diff --git a/codex-cli/src/components/chat/terminal-chat.tsx b/codex-cli/src/components/chat/terminal-chat.tsx
index 9092932a..cf304ad7 100644
--- a/codex-cli/src/components/chat/terminal-chat.tsx
+++ b/codex-cli/src/components/chat/terminal-chat.tsx
@@ -13,7 +13,7 @@ import { useTerminalSize } from "../../hooks/use-terminal-size.js";
 import { AgentLoop } from "../../utils/agent/agent-loop.js";
 import { ReviewDecision } from "../../utils/agent/review.js";
 import { generateCompactSummary } from "../../utils/compact-summary.js";
-import { OPENAI_BASE_URL, saveConfig } from "../../utils/config.js";
+import { getBaseUrl, getApiKey, saveConfig } from "../../utils/config.js";
 import { extractAppliedPatches as _extractAppliedPatches } from "../../utils/extract-applied-patches.js";
 import { getGitDiff } from "../../utils/get-diff.js";
 import { createInputItem } from "../../utils/input-utils.js";
@@ -65,18 +65,21 @@ const colorsByPolicy: Record<ApprovalPolicy, ColorName | undefined> = {
  *
  * @param command The command to explain
  * @param model The model to use for generating the explanation
+ * @param flexMode Whether to use the flex-mode service tier
+ * @param config The configuration object
  * @returns A human-readable explanation of what the command does
  */
 async function generateCommandExplanation(
   command: Array<string>,
   model: string,
   flexMode: boolean,
+  config: AppConfig,
 ): Promise<string> {
   try {
     // Create a temporary OpenAI client
     const oai = new OpenAI({
-      apiKey: process.env["OPENAI_API_KEY"],
-      baseURL: OPENAI_BASE_URL,
+      apiKey: getApiKey(config.provider),
+      baseURL: getBaseUrl(config.provider),
     });
 
     // Format the command for display
@@ -156,6 +159,7 @@ export default function TerminalChat({
         items,
         model,
         Boolean(config.flexMode),
+        config,
       );
       setItems([
         {
@@ -272,6 +276,7 @@ export default function TerminalChat({
             command,
             model,
             Boolean(config.flexMode),
+            config,
           );
           log(`Generated explanation: ${explanation}`);
 
diff --git a/codex-cli/src/components/singlepass-cli-app.tsx b/codex-cli/src/components/singlepass-cli-app.tsx
index 0c5eeb4e..56d1d913 100644
--- a/codex-cli/src/components/singlepass-cli-app.tsx
+++ b/codex-cli/src/components/singlepass-cli-app.tsx
@@ -5,12 +5,7 @@ import type { FileOperation } from "../utils/singlepass/file_ops";
 
 import Spinner from "./vendor/ink-spinner"; // Third‑party / vendor components
 import TextInput from "./vendor/ink-text-input";
-import {
-  OPENAI_TIMEOUT_MS,
-  OPENAI_BASE_URL as _OPENAI_BASE_URL,
-  getBaseUrl,
-  getApiKey,
-} from "../utils/config";
+import { OPENAI_TIMEOUT_MS, getBaseUrl, getApiKey } from "../utils/config";
 import {
   generateDiffSummary,
   generateEditSummary,
@@ -399,8 +394,8 @@ export function SinglePassApp({
       });
 
       const openai = new OpenAI({
-        apiKey: getApiKey(config.provider ?? "openai"),
-        baseURL: getBaseUrl(config.provider ?? "openai"),
+        apiKey: getApiKey(config.provider),
+        baseURL: getBaseUrl(config.provider),
         timeout: OPENAI_TIMEOUT_MS,
       });
       const chatResp = await openai.beta.chat.completions.parse({
diff --git a/codex-cli/src/utils/compact-summary.ts b/codex-cli/src/utils/compact-summary.ts
index 040145da..82a337e3 100644
--- a/codex-cli/src/utils/compact-summary.ts
+++ b/codex-cli/src/utils/compact-summary.ts
@@ -1,8 +1,8 @@
+import type { AppConfig } from "./config.js";
 import type { ResponseItem } from "openai/resources/responses/responses.mjs";
 
-import { OPENAI_BASE_URL } from "./config.js";
+import { getBaseUrl, getApiKey } from "./config.js";
 import OpenAI from "openai";
-
 /**
  * Generate a condensed summary of the conversation items.
  * @param items The list of conversation items to summarize
@@ -14,16 +14,18 @@ import OpenAI from "openai";
  * @param items The list of conversation items to summarize
  * @param model The model to use for generating the summary
  * @param flexMode Whether to use the flex-mode service tier
+ * @param config The configuration object
  * @returns A concise structured summary string
  */
 export async function generateCompactSummary(
   items: Array<ResponseItem>,
   model: string,
   flexMode = false,
+  config: AppConfig,
 ): Promise<string> {
   const oai = new OpenAI({
-    apiKey: process.env["OPENAI_API_KEY"],
-    baseURL: OPENAI_BASE_URL,
+    apiKey: getApiKey(config.provider),
+    baseURL: getBaseUrl(config.provider),
   });
 
   const conversationText = items
diff --git a/codex-cli/src/utils/config.ts b/codex-cli/src/utils/config.ts
index a8d73feb..0c9cffa4 100644
--- a/codex-cli/src/utils/config.ts
+++ b/codex-cli/src/utils/config.ts
@@ -41,15 +41,26 @@ export function setApiKey(apiKey: string): void {
   OPENAI_API_KEY = apiKey;
 }
 
-export function getBaseUrl(provider: string): string | undefined {
+export function getBaseUrl(provider: string = "openai"): string | undefined {
+  // If the provider is `openai` and `OPENAI_BASE_URL` is set, use it
+  if (provider === "openai" && OPENAI_BASE_URL !== "") {
+    return OPENAI_BASE_URL;
+  }
+
   const providerInfo = providers[provider.toLowerCase()];
   if (providerInfo) {
     return providerInfo.baseURL;
   }
+
+  // If the provider not found in the providers list and `OPENAI_BASE_URL` is set, use it
+  if (OPENAI_BASE_URL !== "") {
+    return OPENAI_BASE_URL;
+  }
+
   return undefined;
 }
 
-export function getApiKey(provider: string): string | undefined {
+export function getApiKey(provider: string = "openai"): string | undefined {
   const providerInfo = providers[provider.toLowerCase()];
   if (providerInfo) {
     if (providerInfo.name === "Ollama") {
@@ -58,6 +69,11 @@ export function getApiKey(provider: string): string | undefined {
     return process.env[providerInfo.envKey];
   }
 
+  // If the provider not found in the providers list and `OPENAI_API_KEY` is set, use it
+  if (OPENAI_API_KEY !== "") {
+    return OPENAI_API_KEY;
+  }
+
   return undefined;
 }
 
diff --git a/codex-cli/src/utils/model-utils.ts b/codex-cli/src/utils/model-utils.ts
index 31f1afe6..774371ed 100644
--- a/codex-cli/src/utils/model-utils.ts
+++ b/codex-cli/src/utils/model-utils.ts
@@ -20,9 +20,11 @@ async function fetchModels(provider: string): Promise<Array<string>> {
     throw new Error("No API key configured for provider: " + provider);
   }
 
-  const baseURL = getBaseUrl(provider);
   try {
-    const openai = new OpenAI({ apiKey: getApiKey(provider), baseURL });
+    const openai = new OpenAI({
+      apiKey: getApiKey(provider),
+      baseURL: getBaseUrl(provider),
+    });
     const list = await openai.models.list();
     const models: Array<string> = [];
     for await (const model of list as AsyncIterable<{ id?: string }>) {