Add Google Vertex AI provider (#1163)

# Summary

* Adds first-class **Google Vertex AI provider** using
`@ai-sdk/google-vertex`.
* Supports **Gemini 2.5** models and partner **MaaS (Model Garden)**
models via full publisher IDs.
* New **Vertex-specific settings UI** for Project, Location, and Service
Account JSON.
* Implements a **“thinking” toggle** for Gemini 2.5 Flash

  * Pro: always on
  * Flash: toggleable
  * Flash Lite: none
* Fixes *“AI not found”* for Vertex built-ins by mapping to
`publishers/google` paths.
* Hardens **cross-platform file ops** and ensures all tests pass.

---

# What’s New

### Vertex AI Provider

* Uses `@ai-sdk/google-vertex` with `googleAuthOptions.credentials` from
pasted Service Account JSON.
* Configurable **project** and **location**.
* Base URL → `/projects/{project}/locations/{location}`

  * Built-ins: `publishers/google/models/<id>`
  * Partner MaaS: `publishers/<partner>/models/...`

### Built-in Vertex Models

* `gemini-2.5-pro`
* `gemini-2.5-flash`
* `gemini-2.5-flash-lite`

### Thinking Behavior

* Vertex + Google marked as thinking-capable.
* Pro: always thinking
* Flash: toggle in UI
* Flash Lite: none

### Vertex Settings UI

* New **Google Vertex AI panel** for Project ID, Location, Service
Account JSON.
* Keys encrypted like other secrets.

---

# Fixes

* **Model resolution:** built-ins auto-map to
`publishers/google/models/<id>`.
* **Partner MaaS support:** full publisher IDs work directly (e.g.
DeepSeek).
* **Cross-platform paths:** normalize file ops with `toPosixPath`,
preserve `safeJoin` semantics.

---

# Why This Is Better

* Users can select **Vertex alongside other providers**.
* **More models** available through Model Garden.
* **Dedicated setup UI** reduces misconfig.
* **Thinking toggle** gives control over cost vs. reasoning depth.

---

# Files Changed

* **Provider & Models**: `language_model_helpers.ts`,
`get_model_client.ts`
* **Streaming**: `chat_stream_handlers.ts`
* **Schemas & Encryption**: `schemas.ts`, `settings.ts`
* **Settings UI**: `VertexConfiguration.tsx`, `ApiKeyConfiguration.tsx`
* **Models UI**: `ModelsSection.tsx` (Flash toggle)
* **Setup Detection**: `useLanguageModelProviders.ts`
* **Path Utils**: `path_utils.ts`, `response_processor.ts`
* **Deps**: `package.json` → `@ai-sdk/google-vertex@3.0.16`

---

# Tests & Validation

* **TypeScript**: `npm run ts` → ✅
* **Lint**: `npm run lint` → ✅
* **Unit tests**: `npm test` → ✅ 231 passed, 0 failed

---

# Migration / Notes

* No breaking changes.
* For Vertex usage:

  * Ensure Vertex AI API is enabled.
  * Service Account needs `roles/aiplatform.user`.
  * Region must support model (e.g. `us-central1`).
* Thinking toggle currently affects **only** Gemini 2.5 Flash.

---

# Manual QA

1. Configure Vertex with Project/Location/Service Account JSON.
2. Test built-ins:

   * `gemini-2.5-pro`
   * `gemini-2.5-flash` (toggle on/off)
   * `gemini-2.5-flash-lite`
3. Test MaaS partner model (e.g., DeepSeek) via full publisher ID.
4. Verify other providers remain unaffected.
    
<!-- This is an auto-generated description by cubic. -->
---

## Summary by cubic
Adds a first-class Google Vertex AI provider with Gemini 2.5 models, a
Vertex settings panel, and a “thinking” toggle for Gemini 2.5 Flash.
Also fixes model resolution for Vertex and hardens cross-platform file
operations.

- **New Features**
- Vertex AI provider via @ai-sdk/google-vertex with project, location,
and service account JSON.
- Built-in models: gemini-2.5-pro, gemini-2.5-flash,
gemini-2.5-flash-lite.
- “Thinking” support: Pro always on; Flash toggle in Models UI; Flash
Lite none.
- MaaS partners supported via full publisher paths (e.g.,
publishers/<partner>/models/...).
  - Vertex settings UI with encrypted service account key storage.

- **Bug Fixes**
  - Built-in Vertex models auto-map to publishers/google/models/<id>.
  - Consistent file ops across platforms using toPosixPath.
- Vertex readiness detection requires project/location/service account
JSON.
- Streaming “thinking” behavior respects Vertex Flash toggle and Pro
always-on.

