diff --git a/packages/opencode/opencode-linux-x64.tar.gz b/packages/opencode/opencode-linux-x64.tar.gz
new file mode 100644
index 000000000000..fb63afb3cc2b
Binary files /dev/null and b/packages/opencode/opencode-linux-x64.tar.gz differ
diff --git a/packages/opencode/src/cli/cmd/auth.ts b/packages/opencode/src/cli/cmd/auth.ts
index bbaecfd8c711..7f5eb0d578bc 100644
--- a/packages/opencode/src/cli/cmd/auth.ts
+++ b/packages/opencode/src/cli/cmd/auth.ts
@@ -10,6 +10,7 @@ import { Config } from "../../config/config"
 import { Global } from "../../global"
 import { Plugin } from "../../plugin"
 import { Instance } from "../../project/instance"
+import { PROVIDER_DISPLAY_NAMES } from "../../provider/display-names"
 import type { Hooks } from "@opencode-ai/plugin"
 
 type PluginAuth = NonNullable<Hooks["auth"]>
@@ -274,8 +275,10 @@ export const AuthLoginCommand = cmd({
           "github-copilot": 2,
           openai: 3,
           google: 4,
-          openrouter: 5,
-          vercel: 6,
+          "google-vertex": 5,
+          "google-vertex-anthropic": 6,
+          openrouter: 7,
+          vercel: 8,
         }
         let provider = await prompts.autocomplete({
           message: "Select provider",
@@ -289,12 +292,14 @@ export const AuthLoginCommand = cmd({
                 (x) => x.name ?? x.id,
               ),
               map((x) => ({
-                label: x.name,
+                label: PROVIDER_DISPLAY_NAMES[x.id] ?? x.name,
                 value: x.id,
                 hint: {
                   opencode: "recommended",
                   anthropic: "Claude Max or API key",
                   openai: "ChatGPT Plus/Pro or API key",
+                  "google-vertex": "Service Account",
+                  "google-vertex-anthropic": "Service Account",
                 }[x.id],
               })),
             ),
@@ -352,6 +357,52 @@ export const AuthLoginCommand = cmd({
           prompts.log.info("You can create an api key at https://vercel.link/ai-gateway-token")
         }
 
+        if (provider === "google-vertex" || provider === "google-vertex-anthropic") {
+          prompts.log.info("Paste your service account JSON below.")
+          prompts.log.info("Download from https://console.cloud.google.com/iam-admin/serviceaccounts")
+
+          const serviceAccountJson = await prompts.text({
+            message: "Service Account JSON",
+            placeholder: '{"type": "service_account", ...}',
+            validate: (x) => {
+              if (!x) return "Required"
+              try {
+                const json = JSON.parse(x)
+                if (json.type !== "service_account") return "Invalid: 'type' must be 'service_account'"
+                if (!json.client_email) return "Invalid: missing 'client_email' field"
+                if (!json.private_key) return "Invalid: missing 'private_key' field"
+                if (!json.project_id) return "Invalid: missing 'project_id' field"
+                return undefined
+              } catch (e) {
+                return `Invalid JSON: ${e instanceof Error ? e.message : "parse error"}`
+              }
+            },
+          })
+          if (prompts.isCancel(serviceAccountJson)) throw new UI.CancelledError()
+
+          const json = JSON.parse(serviceAccountJson)
+
+          const defaultLocation = provider === "google-vertex-anthropic" ? "global" : "us-east5"
+          const location = await prompts.text({
+            message: `Location (default: ${defaultLocation})`,
+            placeholder: defaultLocation,
+          })
+          if (prompts.isCancel(location)) throw new UI.CancelledError()
+
+          await Auth.set(provider, {
+            type: "api",
+            key: JSON.stringify({
+              client_email: json.client_email,
+              private_key: json.private_key,
+              project_id: json.project_id,
+              location: location || defaultLocation,
+            }),
+          })
+
+          prompts.outro("Done")
+          return
+        }
+
         if (["cloudflare", "cloudflare-ai-gateway"].includes(provider)) {
           prompts.log.info(
             "Cloudflare AI Gateway can be configured with CLOUDFLARE_GATEWAY_ID, CLOUDFLARE_ACCOUNT_ID, and CLOUDFLARE_API_TOKEN environment variables. Read more: https://opencode.ai/docs/providers/#cloudflare-ai-gateway",
