diff --git a/dist/bindings.d.ts b/dist/bindings.d.ts
index 3520763..7168137 100644
--- a/dist/bindings.d.ts
+++ b/dist/bindings.d.ts
@@ -35,6 +35,9 @@ export type QxValueType = {
 } | {
     kind: "message";
     descriptorId: string;
+} | {
+    kind: "record";
+    fields: Record<string, QxValueType>;
 } | {
     kind: "object-ref";
     expectation: unknown;
diff --git a/dist/bindings.d.ts.map b/dist/bindings.d.ts.map
index ffb6391..aaa2a9a 100644
--- a/dist/bindings.d.ts.map
+++ b/dist/bindings.d.ts.map
@@ -1 +1 @@
-{"version":3,"file":"bindings.d.ts","sourceRoot":"","sources":["../src/bindings.ts"],"names":[],"mappings":"AACA,OAAO,EAAkC,KAAK,KAAK,EAAE,MAAM,oBAAoB,CAAC;AAChF,OAAO,EACgB,KAAK,cAAc,EAAE,KAAK,cAAc,EAAE,MAAM,YAAY,CAAC;AAEpF,YAAY,EAAE,WAAW,EAAE,MAAM,iBAAiB,CAAC;AAEnD,OAAO,CAAC,MAAM,UAAU,EAAE,OAAO,MAAM,CAAC;AACxC,MAAM,MAAM,aAAa,GAAG,MAAM,GAAG;IAAE,QAAQ,CAAC,CAAC,UAAU,CAAC,EAAE,IAAI,CAAA;CAAE,CAAC;AACrE,MAAM,MAAM,cAAc,CAAC,CAAC,IAAI;IAAE,MAAM,CAAC,KAAK,EAAE,CAAC,GAAG,KAAK,CAAC;IAAC,MAAM,CAAC,KAAK,EAAE,KAAK,GAAG,CAAC,CAAA;CAAE,CAAC;AACrF,MAAM,MAAM,YAAY,CAAC,CAAC,IAAI,CAAC,SAAS,cAAc,CAAC,MAAM,CAAC,CAAC,GAAG,CAAC,GAAG,KAAK,CAAC;AAC5E,MAAM,MAAM,SAAS,CAAC,CAAC,EAAE,CAAC,IAAI,CAAC,OAAO,EAAE,CAAC,KAAK,CAAC,GAAG,OAAO,CAAC,CAAC,CAAC,CAAC;AAC7D,MAAM,MAAM,SAAS,CAAC,CAAC,EAAE,CAAC,IAAI;IAAE,IAAI,EAAE,SAAS,CAAC;IAAC,GAAG,EAAE,SAAS,CAAC,CAAC,EAAE,CAAC,CAAC,CAAA;CAAE,CAAC;AACxE,MAAM,MAAM,SAAS,CAAC,CAAC,IAAI;IAAC,EAAE,EAAE,MAAM,CAAC;IAAC,GAAG,CAAC,CAAC,EAAE,IAAI,EAAE,CAAC,OAAO,EAAE,CAAC,KAAK,OAAO,CAAC,CAAC,CAAC,GAAG,OAAO,CAAC,CAAC,CAAC,CAAC;IAAC,KAAK,IAAI,OAAO,CAAC,IAAI,CAAC,CAAA;CAAC,CAAC;AACtH,MAAM,MAAM,kBAAkB,CAAC,CAAC,IAAI;IAAC,MAAM,CAAC,EAAE,WAAW,CAAC;IAAC,WAAW,CAAC,EAAE,MAAM,OAAO,CAAC,SAAS,CAAC,CAAC,CAAC,CAAC,CAAA;CAAC,CAAC;AACtG,eAAO,MAAM,SAAS,GAAI,CAAC,EAAE,CAAC,OAAO,SAAS,CAAC,CAAC,EAAE,CAAC,CAAC,KAAG,SAAS,CAAC,CAAC,EAAE,CAAC,CAA+B,CAAC;AAErG,yEAAyE;AACzE,MAAM,MAAM,WAAW,GACnB;IAAE,IAAI,EAAE,SAAS,CAAC;IAAC,IAAI,EAAE,MAAM,GAAG,cAAc,CAAA;CAAE,GAClD;IAAE,IAAI,EAAE,QAAQ,CAAC;IAAC,IAAI,EAAE,MAAM,CAAA;CAAE,GAChC;IAAE,IAAI,EAAE,SAAS,CAAC;IAAC,YAAY,EAAE,MAAM,CAAA;CAAE,GACzC;IAAE,IAAI,EAAE,YAAY,CAAC;IAAC,WAAW,EAAE,OAAO,CAAA;CAAE,GAC5C;IAAE,IAAI,EAAE,UAAU,GAAG,MAAM,CAAC;IAAC,KAAK,EAAE,WAAW,CAAA;CAAE,CAAC;AACtD,MAAM,MAAM,eAAe,GAAG;IAAE,EAAE,EAAE,MAAM,CAAC;IAAC,SAAS,EAAE,WAAW,CAAC;IAAC,UAAU,EAAE,WAAW,CAAA;CAAE,CAAC;AAC9F,MAAM,MAAM,UAAU,GAClB;IAAE,IAAI,EAAE,OAAO,CAAC;IAAC,EAAE,EAAE,MAAM,CAAC;IAAC,SAAS,EAAE,WAAW,CAAC;IAAC,UAAU,EAAE,MAAM,EAAE,CAAA;CAAE,GAC3E;IAAE,IAAI,EAAE,MAAM,CAAC;IAAC,EAAE,EAAE,MAAM,CAAC;IAAC,UAAU,EAAE,MAAM,EAAE,CAAA;CAAE,GAClD;IAAE,IAAI,EAAE