fix: support OPENAI_BASE_URL and api-key header for Azure APIM-style gateways

src/agent/index.ts

@@ -25,6 +25,7 @@ import {
   isValidModelId,
   normalizeModelId,
   OPENAI_API_KEY_ENV_KEY,
+  OPENAI_BASE_URL_ENV_KEY,
   OPENROUTER_API_KEY_ENV_KEY,
   OPENROUTER_BASE_URL,
   OPENROUTER_FALLBACK_MODEL_IDS,
@@ -71,6 +72,10 @@ export async function runOpenWikiAgent(
   emitDebug(options, `model=${modelId}`);
 
   const debugFetchCapture = installOpenRouterDebugFetch(options);
+  const customBaseURL = process.env[OPENAI_BASE_URL_ENV_KEY];
+  const restoreFileBlockScrubber = customBaseURL
+    ? installFileBlockScrubber(customBaseURL)
+    : null;
 
   try {
     return await runOpenWikiAgentWithModelFallbacks(
@@ -86,6 +91,7 @@ export async function runOpenWikiAgent(
     throw error;
   } finally {
     debugFetchCapture.restore();
+    restoreFileBlockScrubber?.();
   }
 }
 
@@ -377,6 +383,113 @@ function resolveModelId(
   return modelId;
 }
 
+/**
+ * Installs a global fetch interceptor that rewrites chat completion request
+ * bodies destined for a custom base URL, converting any file content blocks
+ * (base64 binary files sent by DeepAgents) into plain text strings before
+ * the request leaves the process.
+ *
+ * This operates at the HTTP level so it catches all code paths regardless of
+ * which internal LangChain method DeepAgents uses to invoke the model.
+ *
+ * Returns a cleanup function that restores the original fetch.
+ */
+function installFileBlockScrubber(baseURL: string): () => void {
+  const originalFetch = globalThis.fetch;
+
+  globalThis.fetch = (async (
+    input: Parameters<typeof fetch>[0],
+    init?: Parameters<typeof fetch>[1],
+  ) => {
+    const url =
+      typeof input === "string"
+        ? input
+        : input instanceof URL
+          ? input.toString()
+          : (input as Request).url;
+
+    if (
+      typeof url === "string" &&
+      url.startsWith(baseURL) &&
+      url.includes("/chat/completions") &&
+      init?.body &&
+      typeof init.body === "string"
+    ) {
+      try {
+        const parsed = JSON.parse(init.body) as Record<string, unknown>;
+
+        if (Array.isArray(parsed.messages)) {
+          parsed.messages = (
+            parsed.messages as Array<Record<string, unknown>>
+          ).map(scrubMessageContent);
+
+          init = { ...init, body: JSON.stringify(parsed) };
+        }
+      } catch {
+        // Not JSON — pass through unchanged
+      }
+    }
+
+    return originalFetch(input, init);
+  }) satisfies typeof fetch;
+
+  return () => {
+    globalThis.fetch = originalFetch;
+  };
+}
+
+function scrubMessageContent(
+  message: Record<string, unknown>,
+): Record<string, unknown> {
+  const { content } = message;
+
+  if (!Array.isArray(content)) {
+    return message;
+  }
+
+  const scrubbed = (content as Array<unknown>).map((part) => {
+    if (
+      typeof part === "object" &&
+      part !== null &&
+      "type" in part &&
+      (part as Record<string, unknown>).type === "file" &&
+      "data" in part &&
+      typeof (part as Record<string, unknown>).data === "string"
+    ) {
+      const text = Buffer.from(
+        (part as Record<string, unknown>).data as string,
+        "base64",
+      ).toString("utf8");
+
+      return { type: "text", text };
+    }
+
+    return part;
+  });
+
+  // Collapse all-text arrays to a plain string — strict gateways like GLM-5.2
+  // via Azure APIM reject array content even when every element is text.
+  const allText = scrubbed.every(
+    (p) =>
+      typeof p === "object" &&
+      p !== null &&
+      (p as Record<string, unknown>).type === "text",
+  );
+
+  return {
+    ...message,
+    content: allText
+      ? scrubbed
+          .map((p) => (p as Record<string, unknown>).text as string)
+          .join("")
+      : scrubbed,
+  };
+}
+
+// Keep TextOnlyChatOpenAI as a thin subclass (no overrides needed now that
+// the fetch interceptor handles everything at the wire level).
+class TextOnlyChatOpenAI extends ChatOpenAI {}
+
 async function createModel(provider: OpenWikiProvider, modelId: string) {
   if (provider === "anthropic") {
     return new ChatAnthropic(modelId, {
@@ -398,16 +511,27 @@ async function createModel(provider: OpenWikiProvider, modelId: string) {
   }
 
   const providerConfig = getProviderConfig(provider);
+  const apiKey = process.env[getProviderApiKeyEnvKey(provider)];
+  const customBaseURL = process.env[OPENAI_BASE_URL_ENV_KEY];
+  const baseURL = customBaseURL ?? providerConfig.baseURL;
 
