diff --git a/src/agents/types.test.ts b/src/agents/types.test.ts
index ad39fb538..dd6b1fe54 100644
--- a/src/agents/types.test.ts
+++ b/src/agents/types.test.ts
@@ -47,8 +47,8 @@ describe("isGptModel", () => {
   });
 
   test("gemini models are not gpt", () => {
-    expect(isGptModel("google/gemini-3-pro")).toBe(false);
-    expect(isGptModel("litellm/gemini-3-pro")).toBe(false);
+    expect(isGptModel("google/gemini-3.1-pro")).toBe(false);
+    expect(isGptModel("litellm/gemini-3.1-pro")).toBe(false);
   });
 
   test("opencode provider is not gpt", () => {
@@ -58,29 +58,29 @@ describe("isGptModel", () => {
 
 describe("isGeminiModel", () => {
   test("#given google provider models #then returns true", () => {
-    expect(isGeminiModel("google/gemini-3-pro")).toBe(true);
+    expect(isGeminiModel("google/gemini-3.1-pro")).toBe(true);
     expect(isGeminiModel("google/gemini-3-flash")).toBe(true);
     expect(isGeminiModel("google/gemini-2.5-pro")).toBe(true);
   });
 
   test("#given google-vertex provider models #then returns true", () => {
-    expect(isGeminiModel("google-vertex/gemini-3-pro")).toBe(true);
+    expect(isGeminiModel("google-vertex/gemini-3.1-pro")).toBe(true);
     expect(isGeminiModel("google-vertex/gemini-3-flash")).toBe(true);
   });
 
   test("#given github copilot gemini models #then returns true", () => {
-    expect(isGeminiModel("github-copilot/gemini-3-pro")).toBe(true);
+    expect(isGeminiModel("github-copilot/gemini-3.1-pro")).toBe(true);
     expect(isGeminiModel("github-copilot/gemini-3-flash")).toBe(true);
   });
 
   test("#given litellm proxied gemini models #then returns true", () => {
-    expect(isGeminiModel("litellm/gemini-3-pro")).toBe(true);
+    expect(isGeminiModel("litellm/gemini-3.1-pro")).toBe(true);
     expect(isGeminiModel("litellm/gemini-3-flash")).toBe(true);
     expect(isGeminiModel("litellm/gemini-2.5-pro")).toBe(true);
   });
 
   test("#given other proxied gemini models #then returns true", () => {
-    expect(isGeminiModel("custom-provider/gemini-3-pro")).toBe(true);
+    expect(isGeminiModel("custom-provider/gemini-3.1-pro")).toBe(true);
     expect(isGeminiModel("ollama/gemini-3-flash")).toBe(true);
   });
 
diff --git a/src/agents/utils.test.ts b/src/agents/utils.test.ts
index fc15d9d48..129329afa 100644
--- a/src/agents/utils.test.ts
+++ b/src/agents/utils.test.ts
@@ -988,7 +988,7 @@ describe("buildAgent with category and skills", () => {
     const agent = buildAgent(source["test-agent"], TEST_MODEL)
 
     // #then - category's built-in model is applied
-    expect(agent.model).toBe("google/gemini-3-pro")
+    expect(agent.model).toBe("google/gemini-3.1-pro")
   })
 
   test("agent with category and existing model keeps existing model", () => {
diff --git a/src/cli/__snapshots__/model-fallback.test.ts.snap b/src/cli/__snapshots__/model-fallback.test.ts.snap
index df91e07b8..a8c3e9112 100644
--- a/src/cli/__snapshots__/model-fallback.test.ts.snap
+++ b/src/cli/__snapshots__/model-fallback.test.ts.snap
@@ -325,7 +325,7 @@ exports[`generateModelConfig single native provider uses Gemini models when only
   "$schema": "https://raw.githubusercontent.com/code-yeongyu/oh-my-opencode/master/assets/oh-my-opencode.schema.json",
   "agents": {
     "atlas": {
-      "model": "google/gemini-3-pro-preview",
+      "model": "google/gemini-3.1-pro-preview",
     },
     "explore": {
       "model": "opencode/gpt-5-nano",
@@ -334,34 +334,34 @@ exports[`generateModelConfig single native provider uses Gemini models when only
       "model": "opencode/glm-4.7-free",
     },
     "metis": {
-      "model": "google/gemini-3-pro-preview",
+      "model": "google/gemini-3.1-pro-preview",
       "variant": "high",
     },
     "momus": {
-      "model": "google/gemini-3-pro-preview",
+      "model": "google/gemini-3.1-pro-preview",
       "variant": "high",
     },
     "multimodal-looker": {
       "model": "google/gemini-3-flash-preview",
     },
     "oracle": {
-      "model": "google/gemini-3-pro-preview",
+      "model": "google/gemini-3.1-pro-preview",
       "variant": "high",
     },
     "prometheus": {
-      "model": "google/gemini-3-pro-preview",
+      "model": "google/gemini-3.1-pro-preview",
     },
   },
   "categories": {
     "artistry": {
-      "model": "google/gemini-3-pro-preview",
+      "model": "google/gemini-3.1-pro-preview",
       "variant": "high",
     },
     "quick": {
       "model": "google/gemini-3-flash-preview",
     },
     "ultrabrain": {
-      "model": "google/gemini-3-pro-preview",
+      "model": "google/gemini-3.1-pro-preview",
       "variant": "high",
     },
     "unspecified-high": {
@@ -371,7 +371,7 @@ exports[`generateModelConfig single native provider uses Gemini models when only
       "model": "google/gemini-3-flash-preview",
     },
     "visual-engineering": {
-      "model": "google/gemini-3-pro-preview",
+      "model": "google/gemini-3.1-pro-preview",
       "variant": "high",
     },
     "writing": {
@@ -386,7 +386,7 @@ exports[`generateModelConfig single native provider uses Gemini models with isMa
   "$schema": "https://raw.githubusercontent.com/code-yeongyu/oh-my-opencode/master/assets/oh-my-opencode.schema.json",
   "agents": {
     "atlas": {
-      "model": "google/gemini-3-pro-preview",
+      "model": "google/gemini-3.1-pro-preview",
     },
     "explore": {
       "model": "opencode/gpt-5-nano",
@@ -395,44 +395,44 @@ exports[`generateModelConfig single native provider uses Gemini models with isMa
       "model": "opencode/glm-4.7-free",
     },
     "metis": {
-      "model": "google/gemini-3-pro-preview",
+      "model": "google/gemini-3.1-pro-preview",
       "variant": "high",
     },
     "momus": {
-      "model": "google/gemini-3-pro-preview",
+      "model": "google/gemini-3.1-pro-preview",
       "variant": "high",
     },
     "multimodal-looker": {
       "model": "google/gemini-3-flash-preview",
     },
     "oracle": {
-      "model": "google/gemini-3-pro-preview",
+      "model": "google/gemini-3.1-pro-preview",
       "variant": "high",
     },
     "prometheus": {
-      "model": "google/gemini-3-pro-preview",
+      "model": "google/gemini-3.1-pro-preview",
     },
   },
   "categories": {
     "artistry": {
-      "model": "google/gemini-3-pro-preview",
+      "model": "google/gemini-3.1-pro-preview",
       "variant": "high",
     },
     "quick": {
       "model": "google/gemini-3-flash-preview",
     },
     "ultrabrain": {
-      "model": "google/gemini-3-pro-preview",
+      "model": "google/gemini-3.1-pro-preview",
       "variant": "high",
     },
     "unspecified-high": {
-      "model": "google/gemini-3-pro-preview",
+      "model": "google/gemini-3.1-pro-preview",
     },
     "unspecified-low": {
       "model": "google/gemini-3-flash-preview",
     },
     "visual-engineering": {
-      "model": "google/gemini-3-pro-preview",
+      "model": "google/gemini-3.1-pro-preview",
       "variant": "high",
     },
     "writing": {
@@ -485,7 +485,7 @@ exports[`generateModelConfig all native providers uses preferred models from fal
   },
   "categories": {
     "artistry": {
-      "model": "google/gemini-3-pro-preview",
+      "model": "google/gemini-3.1-pro-preview",
       "variant": "high",
     },
     "deep": {
@@ -506,7 +506,7 @@ exports[`generateModelConfig all native providers uses preferred models from fal
       "model": "anthropic/claude-sonnet-4-5",
     },
     "visual-engineering": {
-      "model": "google/gemini-3-pro-preview",
+      "model": "google/gemini-3.1-pro-preview",
       "variant": "high",
     },
     "writing": {
@@ -559,7 +559,7 @@ exports[`generateModelConfig all native providers uses preferred models with isM
   },
   "categories": {
     "artistry": {
-      "model": "google/gemini-3-pro-preview",
+      "model": "google/gemini-3.1-pro-preview",
       "variant": "high",
     },
     "deep": {
@@ -581,7 +581,7 @@ exports[`generateModelConfig all native providers uses preferred models with isM
       "model": "anthropic/claude-sonnet-4-5",
     },
     "visual-engineering": {
-      "model": "google/gemini-3-pro-preview",
+      "model": "google/gemini-3.1-pro-preview",
       "variant": "high",
     },
     "writing": {
@@ -634,7 +634,7 @@ exports[`generateModelConfig fallback providers uses OpenCode Zen models when on
   },
   "categories": {
     "artistry": {
-      "model": "opencode/gemini-3-pro",
+      "model": "opencode/gemini-3.1-pro",
       "variant": "high",
     },
     "deep": {
@@ -655,7 +655,7 @@ exports[`generateModelConfig fallback providers uses OpenCode Zen models when on
       "model": "opencode/claude-sonnet-4-5",
     },
     "visual-engineering": {
-      "model": "opencode/gemini-3-pro",
+      "model": "opencode/gemini-3.1-pro",
       "variant": "high",
     },
     "writing": {
@@ -708,7 +708,7 @@ exports[`generateModelConfig fallback providers uses OpenCode Zen models with is
   },
   "categories": {
     "artistry": {
-      "model": "opencode/gemini-3-pro",
+      "model": "opencode/gemini-3.1-pro",
       "variant": "high",
     },
     "deep": {
@@ -730,7 +730,7 @@ exports[`generateModelConfig fallback providers uses OpenCode Zen models with is
       "model": "opencode/claude-sonnet-4-5",
     },
     "visual-engineering": {
-      "model": "opencode/gemini-3-pro",
+      "model": "opencode/gemini-3.1-pro",
       "variant": "high",
     },
     "writing": {
@@ -779,14 +779,14 @@ exports[`generateModelConfig fallback providers uses GitHub Copilot models when
   },
   "categories": {
     "artistry": {
-      "model": "github-copilot/gemini-3-pro-preview",
+      "model": "github-copilot/gemini-3.1-pro-preview",
       "variant": "high",
     },
     "quick": {
       "model": "github-copilot/claude-haiku-4.5",
     },
     "ultrabrain": {
-      "model": "github-copilot/gemini-3-pro-preview",
+      "model": "github-copilot/gemini-3.1-pro-preview",
       "variant": "high",
     },
     "unspecified-high": {
@@ -796,7 +796,7 @@ exports[`generateModelConfig fallback providers uses GitHub Copilot models when
       "model": "github-copilot/claude-sonnet-4.5",
     },
     "visual-engineering": {
-      "model": "github-copilot/gemini-3-pro-preview",
+      "model": "github-copilot/gemini-3.1-pro-preview",
       "variant": "high",
     },
     "writing": {
@@ -845,14 +845,14 @@ exports[`generateModelConfig fallback providers uses GitHub Copilot models with
   },
   "categories": {
     "artistry": {
-      "model": "github-copilot/gemini-3-pro-preview",
+      "model": "github-copilot/gemini-3.1-pro-preview",
       "variant": "high",
     },
     "quick": {
       "model": "github-copilot/claude-haiku-4.5",
     },
     "ultrabrain": {
-      "model": "github-copilot/gemini-3-pro-preview",
+      "model": "github-copilot/gemini-3.1-pro-preview",
       "variant": "high",
     },
     "unspecified-high": {
@@ -863,7 +863,7 @@ exports[`generateModelConfig fallback providers uses GitHub Copilot models with
       "model": "github-copilot/claude-sonnet-4.5",
     },
     "visual-engineering": {
-      "model": "github-copilot/gemini-3-pro-preview",
+      "model": "github-copilot/gemini-3.1-pro-preview",
       "variant": "high",
     },
     "writing": {
@@ -1026,7 +1026,7 @@ exports[`generateModelConfig mixed provider scenarios uses Claude + OpenCode Zen
   },
   "categories": {
     "artistry": {
-      "model": "opencode/gemini-3-pro",
+      "model": "opencode/gemini-3.1-pro",
       "variant": "high",
     },
     "deep": {
@@ -1047,7 +1047,7 @@ exports[`generateModelConfig mixed provider scenarios uses Claude + OpenCode Zen
       "model": "anthropic/claude-sonnet-4-5",
     },
     "visual-engineering": {
-      "model": "opencode/gemini-3-pro",
+      "model": "opencode/gemini-3.1-pro",
       "variant": "high",
     },
     "writing": {
@@ -1100,7 +1100,7 @@ exports[`generateModelConfig mixed provider scenarios uses OpenAI + Copilot comb
   },
   "categories": {
     "artistry": {
-      "model": "github-copilot/gemini-3-pro-preview",
+      "model": "github-copilot/gemini-3.1-pro-preview",
       "variant": "high",
     },
     "deep": {
@@ -1121,7 +1121,7 @@ exports[`generateModelConfig mixed provider scenarios uses OpenAI + Copilot comb
       "model": "github-copilot/claude-sonnet-4.5",
     },
     "visual-engineering": {
-      "model": "github-copilot/gemini-3-pro-preview",
+      "model": "github-copilot/gemini-3.1-pro-preview",
       "variant": "high",
     },
     "writing": {
@@ -1217,7 +1217,7 @@ exports[`generateModelConfig mixed provider scenarios uses Gemini + Claude combi
       "model": "google/gemini-3-flash-preview",
     },
     "oracle": {
-      "model": "google/gemini-3-pro-preview",
+      "model": "google/gemini-3.1-pro-preview",
       "variant": "high",
     },
     "prometheus": {
@@ -1231,14 +1231,14 @@ exports[`generateModelConfig mixed provider scenarios uses Gemini + Claude combi
   },
   "categories": {
     "artistry": {
-      "model": "google/gemini-3-pro-preview",
+      "model": "google/gemini-3.1-pro-preview",
       "variant": "high",
     },
     "quick": {
       "model": "anthropic/claude-haiku-4-5",
     },
     "ultrabrain": {
-      "model": "google/gemini-3-pro-preview",
+      "model": "google/gemini-3.1-pro-preview",
       "variant": "high",
     },
     "unspecified-high": {
@@ -1248,7 +1248,7 @@ exports[`generateModelConfig mixed provider scenarios uses Gemini + Claude combi
       "model": "anthropic/claude-sonnet-4-5",
     },
     "visual-engineering": {
-      "model": "google/gemini-3-pro-preview",
+      "model": "google/gemini-3.1-pro-preview",
       "variant": "high",
     },
     "writing": {
@@ -1301,7 +1301,7 @@ exports[`generateModelConfig mixed provider scenarios uses all fallback provider
   },
   "categories": {
     "artistry": {
-      "model": "github-copilot/gemini-3-pro-preview",
+      "model": "github-copilot/gemini-3.1-pro-preview",
       "variant": "high",
     },
     "deep": {
@@ -1322,7 +1322,7 @@ exports[`generateModelConfig mixed provider scenarios uses all fallback provider
       "model": "github-copilot/claude-sonnet-4.5",
     },
     "visual-engineering": {
-      "model": "github-copilot/gemini-3-pro-preview",
+      "model": "github-copilot/gemini-3.1-pro-preview",
       "variant": "high",
     },
     "writing": {
@@ -1375,7 +1375,7 @@ exports[`generateModelConfig mixed provider scenarios uses all providers togethe
   },
   "categories": {
     "artistry": {
-      "model": "google/gemini-3-pro-preview",
+      "model": "google/gemini-3.1-pro-preview",
       "variant": "high",
     },
     "deep": {
@@ -1396,7 +1396,7 @@ exports[`generateModelConfig mixed provider scenarios uses all providers togethe
       "model": "anthropic/claude-sonnet-4-5",
     },
     "visual-engineering": {
-      "model": "google/gemini-3-pro-preview",
+      "model": "google/gemini-3.1-pro-preview",
       "variant": "high",
     },
     "writing": {
@@ -1449,7 +1449,7 @@ exports[`generateModelConfig mixed provider scenarios uses all providers with is
   },
   "categories": {
     "artistry": {
-      "model": "google/gemini-3-pro-preview",
+      "model": "google/gemini-3.1-pro-preview",
       "variant": "high",
     },
     "deep": {
@@ -1471,7 +1471,7 @@ exports[`generateModelConfig mixed provider scenarios uses all providers with is
       "model": "anthropic/claude-sonnet-4-5",
     },
     "visual-engineering": {
-      "model": "google/gemini-3-pro-preview",
+      "model": "google/gemini-3.1-pro-preview",
       "variant": "high",
     },
     "writing": {
diff --git a/src/cli/config-manager.test.ts b/src/cli/config-manager.test.ts
index ad73c3d44..67571185a 100644
--- a/src/cli/config-manager.test.ts
+++ b/src/cli/config-manager.test.ts
@@ -178,7 +178,7 @@ describe("config-manager ANTIGRAVITY_PROVIDER_CONFIG", () => {
     expect(models).toBeTruthy()
 