diff --git a/packages/opencode/src/cli/cmd/tui/component/dialog-model.tsx b/packages/opencode/src/cli/cmd/tui/component/dialog-model.tsx
index bcbbe69287be..3d376d681d23 100644
--- a/packages/opencode/src/cli/cmd/tui/component/dialog-model.tsx
+++ b/packages/opencode/src/cli/cmd/tui/component/dialog-model.tsx
@@ -7,6 +7,7 @@ import { useDialog } from "@tui/ui/dialog"
 import { createDialogProviderOptions, DialogProvider } from "./dialog-provider"
 import { useKeybind } from "../context/keybind"
 import * as fuzzysort from "fuzzysort"
+import { getProviderDisplayName } from "@/provider/display-names"
 
 export function useConnected() {
   const sync = useSync()
@@ -59,7 +60,7 @@ export function DialogModel(props: { providerID?: string }) {
                 modelID: model.id,
               },
               title: model.name ?? item.modelID,
-              description: provider.name,
+              description: getProviderDisplayName(provider),
               category: "Favorites",
               disabled: provider.id === "opencode" && model.id.includes("-nano"),
               footer: model.cost?.input === 0 && provider.id === "opencode" ? "Free" : undefined,
@@ -92,7 +93,7 @@ export function DialogModel(props: { providerID?: string }) {
                 modelID: model.id,
               },
               title: model.name ?? item.modelID,
-              description: provider.name,
+              description: getProviderDisplayName(provider),
               category: "Recent",
               disabled: provider.id === "opencode" && model.id.includes("-nano"),
               footer: model.cost?.input === 0 && provider.id === "opencode" ? "Free" : undefined,
@@ -115,7 +116,7 @@ export function DialogModel(props: { providerID?: string }) {
       sync.data.provider,
       sortBy(
         (provider) => provider.id !== "opencode",
-        (provider) => provider.name,
+        (provider) => getProviderDisplayName(provider),
       ),
       flatMap((provider) =>
         pipe(
@@ -136,7 +137,7 @@ export function DialogModel(props: { providerID?: string }) {
               )
                 ? "(Favorite)"
                 : undefined,
-              category: connected() ? provider.name : undefined,
+              category: connected() ? getProviderDisplayName(provider) : undefined,
               disabled: provider.id === "opencode" && model.includes("-nano"),
               footer: info.cost?.input === 0 && provider.id === "opencode" ? "Free" : undefined,
               onSelect() {
diff --git a/packages/opencode/src/cli/cmd/tui/component/dialog-provider.tsx b/packages/opencode/src/cli/cmd/tui/component/dialog-provider.tsx
index 4e1171a42017..3229bb1af3d8 100644
--- a/packages/opencode/src/cli/cmd/tui/component/dialog-provider.tsx
+++ b/packages/opencode/src/cli/cmd/tui/component/dialog-provider.tsx
@@ -10,6 +10,7 @@ import { useTheme } from "../context/theme"
 import { TextAttributes } from "@opentui/core"
 import type { ProviderAuthAuthorization } from "@opencode-ai/sdk/v2"
 import { DialogModel } from "./dialog-model"
+import { PROVIDER_DISPLAY_NAMES } from "@/provider/display-names"
 import { useKeyboard } from "@opentui/solid"
 import { Clipboard } from "@tui/util/clipboard"
 import { useToast } from "../ui/toast"
@@ -20,6 +21,9 @@ const PROVIDER_PRIORITY: Record<string, number> = {
   "github-copilot": 2,
   openai: 3,
   google: 4,
+  "google-vertex": 5,
+  "google-vertex-anthropic": 6,
+  openrouter: 7,
 }
 
 export function createDialogProviderOptions() {
@@ -34,12 +38,14 @@ export function createDialogProviderOptions() {
       map((provider) => {
         const isConnected = connected().has(provider.id)
         return {
-          title: provider.name,
+          title: PROVIDER_DISPLAY_NAMES[provider.id] ?? provider.name,
           value: provider.id,
           description: {
             opencode: "(Recommended)",
             anthropic: "(Claude Max or API key)",
             openai: "(ChatGPT Plus/Pro or API key)",
+            "google-vertex": "(Service Account)",
+            "google-vertex-anthropic": "(Service Account)",
           }[provider.id],
           category: provider.id in PROVIDER_PRIORITY ? "Popular" : "Other",
