feat: expose verified image and GPT-OSS models

Author: ualtinok

README.md

@@ -1,8 +1,8 @@
 # Antigravity Auth
 
 Google Antigravity OAuth for coding agents. Authenticate with your Google
-account and access **Gemini 3** and **Claude 4.6** models through Antigravity's
-endpoints.
+account and access **Gemini 3**, **Claude 4.6**, and **GPT-OSS 120B** models through
+Antigravity's endpoints.
 
 This is a monorepo publishing three packages:
 
@@ -33,7 +33,7 @@ configuration, login, and troubleshooting.
 **pi** — install the extension package:
 
 ```bash
-pi package add @cortexkit/pi-antigravity-auth
+pi install npm:@cortexkit/pi-antigravity-auth
 ```
 
 Then `/login google-antigravity`. See the [pi package README](packages/pi/README.md).

packages/core/src/agy-request-metadata.test.ts

@@ -15,8 +15,8 @@ import {
 type ModelMetadataFixture = {
   models: Record<string, {
     modelEnum: string
-    thinkingBudget: number
-    maxOutputTokens: number
+    thinkingBudget: number | null
+    maxOutputTokens: number | null
   }>
 }
 

packages/core/src/agy-request-metadata.ts

@@ -24,6 +24,7 @@ const AGY_MODEL_ENUM_BY_WIRE_MODEL: Readonly<Record<string, string>> = {
   "gemini-pro-agent": "MODEL_PLACEHOLDER_M16",
   "claude-sonnet-4-6": "MODEL_PLACEHOLDER_M35",
   "claude-opus-4-6-thinking": "MODEL_PLACEHOLDER_M26",
+  "gemini-3.1-flash-image": "MODEL_PLACEHOLDER_M21",
   "gpt-oss-120b-medium": "MODEL_OPENAI_GPT_OSS_120B_MEDIUM",
 }
 

packages/core/src/model-registry.test.ts

@@ -28,8 +28,10 @@ describe("model registry", () => {
     expect(modelNames).toEqual([
       "antigravity-claude-opus-4-6-thinking",
       "antigravity-claude-sonnet-4-6-thinking",
+      "antigravity-gemini-3.1-flash-image",
       "antigravity-gemini-3.1-pro",
       "antigravity-gemini-3.5-flash",
+      "antigravity-gpt-oss-120b-medium",
     ])
 
     for (const definition of Object.values(definitions)) {
@@ -53,7 +55,23 @@ describe("model registry", () => {
     expect(aliases["gemini-3.5-flash-medium"]).toBe("gemini-3.5-flash")
     expect(aliases["gemini-claude-opus-4-6-thinking-medium"]).toBe("claude-opus-4-6-thinking")
     expect(aliases["gemini-claude-sonnet-4-6-thinking-high"]).toBe("claude-sonnet-4-6")
+    expect(aliases["gpt-oss-120b"]).toBe("gpt-oss-120b-medium")
+  })
+
+  it("matches the live GPT-OSS capability metadata", () => {
+    expect(getPublicModelDefinitions()["antigravity-gpt-oss-120b-medium"]).toMatchObject({
+      reasoning: true,
+      limit: { context: 131072, output: 32768 },
+    })
+  })
 
-    expect(getPublicModelDefinitions()["antigravity-gpt-oss-120b"]).toBeUndefined()
+  it("advertises image output only on the image route", () => {
+    expect(getPublicModelDefinitions()["antigravity-gemini-3.1-flash-image"]).toMatchObject({
+      reasoning: false,
+      modalities: {
+        input: ["text", "image"],
+        output: ["text", "image"],
+      },
+    })
   })
 })

packages/core/src/model-registry.ts

@@ -137,14 +137,11 @@ const ALL_MODEL_DEFINITIONS: OpencodeModelDefinitions = {
       output: ["text", "image"],
     },
   }),
-  "antigravity-gpt-oss-120b": defineModel("antigravity-gpt-oss-120b", {
-    name: "GPT-OSS 120B (Antigravity)",
-    reasoning: false,
-    limit: { context: 128000, output: 16384 },
+  "antigravity-gpt-oss-120b-medium": defineModel("antigravity-gpt-oss-120b-medium", {
+    name: "GPT-OSS 120B Medium (Antigravity)",
+    reasoning: true,
+    limit: { context: 131072, output: 32768 },
     modalities: DEFAULT_MODALITIES,
-    variants: {
-      medium: {},
-    },
   }),
   "gemini-2.5-flash": defineModel("gemini-2.5-flash", {
     name: "Gemini 2.5 Flash (Gemini CLI)",
@@ -222,6 +219,7 @@ const RESOLVER_ALIASES: Record<string, string> = {
   "claude-sonnet-4-6-thinking-low": "claude-sonnet-4-6",
   "claude-sonnet-4-6-thinking-medium": "claude-sonnet-4-6",
   "claude-sonnet-4-6-thinking-high": "claude-sonnet-4-6",
+  "gpt-oss-120b": "gpt-oss-120b-medium",
 }
 
