fix: ensure variants also work for completely custom models (#6481)

Co-authored-by: Daniel Smolsky <[email protected]>

10 files changed, 955 insertions, 27 deletions

diff --git a/AGENTS.md b/AGENTS.md
index bbb2a96f2..7fc710f6d 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -2,6 +2,10 @@
 
 - To test opencode in the `packages/opencode` directory you can run `bun dev`
 
+## SDK
+
+To regenerate the javascript SDK, run ./packages/sdk/js/script/build.ts
+
 ## Tool Calling
 
 - ALWAYS USE PARALLEL TOOLS WHEN APPLICABLE.
diff --git a/packages/opencode/src/cli/cmd/tui/context/local.tsx b/packages/opencode/src/cli/cmd/tui/context/local.tsx
index 4c5dac499..970e5a48b 100644
--- a/packages/opencode/src/cli/cmd/tui/context/local.tsx
+++ b/packages/opencode/src/cli/cmd/tui/context/local.tsx
@@ -319,9 +319,7 @@ export const { use: useLocal, provider: LocalProvider } = createSimpleContext({
             const provider = sync.data.provider.find((x) => x.id === m.providerID)
             const info = provider?.models[m.modelID]
             if (!info?.variants) return []
-            return Object.entries(info.variants)
-              .filter(([_, v]) => !v.disabled)
-              .map(([name]) => name)
+            return Object.keys(info.variants)
           },
           set(value: string | undefined) {
             const m = currentModel()
diff --git a/packages/opencode/src/config/config.ts b/packages/opencode/src/config/config.ts
index 4f4ff1188..9d34c6e47 100644
--- a/packages/opencode/src/config/config.ts
+++ b/packages/opencode/src/config/config.ts
@@ -620,7 +620,24 @@ export namespace Config {
     .extend({
       whitelist: z.array(z.string()).optional(),
       blacklist: z.array(z.string()).optional(),
-      models: z.record(z.string(), ModelsDev.Model.partial()).optional(),
+      models: z
+        .record(
+          z.string(),
+          ModelsDev.Model.partial().extend({
+            variants: z
+              .record(
+                z.string(),
+                z
+                  .object({
+                    disabled: z.boolean().optional().describe("Disable this variant for the model"),
+                  })
+                  .catchall(z.any()),
+              )
+              .optional()
+              .describe("Variant-specific configuration"),
+          }),
+        )
+        .optional(),
       options: z
         .object({
           apiKey: z.string().optional(),
diff --git a/packages/opencode/src/provider/models.ts b/packages/opencode/src/provider/models.ts
index c58638d28..796dcb7c2 100644
--- a/packages/opencode/src/provider/models.ts
+++ b/packages/opencode/src/provider/models.ts
@@ -60,6 +60,7 @@ export namespace ModelsDev {
     options: z.record(z.string(), z.any()),
     headers: z.record(z.string(), z.string()).optional(),
     provider: z.object({ npm: z.string() }).optional(),
+    variants: z.record(z.string(), z.record(z.string(), z.any())).optional(),
   })
   export type Model = z.infer<typeof Model>
 
diff --git a/packages/opencode/src/provider/provider.ts b/packages/opencode/src/provider/provider.ts
index 4150703d2..4dec3c345 100644
--- a/packages/opencode/src/provider/provider.ts
+++ b/packages/opencode/src/provider/provider.ts
@@ -1,7 +1,7 @@
 import z from "zod"
 import fuzzysort from "fuzzysort"
 import { Config } from "../config/config"
-import { mapValues, mergeDeep, sortBy } from "remeda"
+import { mapValues, mergeDeep, omit, pickBy, sortBy } from "remeda"
 import { NoSuchModelError, type Provider as SDK } from "ai"
 import { Log } from "../util/log"
 import { BunProc } from "../bun"
@@ -405,16 +405,6 @@ export namespace Provider {
     },
   }
 
-  export const Variant = z
-    .object({
-      disabled: z.boolean(),
-    })
-    .catchall(z.any())
-    .meta({
-      ref: "Variant",
-    })
-  export type Variant = z.infer<typeof Variant>
-
   export const Model = z
     .object({
       id: z.string(),
@@ -478,7 +468,7 @@ export namespace Provider {
       options: z.record(z.string(), z.any()),
       headers: z.record(z.string(), z.string()),
       release_date: z.string(),
-      variants: z.record(z.string(), Variant).optional(),
+      variants: z.record(z.string(), z.record(z.string(), z.any())).optional(),
     })
     .meta({
       ref: "Model",
@@ -561,7 +551,7 @@ export namespace Provider {
       variants: {},
     }
 