           footer: isConnected ? "Connected" : undefined,
@@ -97,6 +103,10 @@ export function createDialogProviderOptions() {
               }
             }
             if (method.type === "api") {
+              // Use ServiceAccountMethod for Vertex AI providers
+              if (provider.id === "google-vertex" || provider.id === "google-vertex-anthropic") {
+                return dialog.replace(() => <ServiceAccountMethod providerID={provider.id} />)
+              }
               return dialog.replace(() => <ApiMethod providerID={provider.id} title={method.label} />)
             }
           },
@@ -254,3 +264,164 @@ function ApiMethod(props: ApiMethodProps) {
     />
   )
 }
+
+interface ServiceAccountMethodProps {
+  providerID: string
+}
+function ServiceAccountMethod(props: ServiceAccountMethodProps) {
+  const dialog = useDialog()
+
+  onMount(() => {
+    dialog.setSize("large")
+  })
+
+  return <ServiceAccountPasteInput providerID={props.providerID} />
+}
+
+function ServiceAccountPasteInput(props: { providerID: string }) {
+  const dialog = useDialog()
+  const { theme } = useTheme()
+  const [error, setError] = createSignal("")
+  let textareaRef: { plainText: string; focus: () => void } | undefined
+
+  const providerDisplayName = () =>
+    props.providerID === "google-vertex-anthropic" ? "Google Vertex AI (Anthropic)" : "Google Vertex AI"
+
+  const validateJson = (content: string): { valid: boolean; json?: any; error?: string } => {
+    try {
+      const json = JSON.parse(content)
+      if (json.type !== "service_account") {
+        return { valid: false, error: "Invalid: 'type' must be 'service_account'" }
+      }
+      if (!json.client_email) {
+        return { valid: false, error: "Invalid: missing 'client_email' field" }
+      }
+      if (!json.private_key) {
+        return { valid: false, error: "Invalid: missing 'private_key' field" }
+      }
+      if (!json.project_id) {
+        return { valid: false, error: "Invalid: missing 'project_id' field" }
+      }
+      return { valid: true, json }
+    } catch (e) {
+      return { valid: false, error: `Invalid JSON: ${e instanceof Error ? e.message : "parse error"}` }
+    }
+  }
+
+  const handleSubmit = () => {
+    const content = textareaRef?.plainText || ""
+    setError("")
+
+    if (!content || !content.trim()) {
+      setError("Required - paste your service account JSON")
+      return
+    }
+
+    const result = validateJson(content)
+    if (!result.valid) {
+      setError(result.error!)
+      return
+    }
+
+    dialog.replace(() => (
+      <ServiceAccountLocationInput
+        providerID={props.providerID}
+        serviceAccountJson={content}
+      />
+    ))
+  }
+
+  return (
+    <box gap={1} paddingBottom={1}>
+      <box paddingLeft={4} paddingRight={4}>
+        <box flexDirection="row" justifyContent="space-between">
+          <text fg={theme.text} attributes={TextAttributes.BOLD}>
+            {providerDisplayName()}
+          </text>
+          <text fg={theme.textMuted}>esc</text>
+        </box>
+        <box paddingTop={1}>
+          <text fg={theme.textMuted}>Paste your service account JSON below and press Ctrl+S to submit.</text>
+          <text fg={theme.text}>
+            Download from{" "}
+            <span style={{ fg: theme.primary }}>https://console.cloud.google.com/iam-admin/serviceaccounts</span>
+          </text>
+        </box>
+      </box>
+      <box paddingLeft={4} paddingRight={4} paddingTop={1}>
+        <textarea
+          ref={(r: { plainText: string; focus: () => void }) => {
+            textareaRef = r
+            setTimeout(() => r.focus(), 1)
+          }}
+          height={15}
+          placeholder='{"type": "service_account", ...}'
+          backgroundColor={theme.backgroundElement}
+          cursorColor={theme.primary}
+          keyBindings={[{ name: "return", action: "submit" }]}
+          onSubmit={handleSubmit}
+        />
+      </box>
+      <box paddingLeft={4} paddingRight={4}>
+        <text fg={theme.textMuted}>Paste JSON and press Enter to submit</text>
+        <Show when={error()}>
+          <text fg={theme.error}>{error()}</text>
+        </Show>
+      </box>
+    </box>
+  )
+}
+
