1- Add model service tiers metadata (#20969)

## Why

The model list needs to carry display-ready service tier metadata so
clients can render tier choices with stable IDs, names, and
descriptions. A raw speed-tier string list is not enough for richer UI
copy or future tier labels.

## What changed

- Added `ModelServiceTier` to shared model metadata with string `id`,
`name`, and `description` fields.
- Added `service_tiers` to `ModelInfo` and `ModelPreset`, preserving
empty defaults for older cached model payloads.
- Exposed `serviceTiers` on app-server v2 `Model` responses and threaded
it through TUI app-server model conversion.
- Marked legacy `additional_speed_tiers` / `additionalSpeedTiers`
metadata as deprecated in source and generated schema output.
- Regenerated app-server protocol JSON schema and TypeScript fixtures,
including `ModelServiceTier.ts`.

## Verification

- Ran `just write-app-server-schema`.
- Did not run local tests per repo instruction; relying on PR CI.

---------

Co-authored-by: Codex <noreply@openai.com>

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

@@ -11266,6 +11266,7 @@
         "properties": {
           "additionalSpeedTiers": {
             "default": [],
+            "description": "Deprecated: use `serviceTiers` instead.",
             "items": {
               "type": "string"
             },
@@ -11312,6 +11313,13 @@
           "model": {
             "type": "string"
           },
+          "serviceTiers": {
+            "default": [],
+            "items": {
+              "$ref": "#/definitions/v2/ModelServiceTier"
+            },
+            "type": "array"
+          },
           "supportedReasoningEfforts": {
             "items": {
               "$ref": "#/definitions/v2/ReasoningEffortOption"
@@ -11476,6 +11484,25 @@
         "title": "ModelReroutedNotification",
         "type": "object"
       },
+      "ModelServiceTier": {
+        "properties": {
+          "description": {
+            "type": "string"
+          },
+          "id": {
+            "type": "string"
+          },
+          "name": {
+            "type": "string"
+          }
+        },
+        "required": [
+          "description",
+          "id",
+          "name"
+        ],
+        "type": "object"
+      },
       "ModelUpgradeInfo": {
         "properties": {
           "migrationMarkdown": {

codex-rs/app-server-protocol/schema/json/codex_app_server_protocol.v2.schemas.json

@@ -7877,6 +7877,7 @@
       "properties": {
         "additionalSpeedTiers": {
           "default": [],
+          "description": "Deprecated: use `serviceTiers` instead.",
           "items": {
             "type": "string"
           },
@@ -7923,6 +7924,13 @@
         "model": {
           "type": "string"
         },
+        "serviceTiers": {
+          "default": [],
+          "items": {
+            "$ref": "#/definitions/ModelServiceTier"
+          },
+          "type": "array"
+        },
         "supportedReasoningEfforts": {
           "items": {
             "$ref": "#/definitions/ReasoningEffortOption"
@@ -8087,6 +8095,25 @@
       "title": "ModelReroutedNotification",
       "type": "object"
     },
+    "ModelServiceTier": {
+      "properties": {
+        "description": {
+          "type": "string"
+        },
+        "id": {
+          "type": "string"
+        },
+        "name": {
+          "type": "string"
+        }
+      },
+      "required": [
+        "description",
+        "id",
+        "name"
+      ],
+      "type": "object"
+    },
     "ModelUpgradeInfo": {
       "properties": {
         "migrationMarkdown": {

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

@@ -24,6 +24,7 @@
       "properties": {
         "additionalSpeedTiers": {
           "default": [],
+          "description": "Deprecated: use `serviceTiers` instead.",
           "items": {
             "type": "string"
           },
@@ -70,6 +71,13 @@
         "model": {
           "type": "string"
         },
+        "serviceTiers": {
+          "default": [],
+          "items": {
+            "$ref": "#/definitions/ModelServiceTier"
+          },
+          "type": "array"
+        },
         "supportedReasoningEfforts": {
           "items": {
             "$ref": "#/definitions/ReasoningEffortOption"
@@ -120,6 +128,25 @@
       ],
       "type": "object"
     },
+    "ModelServiceTier": {
+      "properties": {
+        "description": {
+          "type": "string"
+        },
+        "id": {
+          "type": "string"
+        },
+        "name": {
+          "type": "string"
+        }
+      },
+      "required": [
+        "description",
+        "id",
+        "name"
+      ],
+      "type": "object"
+    },
     "ModelUpgradeInfo": {
       "properties": {
         "migrationMarkdown": {

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

@@ -4,7 +4,12 @@
 import type { InputModality } from "../InputModality";
 import type { ReasoningEffort } from "../ReasoningEffort";
 import type { ModelAvailabilityNux } from "./ModelAvailabilityNux";
+import type { ModelServiceTier } from "./ModelServiceTier";
 import type { ModelUpgradeInfo } from "./ModelUpgradeInfo";
 import type { ReasoningEffortOption } from "./ReasoningEffortOption";
 
-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, additionalSpeedTiers: Array<string>, 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,
+/**
+ * Deprecated: use `serviceTiers` instead.
+ */
+additionalSpeedTiers: Array<string>, serviceTiers: Array<ModelServiceTier>, isDefault: boolean, };

codex-rs/app-server-protocol/schema/typescript/v2/ModelServiceTier.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 ModelServiceTier = { id: string, name: string, description: string, };

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

@@ -245,6 +245,7 @@ export type { ModelProviderCapabilitiesReadParams } from "./ModelProviderCapabil
 export type { ModelProviderCapabilitiesReadResponse } from "./ModelProviderCapabilitiesReadResponse";
 export type { ModelRerouteReason } from "./ModelRerouteReason";
 export type { ModelReroutedNotification } from "./ModelReroutedNotification";
+export type { ModelServiceTier } from "./ModelServiceTier";
 export type { ModelUpgradeInfo } from "./ModelUpgradeInfo";
 export type { ModelVerification } from "./ModelVerification";
 export type { ModelVerificationNotification } from "./ModelVerificationNotification";

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

@@ -2511,6 +2511,15 @@ impl From<CoreModelAvailabilityNux> for ModelAvailabilityNux {
     }
 }
 
+#[derive(Serialize, Deserialize, Debug, Clone, PartialEq, JsonSchema, TS)]
+#[serde(rename_all = "camelCase")]
+#[ts(export_to = "v2/")]
+pub struct ModelServiceTier {
+    pub id: String,
+    pub name: String,
+    pub description: String,
+}
+
 #[derive(Serialize, Deserialize, Debug, Clone, PartialEq, JsonSchema, TS)]
 #[serde(rename_all = "camelCase")]
 #[ts(export_to = "v2/")]
@@ -2529,8 +2538,11 @@ pub struct Model {
     pub input_modalities: Vec<InputModality>,
     #[serde(default)]
     pub supports_personality: bool,
+    /// Deprecated: use `serviceTiers` instead.
     #[serde(default)]
     pub additional_speed_tiers: Vec<String>,
+    #[serde(default)]
+    pub service_tiers: Vec<ModelServiceTier>,
     // Only one model should be marked as default.
     pub is_default: bool,
 }