app-server: Return codex home in initialize response (#15689)

This allows clients to get enough information to interact with the codex
skills/configuration/etc.

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

@@ -1,6 +1,10 @@
 {
   "$schema": "http://json-schema.org/draft-07/schema#",
   "definitions": {
+    "AbsolutePathBuf": {
+      "description": "A path that is guaranteed to be absolute and normalized (though it is not guaranteed to be canonicalized or exist on the filesystem).\n\nIMPORTANT: When deserializing an `AbsolutePathBuf`, a base path must be set using [AbsolutePathBufGuard::new]. If no base path is set, the deserialization will fail unless the path being deserialized is already absolute.",
+      "type": "string"
+    },
     "AdditionalFileSystemPermissions": {
       "properties": {
         "read": {
@@ -2305,6 +2309,14 @@
     "InitializeResponse": {
       "$schema": "http://json-schema.org/draft-07/schema#",
       "properties": {
+        "codexHome": {
+          "allOf": [
+            {
+              "$ref": "#/definitions/v2/AbsolutePathBuf"
+            }
+          ],
+          "description": "Absolute path to the server's $CODEX_HOME directory."
+        },
         "platformFamily": {
           "description": "Platform family for the running app-server target, for example `\"unix\"` or `\"windows\"`.",
           "type": "string"
@@ -2318,6 +2330,7 @@
         }
       },
       "required": [
+        "codexHome",
         "platformFamily",
         "platformOs",
         "userAgent"

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

@@ -1,6 +1,20 @@
 {
   "$schema": "http://json-schema.org/draft-07/schema#",
+  "definitions": {
+    "AbsolutePathBuf": {
+      "description": "A path that is guaranteed to be absolute and normalized (though it is not guaranteed to be canonicalized or exist on the filesystem).\n\nIMPORTANT: When deserializing an `AbsolutePathBuf`, a base path must be set using [AbsolutePathBufGuard::new]. If no base path is set, the deserialization will fail unless the path being deserialized is already absolute.",
+      "type": "string"
+    }
+  },
   "properties": {
+    "codexHome": {
+      "allOf": [
+        {
+          "$ref": "#/definitions/AbsolutePathBuf"
+        }
+      ],
+      "description": "Absolute path to the server's $CODEX_HOME directory."
+    },
     "platformFamily": {
       "description": "Platform family for the running app-server target, for example `\"unix\"` or `\"windows\"`.",
       "type": "string"
@@ -14,6 +28,7 @@
     }
   },
   "required": [
+    "codexHome",
     "platformFamily",
     "platformOs",
     "userAgent"

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

@@ -1,8 +1,13 @@
 // GENERATED CODE! DO NOT MODIFY BY HAND!
 
 // This file was generated by [ts-rs](https://github.com/Aleph-Alpha/ts-rs). Do not edit this file manually.
+import type { AbsolutePathBuf } from "./AbsolutePathBuf";
 
 export type InitializeResponse = { userAgent: string, 
+/**
+ * Absolute path to the server's $CODEX_HOME directory.
+ */
+codexHome: AbsolutePathBuf, 
 /**
  * Platform family for the running app-server target, for example
  * `"unix"` or `"windows"`.

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

@@ -56,6 +56,8 @@ pub struct InitializeCapabilities {
 #[serde(rename_all = "camelCase")]
 pub struct InitializeResponse {
     pub user_agent: String,
+    /// Absolute path to the server's $CODEX_HOME directory.
+    pub codex_home: AbsolutePathBuf,
     /// Platform family for the running app-server target, for example
     /// `"unix"` or `"windows"`.
     pub platform_family: String,