 const GEMINI_35_FLASH_ROUTES: Gemini35FlashRouteMetadata = {
@@ -259,6 +257,8 @@ const ANTIGRAVITY_OPENCODE_MODEL_IDS = [
   "antigravity-gemini-3.1-pro",
   "antigravity-claude-sonnet-4-6-thinking",
   "antigravity-claude-opus-4-6-thinking",
+  "antigravity-gemini-3.1-flash-image",
+  "antigravity-gpt-oss-120b-medium",
 ] as const
 
 function pickModelDefinitions(ids: readonly string[]): OpencodeModelDefinitions {

packages/core/src/transform/gemini.test.ts

@@ -1458,6 +1458,34 @@ describe("transform/gemini", () => {
       expect(props["x"]!.type).toBe("STRING");
     });
 
+    it("normalizes existing GPT-OSS function declarations and numeric constraints", () => {
+      const payload: RequestPayload = {
+        contents: [],
+        tools: [{
+          functionDeclarations: [{
+            name: "prompt_tool",
+            parametersJsonSchema: {
+              type: "object",
+              properties: {
+                prompt: { type: "string", minLength: "1" },
+              },
+              required: ["prompt"],
+            },
+          }],
+        }],
+      };
+
+      applyGeminiTransforms(payload, { model: "gpt-oss-120b-medium" });
+
+      const tools = payload.tools as Array<Record<string, unknown>>;
+      const declarations = tools[0]!.functionDeclarations as Array<Record<string, unknown>>;
+      const parameters = declarations[0]!.parameters as Record<string, unknown>;
+      const properties = parameters.properties as Record<string, Record<string, unknown>>;
+      expect(parameters.type).toBe("OBJECT");
+      expect(properties.prompt).toEqual({ type: "STRING", description: "minLength: 1" });
+      expect(declarations[0]).not.toHaveProperty("parametersJsonSchema");
+    });
+
     it("handles mixed tools and googleSearch", () => {
       const payload: RequestPayload = {
         contents: [],

packages/core/src/transform/gemini.ts

@@ -49,14 +49,37 @@ const UNSUPPORTED_SCHEMA_FIELDS = new Set([
   "maxContains",
 ]);
 
-export function toGeminiSchema(schema: unknown): unknown {
+const NUMERIC_SCHEMA_CONSTRAINTS = new Set([
+  "minLength",
+  "maxLength",
+  "minItems",
+  "maxItems",
+  "minProperties",
+  "maxProperties",
+  "minimum",
+  "maximum",
+  "exclusiveMinimum",
+  "exclusiveMaximum",
+  "multipleOf",
+])
+
+export interface GeminiSchemaOptions {
+  /**
+   * AGY's GPT bridge re-encodes protobuf numeric constraints as strings before
+   * OpenAI JSON Schema validation. Move them to descriptions instead.
+   */
+  moveNumericConstraintsToDescription?: boolean
+}
+
+export function toGeminiSchema(schema: unknown, options: GeminiSchemaOptions = {}): unknown {
   // Return primitives and arrays as-is
   if (!schema || typeof schema !== "object" || Array.isArray(schema)) {
     return schema;
   }
 
   const inputSchema = schema as Record<string, unknown>;
   const result: Record<string, unknown> = {};
+  const numericConstraintHints: string[] = [];
 
