From 5bf2e03af0b21a75dfadd85569b98327d77d7fe8 Mon Sep 17 00:00:00 2001
From: nightcityblade <nightcityblade@gmail.com>
Date: Mon, 31 Aug 2026 23:20:57 +0800
Subject: [PATCH 1/2] fix(http-server-csharp): import JsonNodes for record
 arrays

---
 .../src/components/models/model-helpers.ts       |  8 ++++++--
 .../src/components/models/models.test.tsx        | 16 ++++++++++++++++
 2 files changed, 22 insertions(+), 2 deletions(-)

diff --git a/packages/http-server-csharp/src/components/models/model-helpers.ts b/packages/http-server-csharp/src/components/models/model-helpers.ts
index 094d5189b84..e4550f4bd73 100644
--- a/packages/http-server-csharp/src/components/models/model-helpers.ts
+++ b/packages/http-server-csharp/src/components/models/model-helpers.ts
@@ -185,9 +185,13 @@ export function isValueType($: ReturnType<typeof useTsp>["$"], type: Type): bool
 /** Returns true if any property of the model uses Record<T> (mapped to JsonObject). */
 export function modelNeedsJsonNodes($: ReturnType<typeof useTsp>["$"], model: Model): boolean {
   for (const prop of model.properties.values()) {
-    if (prop.type.kind === "Model" && $.record.is(prop.type)) {
+    let type = prop.type;
+    while (type.kind === "Model" && $.array.is(type) && type.indexer?.value) {
+      type = type.indexer.value;
+    }
+    if (type.kind === "Model" && $.record.is(type)) {
       // Only need JsonNodes for Record<unknown> (maps to JsonObject)
-      const valueType = prop.type.indexer?.value;
+      const valueType = type.indexer?.value;
       if (valueType?.kind === "Intrinsic" && valueType.name === "unknown") return true;
     }
   }
diff --git a/packages/http-server-csharp/src/components/models/models.test.tsx b/packages/http-server-csharp/src/components/models/models.test.tsx
index 1b117faed47..d26c0cd3153 100644
--- a/packages/http-server-csharp/src/components/models/models.test.tsx
+++ b/packages/http-server-csharp/src/components/models/models.test.tsx
@@ -8,6 +8,7 @@ import { ClassDeclaration } from "@typespec/emitter-framework/csharp";
 import { HttpCanonicalizer } from "@typespec/http-canonicalization";
 import { beforeEach, expect, it } from "vitest";
 import { resolveServiceTypes } from "../../service-resolution.js";
+import { modelNeedsJsonNodes } from "./model-helpers.js";
 
 let runner: TesterInstance;
 
@@ -130,6 +131,21 @@ it("renders a model with nullable union property", async () => {
   `);
 });
 
+it("detects Record<unknown> nested in array properties", async () => {
+  const { JsonObjectArray, StringMapArray } = await runner.compile(t.code`
+    model ${t.model("JsonObjectArray")} {
+      items: Record<unknown>[][];
+    }
+    model ${t.model("StringMapArray")} {
+      items: Record<string>[];
+    }
+  `);
+  const tk = $(runner.program);
+
+  expect(modelNeedsJsonNodes(tk, JsonObjectArray)).toBe(true);
+  expect(modelNeedsJsonNodes(tk, StringMapArray)).toBe(false);
+});
+
 it("does not emit a model class for an @useAuth scheme model", async () => {
   await runner.compile(`
     @service

From ecc93a041af9604f91daae1faf637725f8963653 Mon Sep 17 00:00:00 2001
From: nightcityblade <nightcityblade@gmail.com>
Date: Tue, 1 Sep 2026 11:03:38 +0800
Subject: [PATCH 2/2] chore: add http server C# change description

---
 .../http-server-csharp-import-json-nodes-2026-09-01.md     | 7 +++++++
 1 file changed, 7 insertions(+)
 create mode 100644 .chronus/changes/http-server-csharp-import-json-nodes-2026-09-01.md

diff --git a/.chronus/changes/http-server-csharp-import-json-nodes-2026-09-01.md b/.chronus/changes/http-server-csharp-import-json-nodes-2026-09-01.md
new file mode 100644
index 00000000000..91a2a10d915
--- /dev/null
+++ b/.chronus/changes/http-server-csharp-import-json-nodes-2026-09-01.md
@@ -0,0 +1,7 @@
+---
+changeKind: fix
+packages:
+  - "@typespec/http-server-csharp"
+---
+
+Import `JsonNode` collection types when generating models containing record arrays.