<!-- End of auto-generated description by cubic. -->

---------

Co-authored-by: Md Rakibul Islam Rocky <mdrirocky08@gmail.com>
Co-authored-by: graphite-app[bot] <96075541+graphite-app[bot]@users.noreply.github.com>
Co-authored-by: Will Chen <willchen90@gmail.com>

package-lock.json

@@ -1,17 +1,18 @@
 {
   "name": "dyad",
-  "version": "0.19.0",
+  "version": "0.20.0-beta.1",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "dyad",
-      "version": "0.19.0",
+      "version": "0.20.0-beta.1",
       "license": "MIT",
       "dependencies": {
         "@ai-sdk/anthropic": "^2.0.4",
         "@ai-sdk/azure": "^2.0.17",
         "@ai-sdk/google": "^2.0.6",
+        "@ai-sdk/google-vertex": "3.0.16",
         "@ai-sdk/openai": "2.0.15",
         "@ai-sdk/openai-compatible": "^1.0.8",
         "@ai-sdk/provider-utils": "^3.0.3",
@@ -129,13 +130,30 @@
       }
     },
     "node_modules/@ai-sdk/anthropic": {
-      "version": "2.0.4",
+      "version": "2.0.9",
-      "resolved": "https://registry.npmjs.org/@ai-sdk/anthropic/-/anthropic-2.0.4.tgz",
+      "resolved": "https://registry.npmjs.org/@ai-sdk/anthropic/-/anthropic-2.0.9.tgz",
-      "integrity": "sha512-ii2bZEUPwBitUiK1dpX+HsOarcDGY71G9TVdSJqbfXSVqa+speJNZ8PA/bjuNMml0NyX8VxNsaMg3SwBUCZspA==",
+      "integrity": "sha512-1kQgL2A3PeqfEcHHmqy4NxRc8rbgLS71bHBuvDFfDz3VAAyndkilPMCLNDSP2mJVGAej2EMWJ1sShRAxzn70jA==",
       "license": "Apache-2.0",
       "dependencies": {
         "@ai-sdk/provider": "2.0.0",
-        "@ai-sdk/provider-utils": "3.0.3"
+        "@ai-sdk/provider-utils": "3.0.7"
+      },
+      "engines": {
+        "node": ">=18"
+      },
+      "peerDependencies": {
+        "zod": "^3.25.76 || ^4"
+      }
+    },
+    "node_modules/@ai-sdk/anthropic/node_modules/@ai-sdk/provider-utils": {
+      "version": "3.0.7",
+      "resolved": "https://registry.npmjs.org/@ai-sdk/provider-utils/-/provider-utils-3.0.7.tgz",
+      "integrity": "sha512-o3BS5/t8KnBL3ubP8k3w77AByOypLm+pkIL/DCw0qKkhDbvhCy+L3hRTGPikpdb8WHcylAeKsjgwOxhj4cqTUA==",
+      "license": "Apache-2.0",
+      "dependencies": {
+        "@ai-sdk/provider": "2.0.0",
+        "@standard-schema/spec": "^1.0.0",
+        "eventsource-parser": "^3.0.5"
       },
       "engines": {
         "node": ">=18"
@@ -212,13 +230,66 @@
       }
     },
     "node_modules/@ai-sdk/google": {
-      "version": "2.0.6",
+      "version": "2.0.11",
-      "resolved": "https://registry.npmjs.org/@ai-sdk/google/-/google-2.0.6.tgz",
+      "resolved": "https://registry.npmjs.org/@ai-sdk/google/-/google-2.0.11.tgz",
-      "integrity": "sha512-8acuseWJI+RRH99JDWM/n7IJRuuGNa4YzLXB/leqE/ZByHyIiVWGADjJi/vfnJnmdM5fQnezJ6SRTF6feI5rSQ==",
+      "integrity": "sha512-dnVIgSz1DZD/0gVau6ifYN3HZFN15HZwC9VjevTFfvrfSfbEvpXj5x/k/zk/0XuQrlQ5g8JiwJtxc9bx24x2xw==",
       "license": "Apache-2.0",
       "dependencies": {
         "@ai-sdk/provider": "2.0.0",
-        "@ai-sdk/provider-utils": "3.0.3"
+        "@ai-sdk/provider-utils": "3.0.7"
+      },
+      "engines": {
+        "node": ">=18"
+      },
+      "peerDependencies": {
+        "zod": "^3.25.76 || ^4"
+      }
+    },
+    "node_modules/@ai-sdk/google-vertex": {
+      "version": "3.0.16",
+      "resolved": "https://registry.npmjs.org/@ai-sdk/google-vertex/-/google-vertex-3.0.16.tgz",
+      "integrity": "sha512-tStlnOCRGRqKKJSCOtXhijX4r9kYVK2v+Vs7miJnfvr3sZfO8nRS0xnNhfgu17xuNi5LMMufeCYURTz4lKxzUQ==",
+      "license": "Apache-2.0",
+      "dependencies": {
+        "@ai-sdk/anthropic": "2.0.9",
+        "@ai-sdk/google": "2.0.11",
+        "@ai-sdk/provider": "2.0.0",
+        "@ai-sdk/provider-utils": "3.0.7",
+        "google-auth-library": "^9.15.0"
+      },
+      "engines": {
+        "node": ">=18"
+      },
+      "peerDependencies": {
+        "zod": "^3.25.76 || ^4"
+      }
+    },
+    "node_modules/@ai-sdk/google-vertex/node_modules/@ai-sdk/provider-utils": {
+      "version": "3.0.7",
+      "resolved": "https://registry.npmjs.org/@ai-sdk/provider-utils/-/provider-utils-3.0.7.tgz",
+      "integrity": "sha512-o3BS5/t8KnBL3ubP8k3w77AByOypLm+pkIL/DCw0qKkhDbvhCy+L3hRTGPikpdb8WHcylAeKsjgwOxhj4cqTUA==",
+      "license": "Apache-2.0",
+      "dependencies": {
+        "@ai-sdk/provider": "2.0.0",
+        "@standard-schema/spec": "^1.0.0",
+        "eventsource-parser": "^3.0.5"
+      },
+      "engines": {
+        "node": ">=18"
+      },
+      "peerDependencies": {
+        "zod": "^3.25.76 || ^4"
+      }
+    },
+    "node_modules/@ai-sdk/google/node_modules/@ai-sdk/provider-utils": {
+      "version": "3.0.7",
+      "resolved": "https://registry.npmjs.org/@ai-sdk/provider-utils/-/provider-utils-3.0.7.tgz",
