app-server: Add platform os and family to init response (#14527)

This allows the client to pick os-specific behavior while interacting
with the app server, e.g. to use proper path separators.

codex-rs/app-server-protocol/schema/json/codex_app_server_protocol.schemas.json

@@ -2171,11 +2171,21 @@
     "InitializeResponse": {
       "$schema": "http://json-schema.org/draft-07/schema#",
       "properties": {
+        "platformFamily": {
+          "description": "Platform family for the running app-server target, for example `\"unix\"` or `\"windows\"`.",
+          "type": "string"
+        },
+        "platformOs": {
+          "description": "Operating system for the running app-server target, for example `\"macos\"`, `\"linux\"`, or `\"windows\"`.",
+          "type": "string"
+        },
         "userAgent": {
           "type": "string"
         }
       },
       "required": [
+        "platformFamily",
+        "platformOs",
         "userAgent"
       ],
       "title": "InitializeResponse",

codex-rs/app-server-protocol/schema/json/v1/InitializeResponse.json

@@ -1,11 +1,21 @@
 {
   "$schema": "http://json-schema.org/draft-07/schema#",
   "properties": {
+    "platformFamily": {
+      "description": "Platform family for the running app-server target, for example `\"unix\"` or `\"windows\"`.",
+      "type": "string"
+    },
+    "platformOs": {
+      "description": "Operating system for the running app-server target, for example `\"macos\"`, `\"linux\"`, or `\"windows\"`.",
+      "type": "string"
+    },
     "userAgent": {
       "type": "string"
     }
   },
   "required": [
+    "platformFamily",
+    "platformOs",
     "userAgent"
   ],
   "title": "InitializeResponse",

codex-rs/app-server-protocol/schema/typescript/InitializeResponse.ts

@@ -2,4 +2,14 @@
 
 // This file was generated by [ts-rs](https://github.com/Aleph-Alpha/ts-rs). Do not edit this file manually.
 
-export type InitializeResponse = { userAgent: string, };
+export type InitializeResponse = { userAgent: string, 
+/**
+ * Platform family for the running app-server target, for example
+ * `"unix"` or `"windows"`.
+ */
+platformFamily: string, 
+/**
+ * Operating system for the running app-server target, for example
+ * `"macos"`, `"linux"`, or `"windows"`.
+ */
+platformOs: string, };

codex-rs/app-server-protocol/src/protocol/v1.rs

@@ -56,6 +56,12 @@ pub struct InitializeCapabilities {
 #[serde(rename_all = "camelCase")]
 pub struct InitializeResponse {
     pub user_agent: String,
+    /// Platform family for the running app-server target, for example
+    /// `"unix"` or `"windows"`.
+    pub platform_family: String,
+    /// Operating system for the running app-server target, for example
+    /// `"macos"`, `"linux"`, or `"windows"`.
+    pub platform_os: String,
 }
 
 #[derive(Serialize, Deserialize, Debug, Clone, PartialEq, JsonSchema, TS)]