Add model availability NUX metadata (#12972)

- replace show_nux with structured availability_nux model metadata
- expose availability NUX data through the app-server model API
- update shared fixtures and tests for the new field

Author: aibrahim-oai

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

@@ -10225,6 +10225,16 @@
       },
       "Model": {
         "properties": {
+          "availabilityNux": {
+            "anyOf": [
+              {
+                "$ref": "#/definitions/v2/ModelAvailabilityNux"
+              },
+              {
+                "type": "null"
+              }
+            ]
+          },
           "defaultReasoningEffort": {
             "$ref": "#/definitions/v2/ReasoningEffort"
           },
@@ -10295,6 +10305,17 @@
         ],
         "type": "object"
       },
+      "ModelAvailabilityNux": {
+        "properties": {
+          "message": {
+            "type": "string"
+          }
+        },
+        "required": [
+          "message"
+        ],
+        "type": "object"
+      },
       "ModelListParams": {
         "$schema": "http://json-schema.org/draft-07/schema#",
         "properties": {

codex-rs/app-server-protocol/schema/json/v2/ModelListResponse.json

@@ -22,6 +22,16 @@
     },
     "Model": {
       "properties": {
+        "availabilityNux": {
+          "anyOf": [
+            {
+              "$ref": "#/definitions/ModelAvailabilityNux"
+            },
+            {
+              "type": "null"
+            }
+          ]
+        },
         "defaultReasoningEffort": {
           "$ref": "#/definitions/ReasoningEffort"
         },
@@ -92,6 +102,17 @@
       ],
       "type": "object"
     },
+    "ModelAvailabilityNux": {
+      "properties": {
+        "message": {
+          "type": "string"
+        }
+      },
+      "required": [
+        "message"
+      ],
+      "type": "object"
+    },
     "ModelUpgradeInfo": {
       "properties": {
         "migrationMarkdown": {

codex-rs/app-server-protocol/schema/typescript/v2/Model.ts

@@ -3,7 +3,8 @@
 // This file was generated by [ts-rs](https://github.com/Aleph-Alpha/ts-rs). Do not edit this file manually.
 import type { InputModality } from "../InputModality";
 import type { ReasoningEffort } from "../ReasoningEffort";
+import type { ModelAvailabilityNux } from "./ModelAvailabilityNux";
 import type { ModelUpgradeInfo } from "./ModelUpgradeInfo";
 import type { ReasoningEffortOption } from "./ReasoningEffortOption";
 
-export type Model = { id: string, model: string, upgrade: string | null, upgradeInfo: ModelUpgradeInfo | null, displayName: string, description: string, hidden: boolean, supportedReasoningEfforts: Array<ReasoningEffortOption>, defaultReasoningEffort: ReasoningEffort, inputModalities: Array<InputModality>, supportsPersonality: boolean, isDefault: boolean, };
+export type Model = { id: string, model: string, upgrade: string | null, upgradeInfo: ModelUpgradeInfo | null, availabilityNux: ModelAvailabilityNux | null, displayName: string, description: string, hidden: boolean, supportedReasoningEfforts: Array<ReasoningEffortOption>, defaultReasoningEffort: ReasoningEffort, inputModalities: Array<InputModality>, supportsPersonality: boolean, isDefault: boolean, };

codex-rs/app-server-protocol/schema/typescript/v2/ModelAvailabilityNux.ts

@@ -0,0 +1,5 @@
+// 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.
+
+export type ModelAvailabilityNux = { message: string, };

codex-rs/app-server-protocol/schema/typescript/v2/index.ts

@@ -107,6 +107,7 @@ export type { McpToolCallResult } from "./McpToolCallResult";
 export type { McpToolCallStatus } from "./McpToolCallStatus";
 export type { MergeStrategy } from "./MergeStrategy";
 export type { Model } from "./Model";
+export type { ModelAvailabilityNux } from "./ModelAvailabilityNux";
 export type { ModelListParams } from "./ModelListParams";
 export type { ModelListResponse } from "./ModelListResponse";
 export type { ModelRerouteReason } from "./ModelRerouteReason";

codex-rs/app-server-protocol/src/protocol/v2.rs

@@ -31,6 +31,7 @@ use codex_protocol::models::MessagePhase;
 use codex_protocol::models::PermissionProfile as CorePermissionProfile;
 use codex_protocol::models::ResponseItem;
 use codex_protocol::openai_models::InputModality;
+use codex_protocol::openai_models::ModelAvailabilityNux as CoreModelAvailabilityNux;
 use codex_protocol::openai_models::ReasoningEffort;
 use codex_protocol::openai_models::default_input_modalities;
 use codex_protocol::parse_command::ParsedCommand as CoreParsedCommand;
@@ -1389,6 +1390,21 @@ pub struct ModelListParams {
     pub include_hidden: Option<bool>,
 }
 
