feat: drive reasoning variants from models.dev reasoning_options

Parse the curated reasoning_options field from models.dev api.json and use
its effort values to generate reasoning variants instead of the hardcoded
per-package tables, in both the v1 provider catalog and the v2 catalog plugin.

- core: ModelsDev.ReasoningOption discriminated union (toggle | effort |
  budget_tokens); effort values stay open strings and unknown option types
  are tolerated since api.json is cast, not decoded
- core: ReasoningVariants shared per-package effort encoder used by v1
  ProviderTransform.variants and the v2 ModelsDevPlugin
- core: v2 catalog generates effort variants from reasoning_options;
  curated experimental modes win id collisions; anthropic profile gains
  the effort semantic
- llm: anthropic protocol supports adaptive thinking, lowers effort to
  output_config.effort, and sends the effort-2025-11-24 beta header
- opencode: resolved Provider.Model carries capabilities.reasoningOptions
  (unknown types and null effort values dropped at the mapping boundary);
  config models accept reasoning_options; models without usable effort
  data fall back to the hardcoded tables unchanged

Catalog-wide audit vs live api.json: 2975 models byte-identical, 38 diffs,
all data correcting stale hardcoded effort lists.

packages/core/src/model-request.ts

@@ -84,7 +84,16 @@ const profiles = new Map<string, Profile>([
       ]),
     },
   ],
-  ["@ai-sdk/anthropic", { namespace: "anthropic", semantics: new Map([["thinking", "thinking"]]) }],
+  [
+    "@ai-sdk/anthropic",
+    {
+      namespace: "anthropic",
+      semantics: new Map([
+        ["thinking", "thinking"],
+        ["effort", "effort"],
+      ]),
+    },
+  ],
 ])
 
 export const namespace = (packageName: string) => profiles.get(packageName)?.namespace

packages/core/src/models-dev.ts

@@ -43,6 +43,30 @@ const Cost = Schema.Struct({
   ),
 })
 
+// models.dev curates reasoning_options per provider model as a discriminated
+// union. The shape is expected to evolve, so stay lenient where it can grow:
+// effort values are open strings (tiers like "xhigh" were added over time) and
+// budget bounds are optional. The api.json payload is cast, never decoded, so
+// option types this union doesn't know about yet can appear at runtime;
+// consumers must filter for the types they understand instead of matching
+// exhaustively.
+export const ReasoningOption = Schema.Union([
+  Schema.Struct({
+    type: Schema.Literal("toggle"),
+  }),
+  Schema.Struct({
+    type: Schema.Literal("effort"),
+    // null means the provider accepts an explicit "no reasoning" effort.
+    values: Schema.Array(Schema.NullOr(Schema.String)),
+  }),
+  Schema.Struct({
+    type: Schema.Literal("budget_tokens"),
+    min: Schema.optional(Schema.Finite),
+    max: Schema.optional(Schema.Finite),
+  }),
+])
+export type ReasoningOption = Schema.Schema.Type<typeof ReasoningOption>
+
 export const Model = Schema.Struct({
   id: Schema.String,
   name: Schema.String,
@@ -50,6 +74,7 @@ export const Model = Schema.Struct({
   release_date: Schema.String,
   attachment: Schema.Boolean,
   reasoning: Schema.Boolean,
+  reasoning_options: Schema.optional(Schema.Array(ReasoningOption)),
   temperature: Schema.Boolean,
   tool_call: Schema.Boolean,
   interleaved: Schema.optional(

packages/core/src/plugin/models-dev.ts

@@ -6,6 +6,7 @@ import { ModelRequest } from "../model-request"
 import { ModelsDev } from "../models-dev"
 import { PluginV2 } from "../plugin"
 import { ProviderV2 } from "../provider"
+import { ReasoningVariants } from "../reasoning-variants"
 
 function released(date: string) {
   const time = Date.parse(date)
@@ -39,8 +40,8 @@ function cost(input: ModelsDev.Model["cost"]) {
   ]
 }
 
-function variants(model: ModelsDev.Model, packageName?: string) {
-  return Object.entries(model.experimental?.modes ?? {}).map(([id, item]) => {
+function variants(model: ModelsDev.Model, providerID: string, packageName?: string) {
+  const modes = Object.entries(model.experimental?.modes ?? {}).map(([id, item]) => {
     const request = ModelRequest.normalizeAiSdkOptions(packageName, item.provider?.body ?? {})
     return {
       id: ModelV2.VariantID.make(id),
@@ -48,6 +49,20 @@ function variants(model: ModelsDev.Model, packageName?: string) {
       ...request,
     }
   })
+  // reasoning_options effort data generates effort variants with the same wire
+  // encodings the v1 catalog uses; curated experimental modes win on id collision.
+  const efforts = ReasoningVariants.fromOptions(
+    { npm: packageName, apiID: model.id, modelID: model.id, providerID },
+    model.reasoning_options,
+  )
+  const fromEfforts = Object.entries(efforts ?? {})
+    .filter(([id]) => !modes.some((mode) => mode.id === id))
+    .map(([id, body]) => ({
+      id: ModelV2.VariantID.make(id),
+      headers: {},
+      ...ModelRequest.normalizeAiSdkOptions(packageName, body),
+    }))
+  return [...modes, ...fromEfforts]
 }
 
 export const ModelsDevPlugin = PluginV2.define({
@@ -102,7 +117,7 @@ export const ModelsDevPlugin = PluginV2.define({
                 input: [...(model.modalities?.input ?? [])],
                 output: [...(model.modalities?.output ?? [])],
               }
-              draft.variants = variants(model, model.provider?.npm ?? item.npm)
+              draft.variants = variants(model, item.id, model.provider?.npm ?? item.npm)
               draft.time.released = released(model.release_date)
               draft.cost = cost(model.cost)
               draft.status = model.status ?? "active"