-    m.variants = mapValues(ProviderTransform.variants(m), (v) => ({ disabled: false, ...v }))
+    m.variants = mapValues(ProviderTransform.variants(m), (v) => v)
 
     return m
   }
@@ -697,7 +687,13 @@ export namespace Provider {
           headers: mergeDeep(existingModel?.headers ?? {}, model.headers ?? {}),
           family: model.family ?? existingModel?.family ?? "",
           release_date: model.release_date ?? existingModel?.release_date ?? "",
+          variants: {},
         }
+        const merged = mergeDeep(ProviderTransform.variants(parsedModel), model.variants ?? {})
+        parsedModel.variants = mapValues(
+          pickBy(merged, (v) => !v.disabled),
+          (v) => omit(v, ["disabled"]),
+        )
         parsed.models[modelID] = parsedModel
       }
       database[providerID] = parsed
@@ -822,6 +818,16 @@ export namespace Provider {
           (configProvider?.whitelist && !configProvider.whitelist.includes(modelID))
         )
           delete provider.models[modelID]
+
+        // Filter out disabled variants from config
+        const configVariants = configProvider?.models?.[modelID]?.variants
+        if (configVariants && model.variants) {
+          const merged = mergeDeep(model.variants, configVariants)
+          model.variants = mapValues(
+            pickBy(merged, (v) => !v.disabled),
+            (v) => omit(v, ["disabled"]),
+          )
+        }
       }
 
       if (Object.keys(provider.models).length === 0) {
diff --git a/packages/opencode/src/provider/transform.ts b/packages/opencode/src/provider/transform.ts
index 9de2ad52c..e99c76d73 100644
--- a/packages/opencode/src/provider/transform.ts
+++ b/packages/opencode/src/provider/transform.ts
@@ -246,7 +246,7 @@ export namespace ProviderTransform {
   const WIDELY_SUPPORTED_EFFORTS = ["low", "medium", "high"]
   const OPENAI_EFFORTS = ["none", "minimal", ...WIDELY_SUPPORTED_EFFORTS, "xhigh"]
 
-  export function variants(model: Provider.Model) {
+  export function variants(model: Provider.Model): Record<string, Record<string, any>> {
     if (!model.capabilities.reasoning) return {}
 
     const id = model.id.toLowerCase()
diff --git a/packages/opencode/src/session/llm.ts b/packages/opencode/src/session/llm.ts
index 0736a1f9e..ccd7af1f0 100644
--- a/packages/opencode/src/session/llm.ts
+++ b/packages/opencode/src/session/llm.ts
@@ -82,13 +82,14 @@ export namespace LLM {
     }
 
     const provider = await Provider.getProvider(input.model.providerID)
-    const variant = input.model.variants && input.user.variant ? input.model.variants[input.user.variant] : undefined
+    const small = input.small ? ProviderTransform.smallOptions(input.model) : {}
+    const variant = input.model.variants && input.user.variant ? input.model.variants[input.user.variant] : {}
     const options = pipe(
       ProviderTransform.options(input.model, input.sessionID, provider.options),
-      mergeDeep(input.small ? ProviderTransform.smallOptions(input.model) : {}),
+      mergeDeep(small),
       mergeDeep(input.model.options),
       mergeDeep(input.agent.options),
-      mergeDeep(variant && !variant.disabled ? variant : {}),
+      mergeDeep(variant),
     )
 