   // First pass: collect all property names for required validation
   const propertyNames = new Set<string>();
@@ -79,18 +102,25 @@ export function toGeminiSchema(schema: unknown): unknown {
       // Recursively transform nested property schemas
       const props: Record<string, unknown> = {};
       for (const [propName, propSchema] of Object.entries(value as Record<string, unknown>)) {
-        props[propName] = toGeminiSchema(propSchema);
+        props[propName] = toGeminiSchema(propSchema, options);
       }
       result[key] = props;
     } else if (key === "items" && typeof value === "object") {
       // Transform array items schema
-      result[key] = toGeminiSchema(value);
+      result[key] = toGeminiSchema(value, options);
     } else if ((key === "anyOf" || key === "oneOf" || key === "allOf") && Array.isArray(value)) {
       // Transform union type schemas
-      result[key] = value.map((item) => toGeminiSchema(item));
+      result[key] = value.map((item) => toGeminiSchema(item, options));
     } else if (key === "enum" && Array.isArray(value)) {
       // Keep enum values as-is
       result[key] = value;
+    } else if (
+      options.moveNumericConstraintsToDescription &&
+      NUMERIC_SCHEMA_CONSTRAINTS.has(key)
+    ) {
+      if (typeof value === "string" || typeof value === "number") {
+        numericConstraintHints.push(`${key}: ${value}`)
+      }
     } else if (key === "default" || key === "examples") {
       // Keep default and examples as-is
       result[key] = value;
@@ -114,6 +144,13 @@ export function toGeminiSchema(schema: unknown): unknown {
     }
   }
 
+  if (numericConstraintHints.length > 0) {
+    const hint = numericConstraintHints.join(", ")
+    result.description = typeof result.description === "string" && result.description
+      ? `${result.description} (${hint})`
+      : hint
+  }
+
   // Issue #80: Ensure array schemas have an 'items' field
   // Gemini API requires: "parameters.properties[X].items: missing field"
   if (result.type === "ARRAY" && !result.items) {
@@ -229,6 +266,7 @@ export function buildImageGenerationConfig(): ImageConfig {
  */
 export function normalizeGeminiTools(
   payload: RequestPayload,
+  schemaOptions: GeminiSchemaOptions = {},
 ): { toolDebugMissing: number; toolDebugSummaries: string[] } {
   let toolDebugMissing = 0;
   const toolDebugSummaries: string[] = [];
@@ -245,6 +283,22 @@ export function normalizeGeminiTools(
       return t;
     }
 
+    if (Array.isArray(t.functionDeclarations)) {
+      return {
+        ...t,
+        functionDeclarations: t.functionDeclarations.map((declaration) => {
+          const normalized = { ...(declaration as Record<string, unknown>) }
+          const rawSchema = normalized.parameters ?? normalized.parametersJsonSchema ?? {
+            type: "OBJECT",
+            properties: {},
+          }
+          normalized.parameters = toGeminiSchema(rawSchema, schemaOptions)
+          delete normalized.parametersJsonSchema
+          return normalized
+        }),
+      }
+    }
+
     const newTool = { ...t };
 
     const schemaCandidates = [
@@ -276,7 +330,7 @@ export function normalizeGeminiTools(
       toolDebugMissing += 1;
     } else {
       // Transform existing schema to Gemini-compatible format
-      schema = toGeminiSchema(schema) as Record<string, unknown>;
+      schema = toGeminiSchema(schema, schemaOptions) as Record<string, unknown>;
     }
 
     const nameCandidate =
@@ -417,7 +471,9 @@ export function applyGeminiTransforms(
   }
 
   // 3. Normalize tools
-  const result = normalizeGeminiTools(payload);
+  const result = normalizeGeminiTools(payload, {
+    moveNumericConstraintsToDescription: model.toLowerCase().startsWith("gpt-oss-"),
+  });
 
   // 4. Wrap tools in functionDeclarations format (fixes #203, #206)
   // Antigravity strict protobuf validation rejects wrapper-level 'parameters' field

packages/core/src/transform/model-resolver.test.ts

@@ -177,7 +177,8 @@ describe("resolveModelWithTier", () => {
       expect(result.isThinkingModel).toBe(true);
       expect(result.thinkingBudget).toBe(1024);
       expect(result.quotaPreference).toBe("antigravity");
-    });  });
+    });
+  });
 
