refactor: centralize model override validation

src/gateway/server.ts

@@ -10,8 +10,7 @@ import {
   resetModelCatalogCacheForTest,
 } from "../agents/model-catalog.js";
 import {
-  buildAllowedModelSet,
-  modelKey,
+  getModelRefStatus,
   resolveConfiguredModelRef,
   resolveHooksGmailModel,
 } from "../agents/model-selection.js";
@@ -1782,22 +1781,21 @@ export async function startGatewayServer(
           defaultModel: DEFAULT_MODEL,
         });
       const catalog = await loadModelCatalog({ config: cfgAtStart });
-      const key = modelKey(hooksModelRef.provider, hooksModelRef.model);
-      const allowed = buildAllowedModelSet({
+      const status = getModelRefStatus({
         cfg: cfgAtStart,
         catalog,
+        ref: hooksModelRef,
         defaultProvider,
         defaultModel,
       });
-      if (!allowed.allowAny && !allowed.allowedKeys.has(key)) {
+      if (!status.allowed) {
         logHooks.warn(
-          `hooks.gmail.model "${key}" not in agents.defaults.models allowlist (will use primary instead)`,
+          `hooks.gmail.model "${status.key}" not in agents.defaults.models allowlist (will use primary instead)`,
         );
       }
-      const inCatalog = catalog.some((e) => modelKey(e.provider, e.id) === key);
-      if (!inCatalog) {
+      if (!status.inCatalog) {
         logHooks.warn(
-          `hooks.gmail.model "${key}" not in the model catalog (may fail at runtime)`,
+          `hooks.gmail.model "${status.key}" not in the model catalog (may fail at runtime)`,
         );
       }
     }

src/gateway/sessions-patch.ts

@@ -3,11 +3,8 @@ import { randomUUID } from "node:crypto";
 import { DEFAULT_MODEL, DEFAULT_PROVIDER } from "../agents/defaults.js";
 import type { ModelCatalogEntry } from "../agents/model-catalog.js";
 import {
-  buildAllowedModelSet,
-  buildModelAliasIndex,
-  modelKey,
+  resolveAllowedModelRef,
   resolveConfiguredModelRef,
-  resolveModelRefFromString,
 } from "../agents/model-selection.js";
 import { normalizeGroupActivation } from "../auto-reply/group-activation.js";
 import {
@@ -168,17 +165,6 @@ export async function applySessionsPatchToStore(params: {
         defaultProvider: DEFAULT_PROVIDER,
         defaultModel: DEFAULT_MODEL,
       });
-      const aliasIndex = buildModelAliasIndex({
-        cfg,
-        defaultProvider: resolvedDefault.provider,
-      });
-      const resolved = resolveModelRefFromString({
-        raw: trimmed,
-        defaultProvider: resolvedDefault.provider,
-        aliasIndex,
-      });
-      if (!resolved) return invalid(`invalid model: ${trimmed}`);
-
       if (!params.loadGatewayModelCatalog) {
         return {
           ok: false,
@@ -189,15 +175,15 @@ export async function applySessionsPatchToStore(params: {
         };
       }
       const catalog = await params.loadGatewayModelCatalog();
-      const allowed = buildAllowedModelSet({
+      const resolved = resolveAllowedModelRef({
         cfg,
         catalog,
+        raw: trimmed,
         defaultProvider: resolvedDefault.provider,
         defaultModel: resolvedDefault.model,
       });
-      const key = modelKey(resolved.ref.provider, resolved.ref.model);
-      if (!allowed.allowAny && !allowed.allowedKeys.has(key)) {
-        return invalid(`model not allowed: ${key}`);
+      if ("error" in resolved) {
+        return invalid(resolved.error);
       }
       if (
         resolved.ref.provider === resolvedDefault.provider &&