From 02d2200f71a4a027c94f2bcab6bb5a141704cb57 Mon Sep 17 00:00:00 2001
From: Luca Martial <lucamrtl@gmail.com>
Date: Tue, 12 May 2026 22:10:21 -0700
Subject: [PATCH] feat(context): resolve Vertex AI config references

---
 packages/context/src/llm/local-config.test.ts | 46 +++++++++++++++++++
 packages/context/src/llm/local-config.ts      | 19 +++++++-
 2 files changed, 64 insertions(+), 1 deletion(-)

diff --git a/packages/context/src/llm/local-config.test.ts b/packages/context/src/llm/local-config.test.ts
index ffb00b36..5d114e12 100644
--- a/packages/context/src/llm/local-config.test.ts
+++ b/packages/context/src/llm/local-config.test.ts
@@ -37,6 +37,52 @@ describe('local KTX LLM config', () => {
     });
   });
 
+  it('resolves Vertex AI env references into a KtxLlmConfig', () => {
+    const config: KtxProjectLlmConfig = {
+      provider: {
+        backend: 'vertex',
+        vertex: { project: 'env:GOOGLE_VERTEX_PROJECT', location: 'env:GOOGLE_VERTEX_LOCATION' },
+      },
+      models: { default: 'env:KTX_MODEL' },
+      promptCaching: { enabled: true, vertexFallbackTo5m: true },
+    };
+
+    expect(
+      resolveLocalKtxLlmConfig(config, {
+        GOOGLE_VERTEX_PROJECT: 'local-gcp-project',
+        GOOGLE_VERTEX_LOCATION: 'us-east5',
+        KTX_MODEL: 'claude-sonnet-4-6',
+      }),
+    ).toEqual({
+      backend: 'vertex',
+      vertex: { project: 'local-gcp-project', location: 'us-east5' },
+      modelSlots: { default: 'claude-sonnet-4-6' },
+      promptCaching: { enabled: true, vertexFallbackTo5m: true },
+    });
+  });
+
+  it('ignores inactive Vertex AI references for non-Vertex backends', () => {
+    const config: KtxProjectLlmConfig = {
+      provider: {
+        backend: 'anthropic',
+        anthropic: { api_key: 'env:ANTHROPIC_API_KEY' }, // pragma: allowlist secret
+        vertex: { location: 'env:MISSING_VERTEX_LOCATION' },
+      },
+      models: { default: 'claude-sonnet-4-6' },
+    };
+
+    expect(
+      resolveLocalKtxLlmConfig(config, {
+        ANTHROPIC_API_KEY: 'sk-ant-test', // pragma: allowlist secret
+      }),
+    ).toEqual({
+      backend: 'anthropic',
+      anthropic: { apiKey: 'sk-ant-test' }, // pragma: allowlist secret
+      modelSlots: { default: 'claude-sonnet-4-6' },
+      promptCaching: undefined,
+    });
+  });
+
   it('returns null when the local LLM backend is disabled', () => {
     expect(
       createLocalKtxLlmProviderFromConfig({
diff --git a/packages/context/src/llm/local-config.ts b/packages/context/src/llm/local-config.ts
index 76f1905f..2709c4b7 100644
--- a/packages/context/src/llm/local-config.ts
+++ b/packages/context/src/llm/local-config.ts
@@ -67,16 +67,33 @@ function resolvedProviderConfig(
   };
 }
 
+function resolvedVertexConfig(
+  config: { project?: string; location?: string } | undefined,
+  env: NodeJS.ProcessEnv,
+): { project?: string; location: string } | undefined {
+  if (!config) {
+    return undefined;
+  }
+
+  const project = resolveOptional(config.project, env);
+  const location = resolveRequired(config.location, env, 'llm.provider.vertex.location is required');
+  return {
+    ...(project ? { project } : {}),
+    location,
+  };
+}
+
 export function resolveLocalKtxLlmConfig(config: KtxProjectLlmConfig, env: NodeJS.ProcessEnv): KtxLlmConfig | null {
   if (config.provider.backend === 'none') {
     return null;
   }
   const modelSlots = resolveModelSlots(config.models, env);
+  const vertex = config.provider.backend === 'vertex' ? resolvedVertexConfig(config.provider.vertex, env) : undefined;
   const anthropic = resolvedProviderConfig(config.provider.anthropic, env);
   const gateway = resolvedProviderConfig(config.provider.gateway, env);
   return {
     backend: config.provider.backend,
-    ...(config.provider.vertex ? { vertex: config.provider.vertex } : {}),
+    ...(vertex ? { vertex } : {}),
     ...(anthropic ? { anthropic } : {}),
     ...(gateway ? { gateway } : {}),
     modelSlots,