feat: Vertex AI support; add google-vertex and google-vertex-anthropic providers (#2347)

3 files changed, 53 insertions, 1 deletions

diff --git a/packages/opencode/package.json b/packages/opencode/package.json
index a8041a000..47a52b24b 100644
--- a/packages/opencode/package.json
+++ b/packages/opencode/package.json
@@ -18,6 +18,7 @@
   },
   "devDependencies": {
     "@ai-sdk/amazon-bedrock": "2.2.10",
+    "@ai-sdk/google-vertex": "3.0.16",
     "@octokit/webhooks-types": "7.6.1",
     "@standard-schema/spec": "1.0.0",
     "@tsconfig/bun": "1.0.7",
diff --git a/packages/opencode/src/cli/cmd/auth.ts b/packages/opencode/src/cli/cmd/auth.ts
index 965983b93..e0980e137 100644
--- a/packages/opencode/src/cli/cmd/auth.ts
+++ b/packages/opencode/src/cli/cmd/auth.ts
@@ -247,6 +247,14 @@ export const AuthLoginCommand = cmd({
           return
         }
 
+        if (provider === "google-vertex") {
+          prompts.log.info(
+            "Google Cloud Vertex AI uses Application Default Credentials. Set GOOGLE_APPLICATION_CREDENTIALS or run 'gcloud auth application-default login'. Optionally set GOOGLE_CLOUD_PROJECT and GOOGLE_CLOUD_LOCATION (or VERTEX_LOCATION)",
+          )
+          prompts.outro("Done")
+          return
+        }
+
         if (provider === "opencode") {
           prompts.log.info("Create an api key at https://opencode.ai/auth")
         }
diff --git a/packages/opencode/src/provider/provider.ts b/packages/opencode/src/provider/provider.ts
index 188639830..c18bc4898 100644
--- a/packages/opencode/src/provider/provider.ts
+++ b/packages/opencode/src/provider/provider.ts
@@ -153,6 +153,40 @@ export namespace Provider {
         },
       }
     },
+    "google-vertex": async () => {
+      const project = process.env["GOOGLE_CLOUD_PROJECT"] ?? process.env["GCP_PROJECT"] ?? process.env["GCLOUD_PROJECT"]
+      const location = process.env["GOOGLE_CLOUD_LOCATION"] ?? process.env["VERTEX_LOCATION"] ?? "us-east5"
+      const autoload = Boolean(project)
+      if (!autoload) return { autoload: false }
+      return {
+        autoload: true,
+        options: {
+          project,
+          location,
+        },
+        async getModel(sdk: any, modelID: string) {
+          const id = String(modelID).trim()
+          return sdk.languageModel(id)
+        },
+      }
+    },
+    "google-vertex-anthropic": async () => {
+      const project = process.env["GOOGLE_CLOUD_PROJECT"] ?? process.env["GCP_PROJECT"] ?? process.env["GCLOUD_PROJECT"]
+      const location = process.env["GOOGLE_CLOUD_LOCATION"] ?? process.env["VERTEX_LOCATION"] ?? "us-east5"
+      const autoload = Boolean(project)
+      if (!autoload) return { autoload: false }
+      return {
+        autoload: true,
+        options: {
+          project,
+          location,
+        },
+        async getModel(sdk: any, modelID: string) {
+          const id = String(modelID).trim()
+          return sdk.languageModel(id)
+        },
+      }
+    },
   }
 
   const state = Instance.state(async () => {
@@ -344,7 +378,16 @@ export namespace Provider {
       const key = Bun.hash.xxHash32(JSON.stringify({ pkg, options }))
       const existing = s.sdk.get(key)
       if (existing) return existing
-      const mod = await import(await BunProc.install(pkg, "latest"))
+      const installedPath = await BunProc.install(pkg, "latest")
+      // The `google-vertex-anthropic` provider points to the `@ai-sdk/google-vertex` package.
+      // Ref: https://github.com/sst/models.dev/blob/0a87de42ab177bebad0620a889e2eb2b4a5dd4ab/providers/google-vertex-anthropic/provider.toml
+      // However, the actual export is at the subpath `@ai-sdk/google-vertex/anthropic`.
+      // Ref: https://ai-sdk.dev/providers/ai-sdk-providers/google-vertex#google-vertex-anthropic-provider-usage
+      // In addition, Bun's dynamic import logic does not support subpath imports,
+      // so we patch the import path to load directly from `dist`.
+      const modPath =
+        provider.id === "google-vertex-anthropic" ? `${installedPath}/dist/anthropic/index.mjs` : installedPath
+      const mod = await import(modPath)
       if (options["timeout"] !== undefined) {
         // Only override fetch if user explicitly sets timeout
         options["fetch"] = async (input: any, init?: any) => {