packages/core/src/reasoning-variants.ts

@@ -0,0 +1,187 @@
+export * as ReasoningVariants from "./reasoning-variants"
+
+// Generates reasoning variants from models.dev `reasoning_options` data. The
+// data only says WHICH efforts a model supports - the wire encoding for each
+// SDK package lives here so the v1 provider catalog and the v2 catalog plugin
+// stay in lockstep. Null effort values and option types we don't understand
+// (toggle, budget_tokens, future additions) are ignored, so models without
+// usable effort data return undefined and callers fall back to their own
+// defaults.
+
+// OpenAI Responses `include` value that returns the encrypted reasoning state
+// needed for stateless multi-turn reasoning (store: false). Hoisted so every
+// branch that requests it stays in lockstep.
+export const INCLUDE_ENCRYPTED_REASONING = ["reasoning.encrypted_content"] as const
+
+export interface Target {
+  readonly npm?: string
+  readonly apiID: string
+  readonly modelID: string
+  readonly providerID: string
+}
+
+export function fromOptions(
+  target: Target,
+  options: ReadonlyArray<{ readonly type: string; readonly values?: ReadonlyArray<string | null> }> | undefined,
+): Record<string, Record<string, unknown>> | undefined {
+  const efforts = [
+    ...new Set(
+      (options ?? [])
+        .flatMap((option) => (option.type === "effort" ? (option.values ?? []) : []))
+        .filter((value): value is string => typeof value === "string"),
+    ),
+  ]
+  if (efforts.length === 0) return undefined
+  return effortVariants(target, efforts)
+}
+
+export function anthropicOpus47OrLater(apiID: string) {
+  // Matches "opus-4.7" (Anthropic/Bedrock/Vertex) and "claude-4.7-opus" (SAP AI Core inverted).
+  // Greedy \d+ correctly extends to multi-digit majors (e.g. "claude-10.0-opus") for forward compatibility.
+  const version = /opus-(\d+)[.-](\d+)(?:[.@-]|$)|claude-(\d+)[.-](\d+)-opus(?:[.@-]|$)/i.exec(apiID)
+  if (!version) return false
+  const major = Number(version[1] ?? version[3])
+  const minor = Number(version[2] ?? version[4])
+  return major > 4 || (major === 4 && minor >= 7)
+}
+
+export function anthropicAdaptiveEfforts(apiID: string): string[] | null {
+  if (anthropicOpus47OrLater(apiID) || apiID.includes("fable-5")) {
+    return ["low", "medium", "high", "xhigh", "max"]
+  }
+  if (
+    ["opus-4-6", "opus-4.6", "4-6-opus", "4.6-opus", "sonnet-4-6", "sonnet-4.6", "4-6-sonnet", "4.6-sonnet"].some((v) =>
+      apiID.includes(v),
+    )
+  ) {
+    return ["low", "medium", "high", "max"]
+  }
+  return null
+}
+
+export function anthropicOmitsThinking(apiID: string) {
+  return anthropicOpus47OrLater(apiID) || apiID.includes("fable-5")
+}
+
+// SAP's Zod schema drops unknown top-level keys; reasoning controls survive
+// only via `modelParams` (catchall), forwarded verbatim by the SAP SDKs.
+export function wrapInSapModelParams(
+  variants: Record<string, Record<string, unknown>>,
+): Record<string, Record<string, unknown>> {
+  return Object.fromEntries(Object.entries(variants).map(([k, v]) => [k, { modelParams: v }]))
+}
+
+function copilotAnthropicEfforts(apiID: string, efforts: string[]) {
+  // Efforts currently supported by copilot are: low, medium, high
+  if (apiID.includes("opus-4.7")) return ["medium"]
+  return efforts.filter((v) => v !== "max" && v !== "xhigh")
+}
+
+function anthropicEffortVariants(target: Target, efforts: string[]): Record<string, Record<string, unknown>> {
+  const filtered = target.providerID === "github-copilot" ? copilotAnthropicEfforts(target.apiID, efforts) : efforts
+  const adaptive = anthropicAdaptiveEfforts(target.apiID) !== null
+  return Object.fromEntries(
+    filtered.map((effort) => [
+      effort,
+      adaptive
+        ? {
+            thinking: {
+              type: "adaptive",
+              // Newer adaptive-only models default `display` to "omitted", which
+              // returns empty thinking blocks. Force "summarized" so summaries
+              // survive (4.6/Sonnet 4.6 already default to "summarized").
+              ...(anthropicOmitsThinking(target.apiID) ? { display: "summarized" } : {}),
+            },
+            effort,
+          }
+        : { effort },
+    ]),
+  )
+}
+
+function effortVariants(target: Target, efforts: string[]): Record<string, Record<string, unknown>> {
+  const fromEffort = (encode: (effort: string) => Record<string, unknown>) =>
+    Object.fromEntries(efforts.map((effort) => [effort, encode(effort)]))
+
+  switch (target.npm) {
+    case "@openrouter/ai-sdk-provider":
+      return fromEffort((effort) => ({ reasoning: { effort } }))
+
+    case "@ai-sdk/gateway":
+      if (target.modelID.includes("anthropic")) return anthropicEffortVariants(target, efforts)
+      if (target.modelID.includes("google"))
+        return fromEffort((effort) => ({ includeThoughts: true, thinkingLevel: effort }))
+      return fromEffort((effort) => ({ reasoningEffort: effort }))
+
+    case "@ai-sdk/github-copilot":
+      // currently github copilot only returns thinking
+      if (target.modelID.includes("gemini")) return {}
+      if (target.modelID.includes("claude")) return fromEffort((effort) => ({ reasoningEffort: effort }))
+      return fromEffort((effort) => ({
+        reasoningEffort: effort,
+        reasoningSummary: "auto",
+        include: INCLUDE_ENCRYPTED_REASONING,
+      }))
+
+    case "@ai-sdk/azure":
+    case "@ai-sdk/amazon-bedrock/mantle":
+    case "@ai-sdk/openai":
+      return fromEffort((effort) => ({
+        reasoningEffort: effort,
+        reasoningSummary: "auto",
+        include: INCLUDE_ENCRYPTED_REASONING,
+      }))
+
+    case "@ai-sdk/anthropic":
+    case "@ai-sdk/google-vertex/anthropic":
+      return anthropicEffortVariants(target, efforts)
+
+    case "@ai-sdk/amazon-bedrock":
+      if (anthropicAdaptiveEfforts(target.apiID)) {
+        return fromEffort((effort) => ({
+          reasoningConfig: {
+            type: "adaptive",
+            maxReasoningEffort: effort,
+            ...(anthropicOmitsThinking(target.apiID) ? { display: "summarized" } : {}),
+          },
+        }))
+      }
+      return fromEffort((effort) => ({
+        reasoningConfig: {
+          type: "enabled",
+          maxReasoningEffort: effort,
+        },
+      }))
+
+    case "@ai-sdk/google-vertex":
+    case "@ai-sdk/google":
+      return fromEffort((effort) => ({ thinkingConfig: { includeThoughts: true, thinkingLevel: effort } }))
+
+    case "@jerome-benoit/sap-ai-provider-v2": {
+      if (target.modelID.toLowerCase().includes("anthropic")) {
+        const adaptive = anthropicAdaptiveEfforts(target.apiID) !== null
+        // Bedrock-flavored Anthropic splits `effort` out into `output_config` (vs
+        // Anthropic native which inlines it).
+        return wrapInSapModelParams(
+          fromEffort((effort) =>
+            adaptive
+              ? {
+                  thinking: {
+                    type: "adaptive",
+                    ...(anthropicOmitsThinking(target.apiID) ? { display: "summarized" } : {}),
+                  },
+                  output_config: { effort },
+                }
+              : { output_config: { effort } },
+          ),
+        )
+      }
+      return wrapInSapModelParams(fromEffort((effort) => ({ reasoning_effort: effort })))
+    }
+  }
+
+  // OpenAI-compatible `reasoning_effort` is the dominant convention; it covers
+  // @ai-sdk/openai-compatible, cerebras, togetherai, xai, deepinfra, venice,
+  // mistral, groq, ai-gateway-provider, and unknown future packages.
+  return fromEffort((effort) => ({ reasoningEffort: effort }))
+}

