From f459206e4aeb21fa55857ee47d0431747209744c Mon Sep 17 00:00:00 2001
From: Matt Peter <mpeter@gmail.com>
Date: Tue, 18 Aug 2026 23:44:09 -0400
Subject: [PATCH] fix(small-model): route anthropic provider through configured
 baseURL
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

The Anthropic small-model dispatch (session-assist recap/suggestion,
walkthrough, etc.) hardcoded https://api.anthropic.com/v1/messages,
ignoring provider.anthropic.options.baseURL — the same override every
other provider branch already respects. Any setup routing the anthropic
provider through a local proxy (e.g. Meridian for Claude Max / Vertex)
had the small-model call bypass the proxy and hit the real Anthropic API
with whatever placeholder credential the proxy config uses, failing with
401 invalid x-api-key on every call.
---
 CHANGELOG.md                                  |  1 +
 packages/web/server/lib/small-model/call.js   |  6 +--
 .../web/server/lib/small-model/call.test.js   | 45 +++++++++++++++++++
 3 files changed, 49 insertions(+), 3 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 30a8f4aa..76d45c88 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -64,6 +64,7 @@ All notable changes to this project will be documented in this file.
 - Git: pull-request checks in Work status stay current as their status changes.
 - UI: the default dialog close button is easier to click or tap (thanks to @rockinrimmer).
 - Desktop/Windows: the close button now aligns correctly with the rest of the window chrome.
+- Session assist: recaps and suggested follow-ups now work when the Anthropic provider is configured to use a custom endpoint; they previously failed every time instead of using that configured connection.
 
 ## [1.19.0] - 2026-08-19
 
diff --git a/packages/web/server/lib/small-model/call.js b/packages/web/server/lib/small-model/call.js
index 27e183c8..86a447de 100644
--- a/packages/web/server/lib/small-model/call.js
+++ b/packages/web/server/lib/small-model/call.js
@@ -340,8 +340,8 @@ const callMessages = async ({ url, headers, modelID, prompt, system, maxOutputTo
   return text;
 };
 
-const callAnthropic = async ({ apiKey, modelID, prompt, system, maxOutputTokens, responseSchema, timeoutMs, signal }) => callMessages({
-  url: 'https://api.anthropic.com/v1/messages',
+const callAnthropic = async ({ apiKey, baseURL, modelID, prompt, system, maxOutputTokens, responseSchema, timeoutMs, signal }) => callMessages({
+  url: `${(baseURL || 'https://api.anthropic.com').replace(/\/+$/, '')}/v1/messages`,
   headers: {
     'x-api-key': apiKey,
     'anthropic-version': '2023-06-01',
@@ -706,7 +706,7 @@ export async function callSmallModel({ auth, catalog, workingDirectory, provider
   }
 
   if (providerID === 'anthropic') {
-    return callAnthropic({ apiKey, modelID, prompt, system, maxOutputTokens: tokens, responseSchema, timeoutMs, signal });
+    return callAnthropic({ apiKey, baseURL: providerConfig?.baseURL, modelID, prompt, system, maxOutputTokens: tokens, responseSchema, timeoutMs, signal });
   }
   if (providerID === 'google') {
     return callGoogle({ apiKey, modelID, prompt, system, maxOutputTokens: tokens, responseSchema, timeoutMs, signal });
diff --git a/packages/web/server/lib/small-model/call.test.js b/packages/web/server/lib/small-model/call.test.js
index 51097d80..7d6584bc 100644
--- a/packages/web/server/lib/small-model/call.test.js
+++ b/packages/web/server/lib/small-model/call.test.js
@@ -316,6 +316,51 @@ describe('callSmallModel — custom provider config', () => {
     });
   });
 
+  describe('anthropic provider custom baseURL override', () => {
+    const anthropicOk = (text) => ({
+      ok: true,
+      status: 200,
+      json: async () => ({ content: [{ type: 'text', text }] }),
+    });
+
+    it('respects provider.anthropic.options.baseURL over the hardcoded Anthropic endpoint', async () => {
+      readConfig.mockReturnValue({
+        provider: { anthropic: { options: { baseURL: 'http://127.0.0.1:3456' } } },
+      });
+      fetchMock.mockResolvedValue(anthropicOk('ok'));
+
+      await callSmallModel({
+        auth: { anthropic: { type: 'api', key: 'dummy' } },
+        catalog: {},
+        workingDirectory: '/proj',
+        providerID: 'anthropic',
+        modelID: 'claude-haiku-4-5',
+        prompt: 'hi',
+      });
+
+      const { url, init } = lastCall(fetchMock);
+      expect(url).toBe('http://127.0.0.1:3456/v1/messages');
+      expect(url).not.toContain('api.anthropic.com');
+      expect(init.headers['x-api-key']).toBe('dummy');
+    });
+
+    it('falls back to https://api.anthropic.com when no anthropic baseURL override is configured', async () => {
+      readConfig.mockReturnValue({});
+      fetchMock.mockResolvedValue(anthropicOk('ok'));
+
+      await callSmallModel({
+        auth: { anthropic: { type: 'api', key: 'sk-ant' } },
+        catalog: {},
+        workingDirectory: '/proj',
+        providerID: 'anthropic',
+        modelID: 'claude-haiku-4-5',
+        prompt: 'hi',
+      });
+
+      expect(lastCall(fetchMock).url).toBe('https://api.anthropic.com/v1/messages');
+    });
+  });
+
   describe('catalog-based base URL (no config override)', () => {
     it('uses the catalog api field when no config baseURL is set', async () => {
       readConfig.mockReturnValue({});