+      "integrity": "sha512-o3BS5/t8KnBL3ubP8k3w77AByOypLm+pkIL/DCw0qKkhDbvhCy+L3hRTGPikpdb8WHcylAeKsjgwOxhj4cqTUA==",
+      "license": "Apache-2.0",
+      "dependencies": {
+        "@ai-sdk/provider": "2.0.0",
+        "@standard-schema/spec": "^1.0.0",
+        "eventsource-parser": "^3.0.5"
       },
       "engines": {
         "node": ">=18"
@@ -7869,6 +7940,15 @@
         "prebuild-install": "^7.1.1"
       }
     },
+    "node_modules/bignumber.js": {
+      "version": "9.3.1",
+      "resolved": "https://registry.npmjs.org/bignumber.js/-/bignumber.js-9.3.1.tgz",
+      "integrity": "sha512-Ko0uX15oIUS7wJ3Rb30Fs6SkVbLmPBAKdlm7q9+ak9bbIeFf0MwuBsQV6z7+X768/cHsfg+WlysDWJcmthjsjQ==",
+      "license": "MIT",
+      "engines": {
+        "node": "*"
+      }
+    },
     "node_modules/bindings": {
       "version": "1.5.0",
       "resolved": "https://registry.npmjs.org/bindings/-/bindings-1.5.0.tgz",
@@ -8000,6 +8080,12 @@
         "node": "*"
       }
     },
+    "node_modules/buffer-equal-constant-time": {
+      "version": "1.0.1",
+      "resolved": "https://registry.npmjs.org/buffer-equal-constant-time/-/buffer-equal-constant-time-1.0.1.tgz",
+      "integrity": "sha512-zRpUiDwd/xk6ADqPMATG8vc9VPrkck7T07OIx0gnjmJAnHnTVXNQG3vfvWNuiZIkwu9KrKdA1iJKfsfTVxE6NA==",
+      "license": "BSD-3-Clause"
+    },
     "node_modules/buffer-from": {
       "version": "1.1.2",
       "resolved": "https://registry.npmjs.org/buffer-from/-/buffer-from-1.1.2.tgz",
@@ -9824,6 +9910,15 @@
       "integrity": "sha512-I88TYZWc9XiYHRQ4/3c5rjjfgkjhLyW2luGIheGERbNQ6OY7yTybanSpDXZa8y7VUP9YmDcYa+eyq4ca7iLqWA==",
       "license": "MIT"
     },
+    "node_modules/ecdsa-sig-formatter": {
+      "version": "1.0.11",
+      "resolved": "https://registry.npmjs.org/ecdsa-sig-formatter/-/ecdsa-sig-formatter-1.0.11.tgz",
+      "integrity": "sha512-nagl3RYrbNv6kQkeJIpt6NJZy8twLB/2vtz6yN9Z4vRKHN4/QZJIEbqohALSgwKdnksuY3k5Addp5lg8sVoVcQ==",
+      "license": "Apache-2.0",
+      "dependencies": {
+        "safe-buffer": "^5.0.1"
+      }
+    },
     "node_modules/electron": {
       "version": "35.1.4",
       "resolved": "https://registry.npmjs.org/electron/-/electron-35.1.4.tgz",
@@ -11123,12 +11218,12 @@
       "license": "MIT"
     },
     "node_modules/eventsource-parser": {
-      "version": "3.0.3",
+      "version": "3.0.6",
-      "resolved": "https://registry.npmjs.org/eventsource-parser/-/eventsource-parser-3.0.3.tgz",
+      "resolved": "https://registry.npmjs.org/eventsource-parser/-/eventsource-parser-3.0.6.tgz",
-      "integrity": "sha512-nVpZkTMM9rF6AQ9gPJpFsNAMt48wIzB5TQgiTLdHiuO8XEDhUgZEhqKlZWXbIzo9VmJ/HvysHqEaVeD5v9TPvA==",
+      "integrity": "sha512-Vo1ab+QXPzZ4tCa8SwIHJFaSzy4R6SHf7BY79rFBDf0idraZWAkYrDjDj8uWaSm3S2TK+hJ7/t1CEmZ7jXw+pg==",
       "license": "MIT",
       "engines": {
-        "node": ">=20.0.0"
+        "node": ">=18.0.0"
       }
     },
     "node_modules/execa": {
@@ -11746,6 +11841,83 @@
       "license": "MIT",
       "optional": true
     },
+    "node_modules/gaxios": {
+      "version": "6.7.1",
+      "resolved": "https://registry.npmjs.org/gaxios/-/gaxios-6.7.1.tgz",
+      "integrity": "sha512-LDODD4TMYx7XXdpwxAVRAIAuB0bzv0s+ywFonY46k126qzQHT9ygyoa9tncmOiQmmDrik65UYsEkv3lbfqQ3yQ==",
+      "license": "Apache-2.0",
+      "dependencies": {
+        "extend": "^3.0.2",
+        "https-proxy-agent": "^7.0.1",
+        "is-stream": "^2.0.0",
+        "node-fetch": "^2.6.9",
+        "uuid": "^9.0.1"
+      },
+      "engines": {
+        "node": ">=14"
+      }
+    },
+    "node_modules/gaxios/node_modules/agent-base": {
+      "version": "7.1.4",
+      "resolved": "https://registry.npmjs.org/agent-base/-/agent-base-7.1.4.tgz",
+      "integrity": "sha512-MnA+YT8fwfJPgBx3m60MNqakm30XOkyIoH1y6huTQvC0PwZG7ki8NacLBcrPbNoo8vEZy7Jpuk7+jMO+CUovTQ==",
+      "license": "MIT",
+      "engines": {
+        "node": ">= 14"
+      }
+    },
+    "node_modules/gaxios/node_modules/https-proxy-agent": {
+      "version": "7.0.6",
+      "resolved": "https://registry.npmjs.org/https-proxy-agent/-/https-proxy-agent-7.0.6.tgz",
+      "integrity": "sha512-vK9P5/iUfdl95AI+JVyUuIcVtd4ofvtrOr3HNtM2yxC9bnMbEdp3x01OhQNnjb8IJYi38VlTE3mBXwcfvywuSw==",
+      "license": "MIT",
+      "dependencies": {
+        "agent-base": "^7.1.2",
+        "debug": "4"
+      },
+      "engines": {
+        "node": ">= 14"
+      }
+    },
+    "node_modules/gaxios/node_modules/is-stream": {
+      "version": "2.0.1",
+      "resolved": "https://registry.npmjs.org/is-stream/-/is-stream-2.0.1.tgz",
+      "integrity": "sha512-hFoiJiTl63nn+kstHGBtewWSKnQLpyb155KHheA1l39uvtO9nWIop1p3udqPcUd/xbF1VLMO4n7OI6p7RbngDg==",
+      "license": "MIT",
+      "engines": {