packages/core/src/v1/config/provider.ts

@@ -12,6 +12,28 @@ export const Model = Schema.Struct({
   release_date: Schema.optional(Schema.String),
   attachment: Schema.optional(Schema.Boolean),
   reasoning: Schema.optional(Schema.Boolean),
+  reasoning_options: Schema.optional(
+    // Mirrors the models.dev reasoning_options union; effort values stay open
+    // strings so new tiers don't break configs.
+    Schema.mutable(
+      Schema.Array(
+        Schema.Union([
+          Schema.Struct({
+            type: Schema.Literal("toggle"),
+          }),
+          Schema.Struct({
+            type: Schema.Literal("effort"),
+            values: Schema.mutable(Schema.Array(Schema.NullOr(Schema.String))),
+          }),
+          Schema.Struct({
+            type: Schema.Literal("budget_tokens"),
+            min: Schema.optional(Schema.Finite),
+            max: Schema.optional(Schema.Finite),
+          }),
+        ]),
+      ),
+    ),
+  ).annotate({ description: "Reasoning controls this model supports; effort values drive reasoning variants" }),
   temperature: Schema.optional(Schema.Boolean),
   tool_call: Schema.optional(Schema.Boolean),
   interleaved: Schema.optional(

packages/core/test/config/config.test.ts

@@ -568,7 +568,12 @@ describe("Config", () => {
                 model: {
                   request: {
                     body: {
-                      output_config: { effort: "high", task_budget: 4096 },
+                      // `effort` stays aisdk-shaped: the catalog re-partitions it
+                      // into the semantic anthropic effort option, which lowers to
+                      // output_config.effort plus the effort beta header. taskBudget
+                      // has no semantic and lowers to a raw output_config overlay.
+                      effort: "high",
+                      output_config: { task_budget: 4096 },
                       metadata: { user_id: "user-1" },
                     },
                   },

packages/core/test/models-dev-plugin.test.ts

@@ -0,0 +1,116 @@
+import { describe, expect } from "bun:test"
+import { Effect, Layer } from "effect"
+import { Catalog } from "@opencode-ai/core/catalog"
+import { EventV2 } from "@opencode-ai/core/event"
+import { Location } from "@opencode-ai/core/location"
+import { ModelV2 } from "@opencode-ai/core/model"
+import { ModelsDev } from "@opencode-ai/core/models-dev"
+import { ModelsDevPlugin } from "@opencode-ai/core/plugin/models-dev"
+import { ProviderV2 } from "@opencode-ai/core/provider"
+import { AbsolutePath } from "@opencode-ai/core/schema"
+import { location } from "./fixture/location"
+import { testEffect } from "./lib/effect"
+
+const model = (input: Partial<ModelsDev.Model> & { id: string }): ModelsDev.Model => ({
+  name: input.id,
+  release_date: "2026-01-01",
+  attachment: false,
+  reasoning: true,
+  temperature: true,
+  tool_call: true,
+  limit: { context: 200_000, output: 64_000 },
+  ...input,
+})
+
+const fixture: Record<string, ModelsDev.Provider> = {
+  anthropic: {
+    id: "anthropic",
+    name: "Anthropic",
+    env: [],
+    npm: "@ai-sdk/anthropic",
+    models: {
+      "claude-sonnet-4-6": model({
+        id: "claude-sonnet-4-6",
+        reasoning_options: [
+          { type: "effort", values: ["low", "medium", "high", "max"] },
+          { type: "budget_tokens", min: 1024 },
+        ],
+      }),
+    },
+  },
+  compat: {
+    id: "compat",
+    name: "Compat",
+    env: [],
+    npm: "@ai-sdk/openai-compatible",
+    models: {
+      "deepseek-v4": model({
+        id: "deepseek-v4",
+        reasoning_options: [{ type: "toggle" }, { type: "effort", values: [null, "high", "max"] }],
+        experimental: {
+          modes: {
+            high: { provider: { body: { reasoning_effort: "high", custom: true } } },
+          },
+        },
+      }),
+    },
+  },
+}
+
+const locationLayer = Layer.succeed(
+  Location.Service,
+  Location.Service.of(location({ directory: AbsolutePath.make("test") })),
+)
+const modelsDevLayer = Layer.succeed(
+  ModelsDev.Service,
+  ModelsDev.Service.of({
+    get: () => Effect.succeed(fixture),
+    refresh: () => Effect.void,
+  }),
+)
+const it = testEffect(
+  Layer.mergeAll(modelsDevLayer, Catalog.locationLayer).pipe(
+    Layer.provideMerge(EventV2.defaultLayer),
+    Layer.provideMerge(locationLayer),
+  ),
+)
+
+describe("ModelsDevPlugin reasoning_options", () => {
+  it.effect("generates anthropic effort variants as semantic thinking + effort options", () =>
+    Effect.gen(function* () {
+      yield* ModelsDevPlugin.effect
+      const catalog = yield* Catalog.Service
+      const info = yield* catalog.model.get(ProviderV2.ID.make("anthropic"), ModelV2.ID.make("claude-sonnet-4-6"))
+      expect(info.variants.map((variant) => variant.id)).toEqual(
+        ["low", "medium", "high", "max"].map((id) => ModelV2.VariantID.make(id)),
+      )
+      expect(info.variants[2]).toMatchObject({
+        id: "high",
+        headers: {},
+        body: {},
+        options: { thinking: { type: "adaptive" }, effort: "high" },
+      })
+    }),
+  )
+
+  it.effect("merges effort variants after curated experimental modes, skipping null values and collisions", () =>
+    Effect.gen(function* () {
+      yield* ModelsDevPlugin.effect
+      const catalog = yield* Catalog.Service
+      const info = yield* catalog.model.get(ProviderV2.ID.make("compat"), ModelV2.ID.make("deepseek-v4"))
+      expect(info.variants.map((variant) => variant.id)).toEqual(["high", "max"].map((id) => ModelV2.VariantID.make(id)))
+      // curated mode wins the "high" id; its body keys survive partitioning
+      expect(info.variants[0]).toMatchObject({
+        id: "high",
+        body: { custom: true },
+        options: { reasoningEffort: "high" },
+      })
+      // data-driven effort variant for "max" uses the openai-compatible encoding
+      expect(info.variants[1]).toMatchObject({
+        id: "max",
+        body: {},
+        options: { reasoningEffort: "max" },
+      })
+    }),
+  )
+})

packages/llm/src/protocols/anthropic-messages.ts

@@ -146,10 +146,20 @@ const AnthropicToolChoice = Schema.Union([
   Schema.Struct({ type: Schema.tag("tool"), name: Schema.String }),
 ])
 
