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diff --git a/src/mongo/db/query/query_shape/cmd_with_let_shape.h b/src/mongo/db/query/query_shape/cmd_with_let_shape.h
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+++ b/src/mongo/db/query/query_shape/cmd_with_let_shape.h
@@ -0,0 +1,109 @@
+/**
+ *    Copyright (C) 2023-present MongoDB, Inc.
+ *
+ *    This program is free software: you can redistribute it and/or modify
+ *    it under the terms of the Server Side Public License, version 1,
+ *    as published by MongoDB, Inc.
+ *
+ *    This program is distributed in the hope that it will be useful,
+ *    but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *    Server Side Public License for more details.
+ *
+ *    You should have received a copy of the Server Side Public License
+ *    along with this program. If not, see
+ *    <http://www.mongodb.com/licensing/server-side-public-license>.
+ *
+ *    As a special exception, the copyright holders give permission to link the
+ *    code of portions of this program with the OpenSSL library under certain
+ *    conditions as described in each individual source file and distribute
+ *    linked combinations including the program with the OpenSSL library. You
+ *    must comply with the Server Side Public License in all respects for
+ *    all of the code used other than as permitted herein. If you modify file(s)
+ *    with this exception, you may extend this exception to your version of the
+ *    file(s), but you are not obligated to do so. If you do not wish to do so,
+ *    delete this exception statement from your version. If you delete this
+ *    exception statement from all source files in the program, then also delete
+ *    it in the license file.
+ */
+
+#pragma once
+
+#include "mongo/bson/bsonobj.h"
+#include "mongo/db/pipeline/expression_context.h"
+#include "mongo/db/query/parsed_find_command.h"
+#include "mongo/db/query/query_shape/query_shape.h"
+#include "mongo/db/query/query_shape/serialization_options.h"
+
+namespace mongo::query_shape {
+
+/**
+ * This struct is bit of a weird one. We want to use it as the shape's _entire_ "specific
+ * components" (rather than introduce more virtual functions to that interface). So, we track here
+ * the let component (as the name suggests) but we also keep an unowned reference to the specific
+ * components of CmdWithLetShape sub-classes. This class doesn't really do all that much with those
+ * components except track a reference to them and ensure their size is accounted for and their hash
+ * value is incorporated.
+ */
+struct LetShapeComponent : public CmdSpecificShapeComponents {
+    LetShapeComponent(boost::optional<BSONObj> let,
+                      const boost::intrusive_ptr<ExpressionContext>& expCtx,
+                      const CmdSpecificShapeComponents& unownedInnerComponents);
+
+    /**
+     * Hashes to include the shapified let parameters and also the hash of 'unownedInnerComponents'.
+     */
+    void HashValue(absl::HashState state) const final;
+
+    /**
+     * Includes the size of the let parameters and the size of 'unownedInnerComponents.'
+     */
+    size_t size() const final;
+
+    /**
+     * Adds _only_ the let params.
+     */
+    void addLetBson(BSONObjBuilder&,
+                    const SerializationOptions&,
+                    const boost::intrusive_ptr<ExpressionContext>&) const;
+
+    BSONObj shapifiedLet;
+    bool hasLet;
+    // Tracked so that this can be hash combined correctly.
+    const CmdSpecificShapeComponents& unownedInnerComponents;
+};
+
+/**
+ * The 'let' command argument is semi-generic in that it is supported in a couple commands. However
+ * it is treated specially since it supports using expressions as the let constants. Using
+ * expressions induces a library dependency that we don't want in the Shape interface itself. So
+ * this class handles tracking and adding the 'let' component of the shape for sub-classes.
+ */
+class CmdWithLetShape : public Shape {
+public:
+    CmdWithLetShape(boost::optional<BSONObj> let,
+                    const boost::intrusive_ptr<ExpressionContext>& expCtx,
+                    const CmdSpecificShapeComponents& unownedInnerComponents,
+                    NamespaceStringOrUUID,
+                    BSONObj collation_);
+
+    const CmdSpecificShapeComponents& specificComponents() const final {
+        return _let;
+    }
+
+protected:
+    void appendCmdSpecificShapeComponents(BSONObjBuilder&,
+                                          OperationContext* opCtx,
+                                          const SerializationOptions& opts) const final;
+    virtual void appendLetCmdSpecificShapeComponents(
+        BSONObjBuilder&,
+        const boost::intrusive_ptr<ExpressionContext>& expCtx,
+        const SerializationOptions&) const = 0;
+
+    LetShapeComponent _let;
+};
+static_assert(sizeof(CmdWithLetShape) == sizeof(Shape) + sizeof(LetShapeComponent),
+              "If the class' members have changed, this assert and the extraSize() calculation may "
+              "need to be updated with a new value.");
+
+}  // namespace mongo::query_shape