     const params = await Plugin.trigger(
diff --git a/packages/opencode/test/provider/provider.test.ts b/packages/opencode/test/provider/provider.test.ts
index c6c6924f0..f6d2df9dd 100644
--- a/packages/opencode/test/provider/provider.test.ts
+++ b/packages/opencode/test/provider/provider.test.ts
@@ -1807,3 +1807,321 @@ test("custom model inherits api.url from models.dev provider", async () => {
     },
   })
 })
+
+test("model variants are generated for reasoning models", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Bun.write(
+        path.join(dir, "opencode.json"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+        }),
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    init: async () => {
+      Env.set("ANTHROPIC_API_KEY", "test-api-key")
+    },
+    fn: async () => {
+      const providers = await Provider.list()
+      // Claude sonnet 4 has reasoning capability
+      const model = providers["anthropic"].models["claude-sonnet-4-20250514"]
+      expect(model.capabilities.reasoning).toBe(true)
+      expect(model.variants).toBeDefined()
+      expect(Object.keys(model.variants!).length).toBeGreaterThan(0)
+    },
+  })
+})
+
+test("model variants can be disabled via config", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Bun.write(
+        path.join(dir, "opencode.json"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+          provider: {
+            anthropic: {
+              models: {
+                "claude-sonnet-4-20250514": {
+                  variants: {
+                    high: { disabled: true },
+                  },
+                },
+              },
+            },
+          },
+        }),
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    init: async () => {
+      Env.set("ANTHROPIC_API_KEY", "test-api-key")
+    },
+    fn: async () => {
+      const providers = await Provider.list()
+      const model = providers["anthropic"].models["claude-sonnet-4-20250514"]
+      expect(model.variants).toBeDefined()
+      expect(model.variants!["high"]).toBeUndefined()
+      // max variant should still exist
+      expect(model.variants!["max"]).toBeDefined()
+    },
+  })
+})
+
+test("model variants can be customized via config", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Bun.write(
+        path.join(dir, "opencode.json"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+          provider: {
+            anthropic: {
+              models: {
+                "claude-sonnet-4-20250514": {
+                  variants: {
+                    high: {
+                      thinking: {
+                        type: "enabled",
+                        budgetTokens: 20000,
+                      },
+                    },
+                  },
+                },
+              },
+            },
+          },
+        }),
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    init: async () => {
+      Env.set("ANTHROPIC_API_KEY", "test-api-key")
+    },
+    fn: async () => {
+      const providers = await Provider.list()
+      const model = providers["anthropic"].models["claude-sonnet-4-20250514"]
+      expect(model.variants!["high"]).toBeDefined()
+      expect(model.variants!["high"].thinking.budgetTokens).toBe(20000)
+    },
+  })
+})
+
+test("disabled key is stripped from variant config", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Bun.write(
+        path.join(dir, "opencode.json"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+          provider: {
+            anthropic: {
+              models: {
+                "claude-sonnet-4-20250514": {
+                  variants: {
+                    max: {
+                      disabled: false,
+                      customField: "test",
+                    },
+                  },
+                },
+              },
+            },
+          },
+        }),
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    init: async () => {
+      Env.set("ANTHROPIC_API_KEY", "test-api-key")
+    },
+    fn: async () => {
+      const providers = await Provider.list()
+      const model = providers["anthropic"].models["claude-sonnet-4-20250514"]
+      expect(model.variants!["max"]).toBeDefined()
+      expect(model.variants!["max"].disabled).toBeUndefined()
+      expect(model.variants!["max"].customField).toBe("test")
+    },
+  })
+})
+
+test("all variants can be disabled via config", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Bun.write(
+        path.join(dir, "opencode.json"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+          provider: {
+            anthropic: {
+              models: {
+                "claude-sonnet-4-20250514": {
+                  variants: {
+                    high: { disabled: true },
+                    max: { disabled: true },
+                  },
+                },
+              },