+function ServiceAccountLocationInput(props: { providerID: string; serviceAccountJson: string }) {
+  const dialog = useDialog()
+  const sdk = useSDK()
+  const sync = useSync()
+  const { theme } = useTheme()
+  const [error, setError] = createSignal("")
+
+  const defaultLocation = () => (props.providerID === "google-vertex-anthropic" ? "global" : "us-east5")
+
+  const handleLocationSubmit = async (location: string) => {
+    try {
+      const json = JSON.parse(props.serviceAccountJson)
+      const finalLocation = location || defaultLocation()
+
+      sdk.client.auth.set({
+        providerID: props.providerID,
+        auth: {
+          type: "api",
+          key: JSON.stringify({
+            client_email: json.client_email,
+            private_key: json.private_key,
+            project_id: json.project_id,
+            location: finalLocation,
+          }),
+        },
+      })
+      await sdk.client.instance.dispose()
+      await sync.bootstrap()
+      dialog.replace(() => <DialogModel providerID={props.providerID} />)
+    } catch (e) {
+      setError(`Failed to save credentials: ${e instanceof Error ? e.message : "unknown error"}`)
+    }
+  }
+
+  return (
+    <DialogPrompt
+      title="Location"
+      placeholder={defaultLocation()}
+      description={() => (
+        <box gap={1}>
+          <text fg={theme.textMuted}>Enter the Vertex AI location (region).</text>
+          <text fg={theme.text}>
+            Press enter to use default: <span style={{ fg: theme.primary }}>{defaultLocation()}</span>
+          </text>
+          <Show when={error()}>
+            <text fg={theme.error}>{error()}</text>
+          </Show>
+        </box>
+      )}
+      onConfirm={handleLocationSubmit}
+    />
+  )
+}
diff --git a/packages/opencode/src/cli/cmd/tui/context/local.tsx b/packages/opencode/src/cli/cmd/tui/context/local.tsx
index d058ce54fb36..458505839e0a 100644
--- a/packages/opencode/src/cli/cmd/tui/context/local.tsx
+++ b/packages/opencode/src/cli/cmd/tui/context/local.tsx
@@ -9,6 +9,7 @@ import { iife } from "@/util/iife"
 import { createSimpleContext } from "./helper"
 import { useToast } from "../ui/toast"
 import { Provider } from "@/provider/provider"
+import { PROVIDER_DISPLAY_NAMES } from "@/provider/display-names"
 import { useArgs } from "./args"
 import { useSDK } from "./sdk"
 import { RGBA } from "@opentui/core"
@@ -220,7 +221,7 @@ export const { use: useLocal, provider: LocalProvider } = createSimpleContext({
           const provider = sync.data.provider.find((x) => x.id === value.providerID)
           const info = provider?.models[value.modelID]
           return {
-            provider: provider?.name ?? value.providerID,
+            provider: PROVIDER_DISPLAY_NAMES[value.providerID] ?? provider?.name ?? value.providerID,
             model: info?.name ?? value.modelID,
             reasoning: info?.capabilities?.reasoning ?? false,
           }
diff --git a/packages/opencode/src/provider/display-names.ts b/packages/opencode/src/provider/display-names.ts
new file mode 100644
index 000000000000..cb9d6091ec16
--- /dev/null
+++ b/packages/opencode/src/provider/display-names.ts
@@ -0,0 +1,15 @@
+/**
+ * Display name overrides for providers.
+ * Used to show user-friendly names instead of provider IDs.
+ */
+export const PROVIDER_DISPLAY_NAMES: Record<string, string> = {
+  "google-vertex": "Google Vertex AI",
+  "google-vertex-anthropic": "Google Vertex AI (Anthropic)",
+}
+
+/**
+ * Get the display name for a provider, falling back to the provider's name or ID.
+ */
+export function getProviderDisplayName(provider: { id: string; name?: string }): string {
+  return PROVIDER_DISPLAY_NAMES[provider.id] ?? provider.name ?? provider.id
+}
diff --git a/packages/opencode/src/provider/provider.ts b/packages/opencode/src/provider/provider.ts
index f898d3be4308..686fa80f969c 100644
--- a/packages/opencode/src/provider/provider.ts
+++ b/packages/opencode/src/provider/provider.ts
@@ -83,8 +83,62 @@ export namespace Provider {
     autoload: boolean
     getModel?: CustomModelLoader
     options?: Record<string, any>
+    key?: string
   }>
 
+  /**
+   * Helper to create Google Vertex AI loaders for both standard and Anthropic variants.
+   * Reduces duplication between google-vertex and google-vertex-anthropic loaders.