-const AnthropicThinking = Schema.Struct({
-  type: Schema.tag("enabled"),
-  budget_tokens: Schema.Number,
-})
+const AnthropicThinking = Schema.Union([
+  Schema.Struct({
+    type: Schema.tag("enabled"),
+    budget_tokens: Schema.Number,
+  }),
+  // Adaptive thinking (Claude 4.6+) lets the model choose its own budget.
+  // `display` controls how thinking is surfaced ("summarized" forces summaries
+  // on models that default to "omitted"); keep it an open string so new display
+  // modes flow through.
+  Schema.Struct({
+    type: Schema.tag("adaptive"),
+    display: Schema.optional(Schema.String),
+  }),
+])
 
 const AnthropicBodyFields = {
   model: Schema.String,
@@ -164,6 +174,8 @@ const AnthropicBodyFields = {
   top_k: Schema.optional(Schema.Number),
   stop_sequences: optionalArray(Schema.String),
   thinking: Schema.optional(AnthropicThinking),
+  // Reasoning effort (beta `effort-2025-11-24`); open string so new tiers flow through.
+  output_config: Schema.optional(Schema.Struct({ effort: Schema.String })),
 }
 const AnthropicMessagesBody = Schema.Struct(AnthropicBodyFields)
 export type AnthropicMessagesBody = Schema.Schema.Type<typeof AnthropicMessagesBody>
@@ -490,7 +502,14 @@ const anthropicOptions = (request: LLMRequest) => request.providerOptions?.anthr
 
 const lowerThinking = Effect.fn("AnthropicMessages.lowerThinking")(function* (request: LLMRequest) {
   const thinking = anthropicOptions(request)?.thinking
-  if (!ProviderShared.isRecord(thinking) || thinking.type !== "enabled") return undefined
+  if (!ProviderShared.isRecord(thinking)) return undefined
+  if (thinking.type === "adaptive") {
+    return {
+      type: "adaptive" as const,
+      ...(typeof thinking.display === "string" ? { display: thinking.display } : {}),
+    }
+  }
+  if (thinking.type !== "enabled") return undefined
   const budget =
     typeof thinking.budgetTokens === "number"
       ? thinking.budgetTokens
@@ -501,6 +520,14 @@ const lowerThinking = Effect.fn("AnthropicMessages.lowerThinking")(function* (re
   return { type: "enabled" as const, budget_tokens: budget }
 })
 
+// Reasoning effort lowers to `output_config.effort` (mirrors @ai-sdk/anthropic);
+// the matching beta header is added by the route headers hook below.
+const lowerOutputConfig = (request: LLMRequest) => {
+  const effort = anthropicOptions(request)?.effort
+  if (typeof effort !== "string") return undefined
+  return { effort }
+}
+
 const fromRequest = Effect.fn("AnthropicMessages.fromRequest")(function* (request: LLMRequest) {
   const toolChoice = request.toolChoice ? yield* lowerToolChoice(request.toolChoice) : undefined
   const generation = request.generation
@@ -539,6 +566,7 @@ const fromRequest = Effect.fn("AnthropicMessages.fromRequest")(function* (reques
     top_k: generation?.topK,
     stop_sequences: generation?.stop,
     thinking: yield* lowerThinking(request),
+    output_config: lowerOutputConfig(request),
   }
 })
 
@@ -839,7 +867,12 @@ export const route = Route.make({
   endpoint: Endpoint.path(PATH, { baseURL: DEFAULT_BASE_URL }),
   auth: Auth.none,
   framing: Framing.sse,
-  headers: () => ({ "anthropic-version": "2023-06-01" }),
+  // `output_config.effort` is beta-gated. Explicit per-request `anthropic-beta`
+  // headers override this hook (the transport spreads request headers last).
+  headers: ({ request }) => ({
+    "anthropic-version": "2023-06-01",
+    ...(typeof anthropicOptions(request)?.effort === "string" ? { "anthropic-beta": "effort-2025-11-24" } : {}),
+  }),
 })
 
 export * as AnthropicMessages from "./anthropic-messages"

packages/llm/test/provider/anthropic-messages.test.ts

@@ -57,6 +57,58 @@ describe("Anthropic Messages route", () => {
     }),
   )
 
+  it.effect("lowers enabled thinking to a budget", () =>
+    Effect.gen(function* () {
+      const prepared = yield* LLMClient.prepare<AnthropicMessages.AnthropicMessagesBody>(
+        LLM.updateRequest(request, {
+          providerOptions: { anthropic: { thinking: { type: "enabled", budgetTokens: 16_000 } } },
+        }),
+      )
+      expect(prepared.body.thinking).toEqual({ type: "enabled", budget_tokens: 16_000 })
+      expect(prepared.body.output_config).toBeUndefined()
+    }),
+  )
+
+  it.effect("lowers adaptive thinking and effort to output_config", () =>
+    Effect.gen(function* () {
+      const prepared = yield* LLMClient.prepare<AnthropicMessages.AnthropicMessagesBody>(
+        LLM.updateRequest(request, {
+          providerOptions: {
+            anthropic: { thinking: { type: "adaptive", display: "summarized" }, effort: "high" },
+          },
+        }),
+      )
+      expect(prepared.body.thinking).toEqual({ type: "adaptive", display: "summarized" })
+      expect(prepared.body.output_config).toEqual({ effort: "high" })
+    }),
+  )
+
+  it.effect("adds the effort beta header only when effort is set", () =>
+    Effect.gen(function* () {
+      const seen: Record<string, string>[] = []
+      const body = () =>
+        sseEvents(
+          { type: "message_start", message: { usage: { input_tokens: 1 } } },
+          { type: "message_delta", delta: { stop_reason: "end_turn" }, usage: { output_tokens: 1 } },
+          { type: "message_stop" },
+        )
+      const layer = dynamicResponse((input) =>
+        Effect.sync(() => {
+          seen.push({ ...input.request.headers })
+          return input.respond(body(), { headers: { "content-type": "text/event-stream" } })
+        }),
+      )
+      yield* LLMClient.generate(
+        LLM.updateRequest(request, { providerOptions: { anthropic: { effort: "high" } } }),
+      ).pipe(Effect.provide(layer))
+      yield* LLMClient.generate(request).pipe(Effect.provide(layer))
+
+      expect(seen[0]["anthropic-version"]).toBe("2023-06-01")
+      expect(seen[0]["anthropic-beta"]).toBe("effort-2025-11-24")
+      expect(seen[1]["anthropic-beta"]).toBeUndefined()
+    }),
+  )
+
   it.effect("lowers chronological system updates natively for Claude Opus 4.8 with cache hints", () =>
     Effect.gen(function* () {
       const prepared = yield* LLMClient.prepare<AnthropicMessages.AnthropicMessagesBody>(

packages/opencode/src/provider/provider.ts

@@ -957,9 +957,30 @@ const ProviderInterleaved = Schema.Union([
   }),
 ])
 