+            },
+          },
+        }),
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    init: async () => {
+      Env.set("ANTHROPIC_API_KEY", "test-api-key")
+    },
+    fn: async () => {
+      const providers = await Provider.list()
+      const model = providers["anthropic"].models["claude-sonnet-4-20250514"]
+      expect(model.variants).toBeDefined()
+      expect(Object.keys(model.variants!).length).toBe(0)
+    },
+  })
+})
+
+test("variant config merges with generated variants", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Bun.write(
+        path.join(dir, "opencode.json"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+          provider: {
+            anthropic: {
+              models: {
+                "claude-sonnet-4-20250514": {
+                  variants: {
+                    high: {
+                      extraOption: "custom-value",
+                    },
+                  },
+                },
+              },
+            },
+          },
+        }),
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    init: async () => {
+      Env.set("ANTHROPIC_API_KEY", "test-api-key")
+    },
+    fn: async () => {
+      const providers = await Provider.list()
+      const model = providers["anthropic"].models["claude-sonnet-4-20250514"]
+      expect(model.variants!["high"]).toBeDefined()
+      // Should have both the generated thinking config and the custom option
+      expect(model.variants!["high"].thinking).toBeDefined()
+      expect(model.variants!["high"].extraOption).toBe("custom-value")
+    },
+  })
+})
+
+test("variants filtered in second pass for database models", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Bun.write(
+        path.join(dir, "opencode.json"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+          provider: {
+            openai: {
+              models: {
+                "gpt-5": {
+                  variants: {
+                    high: { disabled: true },
+                  },
+                },
+              },
+            },
+          },
+        }),
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    init: async () => {
+      Env.set("OPENAI_API_KEY", "test-api-key")
+    },
+    fn: async () => {
+      const providers = await Provider.list()
+      const model = providers["openai"].models["gpt-5"]
+      expect(model.variants).toBeDefined()
+      expect(model.variants!["high"]).toBeUndefined()
+      // Other variants should still exist
+      expect(model.variants!["medium"]).toBeDefined()
+    },
+  })
+})
+
+test("custom model with variants enabled and disabled", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Bun.write(
+        path.join(dir, "opencode.json"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+          provider: {
+            "custom-reasoning": {
+              name: "Custom Reasoning Provider",
+              npm: "@ai-sdk/openai-compatible",
+              env: [],
+              models: {
+                "reasoning-model": {
+                  name: "Reasoning Model",
+                  tool_call: true,
+                  reasoning: true,
+                  limit: { context: 128000, output: 16000 },
+                  variants: {
+                    low: { reasoningEffort: "low" },
+                    medium: { reasoningEffort: "medium" },
+                    high: { reasoningEffort: "high", disabled: true },
+                    custom: { reasoningEffort: "custom", budgetTokens: 5000 },
+                  },
+                },
+              },
+              options: { apiKey: "test-key" },
+            },
+          },
+        }),
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    fn: async () => {
+      const providers = await Provider.list()
+      const model = providers["custom-reasoning"].models["reasoning-model"]
+      expect(model.variants).toBeDefined()
+      // Enabled variants should exist
+      expect(model.variants!["low"]).toBeDefined()
+      expect(model.variants!["low"].reasoningEffort).toBe("low")
+      expect(model.variants!["medium"]).toBeDefined()
+      expect(model.variants!["medium"].reasoningEffort).toBe("medium")
+      expect(model.variants!["custom"]).toBeDefined()
+      expect(model.variants!["custom"].reasoningEffort).toBe("custom")
+      expect(model.variants!["custom"].budgetTokens).toBe(5000)
+      // Disabled variant should not exist
+      expect(model.variants!["high"]).toBeUndefined()
+      // disabled key should be stripped from all variants
+      expect(model.variants!["low"].disabled).toBeUndefined()
+      expect(model.variants!["medium"].disabled).toBeUndefined()
+      expect(model.variants!["custom"].disabled).toBeUndefined()
+    },
+  })
+})
diff --git a/packages/opencode/test/provider/transform.test.ts b/packages/opencode/test/provider/transform.test.ts
