Cherry-pick: fix: update elicitation support logic to align with MCP spec and enhance type handling (Fixes #279) (#295)

Cherry-picked from #294 (merged to release/1.0.x)
Original commit: c1cf59f

Co-authored-by: agentfront[bot] <agentfront[bot]@users.noreply.github.com>
Co-authored-by: frontegg-david <69419539+frontegg-david@users.noreply.github.com>

Author: 3 people

libs/sdk/src/notification/__tests__/elicitation-support.spec.ts

@@ -21,11 +21,20 @@ describe('supportsElicitation', () => {
       expect(supportsElicitation(capabilities)).toBe(false);
     });
 
-    it('should return false when elicitation is empty object', () => {
+    it('should return true when elicitation is empty object (per MCP spec 2025-06-18)', () => {
       const capabilities: ClientCapabilities = {
         elicitation: {},
       };
-      expect(supportsElicitation(capabilities)).toBe(false);
+      // Per MCP spec: presence of elicitation object means client supports it
+      expect(supportsElicitation(capabilities)).toBe(true);
+    });
+
+    it('should return false when checking specific mode on empty elicitation', () => {
+      const capabilities: ClientCapabilities = {
+        elicitation: {},
+      };
+      expect(supportsElicitation(capabilities, 'form')).toBe(false);
+      expect(supportsElicitation(capabilities, 'url')).toBe(false);
     });
   });
 
@@ -268,5 +277,16 @@ describe('supportsElicitation', () => {
 
       expect(supportsElicitation(legacyCapabilities)).toBe(false);
     });
+
+    it('should work with MCP Inspector capabilities (elicitation: {})', () => {
+      // MCP Inspector sends elicitation: {} per MCP spec 2025-06-18
+      const inspectorCapabilities: ClientCapabilities = {
+        sampling: {},
+        elicitation: {},
+        roots: { listChanged: true },
+      };
+
+      expect(supportsElicitation(inspectorCapabilities)).toBe(true);
+    });
   });
 });

libs/sdk/src/notification/notification.service.ts

@@ -119,6 +119,8 @@ export function supportsElicitation(capabilities?: ClientCapabilities, mode?: 'f
     return false;
   }
 
+  // Per MCP spec (2025-06-18): presence of the elicitation object means
+  // the client supports it. Sub-fields (form, url) are optional refinements.
   if (mode === 'form') {
     return capabilities.elicitation.form !== undefined;
   }
@@ -127,8 +129,8 @@ export function supportsElicitation(capabilities?: ClientCapabilities, mode?: 'f
     return capabilities.elicitation.url !== undefined;
   }
 
-  // If no mode specified, check for any elicitation support
-  return capabilities.elicitation.form !== undefined || capabilities.elicitation.url !== undefined;
+  // No mode specified → elicitation object exists, client supports it
+  return true;
 }
 
 /**

scripts/generate-schema-types.mjs

@@ -93,6 +93,12 @@ function getZodTypeName(schema) {
  * Unwrap layers of ZodOptional, ZodDefault, ZodEffects, ZodNullable
  * and collect metadata along the way.
  */
+/** Stringify a JS value using single quotes for strings (prettier-compatible). */
+function toTsLiteral(value) {
+  if (typeof value === 'string') return `'${value.replace(/'/g, "\\'")}'`;
+  return JSON.stringify(value);
+}
+
 function unwrapSchema(schema) {
   let optional = false;
   let defaultValue;
@@ -119,7 +125,11 @@ function unwrapSchema(schema) {
       optional = true;
       const dv = current._def.defaultValue;
       if (typeof dv === 'function') {
-        try { defaultValue = JSON.stringify(dv()); } catch { /* ignore */ }
+        try {
+          defaultValue = JSON.stringify(dv());
+        } catch {
+          /* ignore */
+        }
       } else if (dv !== undefined) {
         defaultValue = JSON.stringify(dv);
       }
@@ -198,19 +208,19 @@ function zodToTsType(schema, depth = 0) {
       return 'unknown';
 
     case 'ZodLiteral':
-      return JSON.stringify(schema._def.value);
+      return toTsLiteral(schema._def.value);
 
     case 'ZodEnum': {
       // Zod v4 uses _def.entries (object), v3 uses _def.values (array)
       const entries = schema._def.entries || {};
       const vals = Array.isArray(schema._def.values) ? schema._def.values : Object.values(entries);
-      return vals.map(v => JSON.stringify(v)).join(' | ');
+      return vals.map((v) => toTsLiteral(v)).join(' | ');
     }
 
     case 'ZodNativeEnum': {
       const enumObj = schema._def.values || {};
-      const vals = Object.values(enumObj).filter(v => typeof v === 'string' || typeof v === 'number');
-      return vals.map(v => JSON.stringify(v)).join(' | ') || 'unknown';
+      const vals = Object.values(enumObj).filter((v) => typeof v === 'string' || typeof v === 'number');
+      return vals.map((v) => toTsLiteral(v)).join(' | ') || 'unknown';
     }
 
     case 'ZodArray':
@@ -240,7 +250,7 @@ function zodToTsType(schema, depth = 0) {
     case 'ZodUnion':
     case 'ZodDiscriminatedUnion': {
       const options = schema._def.options || [];
-      return options.map(o => zodToTsType(o, depth)).join(' | ') || 'unknown';
+      return options.map((o) => zodToTsType(o, depth)).join(' | ') || 'unknown';
     }
 
     case 'ZodIntersection': {
@@ -251,7 +261,7 @@ function zodToTsType(schema, depth = 0) {
 
     case 'ZodTuple': {
       const items = schema._def.items || [];
-      return `[${items.map(i => zodToTsType(i, depth)).join(', ')}]`;
+      return `[${items.map((i) => zodToTsType(i, depth)).join(', ')}]`;
     }
 
     case 'ZodOptional':