+// Mirrors the models.dev reasoning_options union. Option types this union does
+// not know about yet, and null effort values (models.dev's marker for "accepts
+// an explicit no-reasoning effort"), are dropped when mapping models.dev data
+// into the resolved catalog, so this schema only ever sees known variants;
+// effort values stay open strings so new tiers flow through.
+const ProviderReasoningOption = Schema.Union([
+  Schema.Struct({
+    type: Schema.Literal("toggle"),
+  }),
+  Schema.Struct({
+    type: Schema.Literal("effort"),
+    values: Schema.Array(Schema.String),
+  }),
+  Schema.Struct({
+    type: Schema.Literal("budget_tokens"),
+    min: optionalOmitUndefined(Schema.Finite),
+    max: optionalOmitUndefined(Schema.Finite),
+  }),
+])
+
 const ProviderCapabilities = Schema.Struct({
   temperature: Schema.Boolean,
   reasoning: Schema.Boolean,
+  reasoningOptions: optionalOmitUndefined(Schema.Array(ProviderReasoningOption)),
   attachment: Schema.Boolean,
   toolcall: Schema.Boolean,
   input: ProviderModalities,
@@ -1155,6 +1176,20 @@ function cost(c: ModelsDev.Model["cost"]): Model["cost"] {
   return result
 }
 
+// models.dev api.json is cast rather than decoded, so reasoning_options can
+// contain option types newer than our union at runtime; drop those (and null
+// effort values) here so downstream schema boundaries only ever see known
+// variants.
+function reasoningOptions(options: ModelsDev.Model["reasoning_options"]): Model["capabilities"]["reasoningOptions"] {
+  return options
+    ?.filter((option) => option.type === "toggle" || option.type === "effort" || option.type === "budget_tokens")
+    .map((option) =>
+      option.type === "effort"
+        ? { ...option, values: option.values.filter((value): value is string => value !== null) }
+        : { ...option },
+    )
+}
+
 function fromModelsDevModel(provider: ModelsDev.Provider, model: ModelsDev.Model): Model {
   const base: Model = {
     id: ModelV2.ID.make(model.id),
@@ -1178,6 +1213,7 @@ function fromModelsDevModel(provider: ModelsDev.Provider, model: ModelsDev.Model
     capabilities: {
       temperature: model.temperature ?? false,
       reasoning: model.reasoning ?? false,
+      reasoningOptions: reasoningOptions(model.reasoning_options),
       attachment: model.attachment ?? false,
       toolcall: model.tool_call ?? true,
       input: {
@@ -1400,6 +1436,8 @@ export const layer = Layer.effect(
               capabilities: {
                 temperature: model.temperature ?? existingModel?.capabilities.temperature ?? false,
                 reasoning: model.reasoning ?? existingModel?.capabilities.reasoning ?? false,
+                reasoningOptions:
+                  reasoningOptions(model.reasoning_options) ?? existingModel?.capabilities.reasoningOptions,
                 attachment: model.attachment ?? existingModel?.capabilities.attachment ?? false,
                 toolcall: model.tool_call ?? existingModel?.capabilities.toolcall ?? true,
                 input: {

packages/opencode/src/provider/transform.ts

@@ -3,6 +3,7 @@ import { mergeDeep, unique } from "remeda"
 import type { JSONSchema7 } from "@ai-sdk/provider"
 import type * as Provider from "./provider"
 import type * as ModelsDev from "@opencode-ai/core/models-dev"
+import { ReasoningVariants } from "@opencode-ai/core/reasoning-variants"
 import { iife } from "@/util/iife"
 
 type Modality = NonNullable<ModelsDev.Model["modalities"]>["input"][number]
@@ -17,11 +18,6 @@ function mimeToModality(mime: string): Modality | undefined {
 
 export const OUTPUT_TOKEN_MAX = 32_000
 
-// OpenAI Responses `include` value that returns the encrypted reasoning state
-// needed for stateless multi-turn reasoning (store: false). Hoisted so every
-// branch that requests it stays in lockstep.
-const INCLUDE_ENCRYPTED_REASONING = ["reasoning.encrypted_content"] as const
-
 export function sanitizeSurrogates(content: string) {
   return content.replace(/[\uD800-\uDBFF](?![\uDC00-\uDFFF])|(?<![\uD800-\uDBFF])[\uDC00-\uDFFF]/g, "\uFFFD")
 }
@@ -595,34 +591,6 @@ function openaiCompatibleReasoningEfforts(id: string) {
   return gpt5CodexReasoningEfforts(apiId) ?? versionedGpt5ReasoningEfforts(apiId) ?? OPENAI_EFFORTS
 }
 
-function anthropicOpus47OrLater(apiId: string) {
-  // Matches "opus-4.7" (Anthropic/Bedrock/Vertex) and "claude-4.7-opus" (SAP AI Core inverted).
-  // Greedy \d+ correctly extends to multi-digit majors (e.g. "claude-10.0-opus") for forward compatibility.
-  const version = /opus-(\d+)[.-](\d+)(?:[.@-]|$)|claude-(\d+)[.-](\d+)-opus(?:[.@-]|$)/i.exec(apiId)
-  if (!version) return false
-  const major = Number(version[1] ?? version[3])
-  const minor = Number(version[2] ?? version[4])
-  return major > 4 || (major === 4 && minor >= 7)
-}
-
-function anthropicAdaptiveEfforts(apiId: string): string[] | null {
-  if (anthropicOpus47OrLater(apiId) || apiId.includes("fable-5")) {
-    return ["low", "medium", "high", "xhigh", "max"]
-  }
-  if (
-    ["opus-4-6", "opus-4.6", "4-6-opus", "4.6-opus", "sonnet-4-6", "sonnet-4.6", "4-6-sonnet", "4.6-sonnet"].some((v) =>
-      apiId.includes(v),
-    )
-  ) {
-    return ["low", "medium", "high", "max"]
-  }
-  return null
-}
-
-function anthropicOmitsThinking(apiId: string) {
-  return anthropicOpus47OrLater(apiId) || apiId.includes("fable-5")
-}
-
 function googleThinkingLevelEfforts(apiId: string) {
   const id = apiId.toLowerCase()
   if (!id.includes("gemini-3")) return ["low", "high"]
@@ -638,12 +606,6 @@ function googleThinkingBudgetMax(apiId: string) {
   return 24_576
 }
 
-// SAP's Zod schema drops unknown top-level keys; reasoning controls survive
-// only via `modelParams` (catchall), forwarded verbatim by the SAP SDKs.
-function wrapInSapModelParams(variants: Record<string, Record<string, any>>): Record<string, Record<string, any>> {
-  return Object.fromEntries(Object.entries(variants).map(([k, v]) => [k, { modelParams: v }]))
-}
-
 function googleThinkingVariants(model: Provider.Model): Record<string, Record<string, any>> {
   const id = model.api.id.toLowerCase()
   if (id.includes("2.5")) {
@@ -665,6 +627,14 @@ function googleThinkingVariants(model: Provider.Model): Record<string, Record<st
 export function variants(model: Provider.Model): Record<string, Record<string, any>> {
   if (!model.capabilities.reasoning) return {}
 