,WAAW,CAAC;IAAC,EAAE,EAAE,MAAM,CAAC;IAAC,UAAU,EAAE,MAAM,CAAC,MAAM,EAAE,eAAe,CAAC,CAAA;CAAE,GAC9E;IAAE,IAAI,EAAE,aAAa,CAAC;IAAC,EAAE,EAAE,MAAM,CAAC;IAAC,SAAS,EAAE,WAAW,CAAA;CAAE,CAAC;AAChE,MAAM,MAAM,aAAa,GAAG;IAC1B,SAAS,EAAE,WAAW,CAAC;IAAC,UAAU,EAAE,WAAW,CAAC;IAAC,SAAS,CAAC,EAAE,WAAW,CAAC;IACzE,KAAK,EAAE,MAAM,CAAC,MAAM,EAAE,UAAU,CAAC,CAAC;CACnC,CAAC;AACF,MAAM,MAAM,UAAU,GAAG,MAAM,CAAC,MAAM,EAAE,cAAc,CAAC,GAAG,CAAC,CAAC,CAAC;AAG7D,eAAO,MAAM,aAAa,SAAU,WAAW,SAAS,KAAK,GAAG,SAAS,YAAY,UAAU,KAAG,GA8BjG,CAAC;AAOF,eAAO,MAAM,aAAa,SAAU,WAAW,SAAS,GAAG,YAAY,UAAU,KAAG,KAYnF,CAAC;AAiBF,uFAAuF;AACvF,eAAO,MAAM,aAAa,GAAI,CAAC,EAAE,CAAC,QAC1B,aAAa,WAAW,SAAS,CAAC,CAAC,EAAE,CAAC,CAAC,GAAG,SAAS,CAAC,CAAC,EAAE,CAAC,CAAC,YAAY,UAAU,KACpF,cAAc,GAAG,cAyCnB,CAAC"}
\ No newline at end of file
+{"version":3,"file":"bindings.d.ts","sourceRoot":"","sources":["../src/bindings.ts"],"names":[],"mappings":"AACA,OAAO,EAAkC,KAAK,KAAK,EAAE,MAAM,oBAAoB,CAAC;AAChF,OAAO,EACgB,KAAK,cAAc,EAAE,KAAK,cAAc,EAAE,MAAM,YAAY,CAAC;AAEpF,YAAY,EAAE,WAAW,EAAE,MAAM,iBAAiB,CAAC;AAEnD,OAAO,CAAC,MAAM,UAAU,EAAE,OAAO,MAAM,CAAC;AACxC,MAAM,MAAM,aAAa,GAAG,MAAM,GAAG;IAAE,QAAQ,CAAC,CAAC,UAAU,CAAC,EAAE,IAAI,CAAA;CAAE,CAAC;AACrE,MAAM,MAAM,cAAc,CAAC,CAAC,IAAI;IAAE,MAAM,CAAC,KAAK,EAAE,CAAC,GAAG,KAAK,CAAC;IAAC,MAAM,CAAC,KAAK,EAAE,KAAK,GAAG,CAAC,CAAA;CAAE,CAAC;AACrF,MAAM,MAAM,YAAY,CAAC,CAAC,IAAI,CAAC,SAAS,cAAc,CAAC,MAAM,CAAC,CAAC,GAAG,CAAC,GAAG,KAAK,CAAC;AAC5E,MAAM,MAAM,SAAS,CAAC,CAAC,EAAE,CAAC,IAAI,CAAC,OAAO,EAAE,CAAC,KAAK,CAAC,GAAG,OAAO,CAAC,CAAC,CAAC,CAAC;AAC7D,MAAM,MAAM,SAAS,CAAC,CAAC,EAAE,CAAC,IAAI;IAAE,IAAI,EAAE,SAAS,CAAC;IAAC,GAAG,EAAE,SAAS,CAAC,CAAC,EAAE,CAAC,CAAC,CAAA;CAAE,CAAC;AACxE,MAAM,MAAM,SAAS,CAAC,CAAC,IAAI;IAAC,EAAE,EAAE,MAAM,CAAC;IAAC,GAAG,CAAC,CAAC,EAAE,IAAI,EAAE,CAAC,OAAO,EAAE,CAAC,KAAK,OAAO,CAAC,CAAC,CAAC,GAAG,OAAO,CAAC,CAAC,CAAC,CAAC;IAAC,KAAK,IAAI,OAAO,CAAC,IAAI,CAAC,CAAA;CAAC,CAAC;AACtH,MAAM,MAAM,kBAAkB,CAAC,CAAC,IAAI;IAAC,MAAM,CAAC,EAAE,WAAW,CAAC;IAAC,WAAW,CAAC,EAAE,MAAM,OAAO,CAAC,SAAS,CAAC,CAAC,CAAC,CAAC,CAAA;CAAC,CAAC;AACtG,eAAO,MAAM,SAAS,GAAI,CAAC,EAAE,CAAC,OAAO,SAAS,CAAC,CAAC,EAAE,CAAC,CAAC,KAAG,SAAS,CAAC,CAAC,EAAE,CAAC,CAA+B,CAAC;AAErG,yEAAyE;AACzE,MAAM,MAAM,WAAW,GACnB;IAAE,IAAI,EAAE,SAAS,CAAC;IAAC,IAAI,EAAE,MAAM,GAAG,cAAc,CAAA;CAAE,GAClD;IAAE,IAAI,EAAE,QAAQ,CAAC;IAAC,IAAI,EAAE,MAAM,CAAA;CAAE,GAChC;IAAE,IAAI,EAAE,SAAS,CAAC;IAAC,YAAY,EAAE,MAAM,CAAA;CAAE,GACzC;IAAE,IAAI,EAAE,QAAQ,CAAC;IAAC,MAAM,EAAE,MAAM,CAAC,MAAM,EAAE,WAAW,CAAC,CAAA;CAAE,GACvD;IAAE,IAAI,EAAE,YAAY,CAAC;IAAC,WAAW,EAAE,OAAO,CAAA;CAAE,GAC5C;IAAE,IAAI,EAAE,UAAU,GAAG,MAAM,CAAC;IAAC,KAAK,EAAE,WAAW,CAAA;CAAE,CAAC;AACtD,MAAM,MAAM,eAAe,GAAG