+   */
+  async function createGoogleVertexLoader(providerID: string, defaultLocation: string) {
+    // Check for stored auth credentials first (service account JSON)
+    const auth = await Auth.get(providerID)
+    if (auth?.type === "api") {
+      try {
+        const creds = JSON.parse(auth.key)
+        if (creds.client_email && creds.private_key && creds.project_id) {
+          return {
+            autoload: true,
+            key: undefined,
+            options: {
+              apiKey: null,
+              project: creds.project_id,
+              location: creds.location || defaultLocation,
+              googleAuthOptions: {
+                credentials: {
+                  client_email: creds.client_email,
+                  private_key: creds.private_key,
+                },
+              },
+            },
+            async getModel(sdk: { languageModel: (id: string) => unknown }, modelID: string) {
+              return sdk.languageModel(String(modelID).trim())
+            },
+          }
+        }
+      } catch {
+        // Invalid JSON in stored credentials, fall through to env var check
+      }
+    }
+    // Fall back to environment variables (uses ADC or GOOGLE_APPLICATION_CREDENTIALS)
+    const project = Env.get("GOOGLE_CLOUD_PROJECT") ?? Env.get("GCP_PROJECT") ?? Env.get("GCLOUD_PROJECT")
+    const location = Env.get("GOOGLE_CLOUD_LOCATION") ?? Env.get("VERTEX_LOCATION") ?? defaultLocation
+    const autoload = Boolean(project)
+    if (!autoload) return { autoload: false }
+    return {
+      autoload: true,
+      key: undefined,
+      options: {
+        apiKey: null,
+        project,
+        location,
+      },
+      async getModel(sdk: { languageModel: (id: string) => unknown }, modelID: string) {
+        return sdk.languageModel(String(modelID).trim())
+      },
+    }
+  }
+
   const CUSTOM_LOADERS: Record<string, CustomLoader> = {
     async anthropic() {
       return {
@@ -338,40 +392,8 @@ export namespace Provider {
         },
       }
     },
-    "google-vertex": async () => {
-      const project = Env.get("GOOGLE_CLOUD_PROJECT") ?? Env.get("GCP_PROJECT") ?? Env.get("GCLOUD_PROJECT")
-      const location = Env.get("GOOGLE_CLOUD_LOCATION") ?? Env.get("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 = Env.get("GOOGLE_CLOUD_PROJECT") ?? Env.get("GCP_PROJECT") ?? Env.get("GCLOUD_PROJECT")
-      const location = Env.get("GOOGLE_CLOUD_LOCATION") ?? Env.get("VERTEX_LOCATION") ?? "global"
-      const autoload = Boolean(project)
-      if (!autoload) return { autoload: false }
-      return {
-        autoload: true,
-        options: {
-          project,
-          location,
-        },
-        async getModel(sdk: any, modelID) {
-          const id = String(modelID).trim()
-          return sdk.languageModel(id)
-        },
-      }
-    },
+    "google-vertex": () => createGoogleVertexLoader("google-vertex", "us-east5"),
+    "google-vertex-anthropic": () => createGoogleVertexLoader("google-vertex-anthropic", "global"),
     "sap-ai-core": async () => {
       const auth = await Auth.get("sap-ai-core")
       const envServiceKey = iife(() => {
@@ -891,6 +913,13 @@ export namespace Provider {
         if (result.getModel) modelLoaders[providerID] = result.getModel
         const opts = result.options ?? {}
         const patch: Partial<Info> = providers[providerID] ? { options: opts } : { source: "custom", options: opts }
+        // Pass key from custom loader if explicitly set (e.g., undefined for google-vertex)
+        // to override any key previously set from Auth storage
+        if (result.key !== undefined) {
+          patch.key = result.key
+        } else if ("key" in result) {
+          patch.key = undefined
+        }
         mergeProvider(providerID, patch)
       }
     }
diff --git a/packages/opencode/test/preload.ts b/packages/opencode/test/preload.ts
index 1cb7778623e2..fa6cb55a4f22 100644
--- a/packages/opencode/test/preload.ts
+++ b/packages/opencode/test/preload.ts
@@ -22,10 +22,17 @@ process.env["XDG_CACHE_HOME"] = path.join(dir, "cache")
 process.env["XDG_CONFIG_HOME"] = path.join(dir, "config")
 process.env["XDG_STATE_HOME"] = path.join(dir, "state")
 
-// Write the cache version file to prevent global/index.ts from clearing the cache
+// Pre-fetch models.json so tests don't need the macro fallback
+// Also write the cache version file to prevent global/index.ts from clearing the cache
 const cacheDir = path.join(dir, "cache", "opencode")
 await fs.mkdir(cacheDir, { recursive: true })
-await fs.writeFile(path.join(cacheDir, "version"), "14")
+await fs.writeFile(path.join(cacheDir, "version"), "19")
+const response = await fetch("https://models.dev/api.json")
+if (response.ok) {
+  await fs.writeFile(path.join(cacheDir, "models.json"), await response.text())
+}
+// Disable models.dev refresh to avoid race conditions during tests
+process.env["OPENCODE_DISABLE_MODELS_FETCH"] = "true"
 
 // Clear provider env vars to ensure clean test state
 delete process.env["ANTHROPIC_API_KEY"]
diff --git a/packages/opencode/test/provider/provider.test.ts b/packages/opencode/test/provider/provider.test.ts
index 482587d8ac50..f4a8beeece2b 100644
--- a/packages/opencode/test/provider/provider.test.ts
+++ b/packages/opencode/test/provider/provider.test.ts
