diff --git a/src/tools/mongodb/metadata/explain.ts b/src/tools/mongodb/metadata/explain.ts
index a686d9cce..ae9eb822e 100644
--- a/src/tools/mongodb/metadata/explain.ts
+++ b/src/tools/mongodb/metadata/explain.ts
@@ -16,7 +16,7 @@ export class ExplainTool extends MongoDBToolBase {
         ...DbOperationArgs,
         method: z
             .array(
-                z.union([
+                z.discriminatedUnion("name", [
                     z.object({
                         name: z.literal("aggregate"),
                         arguments: z.object(AggregateArgs),
diff --git a/src/tools/mongodb/read/aggregate.ts b/src/tools/mongodb/read/aggregate.ts
index f9868dba8..b74dd7865 100644
--- a/src/tools/mongodb/read/aggregate.ts
+++ b/src/tools/mongodb/read/aggregate.ts
@@ -6,7 +6,7 @@ import { EJSON } from "bson";
 import { checkIndexUsage } from "../../../helpers/indexCheck.js";
 
 export const AggregateArgs = {
-    pipeline: z.array(z.record(z.string(), z.unknown())).describe("An array of aggregation stages to execute"),
+    pipeline: z.array(z.object({}).passthrough()).describe("An array of aggregation stages to execute"),
 };
 
 export class AggregateTool extends MongoDBToolBase {
diff --git a/src/tools/mongodb/read/count.ts b/src/tools/mongodb/read/count.ts
index df3664b57..5f5f44c07 100644
--- a/src/tools/mongodb/read/count.ts
+++ b/src/tools/mongodb/read/count.ts
@@ -6,7 +6,8 @@ import { checkIndexUsage } from "../../../helpers/indexCheck.js";
 
 export const CountArgs = {
     query: z
-        .record(z.string(), z.unknown())
+        .object({})
+        .passthrough()
         .optional()
         .describe(
             "A filter/query parameter. Allows users to filter the documents to count. Matches the syntax of the filter argument of db.collection.count()."
diff --git a/src/tools/mongodb/read/find.ts b/src/tools/mongodb/read/find.ts
index 02c337edb..0649e62dc 100644
--- a/src/tools/mongodb/read/find.ts
+++ b/src/tools/mongodb/read/find.ts
@@ -8,18 +8,23 @@ import { checkIndexUsage } from "../../../helpers/indexCheck.js";
 
 export const FindArgs = {
     filter: z
-        .record(z.string(), z.unknown())
+        .object({})
+        .passthrough()
         .optional()
         .describe("The query filter, matching the syntax of the query argument of db.collection.find()"),
     projection: z
-        .record(z.string(), z.unknown())
+        .object({})
+        .passthrough()
         .optional()
         .describe("The projection, matching the syntax of the projection argument of db.collection.find()"),
     limit: z.number().optional().default(10).describe("The maximum number of documents to return"),
     sort: z
-        .record(z.string(), z.custom<SortDirection>())
+        .object({})
+        .catchall(z.custom<SortDirection>())
         .optional()
-        .describe("A document, describing the sort order, matching the syntax of the sort argument of cursor.sort()"),
+        .describe(
+            "A document, describing the sort order, matching the syntax of the sort argument of cursor.sort(). The keys of the object are the fields to sort on, while the values are the sort directions (1 for ascending, -1 for descending)."
+        ),
 };
 
 export class FindTool extends MongoDBToolBase {