     const required = [
-      "antigravity-gemini-3-pro",
+      "antigravity-gemini-3.1-pro",
       "antigravity-gemini-3-flash",
       "antigravity-claude-sonnet-4-6",
       "antigravity-claude-sonnet-4-6-thinking",
@@ -206,7 +206,7 @@ describe("config-manager ANTIGRAVITY_PROVIDER_CONFIG", () => {
     const models = (ANTIGRAVITY_PROVIDER_CONFIG as any).google.models as Record<string, any>
 
     // #when checking Gemini Pro variants
-    const pro = models["antigravity-gemini-3-pro"]
+    const pro = models["antigravity-gemini-3.1-pro"]
     // #then should have low and high variants
     expect(pro.variants).toBeTruthy()
     expect(pro.variants.low).toBeTruthy()
diff --git a/src/cli/config-manager/antigravity-provider-configuration.ts b/src/cli/config-manager/antigravity-provider-configuration.ts
index 5559d0919..6d847ac5d 100644
--- a/src/cli/config-manager/antigravity-provider-configuration.ts
+++ b/src/cli/config-manager/antigravity-provider-configuration.ts
@@ -4,10 +4,10 @@
  * IMPORTANT: Model names MUST use `antigravity-` prefix for stability.
  *
  * Since opencode-antigravity-auth v1.3.0, models use a variant system:
- * - `antigravity-gemini-3-pro` with variants: low, high
+ * - `antigravity-gemini-3.1-pro` with variants: low, high
  * - `antigravity-gemini-3-flash` with variants: minimal, low, medium, high
  *
- * Legacy tier-suffixed names (e.g., `antigravity-gemini-3-pro-high`) still work
+ * Legacy tier-suffixed names (e.g., `antigravity-gemini-3.1-pro-high`) still work
  * but variants are the recommended approach.
  *
  * @see https://github.com/NoeFabris/opencode-antigravity-auth#models
@@ -16,7 +16,7 @@ export const ANTIGRAVITY_PROVIDER_CONFIG = {
   google: {
     name: "Google",
     models: {
-      "antigravity-gemini-3-pro": {
+      "antigravity-gemini-3.1-pro": {
         name: "Gemini 3 Pro (Antigravity)",
         limit: { context: 1048576, output: 65535 },
         modalities: { input: ["text", "image", "pdf"], output: ["text"] },
diff --git a/src/cli/doctor/checks/model-resolution.test.ts b/src/cli/doctor/checks/model-resolution.test.ts
index cca2f58b5..e311076a8 100644
--- a/src/cli/doctor/checks/model-resolution.test.ts
+++ b/src/cli/doctor/checks/model-resolution.test.ts
@@ -26,7 +26,7 @@ describe("model-resolution check", () => {
       // then: Should have category entries
       const visual = info.categories.find((c) => c.name === "visual-engineering")
       expect(visual).toBeDefined()
-      expect(visual!.requirement.fallbackChain[0]?.model).toBe("gemini-3-pro")
+      expect(visual!.requirement.fallbackChain[0]?.model).toBe("gemini-3.1-pro")
       expect(visual!.requirement.fallbackChain[0]?.providers).toContain("google")
     })
   })
diff --git a/src/cli/model-fallback-requirements.ts b/src/cli/model-fallback-requirements.ts
index f3f43e60b..0ff625005 100644
--- a/src/cli/model-fallback-requirements.ts
+++ b/src/cli/model-fallback-requirements.ts
@@ -24,7 +24,7 @@ export const CLI_AGENT_MODEL_REQUIREMENTS: Record<string, ModelRequirement> = {
   oracle: {
     fallbackChain: [
       { providers: ["openai", "github-copilot", "opencode"], model: "gpt-5.2", variant: "high" },
-      { providers: ["google", "github-copilot", "opencode"], model: "gemini-3-pro", variant: "high" },
+      { providers: ["google", "github-copilot", "opencode"], model: "gemini-3.1-pro", variant: "high" },
       { providers: ["anthropic", "github-copilot", "opencode"], model: "claude-opus-4-6", variant: "max" },
     ],
   },
@@ -59,7 +59,7 @@ export const CLI_AGENT_MODEL_REQUIREMENTS: Record<string, ModelRequirement> = {
       { providers: ["kimi-for-coding"], model: "k2p5" },
       { providers: ["opencode"], model: "kimi-k2.5-free" },
       { providers: ["openai", "github-copilot", "opencode"], model: "gpt-5.2", variant: "high" },
-      { providers: ["google", "github-copilot", "opencode"], model: "gemini-3-pro" },
+      { providers: ["google", "github-copilot", "opencode"], model: "gemini-3.1-pro" },
     ],
   },
   metis: {
@@ -68,14 +68,14 @@ export const CLI_AGENT_MODEL_REQUIREMENTS: Record<string, ModelRequirement> = {
       { providers: ["kimi-for-coding"], model: "k2p5" },
       { providers: ["opencode"], model: "kimi-k2.5-free" },
       { providers: ["openai", "github-copilot", "opencode"], model: "gpt-5.2", variant: "high" },
-      { providers: ["google", "github-copilot", "opencode"], model: "gemini-3-pro", variant: "high" },
+      { providers: ["google", "github-copilot", "opencode"], model: "gemini-3.1-pro", variant: "high" },
     ],
   },
   momus: {
     fallbackChain: [
       { providers: ["openai", "github-copilot", "opencode"], model: "gpt-5.2", variant: "medium" },
       { providers: ["anthropic", "github-copilot", "opencode"], model: "claude-opus-4-6", variant: "max" },
-      { providers: ["google", "github-copilot", "opencode"], model: "gemini-3-pro", variant: "high" },
+      { providers: ["google", "github-copilot", "opencode"], model: "gemini-3.1-pro", variant: "high" },
     ],
   },
   atlas: {
@@ -84,7 +84,7 @@ export const CLI_AGENT_MODEL_REQUIREMENTS: Record<string, ModelRequirement> = {
       { providers: ["opencode"], model: "kimi-k2.5-free" },
       { providers: ["anthropic", "github-copilot", "opencode"], model: "claude-sonnet-4-5" },
       { providers: ["openai", "github-copilot", "opencode"], model: "gpt-5.2" },
-      { providers: ["google", "github-copilot", "opencode"], model: "gemini-3-pro" },
+      { providers: ["google", "github-copilot", "opencode"], model: "gemini-3.1-pro" },
     ],
   },
 }
@@ -92,7 +92,7 @@ export const CLI_AGENT_MODEL_REQUIREMENTS: Record<string, ModelRequirement> = {
 export const CLI_CATEGORY_MODEL_REQUIREMENTS: Record<string, ModelRequirement> = {
   "visual-engineering": {
     fallbackChain: [
-      { providers: ["google", "github-copilot", "opencode"], model: "gemini-3-pro", variant: "high" },
+      { providers: ["google", "github-copilot", "opencode"], model: "gemini-3.1-pro", variant: "high" },
       { providers: ["zai-coding-plan"], model: "glm-5" },
       { providers: ["anthropic", "github-copilot", "opencode"], model: "claude-opus-4-6", variant: "max" },
       { providers: ["kimi-for-coding"], model: "k2p5" },
@@ -101,7 +101,7 @@ export const CLI_CATEGORY_MODEL_REQUIREMENTS: Record<string, ModelRequirement> =
   ultrabrain: {
     fallbackChain: [
       { providers: ["openai", "opencode"], model: "gpt-5.3-codex", variant: "xhigh" },
-      { providers: ["google", "github-copilot", "opencode"], model: "gemini-3-pro", variant: "high" },
+      { providers: ["google", "github-copilot", "opencode"], model: "gemini-3.1-pro", variant: "high" },
       { providers: ["anthropic", "github-copilot", "opencode"], model: "claude-opus-4-6", variant: "max" },
     ],
   },
@@ -109,17 +109,17 @@ export const CLI_CATEGORY_MODEL_REQUIREMENTS: Record<string, ModelRequirement> =
     fallbackChain: [
       { providers: ["openai", "opencode"], model: "gpt-5.3-codex", variant: "medium" },
       { providers: ["anthropic", "github-copilot", "opencode"], model: "claude-opus-4-6", variant: "max" },
-      { providers: ["google", "github-copilot", "opencode"], model: "gemini-3-pro", variant: "high" },
+      { providers: ["google", "github-copilot", "opencode"], model: "gemini-3.1-pro", variant: "high" },
     ],
     requiresModel: "gpt-5.3-codex",
   },
   artistry: {
     fallbackChain: [
-      { providers: ["google", "github-copilot", "opencode"], model: "gemini-3-pro", variant: "high" },
+      { providers: ["google", "github-copilot", "opencode"], model: "gemini-3.1-pro", variant: "high" },
       { providers: ["anthropic", "github-copilot", "opencode"], model: "claude-opus-4-6", variant: "max" },
       { providers: ["openai", "github-copilot", "opencode"], model: "gpt-5.2" },
     ],
-    requiresModel: "gemini-3-pro",
+    requiresModel: "gemini-3.1-pro",
   },
   quick: {
     fallbackChain: [
@@ -139,7 +139,7 @@ export const CLI_CATEGORY_MODEL_REQUIREMENTS: Record<string, ModelRequirement> =
     fallbackChain: [
       { providers: ["anthropic", "github-copilot", "opencode"], model: "claude-opus-4-6", variant: "max" },
       { providers: ["openai", "github-copilot", "opencode"], model: "gpt-5.2", variant: "high" },
-      { providers: ["google", "github-copilot", "opencode"], model: "gemini-3-pro" },
+      { providers: ["google", "github-copilot", "opencode"], model: "gemini-3.1-pro" },
     ],
   },
   writing: {
diff --git a/src/cli/provider-model-id-transform.test.ts b/src/cli/provider-model-id-transform.test.ts
index e13c7846a..17cb9dfb1 100644
--- a/src/cli/provider-model-id-transform.test.ts
+++ b/src/cli/provider-model-id-transform.test.ts
@@ -40,16 +40,16 @@ describe("transformModelForProvider", () => {
 			expect(result).toBe("claude-haiku-4.5")
 		})
 