;IAAE,EAAE,EAAE,MAAM,CAAC;IAAC,SAAS,EAAE,WAAW,CAAC;IAAC,UAAU,EAAE,WAAW,CAAA;CAAE,CAAC;AAC9F,MAAM,MAAM,UAAU,GAClB;IAAE,IAAI,EAAE,OAAO,CAAC;IAAC,EAAE,EAAE,MAAM,CAAC;IAAC,SAAS,EAAE,WAAW,CAAC;IAAC,UAAU,EAAE,MAAM,EAAE,CAAA;CAAE,GAC3E;IAAE,IAAI,EAAE,MAAM,CAAC;IAAC,EAAE,EAAE,MAAM,CAAC;IAAC,UAAU,EAAE,MAAM,EAAE,CAAA;CAAE,GAClD;IAAE,IAAI,EAAE,WAAW,CAAC;IAAC,EAAE,EAAE,MAAM,CAAC;IAAC,UAAU,EAAE,MAAM,CAAC,MAAM,EAAE,eAAe,CAAC,CAAA;CAAE,GAC9E;IAAE,IAAI,EAAE,aAAa,CAAC;IAAC,EAAE,EAAE,MAAM,CAAC;IAAC,SAAS,EAAE,WAAW,CAAA;CAAE,CAAC;AAChE,MAAM,MAAM,aAAa,GAAG;IAC1B,SAAS,EAAE,WAAW,CAAC;IAAC,UAAU,EAAE,WAAW,CAAC;IAAC,SAAS,CAAC,EAAE,WAAW,CAAC;IACzE,KAAK,EAAE,MAAM,CAAC,MAAM,EAAE,UAAU,CAAC,CAAC;CACnC,CAAC;AACF,MAAM,MAAM,UAAU,GAAG,MAAM,CAAC,MAAM,EAAE,cAAc,CAAC,GAAG,CAAC,CAAC,CAAC;AAG7D,eAAO,MAAM,aAAa,SAAU,WAAW,SAAS,KAAK,GAAG,SAAS,YAAY,UAAU,KAAG,GAqCjG,CAAC;AAOF,eAAO,MAAM,aAAa,SAAU,WAAW,SAAS,GAAG,YAAY,UAAU,KAAG,KAqBnF,CAAC;AAiBF,uFAAuF;AACvF,eAAO,MAAM,aAAa,GAAI,CAAC,EAAE,CAAC,QAC1B,aAAa,WAAW,SAAS,CAAC,CAAC,EAAE,CAAC,CAAC,GAAG,SAAS,CAAC,CAAC,EAAE,CAAC,CAAC,YAAY,UAAU,KACpF,cAAc,GAAG,cAyCnB,CAAC"}
\ No newline at end of file
diff --git a/dist/bindings.js b/dist/bindings.js
index eec1164..238f138 100644
--- a/dist/bindings.js
+++ b/dist/bindings.js
@@ -7,8 +7,18 @@ export const qxDerived = (get) => ({ kind: "derived", get });
 export const decodeQxValue = (type, value, messages) => {
     if (type.kind === "builtin" && type.name === "unit")
         return null;
+    if (type.kind === "optional" && !value)
+        return null;
     if (!value)
         throw new Error("Missing QX wire value");
+    if (type.kind === "record") {
+        if (value.kind.case !== "objectValue")
+            throw new Error("Expected QX record");
+        const fields = value.kind.value.fields;
+        if (Object.keys(fields).some((name) => !Object.hasOwn(type.fields, name)))
+            throw new Error("Unexpected QX record field");
+        return Object.fromEntries(Object.entries(type.fields).map(([name, field]) => [name, decodeQxValue(field, fields[name], messages)]));
+    }
     if (type.kind === "optional")
         return value.kind.case === "nullValue" ? null : decodeQxValue(type.value, value, messages);
     if (type.kind === "list") {
@@ -52,6 +62,18 @@ const requireMessage = (messages, id) => {
 export const encodeQxValue = (type, value, messages) => {
     if (type.kind === "builtin" && type.name === "unit")
         return jsToProtoValue(null);
+    if (type.kind === "record") {
+        if (!value || typeof value !== "object" || Array.isArray(value))
+            throw new Error("Expected QX record");