+  // models.dev reasoning_options effort data drives variants when present;
+  // models without usable effort data fall back to the hardcoded tables below.
+  const fromData = ReasoningVariants.fromOptions(
+    { npm: model.api.npm, apiID: model.api.id, modelID: model.id, providerID: model.providerID },
+    model.capabilities.reasoningOptions,
+  )
+  if (fromData) return fromData
+
   const id = model.id.toLowerCase()
   if (
     model.api.id.toLowerCase().includes("minimax-m3") &&
@@ -675,8 +645,8 @@ export function variants(model: Provider.Model): Record<string, Record<string, a
       thinking: { thinking: { type: "adaptive" } },
     }
   }
-  const adaptiveThinkingOmitted = anthropicOmitsThinking(model.api.id)
-  const adaptiveEfforts = anthropicAdaptiveEfforts(model.api.id)
+  const adaptiveThinkingOmitted = ReasoningVariants.anthropicOmitsThinking(model.api.id)
+  const adaptiveEfforts = ReasoningVariants.anthropicAdaptiveEfforts(model.api.id)
   if (
     id.includes("deepseek-chat") ||
     id.includes("deepseek-reasoner") ||
@@ -815,7 +785,7 @@ export function variants(model: Provider.Model): Record<string, Record<string, a
           {
             reasoningEffort: effort,
             reasoningSummary: "auto",
-            include: INCLUDE_ENCRYPTED_REASONING,
+            include: ReasoningVariants.INCLUDE_ENCRYPTED_REASONING,
           },
         ]),
       )
@@ -849,7 +819,7 @@ export function variants(model: Provider.Model): Record<string, Record<string, a
           {
             reasoningEffort: effort,
             reasoningSummary: "auto",
-            include: INCLUDE_ENCRYPTED_REASONING,
+            include: ReasoningVariants.INCLUDE_ENCRYPTED_REASONING,
           },
         ]),
       )
@@ -863,7 +833,7 @@ export function variants(model: Provider.Model): Record<string, Record<string, a
           {
             reasoningEffort: effort,
             reasoningSummary: "auto",
-            include: INCLUDE_ENCRYPTED_REASONING,
+            include: ReasoningVariants.INCLUDE_ENCRYPTED_REASONING,
           },
         ]),
       )
@@ -1010,7 +980,7 @@ export function variants(model: Provider.Model): Record<string, Record<string, a
         if (adaptiveEfforts) {
           // Bedrock adaptive splits `effort` out into `output_config` (vs Anthropic
           // native which inlines it). Opus 4.7+ flipped `display` default to "omitted".
-          return wrapInSapModelParams(
+          return ReasoningVariants.wrapInSapModelParams(
             Object.fromEntries(
               adaptiveEfforts.map((effort) => [
                 effort,
@@ -1022,19 +992,19 @@ export function variants(model: Provider.Model): Record<string, Record<string, a
             ),
           )
         }
-        return wrapInSapModelParams({
+        return ReasoningVariants.wrapInSapModelParams({
           high: { thinking: { type: "enabled", budget_tokens: 16000 } },
           max: { thinking: { type: "enabled", budget_tokens: 31999 } },
         })
       }
       if (id.includes("gemini") && id.includes("2.5")) {
-        return wrapInSapModelParams(googleThinkingVariants(model))
+        return ReasoningVariants.wrapInSapModelParams(googleThinkingVariants(model))
       }
       if (id.includes("gpt") || /\bo[1-9]/.test(id)) {
         const efforts = openaiReasoningEfforts(id, model.release_date)
-        return wrapInSapModelParams(Object.fromEntries(efforts.map((effort) => [effort, { reasoning_effort: effort }])))
+        return ReasoningVariants.wrapInSapModelParams(Object.fromEntries(efforts.map((effort) => [effort, { reasoning_effort: effort }])))
       }
-      return wrapInSapModelParams(
+      return ReasoningVariants.wrapInSapModelParams(
         Object.fromEntries(["low", "medium", "high"].map((effort) => [effort, { reasoning_effort: effort }])),
       )
     }
@@ -1161,7 +1131,7 @@ export function options(input: {
         result["reasoningSummary"] = "auto"
       }
       if (input.model.api.npm === "@ai-sdk/openai" || input.model.api.npm === "@ai-sdk/amazon-bedrock/mantle") {
-        result["include"] = INCLUDE_ENCRYPTED_REASONING
+        result["include"] = ReasoningVariants.INCLUDE_ENCRYPTED_REASONING
       }
     }
 
@@ -1178,7 +1148,7 @@ export function options(input: {
 
     if (input.model.providerID.startsWith("opencode")) {
       result["promptCacheKey"] = input.sessionID
-      result["include"] = INCLUDE_ENCRYPTED_REASONING
+      result["include"] = ReasoningVariants.INCLUDE_ENCRYPTED_REASONING
       result["reasoningSummary"] = "auto"
     }
   }

packages/opencode/test/provider/reasoning-options.test.ts

@@ -0,0 +1,68 @@
+import { describe, expect, test } from "bun:test"
+import { Schema } from "effect"
+import { ConfigProviderV1 } from "@opencode-ai/core/v1/config/provider"
+import { ModelsDev } from "@opencode-ai/core/models-dev"
+import { Provider } from "@/provider/provider"
+
+const options = [
+  { type: "toggle" },
+  { type: "effort", values: [null, "low", "medium", "high", "xhigh", "max", "ultrathink"] },
+  { type: "budget_tokens", min: 1024 },
+  { type: "budget_tokens", min: 0, max: 24_576 },
+]
+
+describe("reasoning_options schemas", () => {
+  test("models.dev model schema decodes all known option shapes", () => {
+    const model = Schema.decodeUnknownSync(ModelsDev.Model)({
+      id: "test-model",
+      name: "Test Model",
+      release_date: "2026-01-01",
+      attachment: false,
+      reasoning: true,
+      reasoning_options: options,
+      temperature: true,
+      tool_call: true,
+      limit: { context: 128000, output: 8192 },
+    })
+    expect(model.reasoning_options).toEqual(options as typeof model.reasoning_options)
+  })
+
+  test("config model schema decodes reasoning_options", () => {
+    const model = Schema.decodeUnknownSync(ConfigProviderV1.Model)({ reasoning_options: options })
+    expect(model.reasoning_options).toEqual(options as typeof model.reasoning_options)
+  })
+
+  test("provider capabilities decode reasoningOptions", () => {
+    // The resolved catalog never carries null effort values; they are stripped
+    // when mapping models.dev data, so the resolved schema rejects them.
+    const resolved = [
+      { type: "toggle" },
+      { type: "effort", values: ["low", "medium", "high", "xhigh", "max", "ultrathink"] },
+      { type: "budget_tokens", min: 1024 },
+      { type: "budget_tokens", min: 0, max: 24_576 },
+    ]
+    const capabilities = Schema.decodeUnknownSync(Provider.Model.fields.capabilities)({
+      temperature: true,
+      reasoning: true,
+      reasoningOptions: resolved,
+      attachment: false,
+      toolcall: true,
+      input: { text: true, audio: false, image: false, video: false, pdf: false },
+      output: { text: true, audio: false, image: false, video: false, pdf: false },
+      interleaved: false,
+    })
+    expect(capabilities.reasoningOptions).toEqual(resolved as typeof capabilities.reasoningOptions)
+    expect(() =>
+      Schema.decodeUnknownSync(Provider.Model.fields.capabilities)({
+        temperature: true,
+        reasoning: true,
+        reasoningOptions: [{ type: "effort", values: [null, "low"] }],
+        attachment: false,
+        toolcall: true,
+        input: { text: true, audio: false, image: false, video: false, pdf: false },
+        output: { text: true, audio: false, image: false, video: false, pdf: false },
+        interleaved: false,
+      }),
+    ).toThrow()
+  })
+})

packages/opencode/test/provider/transform.test.ts

@@ -3962,6 +3962,226 @@ describe("ProviderTransform.variants", () => {
   })
 })
 