-		test("transforms gemini-3-pro to gemini-3-pro-preview", () => {
-			// #given github-copilot provider and gemini-3-pro model
+		test("transforms gemini-3.1-pro to gemini-3.1-pro-preview", () => {
+			// #given github-copilot provider and gemini-3.1-pro model
 			const provider = "github-copilot"
-			const model = "gemini-3-pro"
+			const model = "gemini-3.1-pro"
 
 			// #when transformModelForProvider is called
 			const result = transformModelForProvider(provider, model)
 
-			// #then should transform to gemini-3-pro-preview
-			expect(result).toBe("gemini-3-pro-preview")
+			// #then should transform to gemini-3.1-pro-preview
+			expect(result).toBe("gemini-3.1-pro-preview")
 		})
 
 		test("transforms gemini-3-flash to gemini-3-flash-preview", () => {
@@ -64,16 +64,16 @@ describe("transformModelForProvider", () => {
 			expect(result).toBe("gemini-3-flash-preview")
 		})
 
-		test("prevents double transformation of gemini-3-pro-preview", () => {
-			// #given github-copilot provider and gemini-3-pro-preview model (already transformed)
+		test("prevents double transformation of gemini-3.1-pro-preview", () => {
+			// #given github-copilot provider and gemini-3.1-pro-preview model (already transformed)
 			const provider = "github-copilot"
-			const model = "gemini-3-pro-preview"
+			const model = "gemini-3.1-pro-preview"
 
 			// #when transformModelForProvider is called
 			const result = transformModelForProvider(provider, model)
 
-			// #then should NOT become gemini-3-pro-preview-preview
-			expect(result).toBe("gemini-3-pro-preview")
+			// #then should NOT become gemini-3.1-pro-preview-preview
+			expect(result).toBe("gemini-3.1-pro-preview")
 		})
 
 		test("prevents double transformation of gemini-3-flash-preview", () => {
@@ -102,16 +102,16 @@ describe("transformModelForProvider", () => {
 			expect(result).toBe("gemini-3-flash-preview")
 		})
 
-		test("transforms gemini-3-pro to gemini-3-pro-preview", () => {
-			// #given google provider and gemini-3-pro model
+		test("transforms gemini-3.1-pro to gemini-3.1-pro-preview", () => {
+			// #given google provider and gemini-3.1-pro model
 			const provider = "google"
-			const model = "gemini-3-pro"
+			const model = "gemini-3.1-pro"
 
 			// #when transformModelForProvider is called
 			const result = transformModelForProvider(provider, model)
 
-			// #then should transform to gemini-3-pro-preview
-			expect(result).toBe("gemini-3-pro-preview")
+			// #then should transform to gemini-3.1-pro-preview
+			expect(result).toBe("gemini-3.1-pro-preview")
 		})
 
 		test("passes through other gemini models unchanged", () => {
@@ -138,16 +138,16 @@ describe("transformModelForProvider", () => {
 			expect(result).toBe("gemini-3-flash-preview")
 		})
 
-		test("prevents double transformation of gemini-3-pro-preview", () => {
-			// #given google provider and gemini-3-pro-preview model (already transformed)
+		test("prevents double transformation of gemini-3.1-pro-preview", () => {
+			// #given google provider and gemini-3.1-pro-preview model (already transformed)
 			const provider = "google"
-			const model = "gemini-3-pro-preview"
+			const model = "gemini-3.1-pro-preview"
 
 			// #when transformModelForProvider is called
 			const result = transformModelForProvider(provider, model)
 
-			// #then should NOT become gemini-3-pro-preview-preview
-			expect(result).toBe("gemini-3-pro-preview")
+			// #then should NOT become gemini-3.1-pro-preview-preview
+			expect(result).toBe("gemini-3.1-pro-preview")
 		})
 
 		test("does not transform claude models for google provider", () => {
diff --git a/src/features/background-agent/concurrency.test.ts b/src/features/background-agent/concurrency.test.ts
index 102076eef..682d6029a 100644
--- a/src/features/background-agent/concurrency.test.ts
+++ b/src/features/background-agent/concurrency.test.ts
@@ -34,7 +34,7 @@ describe("ConcurrencyManager.getConcurrencyLimit", () => {
   test("should return provider limit even when modelConcurrency exists but doesn't match", () => {
     // given
     const config: BackgroundTaskConfig = {
-      modelConcurrency: { "google/gemini-3-pro": 5 },
+      modelConcurrency: { "google/gemini-3.1-pro": 5 },
       providerConcurrency: { anthropic: 3 }
     }
     const manager = new ConcurrencyManager(config)
@@ -95,7 +95,7 @@ describe("ConcurrencyManager.getConcurrencyLimit", () => {
     // when
     const modelLimit = manager.getConcurrencyLimit("anthropic/claude-sonnet-4-6")
     const providerLimit = manager.getConcurrencyLimit("anthropic/claude-opus-4-6")
-    const defaultLimit = manager.getConcurrencyLimit("google/gemini-3-pro")
+    const defaultLimit = manager.getConcurrencyLimit("google/gemini-3.1-pro")
 
     // then
     expect(modelLimit).toBe(10)
diff --git a/src/features/task-toast-manager/manager.test.ts b/src/features/task-toast-manager/manager.test.ts
index 323792815..a490f894b 100644
--- a/src/features/task-toast-manager/manager.test.ts
+++ b/src/features/task-toast-manager/manager.test.ts
@@ -162,7 +162,7 @@ describe("TaskToastManager", () => {
         description: "Task with category default model",
         agent: "sisyphus-junior",
         isBackground: false,
-        modelInfo: { model: "google/gemini-3-pro", type: "category-default" as const },
+        modelInfo: { model: "google/gemini-3.1-pro", type: "category-default" as const },
       }
 
       // when - addTask is called
diff --git a/src/hooks/runtime-fallback/index.test.ts b/src/hooks/runtime-fallback/index.test.ts
index 7660f1954..d9c873f16 100644
--- a/src/hooks/runtime-fallback/index.test.ts
+++ b/src/hooks/runtime-fallback/index.test.ts
@@ -125,7 +125,7 @@ describe("runtime-fallback", () => {
       await hook.event({
         event: {
           type: "session.created",
-          properties: { info: { id: sessionID, model: "google/gemini-3-pro" } },
+          properties: { info: { id: sessionID, model: "google/gemini-3.1-pro" } },
         },
       })
 