+        "node": ">=8"
+      },
+      "funding": {
+        "url": "https://github.com/sponsors/sindresorhus"
+      }
+    },
+    "node_modules/gaxios/node_modules/uuid": {
+      "version": "9.0.1",
+      "resolved": "https://registry.npmjs.org/uuid/-/uuid-9.0.1.tgz",
+      "integrity": "sha512-b+1eJOlsR9K8HJpow9Ok3fiWOWSIcIzXodvv0rQjVoOVNpWMpxf1wZNpt4y9h10odCNrqnYp1OBzRktckBe3sA==",
+      "funding": [
+        "https://github.com/sponsors/broofa",
+        "https://github.com/sponsors/ctavan"
+      ],
+      "license": "MIT",
+      "bin": {
+        "uuid": "dist/bin/uuid"
+      }
+    },
+    "node_modules/gcp-metadata": {
+      "version": "6.1.1",
+      "resolved": "https://registry.npmjs.org/gcp-metadata/-/gcp-metadata-6.1.1.tgz",
+      "integrity": "sha512-a4tiq7E0/5fTjxPAaH4jpjkSv/uCaU2p5KC6HVGrvl0cDjA8iBZv4vv1gyzlmK0ZUKqwpOyQMKzZQe3lTit77A==",
+      "license": "Apache-2.0",
+      "dependencies": {
+        "gaxios": "^6.1.1",
+        "google-logging-utils": "^0.0.2",
+        "json-bigint": "^1.0.0"
+      },
+      "engines": {
+        "node": ">=14"
+      }
+    },
     "node_modules/geist": {
       "version": "1.4.2",
       "resolved": "https://registry.npmjs.org/geist/-/geist-1.4.2.tgz",
@@ -12149,6 +12321,32 @@
         "url": "https://github.com/sponsors/sindresorhus"
       }
     },
+    "node_modules/google-auth-library": {
+      "version": "9.15.1",
+      "resolved": "https://registry.npmjs.org/google-auth-library/-/google-auth-library-9.15.1.tgz",
+      "integrity": "sha512-Jb6Z0+nvECVz+2lzSMt9u98UsoakXxA2HGHMCxh+so3n90XgYWkq5dur19JAJV7ONiJY22yBTyJB1TSkvPq9Ng==",
+      "license": "Apache-2.0",
+      "dependencies": {
+        "base64-js": "^1.3.0",
+        "ecdsa-sig-formatter": "^1.0.11",
+        "gaxios": "^6.1.1",
+        "gcp-metadata": "^6.1.0",
+        "gtoken": "^7.0.0",
+        "jws": "^4.0.0"
+      },
+      "engines": {
+        "node": ">=14"
+      }
+    },
+    "node_modules/google-logging-utils": {
+      "version": "0.0.2",
+      "resolved": "https://registry.npmjs.org/google-logging-utils/-/google-logging-utils-0.0.2.tgz",
+      "integrity": "sha512-NEgUnEcBiP5HrPzufUkBzJOD/Sxsco3rLNo1F1TNf7ieU8ryUzBhqba8r756CjLX7rn3fHl6iLEwPYuqpoKgQQ==",
+      "license": "Apache-2.0",
+      "engines": {
+        "node": ">=14"
+      }
+    },
     "node_modules/gopd": {
       "version": "1.2.0",
       "resolved": "https://registry.npmjs.org/gopd/-/gopd-1.2.0.tgz",
@@ -12200,6 +12398,19 @@
       "dev": true,
       "license": "MIT"
     },
+    "node_modules/gtoken": {
+      "version": "7.1.0",
+      "resolved": "https://registry.npmjs.org/gtoken/-/gtoken-7.1.0.tgz",
+      "integrity": "sha512-pCcEwRi+TKpMlxAQObHDQ56KawURgyAf6jtIY046fJ5tIv3zDe/LEIubckAO8fj6JnAxLdmWkUfNyulQ2iKdEw==",
+      "license": "MIT",
+      "dependencies": {
+        "gaxios": "^6.0.0",
+        "jws": "^4.0.0"
+      },
+      "engines": {
+        "node": ">=14.0.0"
+      }
+    },
     "node_modules/happy-dom": {
       "version": "17.6.3",
       "resolved": "https://registry.npmjs.org/happy-dom/-/happy-dom-17.6.3.tgz",
@@ -13553,6 +13764,15 @@
         "node": ">=6"
       }
     },
+    "node_modules/json-bigint": {
+      "version": "1.0.0",
+      "resolved": "https://registry.npmjs.org/json-bigint/-/json-bigint-1.0.0.tgz",
+      "integrity": "sha512-SiPv/8VpZuWbvLSMtTDU8hEfrZWg/mH/nV/b4o0CYbSxu1UIQPLdwKOCIyLQX+VIPO5vrLX3i8qtqFyhdPSUSQ==",
+      "license": "MIT",
+      "dependencies": {
+        "bignumber.js": "^9.0.0"
+      }
+    },
     "node_modules/json-buffer": {
       "version": "3.0.1",
       "resolved": "https://registry.npmjs.org/json-buffer/-/json-buffer-3.0.1.tgz",
@@ -13623,6 +13843,27 @@
         "node": ">=8"
       }
     },
+    "node_modules/jwa": {
+      "version": "2.0.1",
+      "resolved": "https://registry.npmjs.org/jwa/-/jwa-2.0.1.tgz",
+      "integrity": "sha512-hRF04fqJIP8Abbkq5NKGN0Bbr3JxlQ+qhZufXVr0DvujKy93ZCbXZMHDL4EOtodSbCWxOqR8MS1tXA5hwqCXDg==",
+      "license": "MIT",
+      "dependencies": {
+        "buffer-equal-constant-time": "^1.0.1",
+        "ecdsa-sig-formatter": "1.0.11",
+        "safe-buffer": "^5.0.1"
+      }
+    },
+    "node_modules/jws": {
+      "version": "4.0.0",
+      "resolved": "https://registry.npmjs.org/jws/-/jws-4.0.0.tgz",
+      "integrity": "sha512-KDncfTmOZoOMTFG4mBlG0qUIOlc03fmzH+ru6RgYVZhPkyiy/92Owlt/8UEN+a4TXR1FQetfIpJE8ApdvdVxTg==",
+      "license": "MIT",
+      "dependencies": {
+        "jwa": "^2.0.0",
+        "safe-buffer": "^5.0.1"
+      }
+    },
     "node_modules/keyv": {
       "version": "4.5.4",
       "resolved": "https://registry.npmjs.org/keyv/-/keyv-4.5.4.tgz",