@@ -26,6 +26,7 @@ import { tmpdir } from "../fixture/fixture"
 import { Instance } from "../../src/project/instance"
 import { Provider } from "../../src/provider/provider"
 import { Env } from "../../src/env"
+import { Auth } from "../../src/auth"
 
 test("provider loaded from env variable", async () => {
   await using tmp = await tmpdir({
@@ -2148,3 +2149,453 @@ test("custom model with variants enabled and disabled", async () => {
     },
   })
 })
+
+// Google Vertex AI Service Account Authentication Tests
+
+test("google-vertex loads from stored service account credentials", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Bun.write(
+        path.join(dir, "opencode.json"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+        }),
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    init: async () => {
+      // Store service account credentials
+      await Auth.set("google-vertex", {
+        type: "api",
+        key: JSON.stringify({
+          client_email: "test@project.iam.gserviceaccount.com",
+          private_key: "-----BEGIN PRIVATE KEY-----\nMIItest\n-----END PRIVATE KEY-----\n",
+          project_id: "my-gcp-project",
+          location: "us-central1",
+        }),
+      })
+    },
+    fn: async () => {
+      const providers = await Provider.list()
+      expect(providers["google-vertex"]).toBeDefined()
+      expect(providers["google-vertex"].options.project).toBe("my-gcp-project")
+      expect(providers["google-vertex"].options.location).toBe("us-central1")
+      expect(providers["google-vertex"].options.googleAuthOptions).toBeDefined()
+      expect(providers["google-vertex"].options.googleAuthOptions.credentials.client_email).toBe(
+        "test@project.iam.gserviceaccount.com",
+      )
+      // Ensure apiKey is null (not set from service account JSON)
+      expect(providers["google-vertex"].options.apiKey).toBeNull()
+      // Ensure key is undefined (service account JSON should not be exposed as key)
+      expect(providers["google-vertex"].key).toBeUndefined()
+    },
+  })
+})
+
+test("google-vertex-anthropic loads from stored service account credentials", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Bun.write(
+        path.join(dir, "opencode.json"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+        }),
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    init: async () => {
+      // Store service account credentials
+      await Auth.set("google-vertex-anthropic", {
+        type: "api",
+        key: JSON.stringify({
+          client_email: "anthropic-sa@project.iam.gserviceaccount.com",
+          private_key: "-----BEGIN PRIVATE KEY-----\nMIItest\n-----END PRIVATE KEY-----\n",
+          project_id: "my-anthropic-project",
+          location: "global",
+        }),
+      })
+    },
+    fn: async () => {
+      const providers = await Provider.list()
+      expect(providers["google-vertex-anthropic"]).toBeDefined()
+      expect(providers["google-vertex-anthropic"].options.project).toBe("my-anthropic-project")
+      expect(providers["google-vertex-anthropic"].options.location).toBe("global")
+      expect(providers["google-vertex-anthropic"].options.googleAuthOptions).toBeDefined()
+      expect(providers["google-vertex-anthropic"].options.googleAuthOptions.credentials.client_email).toBe(
+        "anthropic-sa@project.iam.gserviceaccount.com",
+      )
+      // Ensure apiKey is null (not set from service account JSON)
+      expect(providers["google-vertex-anthropic"].options.apiKey).toBeNull()
+      // Ensure key is undefined (service account JSON should not be exposed as key)
+      expect(providers["google-vertex-anthropic"].key).toBeUndefined()
+    },
+  })
+})
+
+test("google-vertex uses default location when not specified in credentials", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Bun.write(
+        path.join(dir, "opencode.json"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+        }),
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    init: async () => {
+      // Store service account credentials without location
+      await Auth.set("google-vertex", {
+        type: "api",
+        key: JSON.stringify({
+          client_email: "test@project.iam.gserviceaccount.com",
+          private_key: "-----BEGIN PRIVATE KEY-----\nMIItest\n-----END PRIVATE KEY-----\n",
+          project_id: "my-gcp-project",
+          // no location specified
+        }),
+      })
+    },
+    fn: async () => {
+      const providers = await Provider.list()
+      expect(providers["google-vertex"]).toBeDefined()
+      expect(providers["google-vertex"].options.location).toBe("us-east5") // default location
+      expect(providers["google-vertex"].options.apiKey).toBeNull()
+      expect(providers["google-vertex"].key).toBeUndefined()
+    },
+  })
+})
+
+test("google-vertex-anthropic uses default location 'global' when not specified", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Bun.write(
+        path.join(dir, "opencode.json"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+        }),
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    init: async () => {
+      // Store service account credentials without location
+      await Auth.set("google-vertex-anthropic", {
+        type: "api",