@@ -1841,7 +1841,7 @@ describe("runtime-fallback", () => {
     test("should apply fallback model on next chat.message after error", async () => {
       const hook = createRuntimeFallbackHook(createMockPluginInput(), {
         config: createMockConfig({ notify_on_fallback: false }),
-        pluginConfig: createMockPluginConfigWithCategoryFallback(["openai/gpt-5.2", "google/gemini-3-pro"]),
+        pluginConfig: createMockPluginConfigWithCategoryFallback(["openai/gpt-5.2", "google/gemini-3.1-pro"]),
       })
       const sessionID = "test-session-switch"
       SessionCategoryRegistry.register(sessionID, "test")
@@ -1916,7 +1916,7 @@ describe("runtime-fallback", () => {
       const input = createMockPluginInput()
       const hook = createRuntimeFallbackHook(input, {
         config: createMockConfig({ notify_on_fallback: false }),
-        pluginConfig: createMockPluginConfigWithAgentFallback("oracle", ["openai/gpt-5.2", "google/gemini-3-pro"]),
+        pluginConfig: createMockPluginConfigWithAgentFallback("oracle", ["openai/gpt-5.2", "google/gemini-3.1-pro"]),
       })
       const sessionID = "test-agent-fallback"
 
diff --git a/src/hooks/think-mode/index.test.ts b/src/hooks/think-mode/index.test.ts
index 480eaf30b..b0d744738 100644
--- a/src/hooks/think-mode/index.test.ts
+++ b/src/hooks/think-mode/index.test.ts
@@ -109,7 +109,7 @@ describe("createThinkModeHook", () => {
     const input = createHookInput({
       sessionID,
       providerID: "google",
-      modelID: "gemini-3-pro",
+      modelID: "gemini-3.1-pro",
     })
     const output = createHookOutput("Please solve this directly")
 
diff --git a/src/hooks/think-mode/switcher.test.ts b/src/hooks/think-mode/switcher.test.ts
index 65fa5cde3..bf20122fd 100644
--- a/src/hooks/think-mode/switcher.test.ts
+++ b/src/hooks/think-mode/switcher.test.ts
@@ -49,8 +49,8 @@ describe("think-mode switcher", () => {
 
       it("should handle Gemini preview variants", () => {
         // given Gemini preview model IDs
-        expect(getHighVariant("gemini-3-pro")).toBe(
-          "gemini-3-pro-high"
+        expect(getHighVariant("gemini-3.1-pro")).toBe(
+          "gemini-3-1-pro-high"
         )
         expect(getHighVariant("gemini-3-flash")).toBe(
           "gemini-3-flash-high"
@@ -61,7 +61,7 @@ describe("think-mode switcher", () => {
         // given model IDs that are already high variants
         expect(getHighVariant("claude-opus-4-6-high")).toBeNull()
         expect(getHighVariant("gpt-5-2-high")).toBeNull()
-        expect(getHighVariant("gemini-3-pro-high")).toBeNull()
+        expect(getHighVariant("gemini-3-1-pro-high")).toBeNull()
       })
 
       it("should return null for unknown models", () => {
@@ -77,7 +77,7 @@ describe("think-mode switcher", () => {
       // given model IDs with -high suffix
       expect(isAlreadyHighVariant("claude-opus-4-6-high")).toBe(true)
       expect(isAlreadyHighVariant("gpt-5-2-high")).toBe(true)
-      expect(isAlreadyHighVariant("gemini-3-pro-high")).toBe(true)
+      expect(isAlreadyHighVariant("gemini-3.1-pro-high")).toBe(true)
     })
 
     it("should detect -high suffix after normalization", () => {
@@ -90,7 +90,7 @@ describe("think-mode switcher", () => {
       expect(isAlreadyHighVariant("claude-opus-4-6")).toBe(false)
       expect(isAlreadyHighVariant("claude-opus-4.6")).toBe(false)
       expect(isAlreadyHighVariant("gpt-5.2")).toBe(false)
-      expect(isAlreadyHighVariant("gemini-3-pro")).toBe(false)
+      expect(isAlreadyHighVariant("gemini-3.1-pro")).toBe(false)
     })
 
     it("should return false for models with 'high' in name but not suffix", () => {
@@ -129,7 +129,7 @@ describe("think-mode switcher", () => {
         // given various custom prefixes
         expect(getHighVariant("azure/gpt-5")).toBe("azure/gpt-5-high")
         expect(getHighVariant("bedrock/claude-sonnet-4-6")).toBe("bedrock/claude-sonnet-4-6-high")
-        expect(getHighVariant("custom-llm/gemini-3-pro")).toBe("custom-llm/gemini-3-pro-high")
+        expect(getHighVariant("custom-llm/gemini-3.1-pro")).toBe("custom-llm/gemini-3-1-pro-high")
       })
 
       it("should return null for prefixed models without high variant mapping", () => {
@@ -150,7 +150,7 @@ describe("think-mode switcher", () => {
         // given prefixed model IDs with -high suffix
         expect(isAlreadyHighVariant("vertex_ai/claude-opus-4-6-high")).toBe(true)
         expect(isAlreadyHighVariant("openai/gpt-5-2-high")).toBe(true)
-        expect(isAlreadyHighVariant("custom/gemini-3-pro-high")).toBe(true)
+        expect(isAlreadyHighVariant("custom/gemini-3.1-pro-high")).toBe(true)
       })
 
       it("should return false for prefixed base models", () => {
@@ -167,4 +167,3 @@ describe("think-mode switcher", () => {
     })
 })
 })
-
diff --git a/src/hooks/think-mode/switcher.ts b/src/hooks/think-mode/switcher.ts
index 273019d93..0a1a1dd38 100644
--- a/src/hooks/think-mode/switcher.ts
+++ b/src/hooks/think-mode/switcher.ts
@@ -62,8 +62,8 @@ const HIGH_VARIANT_MAP: Record<string, string> = {
   "claude-sonnet-4-6": "claude-sonnet-4-6-high",
   "claude-opus-4-6": "claude-opus-4-6-high",
    // Gemini
-   "gemini-3-pro": "gemini-3-pro-high",
-   "gemini-3-pro-low": "gemini-3-pro-high",
+   "gemini-3-1-pro": "gemini-3-1-pro-high",
+   "gemini-3-1-pro-low": "gemini-3-1-pro-high",
    "gemini-3-flash": "gemini-3-flash-high",
   // GPT-5
   "gpt-5": "gpt-5-high",
@@ -82,7 +82,7 @@ const HIGH_VARIANT_MAP: Record<string, string> = {
   "gpt-5-2-chat-latest": "gpt-5-2-chat-latest-high",
   "gpt-5-2-pro": "gpt-5-2-pro-high",
   // Antigravity (Google)
-  "antigravity-gemini-3-pro": "antigravity-gemini-3-pro-high",
+  "antigravity-gemini-3-1-pro": "antigravity-gemini-3-1-pro-high",
   "antigravity-gemini-3-flash": "antigravity-gemini-3-flash-high",
 }
 
@@ -114,4 +114,3 @@ export function isAlreadyHighVariant(modelID: string): boolean {
   return ALREADY_HIGH.has(base) || base.endsWith("-high")
 }
 
-
diff --git a/src/plugin-config.test.ts b/src/plugin-config.test.ts
index 9404f7095..1802f00c8 100644
--- a/src/plugin-config.test.ts
+++ b/src/plugin-config.test.ts
@@ -27,7 +27,7 @@ describe("mergeConfigs", () => {
             temperature: 0.3,
           },
           visual: {
-            model: "google/gemini-3-pro",
+            model: "google/gemini-3.1-pro",
           },
         },
       } as unknown as OhMyOpenCodeConfig;
@@ -41,7 +41,7 @@ describe("mergeConfigs", () => {
       // then quick should be preserved from base
       expect(result.categories?.quick?.model).toBe("anthropic/claude-haiku-4-5");
       // then visual should be added from override
-      expect(result.categories?.visual?.model).toBe("google/gemini-3-pro");
+      expect(result.categories?.visual?.model).toBe("google/gemini-3.1-pro");
     });
 
     it("should preserve base categories when override has no categories", () => {
diff --git a/src/plugin-handlers/config-handler.test.ts b/src/plugin-handlers/config-handler.test.ts
index 875a8cee2..7b735afe4 100644
--- a/src/plugin-handlers/config-handler.test.ts
+++ b/src/plugin-handlers/config-handler.test.ts
@@ -570,7 +570,7 @@ describe("Prometheus category config resolution", () => {
 
     // then
     expect(config).toBeDefined()
-    expect(config?.model).toBe("google/gemini-3-pro")
+    expect(config?.model).toBe("google/gemini-3.1-pro")
   })
 
   test("user categories override default categories", () => {
diff --git a/src/shared/migration.test.ts b/src/shared/migration.test.ts
index 7846cc725..eb3d1d101 100644
--- a/src/shared/migration.test.ts
+++ b/src/shared/migration.test.ts
@@ -774,7 +774,7 @@ describe("migrateAgentConfigToCategory", () => {
   test("migrates model to category when mapping exists", () => {
     // given: Config with a model that has a category mapping
     const config = {
-      model: "google/gemini-3-pro",
+      model: "google/gemini-3.1-pro",
       temperature: 0.5,
       top_p: 0.9,
     }
@@ -823,7 +823,7 @@ describe("migrateAgentConfigToCategory", () => {
   test("handles all mapped models correctly", () => {
     // given: Configs for each mapped model
     const configs = [
-      { model: "google/gemini-3-pro" },
+      { model: "google/gemini-3.1-pro" },
       { model: "google/gemini-3-flash" },
       { model: "openai/gpt-5.2" },
       { model: "anthropic/claude-haiku-4-5" },
@@ -893,7 +893,7 @@ describe("shouldDeleteAgentConfig", () => {
     // given: Config with fields matching category defaults
     const config = {
       category: "visual-engineering",
-      model: "google/gemini-3-pro",
+      model: "google/gemini-3.1-pro",
     }
 
     // when: Check if config should be deleted
@@ -1021,7 +1021,7 @@ describe("migrateConfigFile with backup", () => {
       agents: {
         "multimodal-looker": { model: "anthropic/claude-haiku-4-5" },
         oracle: { model: "openai/gpt-5.2" },
-        "my-custom-agent": { model: "google/gemini-3-pro" },
+        "my-custom-agent": { model: "google/gemini-3.1-pro" },
       },
     }
 
@@ -1037,7 +1037,7 @@ describe("migrateConfigFile with backup", () => {
     const agents = rawConfig.agents as Record<string, Record<string, unknown>>
     expect(agents["multimodal-looker"].model).toBe("anthropic/claude-haiku-4-5")
     expect(agents.oracle.model).toBe("openai/gpt-5.2")
-    expect(agents["my-custom-agent"].model).toBe("google/gemini-3-pro")
+    expect(agents["my-custom-agent"].model).toBe("google/gemini-3.1-pro")
   })
 
   test("preserves category setting when explicitly set", () => {
diff --git a/src/shared/migration/agent-category.ts b/src/shared/migration/agent-category.ts
index 51aac23d7..8b7df75a4 100644
--- a/src/shared/migration/agent-category.ts
+++ b/src/shared/migration/agent-category.ts
@@ -12,7 +12,7 @@
  * This map will be removed in a future major version once migration period ends.
  */
 export const MODEL_TO_CATEGORY_MAP: Record<string, string> = {
-  "google/gemini-3-pro": "visual-engineering",
+  "google/gemini-3.1-pro": "visual-engineering",
   "google/gemini-3-flash": "writing",
   "openai/gpt-5.2": "ultrabrain",
   "anthropic/claude-haiku-4-5": "quick",
diff --git a/src/shared/model-availability.test.ts b/src/shared/model-availability.test.ts
index 23a3f00f6..cb469b960 100644
--- a/src/shared/model-availability.test.ts
+++ b/src/shared/model-availability.test.ts
@@ -63,7 +63,7 @@ describe("fetchAvailableModels", () => {
     writeModelsCache({
       openai: { id: "openai", models: { "gpt-5.2": { id: "gpt-5.2" } } },
       anthropic: { id: "anthropic", models: { "claude-opus-4-6": { id: "claude-opus-4-6" } } },
-      google: { id: "google", models: { "gemini-3-pro": { id: "gemini-3-pro" } } },
+      google: { id: "google", models: { "gemini-3.1-pro": { id: "gemini-3.1-pro" } } },
     })
 
     const result = await fetchAvailableModels(undefined, {
@@ -74,7 +74,7 @@ describe("fetchAvailableModels", () => {
     expect(result.size).toBe(3)
     expect(result.has("openai/gpt-5.2")).toBe(true)
     expect(result.has("anthropic/claude-opus-4-6")).toBe(true)
-    expect(result.has("google/gemini-3-pro")).toBe(true)
+    expect(result.has("google/gemini-3.1-pro")).toBe(true)
   })
 