index 78bd296c9..59041b09f 100644
--- a/packages/opencode/test/provider/transform.test.ts
+++ b/packages/opencode/test/provider/transform.test.ts
@@ -409,3 +409,572 @@ describe("ProviderTransform.message - empty image handling", () => {
     })
   })
 })
+
+describe("ProviderTransform.variants", () => {
+  const createMockModel = (overrides: Partial<any> = {}): any => ({
+    id: "test/test-model",
+    providerID: "test",
+    api: {
+      id: "test-model",
+      url: "https://api.test.com",
+      npm: "@ai-sdk/openai",
+    },
+    name: "Test Model",
+    capabilities: {
+      temperature: true,
+      reasoning: true,
+      attachment: true,
+      toolcall: true,
+      input: { text: true, audio: false, image: true, video: false, pdf: false },
+      output: { text: true, audio: false, image: false, video: false, pdf: false },
+      interleaved: false,
+    },
+    cost: {
+      input: 0.001,
+      output: 0.002,
+      cache: { read: 0.0001, write: 0.0002 },
+    },
+    limit: {
+      context: 128000,
+      output: 8192,
+    },
+    status: "active",
+    options: {},
+    headers: {},
+    release_date: "2024-01-01",
+    ...overrides,
+  })
+
+  test("returns empty object when model has no reasoning capabilities", () => {
+    const model = createMockModel({
+      capabilities: { reasoning: false },
+    })
+    const result = ProviderTransform.variants(model)
+    expect(result).toEqual({})
+  })
+
+  test("deepseek returns empty object", () => {
+    const model = createMockModel({
+      id: "deepseek/deepseek-chat",
+      providerID: "deepseek",
+      api: {
+        id: "deepseek-chat",
+        url: "https://api.deepseek.com",
+        npm: "@ai-sdk/openai-compatible",
+      },
+    })
+    const result = ProviderTransform.variants(model)
+    expect(result).toEqual({})
+  })
+
+  test("minimax returns empty object", () => {
+    const model = createMockModel({
+      id: "minimax/minimax-model",
+      providerID: "minimax",
+      api: {
+        id: "minimax-model",
+        url: "https://api.minimax.com",
+        npm: "@ai-sdk/openai-compatible",
+      },
+    })
+    const result = ProviderTransform.variants(model)
+    expect(result).toEqual({})
+  })
+
+  test("glm returns empty object", () => {
+    const model = createMockModel({
+      id: "glm/glm-4",
+      providerID: "glm",
+      api: {
+        id: "glm-4",
+        url: "https://api.glm.com",
+        npm: "@ai-sdk/openai-compatible",
+      },
+    })
+    const result = ProviderTransform.variants(model)
+    expect(result).toEqual({})
+  })
+
+  test("mistral returns empty object", () => {
+    const model = createMockModel({
+      id: "mistral/mistral-large",
+      providerID: "mistral",
+      api: {
+        id: "mistral-large-latest",
+        url: "https://api.mistral.com",
+        npm: "@ai-sdk/mistral",
+      },
+    })
+    const result = ProviderTransform.variants(model)
+    expect(result).toEqual({})
+  })
+
+  describe("@openrouter/ai-sdk-provider", () => {
+    test("returns empty object for non-qualifying models", () => {
+      const model = createMockModel({
+        id: "openrouter/test-model",
+        providerID: "openrouter",
+        api: {
+          id: "test-model",
+          url: "https://openrouter.ai",
+          npm: "@openrouter/ai-sdk-provider",
+        },
+      })
+      const result = ProviderTransform.variants(model)
+      expect(result).toEqual({})
+    })
+
+    test("gpt models return OPENAI_EFFORTS with reasoning", () => {
+      const model = createMockModel({
+        id: "openrouter/gpt-4",
+        providerID: "openrouter",
+        api: {
+          id: "gpt-4",
+          url: "https://openrouter.ai",
+          npm: "@openrouter/ai-sdk-provider",
+        },
+      })
+      const result = ProviderTransform.variants(model)
+      expect(Object.keys(result)).toEqual(["none", "minimal", "low", "medium", "high", "xhigh"])
+      expect(result.low).toEqual({ reasoning: { effort: "low" } })
+      expect(result.high).toEqual({ reasoning: { effort: "high" } })
+    })
+
+    test("gemini-3 returns OPENAI_EFFORTS with reasoning", () => {
+      const model = createMockModel({
+        id: "openrouter/gemini-3-5-pro",
+        providerID: "openrouter",
+        api: {
+          id: "gemini-3-5-pro",
+          url: "https://openrouter.ai",
+          npm: "@openrouter/ai-sdk-provider",
+        },
+      })
+      const result = ProviderTransform.variants(model)
+      expect(Object.keys(result)).toEqual(["none", "minimal", "low", "medium", "high", "xhigh"])
+    })
+
+    test("grok-4 returns OPENAI_EFFORTS with reasoning", () => {
+      const model = createMockModel({
+        id: "openrouter/grok-4",
+        providerID: "openrouter",
+        api: {
+          id: "grok-4",
+          url: "https://openrouter.ai",
+          npm: "@openrouter/ai-sdk-provider",