+describe("ProviderTransform.variants - models.dev reasoning_options", () => {
+  const createModel = (overrides: Partial<any> = {}): any => ({
+    id: "test/test-model",
+    providerID: "test",
+    api: {
+      id: "test-model",
+      url: "https://api.test.com",
+      npm: "@ai-sdk/openai-compatible",
+    },
+    name: "Test Model",
+    capabilities: {
+      temperature: true,
+      reasoning: true,
+      attachment: false,
+      toolcall: true,
+      input: { text: true, audio: false, image: false, video: false, pdf: false },
+      output: { text: true, audio: false, image: false, video: false, pdf: false },
+      interleaved: false,
+    },
+    cost: { input: 0, output: 0, cache: { read: 0, write: 0 } },
+    limit: { context: 200_000, output: 64_000 },
+    status: "active",
+    options: {},
+    headers: {},
+    release_date: "2024-01-01",
+    ...overrides,
+  })
+
+  const withOptions = (model: any, reasoningOptions: any[]) => {
+    model.capabilities.reasoningOptions = reasoningOptions
+    return model
+  }
+
+  test("effort values drive variants for openai-compatible packages", () => {
+    const model = withOptions(createModel(), [{ type: "toggle" }, { type: "effort", values: ["high", "max"] }])
+    expect(ProviderTransform.variants(model)).toEqual({
+      high: { reasoningEffort: "high" },
+      max: { reasoningEffort: "max" },
+    })
+  })
+
+  test("effort values drive variants for openai with summary and encrypted reasoning", () => {
+    const model = withOptions(createModel({ api: { id: "gpt-x", url: "", npm: "@ai-sdk/openai" } }), [
+      { type: "effort", values: ["low", "high"] },
+    ])
+    expect(ProviderTransform.variants(model)).toEqual({
+      low: { reasoningEffort: "low", reasoningSummary: "auto", include: ["reasoning.encrypted_content"] },
+      high: { reasoningEffort: "high", reasoningSummary: "auto", include: ["reasoning.encrypted_content"] },
+    })
+  })
+
+  test("null efforts, duplicates, and unknown option types are ignored", () => {
+    const model = withOptions(createModel(), [
+      { type: "future-thing", anything: true },
+      { type: "effort", values: [null, "low"] },
+      { type: "effort", values: ["low", "high"] },
+    ])
+    expect(ProviderTransform.variants(model)).toEqual({
+      low: { reasoningEffort: "low" },
+      high: { reasoningEffort: "high" },
+    })
+  })
+
+  test("toggle-only data falls back to the hardcoded tables", () => {
+    const model = withOptions(
+      createModel({
+        id: "minimax/minimax-m3",
+        providerID: "minimax",
+        api: { id: "MiniMax-M3", url: "", npm: "@ai-sdk/anthropic" },
+      }),
+      [{ type: "toggle" }],
+    )
+    expect(ProviderTransform.variants(model)).toEqual({
+      none: { thinking: { type: "disabled" } },
+      thinking: { thinking: { type: "adaptive" } },
+    })
+  })
+
+  test("budget-only data falls back to the hardcoded anthropic budget variants", () => {
+    const model = withOptions(
+      createModel({
+        id: "anthropic/claude-haiku-4-5",
+        providerID: "anthropic",
+        api: { id: "claude-haiku-4-5", url: "", npm: "@ai-sdk/anthropic" },
+      }),
+      [{ type: "budget_tokens", min: 1024 }],
+    )
+    expect(ProviderTransform.variants(model)).toEqual({
+      high: { thinking: { type: "enabled", budgetTokens: 16_000 } },
+      max: { thinking: { type: "enabled", budgetTokens: 31_999 } },
+    })
+  })
+
+  test("empty effort values fall back to the hardcoded tables", () => {
+    const model = withOptions(createModel({ api: { id: "gpt-x", url: "", npm: "@ai-sdk/openai" } }), [
+      { type: "effort", values: [] },
+    ])
+    expect(Object.keys(ProviderTransform.variants(model))).toEqual(["low", "medium", "high"])
+  })
+
+  test("anthropic adaptive models wrap data efforts in adaptive thinking", () => {
+    const model = withOptions(
+      createModel({
+        id: "anthropic/claude-sonnet-4-6",
+        providerID: "anthropic",
+        api: { id: "claude-sonnet-4-6", url: "", npm: "@ai-sdk/anthropic" },
+      }),
+      [
+        { type: "effort", values: ["low", "medium", "high", "max"] },
+        { type: "budget_tokens", min: 1024 },
+      ],
+    )
+    expect(ProviderTransform.variants(model)).toEqual({
+      low: { thinking: { type: "adaptive" }, effort: "low" },
+      medium: { thinking: { type: "adaptive" }, effort: "medium" },
+      high: { thinking: { type: "adaptive" }, effort: "high" },
+      max: { thinking: { type: "adaptive" }, effort: "max" },
+    })
+  })
+
+  test("anthropic non-adaptive models encode data efforts as plain effort", () => {
+    const model = withOptions(
+      createModel({
+        id: "anthropic/claude-opus-4-5",
+        providerID: "anthropic",
+        api: { id: "claude-opus-4-5", url: "", npm: "@ai-sdk/anthropic" },
+      }),
+      [{ type: "effort", values: ["low", "medium", "high"] }],
+    )
+    expect(ProviderTransform.variants(model)).toEqual({
+      low: { effort: "low" },
+      medium: { effort: "medium" },
+      high: { effort: "high" },
+    })
+  })
+
+  test("github-copilot anthropic models filter unsupported data efforts", () => {
+    const model = withOptions(
+      createModel({
+        id: "github-copilot/claude-sonnet-4-6",
+        providerID: "github-copilot",
+        api: { id: "claude-sonnet-4-6", url: "", npm: "@ai-sdk/anthropic" },
+      }),
+      [{ type: "effort", values: ["low", "medium", "high", "max"] }],
+    )
+    expect(Object.keys(ProviderTransform.variants(model))).toEqual(["low", "medium", "high"])
+  })
+
+  test("openrouter encodes data efforts as reasoning.effort", () => {
+    const model = withOptions(
+      createModel({
+        id: "openrouter/x-ai/grok-4.3",
+        providerID: "openrouter",
+        api: { id: "x-ai/grok-4.3", url: "", npm: "@openrouter/ai-sdk-provider" },
+      }),
+      [{ type: "effort", values: ["low", "high"] }],
+    )
+    expect(ProviderTransform.variants(model)).toEqual({
+      low: { reasoning: { effort: "low" } },
+      high: { reasoning: { effort: "high" } },
+    })
+  })
+
+  test("google encodes data efforts as thinkingConfig levels", () => {
+    const model = withOptions(
+      createModel({
+        id: "google/gemini-3-pro-preview",
+        providerID: "google",
+        api: { id: "gemini-3-pro-preview", url: "", npm: "@ai-sdk/google" },
+      }),
+      [{ type: "effort", values: ["low", "high"] }],
+    )
+    expect(ProviderTransform.variants(model)).toEqual({
+      low: { thinkingConfig: { includeThoughts: true, thinkingLevel: "low" } },
+      high: { thinkingConfig: { includeThoughts: true, thinkingLevel: "high" } },
+    })
+  })
+
+  test("bedrock non-adaptive models encode data efforts as enabled maxReasoningEffort", () => {
+    const model = withOptions(
+      createModel({
+        id: "amazon-bedrock/anthropic.claude-opus-4-5-20251101-v1:0",
+        providerID: "amazon-bedrock",
+        api: { id: "anthropic.claude-opus-4-5-20251101-v1:0", url: "", npm: "@ai-sdk/amazon-bedrock" },
+      }),
+      [{ type: "effort", values: ["low", "medium", "high"] }],
+    )
+    expect(ProviderTransform.variants(model)).toEqual({
+      low: { reasoningConfig: { type: "enabled", maxReasoningEffort: "low" } },
+      medium: { reasoningConfig: { type: "enabled", maxReasoningEffort: "medium" } },
+      high: { reasoningConfig: { type: "enabled", maxReasoningEffort: "high" } },
+    })
+  })
+
+  test("sap anthropic adaptive models wrap data efforts in modelParams", () => {
+    const model = withOptions(
+      createModel({
+        id: "sap-ai-core/anthropic--claude-4.6-sonnet",
+        providerID: "sap-ai-core",
+        api: { id: "anthropic--claude-4.6-sonnet", url: "", npm: "@jerome-benoit/sap-ai-provider-v2" },
+      }),
+      [{ type: "effort", values: ["low", "max"] }],
+    )
+    expect(ProviderTransform.variants(model)).toEqual({
+      low: { modelParams: { thinking: { type: "adaptive" }, output_config: { effort: "low" } } },
+      max: { modelParams: { thinking: { type: "adaptive" }, output_config: { effort: "max" } } },
+    })
+  })
+
+  test("unknown packages default to openai-compatible reasoningEffort", () => {
+    const model = withOptions(createModel({ api: { id: "some-model", url: "", npm: "@ai-sdk/some-future-sdk" } }), [
+      { type: "effort", values: ["low", "ultrathink"] },
+    ])
+    expect(ProviderTransform.variants(model)).toEqual({
+      low: { reasoningEffort: "low" },
+      ultrathink: { reasoningEffort: "ultrathink" },
+    })
+  })
+})
+
 describe("ProviderTransform.smallOptions - gpt-5 chat/search", () => {
   const createModel = (apiId: string) => {
     const model = {