   it("#given connectedProviders unknown #when fetchAvailableModels called without options #then returns empty Set", async () => {
@@ -97,7 +97,7 @@ describe("fetchAvailableModels", () => {
         list: async () => ({
           data: [
             { id: "gpt-5.3-codex", provider: "openai" },
-            { id: "gemini-3-pro", provider: "google" },
+            { id: "gemini-3.1-pro", provider: "google" },
           ],
         }),
       },
@@ -107,7 +107,7 @@ describe("fetchAvailableModels", () => {
 
     expect(result).toBeInstanceOf(Set)
     expect(result.has("openai/gpt-5.3-codex")).toBe(true)
-    expect(result.has("google/gemini-3-pro")).toBe(false)
+    expect(result.has("google/gemini-3.1-pro")).toBe(false)
   })
 
   it("#given cache file not found #when fetchAvailableModels called with connectedProviders #then returns empty Set", async () => {
@@ -126,7 +126,7 @@ describe("fetchAvailableModels", () => {
         list: async () => ({
           data: [
             { id: "gpt-5.3-codex", provider: "openai" },
-            { id: "gemini-3-pro", provider: "google" },
+            { id: "gemini-3.1-pro", provider: "google" },
           ],
         }),
       },
@@ -136,7 +136,7 @@ describe("fetchAvailableModels", () => {
 
     expect(result).toBeInstanceOf(Set)
     expect(result.has("openai/gpt-5.3-codex")).toBe(true)
-    expect(result.has("google/gemini-3-pro")).toBe(true)
+    expect(result.has("google/gemini-3.1-pro")).toBe(true)
   })
 
   it("#given cache read twice #when second call made with same providers #then reads fresh each time", async () => {
@@ -515,7 +515,7 @@ describe("fetchAvailableModels with connected providers filtering", () => {
 		writeModelsCache({
 			openai: { models: { "gpt-5.2": { id: "gpt-5.2" } } },
 			anthropic: { models: { "claude-opus-4-6": { id: "claude-opus-4-6" } } },
-			google: { models: { "gemini-3-pro": { id: "gemini-3-pro" } } },
+			google: { models: { "gemini-3.1-pro": { id: "gemini-3.1-pro" } } },
 		})
 
 		const result = await fetchAvailableModels(undefined, {
@@ -525,7 +525,7 @@ describe("fetchAvailableModels with connected providers filtering", () => {
 		expect(result.size).toBe(1)
 		expect(result.has("anthropic/claude-opus-4-6")).toBe(true)
 		expect(result.has("openai/gpt-5.2")).toBe(false)
-		expect(result.has("google/gemini-3-pro")).toBe(false)
+		expect(result.has("google/gemini-3.1-pro")).toBe(false)
 	})
 
 	// given cache with multiple providers
@@ -535,7 +535,7 @@ describe("fetchAvailableModels with connected providers filtering", () => {
 		writeModelsCache({
 			openai: { models: { "gpt-5.2": { id: "gpt-5.2" } } },
 			anthropic: { models: { "claude-opus-4-6": { id: "claude-opus-4-6" } } },
-			google: { models: { "gemini-3-pro": { id: "gemini-3-pro" } } },
+			google: { models: { "gemini-3.1-pro": { id: "gemini-3.1-pro" } } },
 		})
 
 		const result = await fetchAvailableModels(undefined, {
@@ -544,7 +544,7 @@ describe("fetchAvailableModels with connected providers filtering", () => {
 
 		expect(result.size).toBe(2)
 		expect(result.has("anthropic/claude-opus-4-6")).toBe(true)
-		expect(result.has("google/gemini-3-pro")).toBe(true)
+		expect(result.has("google/gemini-3.1-pro")).toBe(true)
 		expect(result.has("openai/gpt-5.2")).toBe(false)
 	})
 
@@ -759,7 +759,7 @@ describe("fetchAvailableModels with provider-models cache (whitelist-filtered)",
 			models: {
 				opencode: ["big-pickle"],
 				anthropic: ["claude-opus-4-6"],
-				google: ["gemini-3-pro"]
+				google: ["gemini-3.1-pro"]
 			},
 			connected: ["opencode", "anthropic", "google"]
 		})
@@ -771,7 +771,7 @@ describe("fetchAvailableModels with provider-models cache (whitelist-filtered)",
 		expect(result.size).toBe(1)
 		expect(result.has("opencode/big-pickle")).toBe(true)
 		expect(result.has("anthropic/claude-opus-4-6")).toBe(false)
-		expect(result.has("google/gemini-3-pro")).toBe(false)
+		expect(result.has("google/gemini-3.1-pro")).toBe(false)
 	})
 
 	it("should handle object[] format with metadata (Ollama-style)", async () => {
@@ -953,7 +953,7 @@ describe("fallback model availability", () => {
 			{ providers: ["openai"], model: "gpt-5.2" },
 			{ providers: ["anthropic"], model: "claude-opus-4-6" },
 		]
-		const availableModels = new Set(["google/gemini-3-pro"])
+		const availableModels = new Set(["google/gemini-3.1-pro"])
 
 		// when
 		const result = resolveFirstAvailableFallback(fallbackChain, availableModels)
diff --git a/src/shared/model-requirements.test.ts b/src/shared/model-requirements.test.ts
index 112b2b774..df4cd696a 100644
--- a/src/shared/model-requirements.test.ts
+++ b/src/shared/model-requirements.test.ts
@@ -248,19 +248,19 @@ describe("CATEGORY_MODEL_REQUIREMENTS", () => {
     expect(primary.providers[0]).toBe("openai")
   })
 
-  test("visual-engineering has valid fallbackChain with gemini-3-pro high as primary", () => {
+  test("visual-engineering has valid fallbackChain with gemini-3.1-pro high as primary", () => {
     // given - visual-engineering category requirement
     const visualEngineering = CATEGORY_MODEL_REQUIREMENTS["visual-engineering"]
 
     // when - accessing visual-engineering requirement
-    // then - fallbackChain: gemini-3-pro(high) → glm-5 → opus-4-6(max)
+    // then - fallbackChain: gemini-3.1-pro(high) → glm-5 → opus-4-6(max)
     expect(visualEngineering).toBeDefined()
     expect(visualEngineering.fallbackChain).toBeArray()
     expect(visualEngineering.fallbackChain).toHaveLength(3)
 
     const primary = visualEngineering.fallbackChain[0]
     expect(primary.providers[0]).toBe("google")
-    expect(primary.model).toBe("gemini-3-pro")
+    expect(primary.model).toBe("gemini-3.1-pro")
     expect(primary.variant).toBe("high")
 
     const second = visualEngineering.fallbackChain[1]
@@ -319,39 +319,43 @@ describe("CATEGORY_MODEL_REQUIREMENTS", () => {
     expect(primary.providers).toEqual(["anthropic", "github-copilot", "opencode"])
   })
 
-  test("artistry has valid fallbackChain with gemini-3-pro as primary", () => {
+  test("artistry has valid fallbackChain with gemini-3.1-pro as primary", () => {
     // given - artistry category requirement
     const artistry = CATEGORY_MODEL_REQUIREMENTS["artistry"]
 
     // when - accessing artistry requirement
-    // then - fallbackChain exists with gemini-3-pro as first entry
+    // then - fallbackChain exists with gemini-3.1-pro as first entry
     expect(artistry).toBeDefined()
     expect(artistry.fallbackChain).toBeArray()
     expect(artistry.fallbackChain.length).toBeGreaterThan(0)
 
     const primary = artistry.fallbackChain[0]
-    expect(primary.model).toBe("gemini-3-pro")
+    expect(primary.model).toBe("gemini-3.1-pro")
     expect(primary.variant).toBe("high")
     expect(primary.providers[0]).toBe("google")
   })
 
-  test("writing has valid fallbackChain with gemini-3-flash as primary", () => {
+  test("writing has valid fallbackChain with kimi-k2.5-free as primary", () => {
     // given - writing category requirement
     const writing = CATEGORY_MODEL_REQUIREMENTS["writing"]
 
     // when - accessing writing requirement
-    // then - fallbackChain: gemini-3-flash → claude-sonnet-4-6
+    // then - fallbackChain: kimi-k2.5-free -> gemini-3-flash -> claude-sonnet-4-6
     expect(writing).toBeDefined()
     expect(writing.fallbackChain).toBeArray()
-    expect(writing.fallbackChain).toHaveLength(2)
+    expect(writing.fallbackChain).toHaveLength(3)
 
     const primary = writing.fallbackChain[0]
-    expect(primary.model).toBe("gemini-3-flash")
-    expect(primary.providers[0]).toBe("google")
+    expect(primary.model).toBe("kimi-k2.5-free")
+    expect(primary.providers[0]).toBe("opencode")
 
     const second = writing.fallbackChain[1]
-    expect(second.model).toBe("claude-sonnet-4-6")
-    expect(second.providers[0]).toBe("anthropic")
+    expect(second.model).toBe("gemini-3-flash")
+    expect(second.providers[0]).toBe("google")
+
+    const third = writing.fallbackChain[2]
+    expect(third.model).toBe("claude-sonnet-4-6")
+    expect(third.providers[0]).toBe("anthropic")
   })
 
   test("all 8 categories have valid fallbackChain arrays", () => {
@@ -489,12 +493,12 @@ describe("requiresModel field in categories", () => {
     expect(deep.requiresModel).toBe("gpt-5.3-codex")
   })
 
-  test("artistry category has requiresModel set to gemini-3-pro", () => {
+  test("artistry category has requiresModel set to gemini-3.1-pro", () => {
     // given
     const artistry = CATEGORY_MODEL_REQUIREMENTS["artistry"]
 
     // when / #then
-    expect(artistry.requiresModel).toBe("gemini-3-pro")
+    expect(artistry.requiresModel).toBe("gemini-3.1-pro")
   })
 })
 