package.json

@@ -88,6 +88,7 @@
     "@ai-sdk/anthropic": "^2.0.4",
     "@ai-sdk/azure": "^2.0.17",
     "@ai-sdk/google": "^2.0.6",
+    "@ai-sdk/google-vertex": "3.0.16",
     "@ai-sdk/openai": "2.0.15",
     "@ai-sdk/openai-compatible": "^1.0.8",
     "@ai-sdk/provider-utils": "^3.0.3",

src/components/settings/ApiKeyConfiguration.tsx

@@ -7,6 +7,7 @@ import {
   AccordionTrigger,
 } from "@/components/ui/accordion";
 import { AzureConfiguration } from "./AzureConfiguration";
+import { VertexConfiguration } from "./VertexConfiguration";
 import { Input } from "@/components/ui/input";
 import { Button } from "@/components/ui/button";
 import { UserSettings } from "@/lib/schemas";
@@ -51,6 +52,10 @@ export function ApiKeyConfiguration({
   if (provider === "azure") {
     return <AzureConfiguration envVars={envVars} />;
   }
+  // Special handling for Google Vertex AI which uses service account credentials
+  if (provider === "vertex") {
+    return <VertexConfiguration />;
+  }
 
   const envApiKey = envVarName ? envVars[envVarName] : undefined;
   const userApiKey = settings?.providerSettings?.[provider]?.apiKey?.value;

src/components/settings/ProviderSettingsPage.tsx

@@ -75,8 +75,20 @@ export function ProviderSettingsPage({ provider }: ProviderSettingsPageProps) {
       ? !!(envVars["AZURE_API_KEY"] && envVars["AZURE_RESOURCE_NAME"])
       : false;
 
+  // Special handling for Vertex configuration status
+  const vertexSettings = settings?.providerSettings?.vertex as any;
+  const isVertexConfigured = Boolean(
+    vertexSettings?.projectId &&
+      vertexSettings?.location &&
+      vertexSettings?.serviceAccountKey?.value,
+  );
+
   const isConfigured =
-    provider === "azure" ? isAzureConfigured : isValidUserKey || hasEnvKey; // Configured if either is set
+    provider === "azure"
+      ? isAzureConfigured
+      : provider === "vertex"
+        ? isVertexConfigured
+        : isValidUserKey || hasEnvKey; // Configured if either is set
 