   describe("Image models", () => {
     it("marks antigravity-gemini-3-pro-image as explicit quota", () => {
@@ -195,6 +196,32 @@ describe("resolveModelWithTier", () => {
       expect(result.explicitQuota).toBe(true);
       expect(result.quotaPreference).toBe("antigravity");
     });
+
+    it("resolves the live Gemini 3.1 Flash Image route without thinking", () => {
+      expect(resolveModelWithTier("antigravity-gemini-3.1-flash-image")).toMatchObject({
+        actualModel: "gemini-3.1-flash-image",
+        isThinkingModel: false,
+        isImageModel: true,
+        quotaPreference: "antigravity",
+        explicitQuota: true,
+      });
+    });
+  });
+
+  describe("GPT-OSS", () => {
+    it("resolves the only live GPT-OSS route with its captured thinking budget", () => {
+      expect(resolveModelWithTier("antigravity-gpt-oss-120b-medium")).toMatchObject({
+        actualModel: "gpt-oss-120b-medium",
+        thinkingBudget: 8192,
+        isThinkingModel: true,
+        quotaPreference: "antigravity",
+        explicitQuota: true,
+      });
+    });
+
+    it("maps the short GPT-OSS alias to the medium route", () => {
+      expect(resolveModelWithTier("antigravity-gpt-oss-120b").actualModel).toBe("gpt-oss-120b-medium");
+    });
   });
 });
 

packages/core/src/transform/model-resolver.ts

@@ -194,6 +194,7 @@ export function resolveModelWithTier(requestedModel: string, options: ModelResol
   const isGemini3Flash = isGemini3FlashModel(modelWithoutQuota);
   const isGemini31Pro = /^gemini-3\.1-pro/i.test(baseName);
   const isGemini35Flash = /^gemini-3\.5-flash/i.test(baseName);
+  const isGptOss120b = /^gpt-oss-120b(?:-medium)?$/i.test(baseName);
 
   if (isGemini31Pro && quotaPreference === "antigravity") {
     return {
@@ -216,6 +217,16 @@ export function resolveModelWithTier(requestedModel: string, options: ModelResol
       explicitQuota,
     };
   }
+
+  if (isGptOss120b && quotaPreference === "antigravity") {
+    return {
+      actualModel: "gpt-oss-120b-medium",
+      thinkingBudget: 8192,
+      isThinkingModel: true,
+      quotaPreference,
+      explicitQuota,
+    };
+  }
 
   let antigravityModel = modelWithoutQuota;
   if (skipAlias) {

packages/opencode/README.md

@@ -8,7 +8,7 @@ Enable Opencode to authenticate against **Antigravity** (Google's IDE) via OAuth
 
 ## What You Get
 
-- **Claude Opus 4.6, Sonnet 4.6** and **Gemini 3.1 Pro/Flash** via Google OAuth
+- **Claude Opus 4.6, Sonnet 4.6, Gemini 3.5 Flash, Gemini 3.1 Pro/Image, and GPT-OSS 120B** via Google OAuth
 - **Multi-account support** — add multiple Google accounts, auto-rotates when rate-limited
 - **Dual quota system** — access both Antigravity and Gemini CLI quotas from one plugin
 - **Thinking models** — extended thinking for Claude and Gemini 3 with configurable budgets
@@ -104,15 +104,16 @@ opencode run "Hello" --model=google/antigravity-claude-opus-4-6-thinking --varia
 
 ### Model Reference
 
-**Antigravity quota** (default routing for Claude and Gemini):
+**Antigravity quota:**
 
 | Model | Variants | Notes |
 |-------|----------|-------|
-| `antigravity-gemini-3-pro` | low, high | Gemini 3 Pro with thinking |
-| `antigravity-gemini-3.1-pro` | low, high | Gemini 3.1 Pro with thinking (rollout-dependent) |
-| `antigravity-gemini-3-flash` | minimal, low, medium, high | Gemini 3 Flash with thinking |
-| `antigravity-claude-sonnet-4-6` | — | Claude Sonnet 4.6 |
-| `antigravity-claude-opus-4-6-thinking` | low, max | Claude Opus 4.6 with extended thinking |
+| `antigravity-gemini-3.5-flash` | low, high | Gemini 3.5 Flash with medium as the default |
+| `antigravity-gemini-3.1-pro` | low, high | Gemini 3.1 Pro with thinking |
+| `antigravity-gemini-3.1-flash-image` | — | Gemini 3.1 image generation |
+| `antigravity-claude-sonnet-4-6-thinking` | — | Claude Sonnet 4.6 with thinking |
+| `antigravity-claude-opus-4-6-thinking` | — | Claude Opus 4.6 with thinking |
+| `antigravity-gpt-oss-120b-medium` | — | GPT-OSS 120B medium reasoning |
 
 **Gemini CLI quota** (separate from Antigravity; used when `cli_first` is true or as fallback):