diff --git a/src/shared/model-requirements.ts b/src/shared/model-requirements.ts
index 42a860b96..f8e197ea8 100644
--- a/src/shared/model-requirements.ts
+++ b/src/shared/model-requirements.ts
@@ -32,7 +32,7 @@ export const AGENT_MODEL_REQUIREMENTS: Record<string, ModelRequirement> = {
   oracle: {
     fallbackChain: [
       { providers: ["openai", "github-copilot", "opencode"], model: "gpt-5.2", variant: "high" },
-      { providers: ["google", "github-copilot", "opencode"], model: "gemini-3-pro", variant: "high" },
+      { providers: ["google", "github-copilot", "opencode"], model: "gemini-3.1-pro", variant: "high" },
       { providers: ["anthropic", "github-copilot", "opencode"], model: "claude-opus-4-6", variant: "max" },
     ],
   },
@@ -65,7 +65,7 @@ export const AGENT_MODEL_REQUIREMENTS: Record<string, ModelRequirement> = {
       { providers: ["anthropic", "github-copilot", "opencode"], model: "claude-opus-4-6", variant: "max" },
       { providers: ["openai", "github-copilot", "opencode"], model: "gpt-5.2", variant: "high" },
       { providers: ["opencode"], model: "kimi-k2.5-free" },
-      { providers: ["google", "github-copilot", "opencode"], model: "gemini-3-pro" },
+      { providers: ["google", "github-copilot", "opencode"], model: "gemini-3.1-pro" },
     ],
   },
   metis: {
@@ -73,14 +73,14 @@ export const AGENT_MODEL_REQUIREMENTS: Record<string, ModelRequirement> = {
       { providers: ["anthropic", "github-copilot", "opencode"], model: "claude-opus-4-6", variant: "max" },
       { providers: ["opencode"], model: "kimi-k2.5-free" },
       { providers: ["openai", "github-copilot", "opencode"], model: "gpt-5.2", variant: "high" },
-      { providers: ["google", "github-copilot", "opencode"], model: "gemini-3-pro", variant: "high" },
+      { providers: ["google", "github-copilot", "opencode"], model: "gemini-3.1-pro", variant: "high" },
     ],
   },
   momus: {
     fallbackChain: [
       { providers: ["openai", "github-copilot", "opencode"], model: "gpt-5.2", variant: "medium" },
       { providers: ["anthropic", "github-copilot", "opencode"], model: "claude-opus-4-6", variant: "max" },
-      { providers: ["google", "github-copilot", "opencode"], model: "gemini-3-pro", variant: "high" },
+      { providers: ["google", "github-copilot", "opencode"], model: "gemini-3.1-pro", variant: "high" },
     ],
   },
   atlas: {
@@ -95,7 +95,7 @@ export const AGENT_MODEL_REQUIREMENTS: Record<string, ModelRequirement> = {
 export const CATEGORY_MODEL_REQUIREMENTS: Record<string, ModelRequirement> = {
   "visual-engineering": {
     fallbackChain: [
-      { providers: ["google", "github-copilot", "opencode"], model: "gemini-3-pro", variant: "high" },
+      { providers: ["google", "github-copilot", "opencode"], model: "gemini-3.1-pro", variant: "high" },
       { providers: ["zai-coding-plan", "opencode"], model: "glm-5" },
       { providers: ["anthropic", "github-copilot", "opencode"], model: "claude-opus-4-6", variant: "max" },
     ],
@@ -103,7 +103,7 @@ export const CATEGORY_MODEL_REQUIREMENTS: Record<string, ModelRequirement> = {
   ultrabrain: {
     fallbackChain: [
       { providers: ["openai", "opencode"], model: "gpt-5.3-codex", variant: "xhigh" },
-      { providers: ["google", "github-copilot", "opencode"], model: "gemini-3-pro", variant: "high" },
+      { providers: ["google", "github-copilot", "opencode"], model: "gemini-3.1-pro", variant: "high" },
       { providers: ["anthropic", "github-copilot", "opencode"], model: "claude-opus-4-6", variant: "max" },
     ],
   },
@@ -111,17 +111,17 @@ export const CATEGORY_MODEL_REQUIREMENTS: Record<string, ModelRequirement> = {
     fallbackChain: [
       { providers: ["openai", "opencode"], model: "gpt-5.3-codex", variant: "medium" },
       { providers: ["anthropic", "github-copilot", "opencode"], model: "claude-opus-4-6", variant: "max" },
-      { providers: ["google", "github-copilot", "opencode"], model: "gemini-3-pro", variant: "high" },
+      { providers: ["google", "github-copilot", "opencode"], model: "gemini-3.1-pro", variant: "high" },
     ],
     requiresModel: "gpt-5.3-codex",
   },
   artistry: {
     fallbackChain: [
-      { providers: ["google", "github-copilot", "opencode"], model: "gemini-3-pro", variant: "high" },
+      { providers: ["google", "github-copilot", "opencode"], model: "gemini-3.1-pro", variant: "high" },
       { providers: ["anthropic", "github-copilot", "opencode"], model: "claude-opus-4-6", variant: "max" },
       { providers: ["openai", "github-copilot", "opencode"], model: "gpt-5.2" },
     ],
-    requiresModel: "gemini-3-pro",
+    requiresModel: "gemini-3.1-pro",
   },
   quick: {
     fallbackChain: [
@@ -141,11 +141,12 @@ export const CATEGORY_MODEL_REQUIREMENTS: Record<string, ModelRequirement> = {
     fallbackChain: [
       { providers: ["anthropic", "github-copilot", "opencode"], model: "claude-opus-4-6", variant: "max" },
       { providers: ["openai", "github-copilot", "opencode"], model: "gpt-5.2", variant: "high" },
-      { providers: ["google", "github-copilot", "opencode"], model: "gemini-3-pro" },
+      { providers: ["google", "github-copilot", "opencode"], model: "gemini-3.1-pro" },
     ],
   },
   writing: {
     fallbackChain: [
+      { providers: ["opencode"], model: "kimi-k2.5-free" },
       { providers: ["google", "github-copilot", "opencode"], model: "gemini-3-flash" },
       { providers: ["anthropic", "github-copilot", "opencode"], model: "claude-sonnet-4-6" },
     ],
diff --git a/src/shared/model-resolver.test.ts b/src/shared/model-resolver.test.ts
index fc828f340..d18b46f5a 100644
--- a/src/shared/model-resolver.test.ts
+++ b/src/shared/model-resolver.test.ts
@@ -10,7 +10,7 @@ describe("resolveModel", () => {
       const input: ModelResolutionInput = {
         userModel: "anthropic/claude-opus-4-6",
         inheritedModel: "openai/gpt-5.2",
-        systemDefault: "google/gemini-3-pro",
+        systemDefault: "google/gemini-3.1-pro",
       }
 
       // when
@@ -25,7 +25,7 @@ describe("resolveModel", () => {
       const input: ModelResolutionInput = {
         userModel: undefined,
         inheritedModel: "openai/gpt-5.2",
-        systemDefault: "google/gemini-3-pro",
+        systemDefault: "google/gemini-3.1-pro",
       }
 
       // when
@@ -40,14 +40,14 @@ describe("resolveModel", () => {
       const input: ModelResolutionInput = {
         userModel: undefined,
         inheritedModel: undefined,
-        systemDefault: "google/gemini-3-pro",
+        systemDefault: "google/gemini-3.1-pro",
       }
 
       // when
       const result = resolveModel(input)
 
       // then
-      expect(result).toBe("google/gemini-3-pro")
+      expect(result).toBe("google/gemini-3.1-pro")
     })
   })
 
@@ -57,7 +57,7 @@ describe("resolveModel", () => {
       const input: ModelResolutionInput = {
         userModel: "",
         inheritedModel: "openai/gpt-5.2",
-        systemDefault: "google/gemini-3-pro",
+        systemDefault: "google/gemini-3.1-pro",
       }
 
       // when
@@ -72,14 +72,14 @@ describe("resolveModel", () => {
       const input: ModelResolutionInput = {
         userModel: "   ",
         inheritedModel: "",
-        systemDefault: "google/gemini-3-pro",
+        systemDefault: "google/gemini-3.1-pro",
       }
 
       // when
       const result = resolveModel(input)
 
       // then
-      expect(result).toBe("google/gemini-3-pro")
+      expect(result).toBe("google/gemini-3.1-pro")
     })
   })
 
@@ -89,7 +89,7 @@ describe("resolveModel", () => {
       const input: ModelResolutionInput = {
         userModel: "anthropic/claude-opus-4-6",
         inheritedModel: "openai/gpt-5.2",
-        systemDefault: "google/gemini-3-pro",
+        systemDefault: "google/gemini-3.1-pro",
       }
 
       // when
@@ -123,7 +123,7 @@ describe("resolveModelWithFallback", () => {
           { providers: ["anthropic", "github-copilot"], model: "claude-opus-4-6" },
         ],
         availableModels: new Set(["anthropic/claude-opus-4-6", "github-copilot/claude-opus-4-6-preview"]),
-        systemDefaultModel: "google/gemini-3-pro",
+        systemDefaultModel: "google/gemini-3.1-pro",
       }
 
       // when
@@ -141,7 +141,7 @@ describe("resolveModelWithFallback", () => {
         uiSelectedModel: "opencode/big-pickle",
         userModel: "anthropic/claude-opus-4-6",
         availableModels: new Set(["anthropic/claude-opus-4-6"]),
-        systemDefaultModel: "google/gemini-3-pro",
+        systemDefaultModel: "google/gemini-3.1-pro",
       }
 
       // when
@@ -158,7 +158,7 @@ describe("resolveModelWithFallback", () => {
         uiSelectedModel: "   ",
         userModel: "anthropic/claude-opus-4-6",
         availableModels: new Set(["anthropic/claude-opus-4-6"]),
-        systemDefaultModel: "google/gemini-3-pro",
+        systemDefaultModel: "google/gemini-3.1-pro",
       }
 
       // when
@@ -175,7 +175,7 @@ describe("resolveModelWithFallback", () => {
         uiSelectedModel: "",
         userModel: "anthropic/claude-opus-4-6",
         availableModels: new Set(["anthropic/claude-opus-4-6"]),
-        systemDefaultModel: "google/gemini-3-pro",
+        systemDefaultModel: "google/gemini-3.1-pro",
       }
 
       // when
@@ -195,7 +195,7 @@ describe("resolveModelWithFallback", () => {
           { providers: ["anthropic", "github-copilot"], model: "claude-opus-4-6" },
         ],
         availableModels: new Set(["anthropic/claude-opus-4-6", "github-copilot/claude-opus-4-6-preview"]),
-        systemDefaultModel: "google/gemini-3-pro",
+        systemDefaultModel: "google/gemini-3.1-pro",
       }
 
       // when
@@ -215,7 +215,7 @@ describe("resolveModelWithFallback", () => {
           { providers: ["anthropic"], model: "claude-opus-4-6" },
         ],
         availableModels: new Set(["anthropic/claude-opus-4-6"]),
-        systemDefaultModel: "google/gemini-3-pro",
+        systemDefaultModel: "google/gemini-3.1-pro",
       }
 
       // when
@@ -234,7 +234,7 @@ describe("resolveModelWithFallback", () => {
           { providers: ["anthropic"], model: "claude-opus-4-6" },
         ],
         availableModels: new Set(["anthropic/claude-opus-4-6"]),
-        systemDefaultModel: "google/gemini-3-pro",
+        systemDefaultModel: "google/gemini-3.1-pro",
       }
 
       // when
@@ -252,7 +252,7 @@ describe("resolveModelWithFallback", () => {
           { providers: ["anthropic"], model: "claude-opus-4-6" },
         ],
         availableModels: new Set(["anthropic/claude-opus-4-6"]),
-        systemDefaultModel: "google/gemini-3-pro",
+        systemDefaultModel: "google/gemini-3.1-pro",
       }
 
       // when
@@ -271,7 +271,7 @@ describe("resolveModelWithFallback", () => {
           { providers: ["anthropic", "github-copilot", "opencode"], model: "claude-opus-4-6" },
         ],
         availableModels: new Set(["github-copilot/claude-opus-4-6-preview", "opencode/claude-opus-4-7"]),
-        systemDefaultModel: "google/gemini-3-pro",
+        systemDefaultModel: "google/gemini-3.1-pro",
       }
 
       // when
@@ -294,8 +294,8 @@ describe("resolveModelWithFallback", () => {
         fallbackChain: [
           { providers: ["openai", "anthropic", "google"], model: "gpt-5.2" },
         ],
-        availableModels: new Set(["openai/gpt-5.2", "anthropic/claude-opus-4-6", "google/gemini-3-pro"]),
-        systemDefaultModel: "google/gemini-3-pro",
+        availableModels: new Set(["openai/gpt-5.2", "anthropic/claude-opus-4-6", "google/gemini-3.1-pro"]),
+        systemDefaultModel: "google/gemini-3.1-pro",
       }
 
       // when
@@ -313,7 +313,7 @@ describe("resolveModelWithFallback", () => {
           { providers: ["anthropic", "opencode"], model: "gpt-5-nano" },
         ],
         availableModels: new Set(["opencode/gpt-5-nano"]),
-        systemDefaultModel: "google/gemini-3-pro",
+        systemDefaultModel: "google/gemini-3.1-pro",
       }
 
       // when
@@ -331,7 +331,7 @@ describe("resolveModelWithFallback", () => {
           { providers: ["anthropic", "github-copilot"], model: "claude-opus" },
         ],
         availableModels: new Set(["anthropic/claude-opus-4-6", "github-copilot/claude-opus-4-6-preview"]),
-        systemDefaultModel: "google/gemini-3-pro",
+        systemDefaultModel: "google/gemini-3.1-pro",
       }
 
