDATOR_BACKEND_IMPORT = /^import[^\n]*?from\s+["'](?:ajv|ajv-formats|@cfworker\/json-schema)["']/m;
+const ROOT_VALIDATOR_PROVIDER_EXPORTS = /\b(?:AjvJsonSchemaValidator|CfWorkerJsonSchemaValidator|CfWorkerSchemaDraft)\b/;
 
 function chunkImportsOf(entryPath: string): string[] {
     const visited = new Set<string>();
@@ -68,4 +69,10 @@ describe('@modelcontextprotocol/server root entry is browser-safe', () => {
             }
         }
     });
+
+    test('root declarations do not advertise subpath-only validator providers', () => {
+        for (const declaration of ['index.d.mts', 'index.d.cts']) {
+            expect(readFileSync(join(distDir, declaration), 'utf8')).not.toMatch(ROOT_VALIDATOR_PROVIDER_EXPORTS);
+        }
+    });
 });

scripts/smoke-dist-types.mjs

@@ -14,7 +14,7 @@ try {
         path.join(dir, 'consumer.ts'),
         [
             "import { Client } from '@modelcontextprotocol/client';",
-            "import type { AjvJsonSchemaValidator as ClientAjv } from '@modelcontextprotocol/client';",
+            "import type { JsonSchemaValidator as ClientJsonSchemaValidator } from '@modelcontextprotocol/client';",
             "import { AjvJsonSchemaValidator } from '@modelcontextprotocol/client/validators/ajv';",
             "import { CfWorkerJsonSchemaValidator as ClientCf } from '@modelcontextprotocol/client/validators/cf-worker';",
             "import { StdioClientTransport } from '@modelcontextprotocol/client/stdio';",
@@ -24,7 +24,7 @@ try {
             "import { StdioServerTransport } from '@modelcontextprotocol/server/stdio';",
             "export const c = new Client({ name: 'smoke', version: '1.0.0' });",
             "export const s = new McpServer({ name: 'smoke', version: '1.0.0' });",
-            'export type T = ClientAjv;',
+            'export type T = ClientJsonSchemaValidator<unknown>;',
             'export { AjvJsonSchemaValidator, ServerAjv, ClientCf, ServerCf, StdioClientTransport, StdioServerTransport };',
             ''
         ].join('\n')