-  return new ChatOpenAI({
-    apiKey: process.env[getProviderApiKeyEnvKey(provider)],
-    configuration: providerConfig.baseURL
+  const modelParams = {
+    apiKey,
+    configuration: baseURL
       ? {
-          baseURL: providerConfig.baseURL,
+          baseURL,
+          // Azure APIM and similar gateways use api-key instead of Authorization: Bearer
+          defaultHeaders: customBaseURL ? { "api-key": apiKey } : undefined,
         }
       : undefined,
     model: modelId,
-  });
+  };
+
+  // Use TextOnlyChatOpenAI for custom base URLs — third-party gateways typically
+  // don't support multimodal file content blocks that DeepAgents sends for binary files.
+  return customBaseURL
+    ? new TextOnlyChatOpenAI(modelParams)
+    : new ChatOpenAI(modelParams);
 }
 
 function createModelRoute(
@@ -1262,6 +1386,7 @@ function formatEnvironmentDebug(): string {
     BASETEN_API_KEY_ENV_KEY,
     FIREWORKS_API_KEY_ENV_KEY,
     OPENAI_API_KEY_ENV_KEY,
+    OPENAI_BASE_URL_ENV_KEY,
     ANTHROPIC_API_KEY_ENV_KEY,
     OPENROUTER_API_KEY_ENV_KEY,
     OPENWIKI_MODEL_ID_ENV_KEY,

src/constants.ts

@@ -3,6 +3,7 @@ export const UPDATE_METADATA_PATH = `${OPEN_WIKI_DIR}/.last-update.json`;
 export const BASETEN_API_KEY_ENV_KEY = "BASETEN_API_KEY";
 export const FIREWORKS_API_KEY_ENV_KEY = "FIREWORKS_API_KEY";
 export const OPENAI_API_KEY_ENV_KEY = "OPENAI_API_KEY";
+export const OPENAI_BASE_URL_ENV_KEY = "OPENAI_BASE_URL";
 export const ANTHROPIC_API_KEY_ENV_KEY = "ANTHROPIC_API_KEY";
 export const OPENROUTER_API_KEY_ENV_KEY = "OPENROUTER_API_KEY";
 export const OPENWIKI_PROVIDER_ENV_KEY = "OPENWIKI_PROVIDER";

src/env.ts

@@ -8,6 +8,7 @@ import {
   isValidModelId,
   normalizeProvider,
   OPENAI_API_KEY_ENV_KEY,
+  OPENAI_BASE_URL_ENV_KEY,
   OPENROUTER_API_KEY_ENV_KEY,
   OPENWIKI_MODEL_ID_ENV_KEY,
   OPENWIKI_PROVIDER_ENV_KEY,
@@ -34,6 +35,7 @@ const managedEnvKeys = [
   BASETEN_API_KEY_ENV_KEY,
   FIREWORKS_API_KEY_ENV_KEY,
   OPENAI_API_KEY_ENV_KEY,
+  OPENAI_BASE_URL_ENV_KEY,
   ANTHROPIC_API_KEY_ENV_KEY,
   OPENROUTER_API_KEY_ENV_KEY,
   OPENWIKI_PROVIDER_ENV_KEY,
@@ -44,7 +46,6 @@ const managedEnvKeys = [
 ];
 
 const deprecatedEnvKeys = [
-  "OPENAI_BASE_URL",
   "OPENAI_ORG_ID",
   "OPENAI_PROJECT",
 ];
@@ -75,6 +76,7 @@ export async function getCredentialDiagnostics(): Promise<
     createCredentialDiagnostic(BASETEN_API_KEY_ENV_KEY, fileEnv),
     createCredentialDiagnostic(FIREWORKS_API_KEY_ENV_KEY, fileEnv),
     createCredentialDiagnostic(OPENAI_API_KEY_ENV_KEY, fileEnv),
+    createCredentialDiagnostic(OPENAI_BASE_URL_ENV_KEY, fileEnv),
     createCredentialDiagnostic(ANTHROPIC_API_KEY_ENV_KEY, fileEnv),
     createCredentialDiagnostic(OPENROUTER_API_KEY_ENV_KEY, fileEnv),
     createCredentialDiagnostic(OPENWIKI_MODEL_ID_ENV_KEY, fileEnv),