   // --- Save Handler ---
   const handleSaveKey = async () => {

src/components/settings/VertexConfiguration.tsx

@@ -0,0 +1,141 @@
+import { useState, useEffect } from "react";
+import { Input } from "@/components/ui/input";
+import { Button } from "@/components/ui/button";
+import { Textarea } from "@/components/ui/textarea";
+import { Alert, AlertDescription, AlertTitle } from "@/components/ui/alert";
+import { Info, CheckCircle2 } from "lucide-react";
+import { useSettings } from "@/hooks/useSettings";
+import type { UserSettings, VertexProviderSetting } from "@/lib/schemas";
+
+export function VertexConfiguration() {
+  const { settings, updateSettings } = useSettings();
+  const existing =
+    (settings?.providerSettings?.vertex as VertexProviderSetting) ?? {};
+
+  const [projectId, setProjectId] = useState(existing.projectId || "");
+  const [location, setLocation] = useState(existing.location || "");
+  const [serviceAccountKey, setServiceAccountKey] = useState(
+    existing.serviceAccountKey?.value || "",
+  );
+  const [saving, setSaving] = useState(false);
+  const [error, setError] = useState<string | null>(null);
+  const [saved, setSaved] = useState(false);
+
+  useEffect(() => {
+    setProjectId(existing.projectId || "");
+    setLocation(existing.location || "");
+    setServiceAccountKey(existing.serviceAccountKey?.value || "");
+  }, [settings?.providerSettings?.vertex]);
+
+  const onSave = async () => {
+    setError(null);
+    setSaved(false);
+    try {
+      // If provided, ensure the service account JSON parses
+      if (serviceAccountKey) {
+        JSON.parse(serviceAccountKey);
+      }
+    } catch (e: any) {
+      setError("Service account JSON is invalid: " + e.message);
+      return;
+    }
+
+    setSaving(true);
+    try {
+      const settingsUpdate: Partial<UserSettings> = {
+        providerSettings: {
+          ...settings?.providerSettings,
+          vertex: {
+            ...existing,
+            projectId: projectId.trim() || undefined,
+            location: location || undefined,
+            serviceAccountKey: serviceAccountKey
+              ? { value: serviceAccountKey }
+              : undefined,
+          },
+        },
+      };
+      await updateSettings(settingsUpdate);
+      setSaved(true);
+    } catch (e: any) {
+      setError(e?.message || "Failed to save Vertex settings");
+    } finally {
+      setSaving(false);
+    }
+  };
+
+  const isConfigured = Boolean(
+    (projectId.trim() && location && serviceAccountKey) ||
+      (existing.projectId &&
+        existing.location &&
+        existing.serviceAccountKey?.value),
+  );
+
+  return (
+    <div className="space-y-4">
+      <div className="grid grid-cols-1 gap-4">
+        <div>
+          <label className="block text-sm font-medium mb-1">Project ID</label>
+          <Input
+            value={projectId}
+            onChange={(e) => setProjectId(e.target.value)}
+            placeholder="your-gcp-project-id"
+          />
+        </div>
+        <div>
+          <label className="block text-sm font-medium mb-1">Location</label>
+          <Input
+            value={location}
+            onChange={(e) => setLocation(e.target.value)}
+            placeholder="us-central1"
+          />
+          <p className="mt-1 text-xs text-muted-foreground">
+            If you see a "model not found" error, try a different region. Some
+            partner models (MaaS) are only available in specific locations
+            (e.g., us-central1, us-west2).
+          </p>
+        </div>
+        <div>
+          <label className="block text-sm font-medium mb-1">
+            Service Account JSON Key
+          </label>
+          <Textarea
+            value={serviceAccountKey}
+            onChange={(e) => setServiceAccountKey(e.target.value)}
+            placeholder="Paste the full JSON contents of your service account key here"
+            className="min-h-40"
+          />
+        </div>
+      </div>
+
+      <div className="flex items-center gap-2">
+        <Button onClick={onSave} disabled={saving}>
+          {saving ? "Saving..." : "Save Settings"}
+        </Button>
+        {saved && !error && (
+          <span className="flex items-center text-green-600 text-sm">
+            <CheckCircle2 className="h-4 w-4 mr-1" /> Saved
+          </span>
+        )}
+      </div>
+
+      {!isConfigured && (
+        <Alert variant="default">
+          <Info className="h-4 w-4" />
+          <AlertTitle>Configuration Required</AlertTitle>
+          <AlertDescription>
+            Provide Project, Location, and a service account JSON key with
+            Vertex AI access.
+          </AlertDescription>
+        </Alert>
+      )}
+
+      {error && (
+        <Alert variant="destructive">
+          <AlertTitle>Save Error</AlertTitle>
+          <AlertDescription>{error}</AlertDescription>
+        </Alert>
+      )}
+    </div>
+  );
+}

src/hooks/useLanguageModelProviders.ts

@@ -2,7 +2,7 @@ import { useQuery } from "@tanstack/react-query";
 import { IpcClient } from "@/ipc/ipc_client";
 import type { LanguageModelProvider } from "@/ipc/ipc_types";
 import { useSettings } from "./useSettings";
-import { cloudProviders } from "@/lib/schemas";
+import { cloudProviders, VertexProviderSetting } from "@/lib/schemas";
 
