fix(executors): route Claude-via-Vertex through native rawPredict with real streaming

changelog.d/fixes/8909-vertex-claude-rawpredict-streaming.md

@@ -0,0 +1 @@
+- **fix(executors):** Vertex AI now routes Claude models through the native Anthropic `rawPredict` endpoint instead of the generic OpenAI-compatible partner endpoint, and synthesizes a real streaming response so Claude-via-Vertex works with `stream: true` ([#8909](https://github.com/diegosouzapw/OmniRoute/pull/8909)) — thanks @wgordon17

config/quality/eslint-suppressions.json

@@ -3319,4 +3319,4 @@
       "count": 5
     }
   }
-}
+}

open-sse/utils/stream.ts

@@ -1881,7 +1881,6 @@ export function createSSEStream(options: StreamOptions = {}) {
                     passthroughSawFinishReason = true;
                   }
 
-
                   if (isFinishChunk && passthroughHasToolCalls) {
                     toolFinishTime = now;
                     try {
@@ -2220,7 +2219,8 @@ export function createSSEStream(options: StreamOptions = {}) {
               },
               pushProviderPayload: (payload: unknown) => providerPayloadCollector.push(payload),
               pushClientPayload: (payload: unknown) => clientPayloadCollector.push(payload),
-              sanitizeUsagePayload: (payload: unknown) => sanitizeUsagePayloadForRequest(payload, body, clientResponseFormat),
+              sanitizeUsagePayload: (payload: unknown) =>
+                sanitizeUsagePayloadForRequest(payload, body, clientResponseFormat),
               setPassthroughResponsesId: (value: string) => {
                 passthroughResponsesId = value;
               },
@@ -2281,7 +2281,8 @@ export function createSSEStream(options: StreamOptions = {}) {
               const bufferedPayload = parseSSELine(bufferedLine);
               if (bufferedPayload) {
                 providerPayloadCollector.push(bufferedPayload);
-                if (sanitizeUsagePayloadForRequest(bufferedPayload, body, clientResponseFormat)) output = `data: ${JSON.stringify(bufferedPayload)}\n\n`;
+                if (sanitizeUsagePayloadForRequest(bufferedPayload, body, clientResponseFormat))
+                  output = `data: ${JSON.stringify(bufferedPayload)}\n\n`;
                 if (
                   shouldInjectClaudeEmptyResponseBeforeCurrentEvent(
                     claudeEmptyResponseLifecycle,

tests/unit/executor-vertex-extended.test.ts

@@ -68,7 +68,10 @@ test("VertexExecutor.buildUrl routes a non-JSON Express API key to the project-l
     expressUrl,
     "https://aiplatform.googleapis.com/v1/publishers/google/models/gemini-2.5-flash:generateContent?key=express-key-abc"
   );
-  assert.ok(!expressUrl.includes("/projects/"), "Express key URL must not route through a project path");
+  assert.ok(
+    !expressUrl.includes("/projects/"),
+    "Express key URL must not route through a project path"
+  );
 });
 
 test("VertexExecutor.buildUrl routes partner and org-prefixed models to the global partner endpoint", () => {