       // when
@@ -346,7 +346,7 @@ describe("resolveModelWithFallback", () => {
       // given
       const input: ExtendedModelResolutionInput = {
         availableModels: new Set(["anthropic/claude-opus-4-6"]),
-        systemDefaultModel: "google/gemini-3-pro",
+        systemDefaultModel: "google/gemini-3.1-pro",
       }
 
       // when
@@ -361,7 +361,7 @@ describe("resolveModelWithFallback", () => {
       const input: ExtendedModelResolutionInput = {
         fallbackChain: [],
         availableModels: new Set(["anthropic/claude-opus-4-6"]),
-        systemDefaultModel: "google/gemini-3-pro",
+        systemDefaultModel: "google/gemini-3.1-pro",
       }
 
       // when
@@ -378,7 +378,7 @@ describe("resolveModelWithFallback", () => {
           { providers: ["anthropic"], model: "CLAUDE-OPUS" },
         ],
         availableModels: new Set(["anthropic/claude-opus-4-6"]),
-        systemDefaultModel: "google/gemini-3-pro",
+        systemDefaultModel: "google/gemini-3.1-pro",
       }
 
       // when
@@ -397,7 +397,7 @@ describe("resolveModelWithFallback", () => {
           { providers: ["anthropic"], model: "claude-sonnet-4-6" },
         ],
         availableModels: new Set(["opencode/glm-5", "anthropic/claude-sonnet-4-6"]),
-        systemDefaultModel: "google/gemini-3-pro",
+        systemDefaultModel: "google/gemini-3.1-pro",
       }
 
       // when
@@ -420,7 +420,7 @@ describe("resolveModelWithFallback", () => {
           { providers: ["zai-coding-plan"], model: "glm-5" },
         ],
         availableModels: new Set(["zai-coding-plan/glm-5", "opencode/glm-5"]),
-        systemDefaultModel: "google/gemini-3-pro",
+        systemDefaultModel: "google/gemini-3.1-pro",
       }
 
       // when
@@ -438,7 +438,7 @@ describe("resolveModelWithFallback", () => {
           { providers: ["zai-coding-plan"], model: "glm-5", variant: "high" },
         ],
         availableModels: new Set(["opencode/glm-5"]),
-        systemDefaultModel: "google/gemini-3-pro",
+        systemDefaultModel: "google/gemini-3.1-pro",
       }
 
       // when
@@ -457,7 +457,7 @@ describe("resolveModelWithFallback", () => {
           { providers: ["anthropic"], model: "claude-sonnet-4-6" },
         ],
         availableModels: new Set(["anthropic/claude-sonnet-4-6"]),
-        systemDefaultModel: "google/gemini-3-pro",
+        systemDefaultModel: "google/gemini-3.1-pro",
       }
 
       // when
@@ -477,14 +477,14 @@ describe("resolveModelWithFallback", () => {
           { providers: ["anthropic"], model: "nonexistent-model" },
         ],
         availableModels: new Set(["openai/gpt-5.2", "anthropic/claude-opus-4-6"]),
-        systemDefaultModel: "google/gemini-3-pro",
+        systemDefaultModel: "google/gemini-3.1-pro",
       }
 
       // when
       const result = resolveModelWithFallback(input)
 
       // then
-      expect(result!.model).toBe("google/gemini-3-pro")
+      expect(result!.model).toBe("google/gemini-3.1-pro")
       expect(result!.source).toBe("system-default")
       expect(logSpy).toHaveBeenCalledWith("No available model found in fallback chain, falling through to system default")
     })
@@ -516,7 +516,7 @@ describe("resolveModelWithFallback", () => {
           { providers: ["anthropic", "openai"], model: "claude-opus-4-6" },
         ],
         availableModels: new Set(),
-        systemDefaultModel: "google/gemini-3-pro",
+        systemDefaultModel: "google/gemini-3.1-pro",
       }
 
       // when
@@ -533,7 +533,7 @@ describe("resolveModelWithFallback", () => {
       const cacheSpy = spyOn(connectedProvidersCache, "readConnectedProvidersCache").mockReturnValue(["github-copilot"])
       const input: ExtendedModelResolutionInput = {
         fallbackChain: [
-          { providers: ["google", "github-copilot", "opencode"], model: "gemini-3-pro" },
+          { providers: ["google", "github-copilot", "opencode"], model: "gemini-3.1-pro" },
         ],
         availableModels: new Set(),
         systemDefaultModel: "anthropic/claude-sonnet-4-6",
@@ -544,7 +544,7 @@ describe("resolveModelWithFallback", () => {
 
       // then - should use github-copilot (second provider) since google not connected
       // model name is transformed to preview variant for github-copilot provider
-      expect(result!.model).toBe("github-copilot/gemini-3-pro-preview")
+      expect(result!.model).toBe("github-copilot/gemini-3.1-pro-preview")
       expect(result!.source).toBe("provider-fallback")
       cacheSpy.mockRestore()
     })
@@ -577,14 +577,14 @@ describe("resolveModelWithFallback", () => {
           { providers: ["anthropic"], model: "claude-opus-4-6" },
         ],
         availableModels: new Set(),
-        systemDefaultModel: "google/gemini-3-pro",
+        systemDefaultModel: "google/gemini-3.1-pro",
       }
 
       // when
       const result = resolveModelWithFallback(input)
 
       // then - should fall through to system default
-      expect(result!.model).toBe("google/gemini-3-pro")
+      expect(result!.model).toBe("google/gemini-3.1-pro")
       expect(result!.source).toBe("system-default")
       cacheSpy.mockRestore()
     })
@@ -593,14 +593,14 @@ describe("resolveModelWithFallback", () => {
       // given
       const input: ExtendedModelResolutionInput = {
         availableModels: new Set(["openai/gpt-5.2"]),
-        systemDefaultModel: "google/gemini-3-pro",
+        systemDefaultModel: "google/gemini-3.1-pro",
       }
 
       // when
       const result = resolveModelWithFallback(input)
 
       // then
-      expect(result!.model).toBe("google/gemini-3-pro")
+      expect(result!.model).toBe("google/gemini-3.1-pro")
       expect(result!.source).toBe("system-default")
     })
   })
@@ -627,20 +627,20 @@ describe("resolveModelWithFallback", () => {
 
     test("tries all providers in first entry before moving to second entry", () => {
       // given
-      const availableModels = new Set(["google/gemini-3-pro"])
+      const availableModels = new Set(["google/gemini-3.1-pro"])
 
       // when
       const result = resolveModelWithFallback({
         fallbackChain: [
           { providers: ["openai", "anthropic"], model: "gpt-5.2" },
-          { providers: ["google"], model: "gemini-3-pro" },
+          { providers: ["google"], model: "gemini-3.1-pro" },
         ],
         availableModels,
         systemDefaultModel: "system/default",
       })
 
       // then
-      expect(result!.model).toBe("google/gemini-3-pro")
+      expect(result!.model).toBe("google/gemini-3.1-pro")
       expect(result!.source).toBe("provider-fallback")
     })
 
@@ -675,7 +675,7 @@ describe("resolveModelWithFallback", () => {
         fallbackChain: [
           { providers: ["openai"], model: "gpt-5.2" },
           { providers: ["anthropic"], model: "claude-opus-4-6" },
-          { providers: ["google"], model: "gemini-3-pro" },
+          { providers: ["google"], model: "gemini-3.1-pro" },
         ],
         availableModels,
         systemDefaultModel: "system/default",
@@ -693,7 +693,7 @@ describe("resolveModelWithFallback", () => {
       const input: ExtendedModelResolutionInput = {
         userModel: "anthropic/claude-opus-4-6",
         availableModels: new Set(),
-        systemDefaultModel: "google/gemini-3-pro",
+        systemDefaultModel: "google/gemini-3.1-pro",
       }
 
       // when
@@ -708,32 +708,32 @@ describe("resolveModelWithFallback", () => {
 
   describe("categoryDefaultModel (fuzzy matching for category defaults)", () => {
     test("applies fuzzy matching to categoryDefaultModel when userModel not provided", () => {
-      // given - gemini-3-pro is the category default, but only gemini-3-pro-preview is available
+      // given - gemini-3.1-pro is the category default, but only gemini-3.1-pro-preview is available
       const input: ExtendedModelResolutionInput = {
-        categoryDefaultModel: "google/gemini-3-pro",
+        categoryDefaultModel: "google/gemini-3.1-pro",
         fallbackChain: [
-          { providers: ["google", "github-copilot", "opencode"], model: "gemini-3-pro" },
+          { providers: ["google", "github-copilot", "opencode"], model: "gemini-3.1-pro" },
         ],
-        availableModels: new Set(["google/gemini-3-pro-preview", "anthropic/claude-opus-4-6"]),
+        availableModels: new Set(["google/gemini-3.1-pro-preview", "anthropic/claude-opus-4-6"]),
         systemDefaultModel: "anthropic/claude-sonnet-4-6",
       }
 
       // when
       const result = resolveModelWithFallback(input)
 
-      // then - should fuzzy match gemini-3-pro → gemini-3-pro-preview
-      expect(result!.model).toBe("google/gemini-3-pro-preview")
+      // then - should fuzzy match gemini-3.1-pro → gemini-3.1-pro-preview
+      expect(result!.model).toBe("google/gemini-3.1-pro-preview")
       expect(result!.source).toBe("category-default")
     })
 
     test("categoryDefaultModel uses exact match when available", () => {
       // given - exact match exists
       const input: ExtendedModelResolutionInput = {
-        categoryDefaultModel: "google/gemini-3-pro",
+        categoryDefaultModel: "google/gemini-3.1-pro",
         fallbackChain: [
-          { providers: ["google"], model: "gemini-3-pro" },
+          { providers: ["google"], model: "gemini-3.1-pro" },
         ],
-        availableModels: new Set(["google/gemini-3-pro", "google/gemini-3-pro-preview"]),
+        availableModels: new Set(["google/gemini-3.1-pro", "google/gemini-3.1-pro-preview"]),
         systemDefaultModel: "anthropic/claude-sonnet-4-6",
       }
 
@@ -741,14 +741,14 @@ describe("resolveModelWithFallback", () => {
       const result = resolveModelWithFallback(input)
 
       // then - should use exact match
-      expect(result!.model).toBe("google/gemini-3-pro")
+      expect(result!.model).toBe("google/gemini-3.1-pro")
       expect(result!.source).toBe("category-default")
     })
 
     test("categoryDefaultModel falls through to fallbackChain when no match in availableModels", () => {
       // given - categoryDefaultModel has no match, but fallbackChain does
       const input: ExtendedModelResolutionInput = {
-        categoryDefaultModel: "google/gemini-3-pro",
+        categoryDefaultModel: "google/gemini-3.1-pro",
         fallbackChain: [
           { providers: ["anthropic"], model: "claude-opus-4-6" },
         ],
@@ -768,11 +768,11 @@ describe("resolveModelWithFallback", () => {
       // given - both userModel and categoryDefaultModel provided
       const input: ExtendedModelResolutionInput = {
         userModel: "anthropic/claude-opus-4-6",
-        categoryDefaultModel: "google/gemini-3-pro",
+        categoryDefaultModel: "google/gemini-3.1-pro",
         fallbackChain: [
-          { providers: ["google"], model: "gemini-3-pro" },
+          { providers: ["google"], model: "gemini-3.1-pro" },
         ],
-        availableModels: new Set(["google/gemini-3-pro-preview", "anthropic/claude-opus-4-6"]),
+        availableModels: new Set(["google/gemini-3.1-pro-preview", "anthropic/claude-opus-4-6"]),
         systemDefaultModel: "system/default",
       }
 
