diff --git a/packages/pi-ai/src/providers/anthropic-auth.test.ts b/packages/pi-ai/src/providers/anthropic-auth.test.ts
new file mode 100644
index 000000000..4593e1a5d
--- /dev/null
+++ b/packages/pi-ai/src/providers/anthropic-auth.test.ts
@@ -0,0 +1,32 @@
+import test from "node:test";
+import assert from "node:assert/strict";
+import { readFileSync } from "node:fs";
+import { dirname, join } from "node:path";
+import { fileURLToPath } from "node:url";
+
+import { usesAnthropicBearerAuth } from "./anthropic.js";
+
+const __dirname = dirname(fileURLToPath(import.meta.url));
+
+test("usesAnthropicBearerAuth covers Bearer-only Anthropic-compatible providers (#3783)", () => {
+	assert.equal(usesAnthropicBearerAuth("alibaba-coding-plan"), true);
+	assert.equal(usesAnthropicBearerAuth("minimax"), true);
+	assert.equal(usesAnthropicBearerAuth("minimax-cn"), true);
+	assert.equal(usesAnthropicBearerAuth("anthropic"), false);
+});
+
+test("createClient routes Bearer-auth providers through authToken (#3783)", () => {
+	const source = readFileSync(join(__dirname, "..", "..", "src", "providers", "anthropic.ts"), "utf-8");
+	assert.ok(
+		source.includes("const usesBearerAuth = usesAnthropicBearerAuth(model.provider);"),
+		"createClient should derive auth mode from usesAnthropicBearerAuth",
+	);
+	assert.ok(
+		source.includes("apiKey: usesBearerAuth ? null : apiKey"),
+		"Bearer-auth providers should skip x-api-key auth",
+	);
+	assert.ok(
+		source.includes("authToken: usesBearerAuth ? apiKey : undefined"),
+		"Bearer-auth providers should send authToken instead",
+	);
+});
diff --git a/packages/pi-ai/src/providers/anthropic.ts b/packages/pi-ai/src/providers/anthropic.ts
index 57ee1b5be..ec9b21fde 100644
--- a/packages/pi-ai/src/providers/anthropic.ts
+++ b/packages/pi-ai/src/providers/anthropic.ts
@@ -44,6 +44,10 @@ function mergeHeaders(...headerSources: (Record<string, string> | undefined)[]):
 	return merged;
 }
 
+export function usesAnthropicBearerAuth(provider: Model<"anthropic-messages">["provider"]): boolean {
+	return provider === "alibaba-coding-plan" || provider === "minimax" || provider === "minimax-cn";
+}
+
 async function createClient(
 	model: Model<"anthropic-messages">,
 	apiKey: string,
@@ -91,11 +95,11 @@ async function createClient(
 	}
 
 	// API key auth (Anthropic OAuth removed per TOS compliance — use API keys or Claude CLI)
-	// Alibaba Coding Plan uses Bearer token auth instead of x-api-key
-	const isAlibabaProvider = model.provider === "alibaba-coding-plan";
+	// Some Anthropic-compatible providers require Bearer auth instead of x-api-key.
+	const usesBearerAuth = usesAnthropicBearerAuth(model.provider);
 	const client = new AnthropicClass({
-		apiKey: isAlibabaProvider ? null : apiKey,
-		authToken: isAlibabaProvider ? apiKey : undefined,
+		apiKey: usesBearerAuth ? null : apiKey,
+		authToken: usesBearerAuth ? apiKey : undefined,
 		baseURL: model.baseUrl,
 		dangerouslyAllowBrowser: true,
 		defaultHeaders: mergeHeaders(