 export function useLanguageModelProviders() {
   const ipcClient = IpcClient.getInstance();
@@ -20,6 +20,18 @@ export function useLanguageModelProviders() {
     if (queryResult.isLoading) {
       return false;
     }
+    // Vertex uses service account credentials instead of an API key
+    if (provider === "vertex") {
+      const vertexSettings = providerSettings as VertexProviderSetting;
+      if (
+        vertexSettings?.serviceAccountKey?.value &&
+        vertexSettings?.projectId &&
+        vertexSettings?.location
+      ) {
+        return true;
+      }
+      return false;
+    }
     if (providerSettings?.apiKey?.value) {
       return true;
     }

src/ipc/handlers/chat_stream_handlers.ts

@@ -667,28 +667,53 @@ This conversation includes one or more image attachments. When the user uploads
           } else {
             logger.log("sending AI request");
           }
+          // Build provider options with correct Google/Vertex thinking config gating
+          const providerOptions: Record<string, any> = {
+            "dyad-engine": {
+              dyadRequestId,
+            },
+            "dyad-gateway": getExtraProviderOptions(
+              modelClient.builtinProviderId,
+              settings,
+            ),
+            openai: {
+              reasoningSummary: "auto",
+            } satisfies OpenAIResponsesProviderOptions,
+          };
+
+          // Conditionally include Google thinking config only for supported models
+          const selectedModelName = settings.selectedModel.name || "";
+          const providerId = modelClient.builtinProviderId;
+          const isVertex = providerId === "vertex";
+          const isGoogle = providerId === "google";
+          const isPartnerModel = selectedModelName.includes("/");
+          const isGeminiModel = selectedModelName.startsWith("gemini");
+          const isFlashLite = selectedModelName.includes("flash-lite");
+
+          // Keep Google provider behavior unchanged: always include includeThoughts
+          if (isGoogle) {
+            providerOptions.google = {
+              thinkingConfig: {
+                includeThoughts: true,
+              },
+            } satisfies GoogleGenerativeAIProviderOptions;
+          }
+
+          // Vertex-specific fix: only enable thinking on supported Gemini models
+          if (isVertex && isGeminiModel && !isFlashLite && !isPartnerModel) {
+            providerOptions.google = {
+              thinkingConfig: {
+                includeThoughts: true,
+              },
+            } satisfies GoogleGenerativeAIProviderOptions;
+          }
+
           return streamText({
             maxOutputTokens: await getMaxTokens(settings.selectedModel),
             temperature: await getTemperature(settings.selectedModel),
             maxRetries: 2,
             model: modelClient.model,
-            providerOptions: {
+            providerOptions,
-              "dyad-engine": {
-                dyadRequestId,
-              },
-              "dyad-gateway": getExtraProviderOptions(
-                modelClient.builtinProviderId,
-                settings,
-              ),
-              google: {
-                thinkingConfig: {
-                  includeThoughts: true,
-                },
-              } satisfies GoogleGenerativeAIProviderOptions,
-              openai: {
-                reasoningSummary: "auto",
-              } satisfies OpenAIResponsesProviderOptions,
-            },
             system: systemPrompt,
             messages: chatMessages.filter((m) => m.content),
             onError: (error: any) => {

src/ipc/shared/language_model_helpers.ts

@@ -8,6 +8,7 @@ import { eq } from "drizzle-orm";
 
 export const PROVIDERS_THAT_SUPPORT_THINKING: (keyof typeof MODEL_OPTIONS)[] = [
   "google",
+  "vertex",
   "auto",
 ];
 
@@ -144,6 +145,26 @@ export const MODEL_OPTIONS: Record<string, ModelOption[]> = {
       dollarSigns: 2,
     },
   ],
+  vertex: [
+    // Vertex Gemini 2.5 Pro
+    {
+      name: "gemini-2.5-pro",
+      displayName: "Gemini 2.5 Pro",
+      description: "Vertex Gemini 2.5 Pro",
+      maxOutputTokens: 65_536 - 1,
+      contextWindow: 1_048_576,
+      temperature: 0,
+    },
+    // Vertex Gemini 2.5 Flash
+    {
+      name: "gemini-2.5-flash",
+      displayName: "Gemini 2.5 Flash",
+      description: "Vertex Gemini 2.5 Flash",
+      maxOutputTokens: 65_536 - 1,
+      contextWindow: 1_048_576,
+      temperature: 0,
+    },
+  ],
   openrouter: [
     {
       name: "qwen/qwen3-coder",
@@ -270,6 +291,14 @@ export const CLOUD_PROVIDERS: Record<
     websiteUrl: "https://aistudio.google.com/app/apikey",
     gatewayPrefix: "gemini/",
   },
+  vertex: {
+    displayName: "Google Vertex AI",
+    hasFreeTier: false,
+    websiteUrl: "https://console.cloud.google.com/vertex-ai",
+    // Use the same gateway prefix as Google Gemini for Dyad Pro compatibility.
+    gatewayPrefix: "gemini/",
+    secondary: true,
+  },
   openrouter: {
     displayName: "OpenRouter",
     hasFreeTier: true,