@@ -788,7 +788,7 @@ describe("resolveModelWithFallback", () => {
       // given - no availableModels but connected provider cache exists
       const cacheSpy = spyOn(connectedProvidersCache, "readConnectedProvidersCache").mockReturnValue(["google"])
       const input: ExtendedModelResolutionInput = {
-        categoryDefaultModel: "google/gemini-3-pro",
+        categoryDefaultModel: "google/gemini-3.1-pro",
         availableModels: new Set(),
         systemDefaultModel: "anthropic/claude-sonnet-4-6",
       }
@@ -797,7 +797,7 @@ describe("resolveModelWithFallback", () => {
       const result = resolveModelWithFallback(input)
 
       // then - should use transformed categoryDefaultModel since google is connected
-      expect(result!.model).toBe("google/gemini-3-pro-preview")
+      expect(result!.model).toBe("google/gemini-3.1-pro-preview")
       expect(result!.source).toBe("category-default")
       cacheSpy.mockRestore()
     })
@@ -824,7 +824,7 @@ describe("resolveModelWithFallback", () => {
       // given - category default already has -preview suffix
       const cacheSpy = spyOn(connectedProvidersCache, "readConnectedProvidersCache").mockReturnValue(["google"])
       const input: ExtendedModelResolutionInput = {
-        categoryDefaultModel: "google/gemini-3-pro-preview",
+        categoryDefaultModel: "google/gemini-3.1-pro-preview",
         availableModels: new Set(),
         systemDefaultModel: "anthropic/claude-sonnet-4-5",
       }
@@ -832,18 +832,18 @@ describe("resolveModelWithFallback", () => {
       // when
       const result = resolveModelWithFallback(input)
 
-      // then - should NOT become gemini-3-pro-preview-preview
-      expect(result!.model).toBe("google/gemini-3-pro-preview")
+      // then - should NOT become gemini-3.1-pro-preview-preview
+      expect(result!.model).toBe("google/gemini-3.1-pro-preview")
       expect(result!.source).toBe("category-default")
       cacheSpy.mockRestore()
     })
 
-    test("transforms gemini-3-pro in fallback chain for google connected provider", () => {
-      // given - google connected, fallback chain has gemini-3-pro
+    test("transforms gemini-3.1-pro in fallback chain for google connected provider", () => {
+      // given - google connected, fallback chain has gemini-3.1-pro
       const cacheSpy = spyOn(connectedProvidersCache, "readConnectedProvidersCache").mockReturnValue(["google"])
       const input: ExtendedModelResolutionInput = {
         fallbackChain: [
-          { providers: ["google", "github-copilot"], model: "gemini-3-pro" },
+          { providers: ["google", "github-copilot"], model: "gemini-3.1-pro" },
         ],
         availableModels: new Set(),
         systemDefaultModel: "anthropic/claude-sonnet-4-5",
@@ -853,7 +853,7 @@ describe("resolveModelWithFallback", () => {
       const result = resolveModelWithFallback(input)
 
       // then - should transform to preview variant for google provider
-      expect(result!.model).toBe("google/gemini-3-pro-preview")
+      expect(result!.model).toBe("google/gemini-3.1-pro-preview")
       expect(result!.source).toBe("provider-fallback")
       cacheSpy.mockRestore()
     })
diff --git a/src/shared/provider-model-id-transform.ts b/src/shared/provider-model-id-transform.ts
index 5b8c810bb..0cf8eb801 100644
--- a/src/shared/provider-model-id-transform.ts
+++ b/src/shared/provider-model-id-transform.ts
@@ -6,12 +6,12 @@ export function transformModelForProvider(provider: string, model: string): stri
 			.replace("claude-sonnet-4-5", "claude-sonnet-4.5")
 			.replace("claude-haiku-4-5", "claude-haiku-4.5")
 			.replace("claude-sonnet-4", "claude-sonnet-4")
-			.replace(/gemini-3-pro(?!-)/g, "gemini-3-pro-preview")
+			.replace(/gemini-3\.1-pro(?!-)/g, "gemini-3.1-pro-preview")
 			.replace(/gemini-3-flash(?!-)/g, "gemini-3-flash-preview")
 	}
 	if (provider === "google") {
 		return model
-			.replace(/gemini-3-pro(?!-)/g, "gemini-3-pro-preview")
+			.replace(/gemini-3\.1-pro(?!-)/g, "gemini-3.1-pro-preview")
 			.replace(/gemini-3-flash(?!-)/g, "gemini-3-flash-preview")
 	}
 	return model
diff --git a/src/tools/delegate-task/constants.ts b/src/tools/delegate-task/constants.ts
index 146838a42..ecf37135f 100644
--- a/src/tools/delegate-task/constants.ts
+++ b/src/tools/delegate-task/constants.ts
@@ -208,10 +208,10 @@ You are NOT an interactive assistant. You are an autonomous problem-solver.
 
 
 export const DEFAULT_CATEGORIES: Record<string, CategoryConfig> = {
-  "visual-engineering": { model: "google/gemini-3-pro", variant: "high" },
+  "visual-engineering": { model: "google/gemini-3.1-pro", variant: "high" },
   ultrabrain: { model: "openai/gpt-5.3-codex", variant: "xhigh" },
   deep: { model: "openai/gpt-5.3-codex", variant: "medium" },
-  artistry: { model: "google/gemini-3-pro", variant: "high" },
+  artistry: { model: "google/gemini-3.1-pro", variant: "high" },
   quick: { model: "anthropic/claude-haiku-4-5" },
   "unspecified-low": { model: "anthropic/claude-sonnet-4-6" },
   "unspecified-high": { model: "anthropic/claude-opus-4-6", variant: "max" },
diff --git a/src/tools/delegate-task/tools.test.ts b/src/tools/delegate-task/tools.test.ts
index b9b1274bc..8c0b01acf 100644
--- a/src/tools/delegate-task/tools.test.ts
+++ b/src/tools/delegate-task/tools.test.ts
@@ -17,7 +17,7 @@ const TEST_AVAILABLE_MODELS = new Set([
   "anthropic/claude-opus-4-6",
   "anthropic/claude-sonnet-4-6",
   "anthropic/claude-haiku-4-5",
-  "google/gemini-3-pro",
+  "google/gemini-3.1-pro",
   "google/gemini-3-flash",
   "openai/gpt-5.2",
   "openai/gpt-5.3-codex",
@@ -52,7 +52,7 @@ describe("sisyphus-task", () => {
     providerModelsSpy = spyOn(connectedProvidersCache, "readProviderModelsCache").mockReturnValue({
       models: {
         anthropic: ["claude-opus-4-6", "claude-sonnet-4-6", "claude-haiku-4-5"],
-        google: ["gemini-3-pro", "gemini-3-flash"],
+        google: ["gemini-3.1-pro", "gemini-3-flash"],
         openai: ["gpt-5.2", "gpt-5.3-codex"],
       },
       connected: ["anthropic", "google", "openai"],
@@ -73,7 +73,7 @@ describe("sisyphus-task", () => {
 
       // when / #then
       expect(category).toBeDefined()
-      expect(category.model).toBe("google/gemini-3-pro")
+      expect(category.model).toBe("google/gemini-3.1-pro")
       expect(category.variant).toBe("high")
     })
 
@@ -781,7 +781,7 @@ describe("sisyphus-task", () => {
 
       // then
       expect(result).not.toBeNull()
-      expect(result!.config.model).toBe("google/gemini-3-pro")
+      expect(result!.config.model).toBe("google/gemini-3.1-pro")
       expect(result!.promptAppend).toContain("VISUAL/UI")
     })
 
@@ -805,7 +805,7 @@ describe("sisyphus-task", () => {
       const categoryName = "visual-engineering"
       const userCategories = {
         "visual-engineering": {
-          model: "google/gemini-3-pro",
+          model: "google/gemini-3.1-pro",
           prompt_append: "Custom instructions here",
         },
       }
@@ -845,7 +845,7 @@ describe("sisyphus-task", () => {
       const categoryName = "visual-engineering"
       const userCategories = {
         "visual-engineering": {
-          model: "google/gemini-3-pro",
+          model: "google/gemini-3.1-pro",
           temperature: 0.3,
         },
       }
@@ -868,7 +868,7 @@ describe("sisyphus-task", () => {
 
       // then - category's built-in model wins over inheritedModel
       expect(result).not.toBeNull()
-      expect(result!.config.model).toBe("google/gemini-3-pro")
+      expect(result!.config.model).toBe("google/gemini-3.1-pro")
     })
 
     test("systemDefaultModel is used as fallback when custom category has no model", () => {
@@ -910,7 +910,7 @@ describe("sisyphus-task", () => {
 
       // then
       expect(result).not.toBeNull()
-      expect(result!.config.model).toBe("google/gemini-3-pro")
+      expect(result!.config.model).toBe("google/gemini-3.1-pro")
     })
   })
 
@@ -1738,7 +1738,7 @@ describe("sisyphus-task", () => {
        const mockClient = {
          app: { agents: async () => ({ data: [] }) },
          config: { get: async () => ({ data: { model: SYSTEM_DEFAULT_MODEL } }) },
-         model: { list: async () => [{ provider: "google", id: "gemini-3-pro" }] },
+         model: { list: async () => [{ provider: "google", id: "gemini-3.1-pro" }] },
          session: {
            get: async () => ({ data: { directory: "/project" } }),
            create: async () => ({ data: { id: "ses_unstable_gemini" } }),
@@ -2001,7 +2001,7 @@ describe("sisyphus-task", () => {
        const mockClient = {
          app: { agents: async () => ({ data: [] }) },
          config: { get: async () => ({ data: { model: SYSTEM_DEFAULT_MODEL } }) },
-         model: { list: async () => [{ provider: "google", id: "gemini-3-pro" }] },
+         model: { list: async () => [{ provider: "google", id: "gemini-3.1-pro" }] },
          session: {
            get: async () => ({ data: { directory: "/project" } }),
            create: async () => ({ data: { id: "ses_artistry_gemini" } }),
@@ -2028,7 +2028,7 @@ describe("sisyphus-task", () => {
         abort: new AbortController().signal,
       }
       
-      // when - artistry category (gemini-3-pro with high variant)
+      // when - artistry category (gemini-3.1-pro with high variant)
       const result = await tool.execute(
         {
           description: "Test artistry forced background",
@@ -3026,9 +3026,9 @@ describe("sisyphus-task", () => {
       // when resolveCategoryConfig is called
       const resolved = resolveCategoryConfig(categoryName, { userCategories, inheritedModel, systemDefaultModel: SYSTEM_DEFAULT_MODEL })
       
-      // then should use category's built-in model (gemini-3-pro for visual-engineering)
+      // then should use category's built-in model (gemini-3.1-pro for visual-engineering)
       expect(resolved).not.toBeNull()
-      expect(resolved!.model).toBe("google/gemini-3-pro")
+      expect(resolved!.model).toBe("google/gemini-3.1-pro")
     })
 
     test("systemDefaultModel is used when no other model is available", () => {
@@ -3522,7 +3522,7 @@ describe("sisyphus-task", () => {
       )
 
       // then - should resolve via AGENT_MODEL_REQUIREMENTS fallback chain for oracle
-      // oracle fallback chain: gpt-5.2 (openai) > gemini-3-pro (google) > claude-opus-4-6 (anthropic)
+      // oracle fallback chain: gpt-5.2 (openai) > gemini-3.1-pro (google) > claude-opus-4-6 (anthropic)
       // Since openai is in connectedProviders, should resolve to openai/gpt-5.2
       expect(promptBody.model).toBeDefined()
       expect(promptBody.model.providerID).toBe("openai")