Preserve image detail in app-server inputs (#20693)

## Summary

- Add optional image detail to user image inputs across core, app-server
v2, thread history/event mapping, and the generated app-server
schemas/types.
- Preserve requested detail when serializing Responses image inputs:
omitted detail stays on the existing `high` default, while explicit
`original` keeps local images on the original-resolution path.
- Support `high`/`original` consistently for tool image outputs,
including MCP `codex/imageDetail`, code-mode image helpers, and
`view_image`.

codex-rs/code-mode/src/description.rs

@@ -24,7 +24,7 @@ const EXEC_DESCRIPTION_TEMPLATE: &str = r#"Run JavaScript code to orchestrate/co
 - Global helpers:
 - `exit()`: Immediately ends the current script successfully (like an early return from the top level).
 - `text(value: string | number | boolean | undefined | null)`: Appends a text item. Non-string values are stringified with `JSON.stringify(...)` when possible.
-- `image(imageUrlOrItem: string | { image_url: string; detail?: "auto" | "low" | "high" | "original" | null } | ImageContent, detail?: "auto" | "low" | "high" | "original" | null)`: Appends an image item. `image_url` can be an HTTPS URL or a base64-encoded `data:` URL. To forward an MCP tool image, pass an individual `ImageContent` block from `result.content`, for example `image(result.content[0])`. MCP image blocks may request detail with `_meta: { "codex/imageDetail": "original" }`. When provided, the second `detail` argument overrides any detail embedded in the first argument.
+- `image(imageUrlOrItem: string | { image_url: string; detail?: "high" | "original" | null } | ImageContent, detail?: "high" | "original" | null)`: Appends an image item. `image_url` can be an HTTPS URL or a base64-encoded `data:` URL. To forward an MCP tool image, pass an individual `ImageContent` block from `result.content`, for example `image(result.content[0])`. MCP image blocks may request detail with `_meta: { "codex/imageDetail": "original" }`. When provided, the second `detail` argument overrides any detail embedded in the first argument.
 - `store(key: string, value: any)`: stores a serializable value under a string key for later `exec` calls in the same session.
 - `load(key: string)`: returns the stored value for a string key, or `undefined` if it is missing.
 - `notify(value: string | number | boolean | undefined | null)`: immediately injects an extra `custom_tool_call_output` for the current `exec` call. Values are stringified like `text(...)`.

codex-rs/code-mode/src/response.rs

@@ -4,8 +4,6 @@ use serde::Serialize;
 #[derive(Debug, Clone, Copy, Serialize, Deserialize, PartialEq, Eq)]
 #[serde(rename_all = "lowercase")]
 pub enum ImageDetail {
-    Auto,
-    Low,
     High,
     Original,
 }

codex-rs/code-mode/src/runtime/value.rs

@@ -71,14 +71,10 @@ pub(super) fn normalize_output_image(
             Some(detail) => {
                 let normalized = detail.to_ascii_lowercase();
                 Some(match normalized.as_str() {
-                    "auto" => ImageDetail::Auto,
-                    "low" => ImageDetail::Low,
                     "high" => ImageDetail::High,
                     "original" => ImageDetail::Original,
                     _ => {
-                        return Err(
-                            "image detail must be one of: auto, low, high, original".to_string()
-                        );
+                        return Err("image detail must be one of: high, original".to_string());
                     }
                 })
             }
@@ -160,7 +156,7 @@ fn parse_mcp_output_image(
         .and_then(JsonValue::as_object)
         .and_then(|meta| meta.get(CODEX_IMAGE_DETAIL_META_KEY))
         .and_then(JsonValue::as_str)
-        .filter(|detail| matches!(*detail, "auto" | "low" | "high" | "original"))
+        .filter(|detail| matches!(*detail, "high" | "original"))
         .map(str::to_string);
     Ok((image_url, detail))
 }

codex-rs/code-mode/src/service.rs

@@ -1308,7 +1308,7 @@ image({
 image(
   {
     image_url: "https://example.com/image.jpg",
-    detail: "low",
+    detail: "high",
   },
   "original",
 );
@@ -1348,7 +1348,7 @@ image(
     mimeType: "image/png",
     _meta: { "codex/imageDetail": "original" },
   },
-  "low",
+  "high",
 );
 "#
                 .to_string(),
@@ -1364,7 +1364,7 @@ image(
                 cell_id: "1".to_string(),
                 content_items: vec![FunctionCallOutputContentItem::InputImage {
                     image_url: "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVR4nGP4z8DwHwAFAAH/iZk9HQAAAABJRU5ErkJggg==".to_string(),
-                    detail: Some(crate::ImageDetail::Low),
+                    detail: Some(crate::ImageDetail::High),
                 }],
                 stored_values: HashMap::new(),
                 error_text: None,
@@ -1372,6 +1372,36 @@ image(
         );
     }
 
+    #[tokio::test]
+    async fn image_helper_rejects_unsupported_detail() {
+        let service = CodeModeService::new();
+
+        let response = service
+            .execute(ExecuteRequest {
+                source: r#"
+image({
+  image_url: "https://example.com/image.jpg",
+  detail: "low",
+});
+"#
+                .to_string(),
+                yield_time_ms: None,
+                ..execute_request("")
+            })
+            .await
+            .unwrap();
+
+        assert_eq!(
+            response,
+            RuntimeResponse::Result {
+                cell_id: "1".to_string(),
+                content_items: Vec::new(),
+                stored_values: HashMap::new(),
+                error_text: Some("image detail must be one of: high, original".to_string()),
+            }
+        );
+    }
+
     #[tokio::test]
     async fn image_helper_rejects_raw_mcp_result_container() {
         let service = CodeModeService::new();