src/ipc/utils/get_model_client.ts

@@ -1,10 +1,15 @@
 import { createOpenAI } from "@ai-sdk/openai";
 import { createGoogleGenerativeAI as createGoogle } from "@ai-sdk/google";
 import { createAnthropic } from "@ai-sdk/anthropic";
+import { createVertex as createGoogleVertex } from "@ai-sdk/google-vertex";
 import { azure } from "@ai-sdk/azure";
 import { createOpenRouter } from "@openrouter/ai-sdk-provider";
 import { createOpenAICompatible } from "@ai-sdk/openai-compatible";
-import type { LargeLanguageModel, UserSettings } from "../../lib/schemas";
+import type {
+  LargeLanguageModel,
+  UserSettings,
+  VertexProviderSetting,
+} from "../../lib/schemas";
 import { getEnvVar } from "./read_env";
 import log from "electron-log";
 import { getLanguageModelProviders } from "../shared/language_model_helpers";
@@ -216,6 +221,45 @@ function getRegularModelClient(
         backupModelClients: [],
       };
     }
+    case "vertex": {
+      // Vertex uses Google service account credentials with project/location
+      const vertexSettings = settings.providerSettings?.[
+        model.provider
+      ] as VertexProviderSetting;
+      const project = vertexSettings?.projectId;
+      const location = vertexSettings?.location;
+      const serviceAccountKey = vertexSettings?.serviceAccountKey?.value;
+
+      // Use a baseURL that does NOT pin to publishers/google so that
+      // full publisher model IDs (e.g. publishers/deepseek-ai/models/...) work.
+      const regionHost = `${location === "global" ? "" : `${location}-`}aiplatform.googleapis.com`;
+      const baseURL = `https://${regionHost}/v1/projects/${project}/locations/${location}`;
+      const provider = createGoogleVertex({
+        project,
+        location,
+        baseURL,
+        googleAuthOptions: serviceAccountKey
+          ? {
+              // Expecting the user to paste the full JSON of the service account key
+              credentials: JSON.parse(serviceAccountKey),
+            }
+          : undefined,
+      });
+      return {
+        modelClient: {
+          // For built-in Google models on Vertex, the path must include
+          // publishers/google/models/<model>. For partner MaaS models the
+          // full publisher path is already included.
+          model: provider(
+            model.name.includes("/")
+              ? model.name
+              : `publishers/google/models/${model.name}`,
+          ),
+          builtinProviderId: providerId,
+        },
+        backupModelClients: [],
+      };
+    }
     case "openrouter": {
       const provider = createOpenRouter({ apiKey });
       return {

src/lib/schemas.ts

@@ -30,6 +30,7 @@ const providers = [
   "openai",
   "anthropic",
   "google",
+  "vertex",
   "auto",
   "openrouter",
   "ollama",
@@ -57,15 +58,35 @@ export type LargeLanguageModel = z.infer<typeof LargeLanguageModelSchema>;
 
 /**
  * Zod schema for provider settings
+ * Regular providers use only apiKey. Vertex has additional optional fields.
  */
-export const ProviderSettingSchema = z.object({
+export const RegularProviderSettingSchema = z.object({
   apiKey: SecretSchema.optional(),
 });
 
+export const VertexProviderSettingSchema = z.object({
+  // We make this undefined so that it makes existing callsites easier.
+  apiKey: z.undefined(),
+  projectId: z.string().optional(),
+  location: z.string().optional(),
+  serviceAccountKey: SecretSchema.optional(),
+});
+
+export const ProviderSettingSchema = z.union([
+  // Must use more specific type first!
+  // Zod uses the first type that matches.
+  VertexProviderSettingSchema,
+  RegularProviderSettingSchema,
+]);
+
 /**
  * Type derived from the ProviderSettingSchema
  */
 export type ProviderSetting = z.infer<typeof ProviderSettingSchema>;
+export type RegularProviderSetting = z.infer<
+  typeof RegularProviderSettingSchema
+>;
+export type VertexProviderSetting = z.infer<typeof VertexProviderSettingSchema>;
 
 export const RuntimeModeSchema = z.enum(["web-sandbox", "local-node", "unset"]);
 export type RuntimeMode = z.infer<typeof RuntimeModeSchema>;

src/main/settings.ts

@@ -1,7 +1,12 @@
 import fs from "node:fs";
 import path from "node:path";
 import { getUserDataPath } from "../paths/paths";
-import { UserSettingsSchema, type UserSettings, Secret } from "../lib/schemas";
+import {
+  UserSettingsSchema,
+  type UserSettings,
+  Secret,
+  VertexProviderSetting,
+} from "../lib/schemas";
 import { safeStorage } from "electron";
 import { v4 as uuidv4 } from "uuid";
 import log from "electron-log";
@@ -114,6 +119,17 @@ export function readSettings(): UserSettings {
           encryptionType,
         };
       }
+      // Decrypt Vertex service account key if present
+      const v = combinedSettings.providerSettings[
+        provider
+      ] as VertexProviderSetting;
+      if (provider === "vertex" && v?.serviceAccountKey) {
+        const encryptionType = v.serviceAccountKey.encryptionType;
+        v.serviceAccountKey = {
+          value: decrypt(v.serviceAccountKey),
+          encryptionType,
+        };
+      }
     }
 
     // Validate and merge with defaults
@@ -171,6 +187,11 @@ export function writeSettings(settings: Partial<UserSettings>): void {
           newSettings.providerSettings[provider].apiKey.value,
         );
       }
+      // Encrypt Vertex service account key if present
+      const v = newSettings.providerSettings[provider] as VertexProviderSetting;
+      if (provider === "vertex" && v?.serviceAccountKey) {
+        v.serviceAccountKey = encrypt(v.serviceAccountKey.value);
+      }
     }
     const validatedSettings = UserSettingsSchema.parse(newSettings);
     fs.writeFileSync(filePath, JSON.stringify(validatedSettings, null, 2));