+        if (Object.keys(value).some((name) => !Object.hasOwn(type.fields, name)))
+            throw new Error("Unexpected QX record field");
+        const fields = Object.fromEntries(Object.entries(type.fields).map(([name, field]) => {
+            if (!Object.hasOwn(value, name) && field.kind !== "optional")
+                throw new Error(`Missing QX record field ${name}`);
+            return [name, encodeQxValue(field, value[name] ?? (field.kind === "optional" ? null : value[name]), messages)];
+        }));
+        return create(ValueSchema, { kind: { case: "objectValue", value: create(ObjectValueSchema, { fields }) } });
+    }
     if (type.kind === "optional")
         return value === null ? jsToProtoValue(null) : encodeQxValue(type.value, value, messages);
     if (type.kind === "list")
@@ -69,7 +91,7 @@ export const encodeQxValue = (type, value, messages) => {
     return jsToProtoValue(value);
 };
 const inputValue = (context, type) => {
-    if (type.kind === "message")
+    if (type.kind === "message" || type.kind === "record")
         return create(ValueSchema, { kind: { case: "objectValue",
                 value: create(ObjectValueSchema, { fields: context.inputProto }) } });
     return context.inputProto.value;
@@ -78,7 +100,7 @@ const inputFields = (type, value, messages) => {
     if (type.kind === "builtin" && type.name === "unit")
         return {};
     const encoded = encodeQxValue(type, value, messages);
-    if (type.kind === "message") {
+    if (type.kind === "message" || type.kind === "record") {
         if (encoded.kind.case !== "objectValue")
             throw new Error("Message inputs must encode an object value");
         return Object.fromEntries(Object.entries(encoded.kind.value.fields).map(([key, entry]) => [key, liveValue(entry)]));
diff --git a/src/bindings.ts b/src/bindings.ts
index 96a063f..cb5f67b 100644
--- a/src/bindings.ts
+++ b/src/bindings.ts
@@ -20,6 +20,7 @@ export type QxValueType =
   | { kind: "builtin"; name: "unit" | "watch-handle" }
   | { kind: "scalar"; name: string }
   | { kind: "message"; descriptorId: string }
+  | { kind: "record"; fields: Record<string, QxValueType> }
   | { kind: "object-ref"; expectation: unknown }
   | { kind: "optional" | "list"; value: QxValueType };
 export type QxOperationSpec = { id: string; inputType: QxValueType; outputType: QxValueType };
@@ -37,7 +38,14 @@ export type QxMessages = Record<string, MessageBinding<any>>;
 // Conversion belongs at the binding boundary. It does not add orchestrator validation.