+        },
+      })
+      const result = ProviderTransform.variants(model)
+      expect(Object.keys(result)).toEqual(["none", "minimal", "low", "medium", "high", "xhigh"])
+    })
+  })
+
+  describe("@ai-sdk/gateway", () => {
+    test("returns OPENAI_EFFORTS with reasoningEffort", () => {
+      const model = createMockModel({
+        id: "gateway/gateway-model",
+        providerID: "gateway",
+        api: {
+          id: "gateway-model",
+          url: "https://gateway.ai",
+          npm: "@ai-sdk/gateway",
+        },
+      })
+      const result = ProviderTransform.variants(model)
+      expect(Object.keys(result)).toEqual(["none", "minimal", "low", "medium", "high", "xhigh"])
+      expect(result.low).toEqual({ reasoningEffort: "low" })
+      expect(result.high).toEqual({ reasoningEffort: "high" })
+    })
+  })
+
+  describe("@ai-sdk/cerebras", () => {
+    test("returns WIDELY_SUPPORTED_EFFORTS with reasoningEffort", () => {
+      const model = createMockModel({
+        id: "cerebras/llama-4",
+        providerID: "cerebras",
+        api: {
+          id: "llama-4-sc",
+          url: "https://api.cerebras.ai",
+          npm: "@ai-sdk/cerebras",
+        },
+      })
+      const result = ProviderTransform.variants(model)
+      expect(Object.keys(result)).toEqual(["low", "medium", "high"])
+      expect(result.low).toEqual({ reasoningEffort: "low" })
+      expect(result.high).toEqual({ reasoningEffort: "high" })
+    })
+  })
+
+  describe("@ai-sdk/togetherai", () => {
+    test("returns WIDELY_SUPPORTED_EFFORTS with reasoningEffort", () => {
+      const model = createMockModel({
+        id: "togetherai/llama-4",
+        providerID: "togetherai",
+        api: {
+          id: "llama-4-sc",
+          url: "https://api.togetherai.com",
+          npm: "@ai-sdk/togetherai",
+        },
+      })
+      const result = ProviderTransform.variants(model)
+      expect(Object.keys(result)).toEqual(["low", "medium", "high"])
+      expect(result.low).toEqual({ reasoningEffort: "low" })
+      expect(result.high).toEqual({ reasoningEffort: "high" })
+    })
+  })
+
+  describe("@ai-sdk/xai", () => {
+    test("returns WIDELY_SUPPORTED_EFFORTS with reasoningEffort", () => {
+      const model = createMockModel({
+        id: "xai/grok-3",
+        providerID: "xai",
+        api: {
+          id: "grok-3",
+          url: "https://api.x.ai",
+          npm: "@ai-sdk/xai",
+        },
+      })
+      const result = ProviderTransform.variants(model)
+      expect(Object.keys(result)).toEqual(["low", "medium", "high"])
+      expect(result.low).toEqual({ reasoningEffort: "low" })
+      expect(result.high).toEqual({ reasoningEffort: "high" })
+    })
+  })
+
+  describe("@ai-sdk/deepinfra", () => {
+    test("returns WIDELY_SUPPORTED_EFFORTS with reasoningEffort", () => {
+      const model = createMockModel({
+        id: "deepinfra/llama-4",
+        providerID: "deepinfra",
+        api: {
+          id: "llama-4-sc",
+          url: "https://api.deepinfra.com",
+          npm: "@ai-sdk/deepinfra",
+        },
+      })
+      const result = ProviderTransform.variants(model)
+      expect(Object.keys(result)).toEqual(["low", "medium", "high"])
+      expect(result.low).toEqual({ reasoningEffort: "low" })
+      expect(result.high).toEqual({ reasoningEffort: "high" })
+    })
+  })
+
+  describe("@ai-sdk/openai-compatible", () => {
+    test("returns WIDELY_SUPPORTED_EFFORTS with reasoningEffort", () => {
+      const model = createMockModel({
+        id: "custom-provider/custom-model",
+        providerID: "custom-provider",
+        api: {
+          id: "custom-model",
+          url: "https://api.custom.com",
+          npm: "@ai-sdk/openai-compatible",
+        },
+      })
+      const result = ProviderTransform.variants(model)
+      expect(Object.keys(result)).toEqual(["low", "medium", "high"])
+      expect(result.low).toEqual({ reasoningEffort: "low" })
+      expect(result.high).toEqual({ reasoningEffort: "high" })
+    })
+  })
+
+  describe("@ai-sdk/azure", () => {
+    test("o1-mini returns empty object", () => {
+      const model = createMockModel({
+        id: "o1-mini",
+        providerID: "azure",
+        api: {
+          id: "o1-mini",
+          url: "https://azure.com",
+          npm: "@ai-sdk/azure",
+        },
+      })
+      const result = ProviderTransform.variants(model)
+      expect(result).toEqual({})
+    })
+
+    test("standard azure models return custom efforts with reasoningSummary", () => {
+      const model = createMockModel({
+        id: "azure/gpt-4o",
+        providerID: "azure",
+        api: {
+          id: "gpt-4o",
+          url: "https://azure.com",
+          npm: "@ai-sdk/azure",
+        },
+      })
+      const result = ProviderTransform.variants(model)
