diff --git a/scripts/debug-claude-usage.ts b/scripts/debug-claude-usage.ts
index 4a5d46ea1..58af153e5 100644
--- a/scripts/debug-claude-usage.ts
+++ b/scripts/debug-claude-usage.ts
@@ -69,7 +69,9 @@ const pickAnthropicTokens = (store: {
 };
 
 const fetchAnthropicOAuthUsage = async (token: string) => {
-  const res = await fetch("https://api.anthropic.com/api/oauth/usage", {
+  const baseUrl = process.env.ANTHROPIC_BASE_URL?.trim() || "https://api.anthropic.com";
+  const url = `${baseUrl}/api/oauth/usage`;
+  const res = await fetch(url, {
     headers: {
       Authorization: `Bearer ${token}`,
       Accept: "application/json",
diff --git a/src/agents/models-config.providers.ts b/src/agents/models-config.providers.ts
index 0cd034c82..11c19cc1e 100644
--- a/src/agents/models-config.providers.ts
+++ b/src/agents/models-config.providers.ts
@@ -246,6 +246,15 @@ export function normalizeProviders(params: {
       normalizedProvider = googleNormalized;
     }
 
+    // Apply ANTHROPIC_BASE_URL environment variable override
+    if (normalizedKey === "anthropic") {
+      const baseUrl = process.env.ANTHROPIC_BASE_URL?.trim();
+      if (baseUrl && normalizedProvider.baseUrl !== baseUrl) {
+        mutated = true;
+        normalizedProvider = { ...normalizedProvider, baseUrl };
+      }
+    }
+
     next[key] = normalizedProvider;
   }
 
@@ -396,6 +405,15 @@ export async function resolveImplicitProviders(params: {
     allowKeychainPrompt: false,
   });
 
+  // Add Anthropic provider if ANTHROPIC_BASE_URL is set
+  const anthropicBaseUrl = process.env.ANTHROPIC_BASE_URL?.trim();
+  if (anthropicBaseUrl) {
+    providers.anthropic = {
+      baseUrl: anthropicBaseUrl,
+      models: [],
+    };
+  }
+
   const minimaxKey =
     resolveEnvApiKeyVarName("minimax") ??
     resolveApiKeyFromProfiles({ provider: "minimax", store: authStore });
diff --git a/src/infra/provider-usage.fetch.claude.ts b/src/infra/provider-usage.fetch.claude.ts
index 654962c93..79fabda64 100644
--- a/src/infra/provider-usage.fetch.claude.ts
+++ b/src/infra/provider-usage.fetch.claude.ts
@@ -99,8 +99,10 @@ export async function fetchClaudeUsage(
   timeoutMs: number,
   fetchFn: typeof fetch,
 ): Promise<ProviderUsageSnapshot> {
+  const baseUrl = process.env.ANTHROPIC_BASE_URL?.trim() || "https://api.anthropic.com";
+  const url = `${baseUrl}/api/oauth/usage`;
   const res = await fetchJson(
-    "https://api.anthropic.com/api/oauth/usage",
+    url,
     {
       headers: {
         Authorization: `Bearer ${token}`,