From 3e14e721f729e45565a17e1faaeecbda749d3bca Mon Sep 17 00:00:00 2001
From: tzh476 <tzh476@gmail.com>
Date: Sun, 23 Aug 2026 16:32:58 +0800
Subject: [PATCH 1/2] fix: allow excess protocol-specific fields on Binding
 (issue #735)

Change-Id: I2b53925665dd23e273e90fe42eb8ee90b4342907
---
 packages/parser/src/spec-types/v2.ts            | 2 ++
 packages/parser/src/spec-types/v3.ts            | 2 ++
 packages/parser/test/models/v2/bindings.spec.ts | 9 +++++++++
 3 files changed, 13 insertions(+)

diff --git a/packages/parser/src/spec-types/v2.ts b/packages/parser/src/spec-types/v2.ts
index 758cd3035..ac95402ce 100644
--- a/packages/parser/src/spec-types/v2.ts
+++ b/packages/parser/src/spec-types/v2.ts
@@ -440,6 +440,8 @@ export interface CorrelationIDObject extends SpecificationExtensions {
 
 export interface Binding {
   bindingVersion?: string;
+  // protocol-specific binding fields (excess properties)
+  [propName: string]: any;
 }
 
 export interface SpecificationExtensions {
diff --git a/packages/parser/src/spec-types/v3.ts b/packages/parser/src/spec-types/v3.ts
index d3d11069d..ce78f2c9d 100644
--- a/packages/parser/src/spec-types/v3.ts
+++ b/packages/parser/src/spec-types/v3.ts
@@ -484,6 +484,8 @@ export interface AsyncAPISchemaDefinition extends SpecificationExtensions {
 
 export interface Binding {
   bindingVersion?: string;
+  // protocol-specific binding fields (excess properties)
+  [propName: string]: any;
 }
 
 export interface SpecificationExtensions {
diff --git a/packages/parser/test/models/v2/bindings.spec.ts b/packages/parser/test/models/v2/bindings.spec.ts
index 4075508a6..2680a51f0 100644
--- a/packages/parser/test/models/v2/bindings.spec.ts
+++ b/packages/parser/test/models/v2/bindings.spec.ts
@@ -61,4 +61,13 @@ describe('Bindings model', function () {
       expect(bindings.extensions().get('x-anotherOne')?.value()).toEqual({ someKey: 123 });
     });
   });
+
+  describe('excess properties (issue #735)', function () {
+    it('should preserve protocol-specific excess fields on a binding value', function () {
+      const b = new Binding({ clientId: 'my-client', clean: true } as any, { asyncapi: {} as any, pointer: '', protocol: 'mqtt' });
+      const value = b.value() as Record<string, any>;
+      expect(value).toHaveProperty('clientId', 'my-client');
+      expect(value).toHaveProperty('clean', true);
+    });
+  });
 });

From e3656303a9082e46173181e250bddfb197c863f3 Mon Sep 17 00:00:00 2001
From: tzh476 <tzh476@gmail.com>
Date: Mon, 24 Aug 2026 01:17:10 +0800
Subject: [PATCH 2/2] chore: changeset for #735

Change-Id: Ie4f192783e7f7fb3e533f058974c6a5bb51a3eb8
---
 .changeset/735-binding-excess.md | 5 +++++
 1 file changed, 5 insertions(+)
 create mode 100644 .changeset/735-binding-excess.md

diff --git a/.changeset/735-binding-excess.md b/.changeset/735-binding-excess.md
new file mode 100644
index 000000000..f912fb631
--- /dev/null
+++ b/.changeset/735-binding-excess.md
@@ -0,0 +1,5 @@
+---
+'@asyncapi/parser': patch
+---
+
+Allow protocol-specific excess properties on the `Binding` type (issue #735).