+      expect(Object.keys(result)).toEqual(["low", "medium", "high"])
+      expect(result.low).toEqual({
+        reasoningEffort: "low",
+        reasoningSummary: "auto",
+        include: ["reasoning.encrypted_content"],
+      })
+    })
+
+    test("gpt-5 adds minimal effort", () => {
+      const model = createMockModel({
+        id: "azure/gpt-5",
+        providerID: "azure",
+        api: {
+          id: "gpt-5",
+          url: "https://azure.com",
+          npm: "@ai-sdk/azure",
+        },
+      })
+      const result = ProviderTransform.variants(model)
+      expect(Object.keys(result)).toEqual(["minimal", "low", "medium", "high"])
+    })
+  })
+
+  describe("@ai-sdk/openai", () => {
+    test("gpt-5-pro returns empty object", () => {
+      const model = createMockModel({
+        id: "gpt-5-pro",
+        providerID: "openai",
+        api: {
+          id: "gpt-5-pro",
+          url: "https://api.openai.com",
+          npm: "@ai-sdk/openai",
+        },
+      })
+      const result = ProviderTransform.variants(model)
+      expect(result).toEqual({})
+    })
+
+    test("standard openai models return custom efforts with reasoningSummary", () => {
+      const model = createMockModel({
+        id: "openai/gpt-4o",
+        providerID: "openai",
+        api: {
+          id: "gpt-4o",
+          url: "https://api.openai.com",
+          npm: "@ai-sdk/openai",
+        },
+        release_date: "2024-06-01",
+      })
+      const result = ProviderTransform.variants(model)
+      expect(Object.keys(result)).toEqual(["minimal", "low", "medium", "high"])
+      expect(result.low).toEqual({
+        reasoningEffort: "low",
+        reasoningSummary: "auto",
+        include: ["reasoning.encrypted_content"],
+      })
+    })
+
+    test("models after 2025-11-13 include 'none' effort", () => {
+      const model = createMockModel({
+        id: "openai/gpt-4.5",
+        providerID: "openai",
+        api: {
+          id: "gpt-4.5",
+          url: "https://api.openai.com",
+          npm: "@ai-sdk/openai",
+        },
+        release_date: "2025-11-14",
+      })
+      const result = ProviderTransform.variants(model)
+      expect(Object.keys(result)).toEqual(["none", "minimal", "low", "medium", "high"])
+    })
+
+    test("models after 2025-12-04 include 'xhigh' effort", () => {
+      const model = createMockModel({
+        id: "openai/gpt-5-chat",
+        providerID: "openai",
+        api: {
+          id: "gpt-5-chat",
+          url: "https://api.openai.com",
+          npm: "@ai-sdk/openai",
+        },
+        release_date: "2025-12-05",
+      })
+      const result = ProviderTransform.variants(model)
+      expect(Object.keys(result)).toEqual(["none", "minimal", "low", "medium", "high", "xhigh"])
+    })
+  })
+
+  describe("@ai-sdk/anthropic", () => {
+    test("returns high and max with thinking config", () => {
+      const model = createMockModel({
+        id: "anthropic/claude-4",
+        providerID: "anthropic",
+        api: {
+          id: "claude-4",
+          url: "https://api.anthropic.com",
+          npm: "@ai-sdk/anthropic",
+        },
+      })
+      const result = ProviderTransform.variants(model)
+      expect(Object.keys(result)).toEqual(["high", "max"])
+      expect(result.high).toEqual({
+        thinking: {
+          type: "enabled",
+          budgetTokens: 16000,
+        },
+      })
+      expect(result.max).toEqual({
+        thinking: {
+          type: "enabled",
+          budgetTokens: 31999,
+        },
+      })
+    })
+  })
+
+  describe("@ai-sdk/amazon-bedrock", () => {
+    test("returns WIDELY_SUPPORTED_EFFORTS with reasoningConfig", () => {
+      const model = createMockModel({
+        id: "bedrock/llama-4",
+        providerID: "bedrock",
+        api: {
+          id: "llama-4-sc",
+          url: "https://bedrock.amazonaws.com",
+          npm: "@ai-sdk/amazon-bedrock",
+        },
+      })
+      const result = ProviderTransform.variants(model)
+      expect(Object.keys(result)).toEqual(["low", "medium", "high"])
+      expect(result.low).toEqual({
+        reasoningConfig: {
+          type: "enabled",
+          maxReasoningEffort: "low",
+        },
+      })
+    })
+  })
+
+  describe("@ai-sdk/google", () => {
+    test("gemini-2.5 returns high and max with thinkingConfig and thinkingBudget", () => {
+      const model = createMockModel({
+        id: "google/gemini-2.5-pro",
+        providerID: "google",
+        api: {
+          id: "gemini-2.5-pro",
+          url: "https://generativelanguage.googleapis.com",
+          npm: "@ai-sdk/google",
+        },
+      })
+      const result = ProviderTransform.variants(model)
+      expect(Object.keys(result)).toEqual(["high", "max"])
+      expect(result.high).toEqual({
+        thinkingConfig: {
+          includeThoughts: true,
+          thinkingBudget: 16000,
+        },