packages/sdk/js/src/v2/gen/types.gen.ts

@@ -1816,6 +1816,20 @@ export type ProviderConfig = {
       release_date?: string
       attachment?: boolean
       reasoning?: boolean
+      reasoning_options?: Array<
+        | {
+            type: "toggle"
+          }
+        | {
+            type: "effort"
+            values: Array<string>
+          }
+        | {
+            type: "budget_tokens"
+            min?: number
+            max?: number
+          }
+      >
       temperature?: boolean
       tool_call?: boolean
       interleaved?:
@@ -2082,6 +2096,20 @@ export type Model = {
   capabilities: {
     temperature: boolean
     reasoning: boolean
+    reasoningOptions?: Array<
+      | {
+          type: "toggle"
+        }
+      | {
+          type: "effort"
+          values: Array<string>
+        }
+      | {
+          type: "budget_tokens"
+          min?: number
+          max?: number
+        }
+    >
     attachment: boolean
     toolcall: boolean
     input: {

packages/sdk/openapi.json

@@ -17917,6 +17917,58 @@
                 "reasoning": {
                   "type": "boolean"
                 },
+                "reasoning_options": {
+                  "type": "array",
+                  "items": {
+                    "anyOf": [
+                      {
+                        "type": "object",
+                        "properties": {
+                          "type": {
+                            "type": "string",
+                            "enum": ["toggle"]
+                          }
+                        },
+                        "required": ["type"],
+                        "additionalProperties": false
+                      },
+                      {
+                        "type": "object",
+                        "properties": {
+                          "type": {
+                            "type": "string",
+                            "enum": ["effort"]
+                          },
+                          "values": {
+                            "type": "array",
+                            "items": {
+                              "type": "string"
+                            }
+                          }
+                        },
+                        "required": ["type", "values"],
+                        "additionalProperties": false
+                      },
+                      {
+                        "type": "object",
+                        "properties": {
+                          "type": {
+                            "type": "string",
+                            "enum": ["budget_tokens"]
+                          },
+                          "min": {
+                            "type": "number"
+                          },
+                          "max": {
+                            "type": "number"
+                          }
+                        },
+                        "required": ["type"],
+                        "additionalProperties": false
+                      }
+                    ]
+                  }
+                },
                 "temperature": {
                   "type": "boolean"
                 },
@@ -18652,6 +18704,58 @@
               "reasoning": {
                 "type": "boolean"
               },
+              "reasoningOptions": {
+                "type": "array",
+                "items": {
+                  "anyOf": [
+                    {
+                      "type": "object",
+                      "properties": {
+                        "type": {
+                          "type": "string",
+                          "enum": ["toggle"]
+                        }
+                      },
+                      "required": ["type"],
+                      "additionalProperties": false
+                    },
+                    {
+                      "type": "object",
+                      "properties": {
+                        "type": {
+                          "type": "string",
+                          "enum": ["effort"]
+                        },
+                        "values": {
+                          "type": "array",
+                          "items": {
+                            "type": "string"
+                          }
+                        }
+                      },
+                      "required": ["type", "values"],
+                      "additionalProperties": false
+                    },
+                    {
+                      "type": "object",
+                      "properties": {
+                        "type": {
+                          "type": "string",
+                          "enum": ["budget_tokens"]
+                        },
+                        "min": {
+                          "type": "number"
+                        },
+                        "max": {
+                          "type": "number"
+                        }
+                      },
+                      "required": ["type"],
+                      "additionalProperties": false
+                    }
+                  ]
+                }
+              },
               "attachment": {
                 "type": "boolean"
               },