+#[derive(Serialize, Deserialize, Debug, Clone, PartialEq, JsonSchema, TS)]
+#[serde(rename_all = "camelCase")]
+#[ts(export_to = "v2/")]
+pub struct ModelAvailabilityNux {
+    pub message: String,
+}
+
+impl From<CoreModelAvailabilityNux> for ModelAvailabilityNux {
+    fn from(value: CoreModelAvailabilityNux) -> Self {
+        Self {
+            message: value.message,
+        }
+    }
+}
+
 #[derive(Serialize, Deserialize, Debug, Clone, PartialEq, JsonSchema, TS)]
 #[serde(rename_all = "camelCase")]
 #[ts(export_to = "v2/")]
@@ -1397,6 +1413,7 @@ pub struct Model {
     pub model: String,
     pub upgrade: Option<String>,
     pub upgrade_info: Option<ModelUpgradeInfo>,
+    pub availability_nux: Option<ModelAvailabilityNux>,
     pub display_name: String,
     pub description: String,
     pub hidden: bool,

codex-rs/app-server/README.md

@@ -142,7 +142,7 @@ Example with notification opt-out:
 - `thread/realtime/stop` — stop the active realtime session for the thread (experimental); returns `{}`.
 - `review/start` — kick off Codex’s automated reviewer for a thread; responds like `turn/start` and emits `item/started`/`item/completed` notifications with `enteredReviewMode` and `exitedReviewMode` items, plus a final assistant `agentMessage` containing the review.
 - `command/exec` — run a single command under the server sandbox without starting a thread/turn (handy for utilities and validation).
-- `model/list` — list available models (set `includeHidden: true` to include entries with `hidden: true`), with reasoning effort options, optional legacy `upgrade` model ids, and optional `upgradeInfo` metadata (`model`, `upgradeCopy`, `modelLink`, `migrationMarkdown`).
+- `model/list` — list available models (set `includeHidden: true` to include entries with `hidden: true`), with reasoning effort options, optional legacy `upgrade` model ids, optional `upgradeInfo` metadata (`model`, `upgradeCopy`, `modelLink`, `migrationMarkdown`), and optional `availabilityNux` metadata.
 - `experimentalFeature/list` — list feature flags with stage metadata (`beta`, `underDevelopment`, `stable`, etc.), enabled/default-enabled state, and cursor pagination. For non-beta flags, `displayName`/`description`/`announcement` are `null`.
 - `collaborationMode/list` — list available collaboration mode presets (experimental, no pagination). This response omits built-in developer instructions; clients should either pass `settings.developer_instructions: null` when setting a mode to use Codex's built-in instructions, or provide their own instructions explicitly.
 - `skills/list` — list skills for one or more `cwd` values (optional `forceReload`).

codex-rs/app-server/src/models.rs

@@ -32,6 +32,7 @@ fn model_from_preset(preset: ModelPreset) -> Model {
             model_link: upgrade.model_link.clone(),
             migration_markdown: upgrade.migration_markdown.clone(),
         }),
+        availability_nux: preset.availability_nux.map(Into::into),
         display_name: preset.display_name.to_string(),
         description: preset.description.to_string(),
         hidden: !preset.show_in_picker,

codex-rs/app-server/tests/common/models_cache.rs

@@ -34,6 +34,7 @@ fn preset_to_info(preset: &ModelPreset, priority: i32) -> ModelInfo {
         default_reasoning_summary: ReasoningSummary::Auto,
         support_verbosity: false,
         default_verbosity: None,
+        availability_nux: None,
         apply_patch_tool_type: None,
         truncation_policy: TruncationPolicyConfig::bytes(10_000),
         supports_parallel_tool_calls: false,

codex-rs/app-server/tests/suite/v2/model_list.rs

@@ -31,6 +31,7 @@ fn model_from_preset(preset: &ModelPreset) -> Model {
             model_link: upgrade.model_link.clone(),
             migration_markdown: upgrade.migration_markdown.clone(),
         }),
+        availability_nux: preset.availability_nux.clone().map(Into::into),
         display_name: preset.display_name.clone(),
         description: preset.description.clone(),
         hidden: !preset.show_in_picker,
@@ -134,50 +135,6 @@ async fn list_models_includes_hidden_models() -> Result<()> {
     Ok(())
 }
 
-#[tokio::test]
-async fn list_models_returns_upgrade_info_metadata() -> Result<()> {
-    let codex_home = TempDir::new()?;
-    write_models_cache(codex_home.path())?;
-    let mut mcp = McpProcess::new(codex_home.path()).await?;
-
-    timeout(DEFAULT_TIMEOUT, mcp.initialize()).await??;
-
-    let request_id = mcp
-        .send_list_models_request(ModelListParams {
-            limit: Some(100),
-            cursor: None,
-            include_hidden: Some(true),
-        })
-        .await?;
-
-    let response: JSONRPCResponse = timeout(
-        DEFAULT_TIMEOUT,
-        mcp.read_stream_until_response_message(RequestId::Integer(request_id)),
-    )
-    .await??;
-
-    let ModelListResponse { data: items, .. } = to_response::<ModelListResponse>(response)?;
-
-    let item = items
-        .iter()
-        .find(|item| item.upgrade_info.is_some())
-        .expect("expected at least one model with upgrade info");
-    let upgrade_info = item
-        .upgrade_info
-        .as_ref()
-        .expect("expected upgrade info to be populated");
-
-    assert_eq!(item.upgrade.as_ref(), Some(&upgrade_info.model));
-    assert!(!upgrade_info.model.is_empty());
-    assert!(
-        upgrade_info.upgrade_copy.is_some()
-            || upgrade_info.model_link.is_some()
-            || upgrade_info.migration_markdown.is_some()
-    );
-
-    Ok(())
-}
-
 #[tokio::test]
 async fn list_models_pagination_works() -> Result<()> {
     let codex_home = TempDir::new()?;