+      })
+      expect(result.max).toEqual({
+        thinkingConfig: {
+          includeThoughts: true,
+          thinkingBudget: 24576,
+        },
+      })
+    })
+
+    test("other gemini models return low and high with thinkingLevel", () => {
+      const model = createMockModel({
+        id: "google/gemini-2.0-pro",
+        providerID: "google",
+        api: {
+          id: "gemini-2.0-pro",
+          url: "https://generativelanguage.googleapis.com",
+          npm: "@ai-sdk/google",
+        },
+      })
+      const result = ProviderTransform.variants(model)
+      expect(Object.keys(result)).toEqual(["low", "high"])
+      expect(result.low).toEqual({
+        includeThoughts: true,
+        thinkingLevel: "low",
+      })
+      expect(result.high).toEqual({
+        includeThoughts: true,
+        thinkingLevel: "high",
+      })
+    })
+  })
+
+  describe("@ai-sdk/google-vertex", () => {
+    test("gemini-2.5 returns high and max with thinkingConfig and thinkingBudget", () => {
+      const model = createMockModel({
+        id: "google-vertex/gemini-2.5-pro",
+        providerID: "google-vertex",
+        api: {
+          id: "gemini-2.5-pro",
+          url: "https://vertexai.googleapis.com",
+          npm: "@ai-sdk/google-vertex",
+        },
+      })
+      const result = ProviderTransform.variants(model)
+      expect(Object.keys(result)).toEqual(["high", "max"])
+    })
+
+    test("other vertex models return low and high with thinkingLevel", () => {
+      const model = createMockModel({
+        id: "google-vertex/gemini-2.0-pro",
+        providerID: "google-vertex",
+        api: {
+          id: "gemini-2.0-pro",
+          url: "https://vertexai.googleapis.com",
+          npm: "@ai-sdk/google-vertex",
+        },
+      })
+      const result = ProviderTransform.variants(model)
+      expect(Object.keys(result)).toEqual(["low", "high"])
+    })
+  })
+
+  describe("@ai-sdk/cohere", () => {
+    test("returns empty object", () => {
+      const model = createMockModel({
+        id: "cohere/command-r",
+        providerID: "cohere",
+        api: {
+          id: "command-r",
+          url: "https://api.cohere.com",
+          npm: "@ai-sdk/cohere",
+        },
+      })
+      const result = ProviderTransform.variants(model)
+      expect(result).toEqual({})
+    })
+  })
+
+  describe("@ai-sdk/groq", () => {
+    test("returns none and WIDELY_SUPPORTED_EFFORTS with thinkingLevel", () => {
+      const model = createMockModel({
+        id: "groq/llama-4",
+        providerID: "groq",
+        api: {
+          id: "llama-4-sc",
+          url: "https://api.groq.com",
+          npm: "@ai-sdk/groq",
+        },
+      })
+      const result = ProviderTransform.variants(model)
+      expect(Object.keys(result)).toEqual(["none", "low", "medium", "high"])
+      expect(result.none).toEqual({
+        includeThoughts: true,
+        thinkingLevel: "none",
+      })
+      expect(result.low).toEqual({
+        includeThoughts: true,
+        thinkingLevel: "low",
+      })
+    })
+  })
+
+  describe("@ai-sdk/perplexity", () => {
+    test("returns empty object", () => {
+      const model = createMockModel({
+        id: "perplexity/sonar-plus",
+        providerID: "perplexity",
+        api: {
+          id: "sonar-plus",
+          url: "https://api.perplexity.ai",
+          npm: "@ai-sdk/perplexity",
+        },
+      })
+      const result = ProviderTransform.variants(model)
+      expect(result).toEqual({})
+    })
+  })
+})
diff --git a/packages/sdk/js/src/v2/gen/types.gen.ts b/packages/sdk/js/src/v2/gen/types.gen.ts
index 58b44fe17..947636f7c 100644
--- a/packages/sdk/js/src/v2/gen/types.gen.ts
+++ b/packages/sdk/js/src/v2/gen/types.gen.ts
@@ -1309,6 +1309,18 @@ export type ProviderConfig = {
       provider?: {
         npm: string
       }
+      /**
+       * Variant-specific configuration
+       */
+      variants?: {
+        [key: string]: {
+          /**
+           * Disable this variant for the model
+           */
+          disabled?: boolean
+          [key: string]: unknown | boolean | undefined
+        }
+      }
     }
   }
   whitelist?: Array<string>
@@ -1717,11 +1729,6 @@ export type Command = {
   subtask?: boolean
 }
 
-export type Variant = {
-  disabled: boolean
-  [key: string]: unknown | boolean
-}
-
 export type Model = {
   id: string
   providerID: string
@@ -1786,7 +1793,9 @@ export type Model = {
   }
   release_date: string
   variants?: {
-    [key: string]: Variant
+    [key: string]: {
+      [key: string]: unknown
+    }
   }
 }
 
@@ -3497,6 +3506,11 @@ export type ProviderListResponses = {
           provider?: {
             npm: string
           }
+          variants?: {
+            [key: string]: {
+              [key: string]: unknown
+            }
+          }
         }
       }
     }>