Move getSupportedElicitationModes into client (not shared)

Author: nbarbettini

src/client/index.test.ts

@@ -1,7 +1,7 @@
 /* eslint-disable @typescript-eslint/no-unused-vars */
 /* eslint-disable no-constant-binary-expression */
 /* eslint-disable @typescript-eslint/no-unused-expressions */
-import { Client } from './index.js';
+import { Client, getSupportedElicitationModes } from './index.js';
 import { z } from 'zod';
 import {
     RequestSchema,
@@ -1543,3 +1543,59 @@ describe('outputSchema validation', () => {
         );
     });
 });
+
+describe('getSupportedElicitationModes', () => {
+    test('should support nothing when capabilities are undefined', () => {
+        const result = getSupportedElicitationModes(undefined);
+        expect(result.supportsFormMode).toBe(false);
+        expect(result.supportsUrlMode).toBe(false);
+    });
+
+    test('should default to form mode when capabilities are an empty object', () => {
+        const result = getSupportedElicitationModes({});
+        expect(result.supportsFormMode).toBe(true);
+        expect(result.supportsUrlMode).toBe(false);
+    });
+
+    test('should support form mode when form is explicitly declared', () => {
+        const result = getSupportedElicitationModes({ form: {} });
+        expect(result.supportsFormMode).toBe(true);
+        expect(result.supportsUrlMode).toBe(false);
+    });
+
+    test('should support url mode when url is explicitly declared', () => {
+        const result = getSupportedElicitationModes({ url: {} });
+        expect(result.supportsFormMode).toBe(false);
+        expect(result.supportsUrlMode).toBe(true);
+    });
+
+    test('should support both modes when both are explicitly declared', () => {
+        const result = getSupportedElicitationModes({ form: {}, url: {} });
+        expect(result.supportsFormMode).toBe(true);
+        expect(result.supportsUrlMode).toBe(true);
+    });
+
+    test('should support form mode when only applyDefaults is present', () => {
+        const result = getSupportedElicitationModes({ applyDefaults: true });
+        expect(result.supportsFormMode).toBe(true);
+        expect(result.supportsUrlMode).toBe(false);
+    });
+
+    test('should support form mode when applyDefaults and form are present', () => {
+        const result = getSupportedElicitationModes({ applyDefaults: true, form: {} });
+        expect(result.supportsFormMode).toBe(true);
+        expect(result.supportsUrlMode).toBe(false);
+    });
+
+    test('should support url mode when applyDefaults and url are present', () => {
+        const result = getSupportedElicitationModes({ applyDefaults: true, url: {} });
+        expect(result.supportsFormMode).toBe(false);
+        expect(result.supportsUrlMode).toBe(true);
+    });
+
+    test('should support both modes when applyDefaults, form, and url are present', () => {
+        const result = getSupportedElicitationModes({ applyDefaults: true, form: {}, url: {} });
+        expect(result.supportsFormMode).toBe(true);
+        expect(result.supportsUrlMode).toBe(true);
+    });
+});

src/client/index.ts

@@ -1,6 +1,5 @@
 import { mergeCapabilities, Protocol, type ProtocolOptions, type RequestOptions } from '../shared/protocol.js';
 import type { Transport } from '../shared/transport.js';
-import { getSupportedElicitationModes } from '../shared/elicitation-utils.js';
 import {
     type CallToolRequest,
     CallToolResultSchema,
@@ -86,6 +85,34 @@ function applyElicitationDefaults(schema: JsonSchemaType | undefined, data: unkn
     }
 }
 
+/**
+ * Determines which elicitation modes are supported based on declared client capabilities.
+ *
+ * According to the spec:
+ * - An empty elicitation capability object defaults to form mode support (backwards compatibility)
+ * - URL mode is only supported if explicitly declared
+ *
+ * @param capabilities - The client's elicitation capabilities
+ * @returns An object indicating which modes are supported
+ */
+export function getSupportedElicitationModes(capabilities: ClientCapabilities['elicitation']): {
+    supportsFormMode: boolean;
+    supportsUrlMode: boolean;
+} {
+    if (!capabilities) {
+        return { supportsFormMode: false, supportsUrlMode: false };
+    }
+
+    const hasFormCapability = Object.prototype.hasOwnProperty.call(capabilities, 'form');
+    const hasUrlCapability = Object.prototype.hasOwnProperty.call(capabilities, 'url');
+
+    // If neither form nor url are explicitly declared, form mode is supported (backwards compatibility)
+    const supportsFormMode = hasFormCapability || (!hasFormCapability && !hasUrlCapability);
+    const supportsUrlMode = hasUrlCapability;
+
+    return { supportsFormMode, supportsUrlMode };
+}
+
 export type ClientOptions = ProtocolOptions & {
     /**
      * Capabilities to advertise as being supported by this client.