+        key: JSON.stringify({
+          client_email: "test@project.iam.gserviceaccount.com",
+          private_key: "-----BEGIN PRIVATE KEY-----\nMIItest\n-----END PRIVATE KEY-----\n",
+          project_id: "my-gcp-project",
+          // no location specified
+        }),
+      })
+    },
+    fn: async () => {
+      const providers = await Provider.list()
+      expect(providers["google-vertex-anthropic"]).toBeDefined()
+      expect(providers["google-vertex-anthropic"].options.location).toBe("global") // default location for anthropic
+      expect(providers["google-vertex-anthropic"].options.apiKey).toBeNull()
+      expect(providers["google-vertex-anthropic"].key).toBeUndefined()
+    },
+  })
+})
+
+test("google-vertex falls back to env vars when no stored credentials", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Bun.write(
+        path.join(dir, "opencode.json"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+        }),
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    init: async () => {
+      // Remove any existing auth
+      await Auth.remove("google-vertex")
+      // Set env vars instead of stored credentials
+      Env.set("GOOGLE_CLOUD_PROJECT", "env-project")
+      Env.set("VERTEX_LOCATION", "europe-west1")
+    },
+    fn: async () => {
+      const providers = await Provider.list()
+      expect(providers["google-vertex"]).toBeDefined()
+      expect(providers["google-vertex"].options.project).toBe("env-project")
+      expect(providers["google-vertex"].options.location).toBe("europe-west1")
+      // No googleAuthOptions when using env vars
+      expect(providers["google-vertex"].options.googleAuthOptions).toBeUndefined()
+      // apiKey should still be null to prevent fallback to other API keys
+      expect(providers["google-vertex"].options.apiKey).toBeNull()
+      expect(providers["google-vertex"].key).toBeUndefined()
+    },
+  })
+})
+
+test("google-vertex not loaded when neither credentials nor env vars set", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Bun.write(
+        path.join(dir, "opencode.json"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+        }),
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    init: async () => {
+      // Clean up any existing auth and env vars
+      await Auth.remove("google-vertex")
+      // Clear the env vars that the custom loader checks
+      Env.set("GOOGLE_CLOUD_PROJECT", "")
+      Env.set("GCP_PROJECT", "")
+      Env.set("GCLOUD_PROJECT", "")
+      // Also clear the env vars that the database env loader checks
+      Env.set("GOOGLE_VERTEX_PROJECT", "")
+      Env.set("GOOGLE_VERTEX_LOCATION", "")
+      Env.set("GOOGLE_APPLICATION_CREDENTIALS", "")
+    },
+    fn: async () => {
+      const providers = await Provider.list()
+      expect(providers["google-vertex"]).toBeUndefined()
+    },
+  })
+})
+
+test("google-vertex ignores incomplete stored credentials", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Bun.write(
+        path.join(dir, "opencode.json"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+        }),
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    init: async () => {
+      // Store incomplete credentials (missing private_key)
+      await Auth.set("google-vertex", {
+        type: "api",
+        key: JSON.stringify({
+          client_email: "test@project.iam.gserviceaccount.com",
+          // missing private_key
+          project_id: "my-gcp-project",
+        }),
+      })
+      // Also set env vars as fallback
+      Env.set("GOOGLE_CLOUD_PROJECT", "fallback-project")
+    },
+    fn: async () => {
+      const providers = await Provider.list()
+      expect(providers["google-vertex"]).toBeDefined()
+      // Should fall back to env vars
+      expect(providers["google-vertex"].options.project).toBe("fallback-project")
+      expect(providers["google-vertex"].options.googleAuthOptions).toBeUndefined()
+    },
+  })
+})
+
+test("google-vertex ignores invalid JSON in stored credentials", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Bun.write(
+        path.join(dir, "opencode.json"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+        }),
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    init: async () => {
+      // Store invalid JSON
+      await Auth.set("google-vertex", {
+        type: "api",
+        key: "not valid json",
+      })
+      // Also set env vars as fallback
+      Env.set("GOOGLE_CLOUD_PROJECT", "fallback-project")
+    },
+    fn: async () => {
+      const providers = await Provider.list()
+      expect(providers["google-vertex"]).toBeDefined()
+      // Should fall back to env vars
+      expect(providers["google-vertex"].options.project).toBe("fallback-project")
+    },
+  })
+})
+
+test("google-vertex stored credentials take priority over env vars", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Bun.write(
+        path.join(dir, "opencode.json"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+        }),
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    init: async () => {
+      // Store service account credentials
+      await Auth.set("google-vertex", {
+        type: "api",
+        key: JSON.stringify({
+          client_email: "stored@project.iam.gserviceaccount.com",