 export const decodeQxValue = (type: QxValueType, value: Value | undefined, messages: QxMessages): any => {
   if (type.kind === "builtin" && type.name === "unit") return null;
+  if (type.kind === "optional" && !value) return null;
   if (!value) throw new Error("Missing QX wire value");
+  if (type.kind === "record") {
+    if (value.kind.case !== "objectValue") throw new Error("Expected QX record");
+    const fields = value.kind.value.fields;
+    if (Object.keys(fields).some((name) => !Object.hasOwn(type.fields, name))) throw new Error("Unexpected QX record field");
+    return Object.fromEntries(Object.entries(type.fields).map(([name, field]) => [name, decodeQxValue(field, fields[name], messages)]));
+  }
   if (type.kind === "optional") return value.kind.case === "nullValue" ? null : decodeQxValue(type.value, value, messages);
   if (type.kind === "list") {
     if (value.kind.case !== "listValue") throw new Error("Expected QX list");
@@ -74,6 +82,15 @@ const requireMessage = (messages: QxMessages, id: string) => {
 };
 export const encodeQxValue = (type: QxValueType, value: any, messages: QxMessages): Value => {
   if (type.kind === "builtin" && type.name === "unit") return jsToProtoValue(null);
+  if (type.kind === "record") {
+    if (!value || typeof value !== "object" || Array.isArray(value)) throw new Error("Expected QX record");
+    if (Object.keys(value).some((name) => !Object.hasOwn(type.fields, name))) throw new Error("Unexpected QX record field");
+    const fields = Object.fromEntries(Object.entries(type.fields).map(([name, field]) => {
+      if (!Object.hasOwn(value, name) && field.kind !== "optional") throw new Error(`Missing QX record field ${name}`);
+      return [name, encodeQxValue(field, value[name] ?? (field.kind === "optional" ? null : value[name]), messages)];
+    }));
+    return create(ValueSchema, {kind: {case: "objectValue", value: create(ObjectValueSchema, {fields})}});
+  }
   if (type.kind === "optional") return value === null ? jsToProtoValue(null) : encodeQxValue(type.value, value, messages);
   if (type.kind === "list") return jsToProtoValue(value.map((entry: unknown) => liveValue(encodeQxValue(type.value, entry, messages))));
   if (type.kind === "object-ref") { referenceToWire(value); return jsToProtoValue(value); }
@@ -87,14 +104,14 @@ export const encodeQxValue = (type: QxValueType, value: any, messages: QxMessage
 };
 
 const inputValue = (context: RuntimeContext, type: QxValueType) => {
-  if (type.kind === "message") return create(ValueSchema, { kind: { case: "objectValue",
+  if (type.kind === "message" || type.kind === "record") return create(ValueSchema, { kind: { case: "objectValue",