+          private_key: "-----BEGIN PRIVATE KEY-----\nMIItest\n-----END PRIVATE KEY-----\n",
+          project_id: "stored-project",
+          location: "stored-location",
+        }),
+      })
+      // Also set env vars
+      Env.set("GOOGLE_CLOUD_PROJECT", "env-project")
+      Env.set("VERTEX_LOCATION", "env-location")
+    },
+    fn: async () => {
+      const providers = await Provider.list()
+      expect(providers["google-vertex"]).toBeDefined()
+      // Stored credentials should take priority
+      expect(providers["google-vertex"].options.project).toBe("stored-project")
+      expect(providers["google-vertex"].options.location).toBe("stored-location")
+      expect(providers["google-vertex"].options.googleAuthOptions).toBeDefined()
+      // Ensure apiKey is null even when env vars are set
+      expect(providers["google-vertex"].options.apiKey).toBeNull()
+      expect(providers["google-vertex"].key).toBeUndefined()
+    },
+  })
+})
+
+test("google-vertex and google (Gemini) providers are completely separate", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Bun.write(
+        path.join(dir, "opencode.json"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+        }),
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    init: async () => {
+      // Set up google (Gemini) with API key
+      Env.set("GOOGLE_GENERATIVE_AI_API_KEY", "my-gemini-api-key")
+
+      // Set up google-vertex with service account credentials
+      await Auth.set("google-vertex", {
+        type: "api",
+        key: JSON.stringify({
+          client_email: "vertex@project.iam.gserviceaccount.com",
+          private_key: "-----BEGIN PRIVATE KEY-----\nMIItest\n-----END PRIVATE KEY-----\n",
+          project_id: "vertex-project",
+          location: "us-central1",
+        }),
+      })
+    },
+    fn: async () => {
+      const providers = await Provider.list()
+
+      // Both providers should be loaded
+      expect(providers["google"]).toBeDefined()
+      expect(providers["google-vertex"]).toBeDefined()
+
+      // google (Gemini) is loaded from env var (google has multiple env vars so key isn't stored directly)
+      expect(providers["google"].source).toBe("env")
+
+      // google-vertex should NOT use the Gemini API key
+      expect(providers["google-vertex"].key).toBeUndefined()
+      expect(providers["google-vertex"].options.apiKey).toBeNull()
+
+      // google-vertex should use service account auth
+      expect(providers["google-vertex"].options.project).toBe("vertex-project")
+      expect(providers["google-vertex"].options.googleAuthOptions).toBeDefined()
+      expect(providers["google-vertex"].options.googleAuthOptions.credentials.client_email).toBe(
+        "vertex@project.iam.gserviceaccount.com",
+      )
+    },
+  })
+})
+
+test("google-vertex-anthropic is separate from google and google-vertex", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Bun.write(
+        path.join(dir, "opencode.json"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+        }),
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    init: async () => {
+      // Set up all three providers
+      Env.set("GOOGLE_GENERATIVE_AI_API_KEY", "gemini-key")
+
+      await Auth.set("google-vertex", {
+        type: "api",
+        key: JSON.stringify({
+          client_email: "vertex@project.iam.gserviceaccount.com",
+          private_key: "-----BEGIN PRIVATE KEY-----\nMIItest\n-----END PRIVATE KEY-----\n",
+          project_id: "vertex-project",
+          location: "us-central1",
+        }),
+      })
+
+      await Auth.set("google-vertex-anthropic", {
+        type: "api",
+        key: JSON.stringify({
+          client_email: "anthropic@project.iam.gserviceaccount.com",
+          private_key: "-----BEGIN PRIVATE KEY-----\nMIItest2\n-----END PRIVATE KEY-----\n",
+          project_id: "anthropic-project",
+          location: "global",
+        }),
+      })
+    },
+    fn: async () => {
+      const providers = await Provider.list()
+
+      // All three should be separate
+      expect(providers["google"]).toBeDefined()
+      expect(providers["google-vertex"]).toBeDefined()
+      expect(providers["google-vertex-anthropic"]).toBeDefined()
+
+      // google is loaded from env var (google has multiple env vars so key isn't stored directly)
+      expect(providers["google"].source).toBe("env")
+
+      // google-vertex uses its own service account
+      expect(providers["google-vertex"].options.project).toBe("vertex-project")
+      expect(providers["google-vertex"].options.googleAuthOptions.credentials.client_email).toBe(
+        "vertex@project.iam.gserviceaccount.com",
+      )
+      expect(providers["google-vertex"].key).toBeUndefined()
+      expect(providers["google-vertex"].options.apiKey).toBeNull()
+
+      // google-vertex-anthropic uses its own separate service account
+      expect(providers["google-vertex-anthropic"].options.project).toBe("anthropic-project")
+      expect(providers["google-vertex-anthropic"].options.googleAuthOptions.credentials.client_email).toBe(
+        "anthropic@project.iam.gserviceaccount.com",
+      )
+      expect(providers["google-vertex-anthropic"].key).toBeUndefined()
+      expect(providers["google-vertex-anthropic"].options.apiKey).toBeNull()
+    },
+  })
+})