     value: create(ObjectValueSchema, { fields: context.inputProto }) } });
   return context.inputProto.value;
 };
 const inputFields = (type: QxValueType, value: unknown, messages: QxMessages): Record<string, unknown> => {
   if (type.kind === "builtin" && type.name === "unit") return {};
   const encoded = encodeQxValue(type, value, messages);
-  if (type.kind === "message") {
+  if (type.kind === "message" || type.kind === "record") {
     if (encoded.kind.case !== "objectValue") throw new Error("Message inputs must encode an object value");
     return Object.fromEntries(Object.entries(encoded.kind.value.fields).map(([key, entry]) => [key, liveValue(entry)]));
   }
diff --git a/test/bindings.test.mjs b/test/bindings.test.mjs
index 953fdd8..3e0c8e7 100644
--- a/test/bindings.test.mjs
+++ b/test/bindings.test.mjs
@@ -4,6 +4,27 @@ import { referenceFromWire } from "../dist/references.js";
 import { bindQxHandler, decodeQxValue, encodeQxValue, jsToProtoValue, liveValue, protoValueToJs } from "../dist/index.js";
 const scalar = (name) => ({ kind: "scalar", name });
 const unit = { kind: "builtin", name: "unit" };
+test("declared record inputs preserve opaque references without opening message codecs", async () => {
+  const target = referenceFromWire("obj:board");
+  const type = {kind: "record", fields: {
+    target: {kind: "object-ref", expectation: {kind: "atom", atomId: "board"}},
+    x: scalar("double"), note: {kind: "optional", value: scalar("string")},
+  }};
+  const encoded = encodeQxValue(type, {target, x: 12}, {});
+  const decoded = decodeQxValue(type, encoded, {});
+  assert.ok(decoded.target.equals(target));
+  assert.equal(decoded.x, 12);
+  assert.equal(decoded.note, null);
+  assert.throws(() => JSON.stringify(decoded), /cannot be serialized/);
+  assert.throws(() => encodeQxValue(type, {target, x: 12, hidden: target}, {}), /Unexpected/);
+  assert.throws(() => encodeQxValue(type, {x: 12}, {}), /Missing/);
+  assert.throws(() => encodeQxValue(type, {target: "obj:board", x: 12}, {}), /opaque object reference/);
+  const handler = bindQxHandler({inputType: type, outputType: unit, ports: {}}, async (context) => {
+    assert.ok(context.input.target.equals(target));
+    assert.equal(context.input.x, 12);
+  }, {});
+  await handler({objectId: target, inputProto: encoded.kind.value.fields});
+});
 test("typed sessions rebind ports and cancellation to each acquired invocation", async () => {
   const first = new AbortController(), second = new AbortController();
   let closed = false;