feat(opencode): use adaptive thinking effort for kimi family on anthr…

packages/opencode/src/provider/transform.ts

@@ -26,6 +26,20 @@ export function sanitizeSurrogates(content: string) {
   return content.replace(/[\uD800-\uDBFF](?![\uDC00-\uDFFF])|(?<![\uD800-\uDBFF])[\uDC00-\uDFFF]/g, "\uFFFD")
 }
 
+function isKimiFamily(model: Provider.Model) {
+  if (
+    [model.providerID, model.api.id].some((id) => {
+      const value = id.toLowerCase()
+      return value.includes("kimi") || value.includes("moonshot")
+    })
+  )
+    return true
+  const url = model.api.url.toLowerCase()
+  return ["api.kimi.com", "api.moonshot.ai", "api.moonshot.cn", "api.moonshotai.cn"].some((host) =>
+    url.includes(host),
+  )
+}
+
 // Maps npm package to the key the AI SDK expects for providerOptions
 function sdkKey(npm: string): string | undefined {
   switch (npm) {
@@ -707,6 +721,15 @@ export function variants(model: Provider.Model): Record<string, Record<string, a
       max: { effort: "max" },
     }
   }
+  // Kimi's Anthropic-compatible transports implement adaptive thinking effort.
+  if (isKimiFamily(model) && ["@ai-sdk/anthropic", "@ai-sdk/google-vertex/anthropic"].includes(model.api.npm)) {
+    return Object.fromEntries(
+      ["low", "medium", "high", "xhigh", "max"].map((effort) => [
+        effort,
+        { thinking: { type: "adaptive", display: "summarized" }, effort },
+      ]),
+    )
+  }
   if (
     id.includes("deepseek-chat") ||
     id.includes("deepseek-reasoner") ||
@@ -1173,15 +1196,15 @@ export function options(input: {
     result["thinking"] = { type: "adaptive" }
   }
 
-  // Enable thinking by default for kimi models using anthropic SDK
+  // Moonshot's Anthropic-compatible API uses adaptive effort rather than token budgets.
+  // Request summaries so thinking content survives replay on subsequent turns.
   if (
-    (input.model.api.npm === "@ai-sdk/anthropic" || input.model.api.npm === "@ai-sdk/google-vertex/anthropic") &&
-    (modelId.includes("k2p") || modelId.includes("kimi-k2.") || modelId.includes("kimi-k2p"))
+    ["@ai-sdk/anthropic", "@ai-sdk/google-vertex/anthropic"].includes(input.model.api.npm) &&
+    isKimiFamily(input.model) &&
+    input.model.capabilities.reasoning
   ) {
-    result["thinking"] = {
-      type: "enabled",
-      budgetTokens: Math.min(16_000, Math.floor(input.model.limit.output / 2 - 1)),
-    }
+    result["thinking"] = { type: "adaptive", display: "summarized" }
+    result["effort"] = "high"
   }
 
   // Enable thinking for reasoning models on alibaba-cn (DashScope).
@@ -1705,6 +1728,8 @@ function reasoningEffort(model: Provider.Model, effort: string) {
 
 function anthropicEffort(model: Provider.Model, effort: string) {
   if (["opus-4-5", "opus-4.5"].some((value) => model.api.id.includes(value))) return { effort }
+  // Kimi defaults to omitting adaptive thinking text unless summarized display is requested.
+  if (isKimiFamily(model)) return { thinking: { type: "adaptive", display: "summarized" }, effort }
   if (!anthropicAdaptiveEfforts(model.api.id)) return
   return {
     thinking: {

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

@@ -3029,7 +3029,13 @@ describe("ProviderTransform.temperature - Cohere North", () => {
 describe("ProviderTransform.reasoningVariants", () => {
   const model = (reasoning_options: ModelsDev.Model["reasoning_options"]) => ({ reasoning_options }) as ModelsDev.Model
   const target = (npm: string, id = "test-model") =>
-    ({ id, api: { id, npm, url: "" }, capabilities: { reasoning: true }, limit: { output: 64_000 } }) as any
+    ({
+      id,
+      providerID: "test",
+      api: { id, npm, url: "" },
+      capabilities: { reasoning: true },
+      limit: { output: 64_000 },
+    }) as any
 
   test("respects explicitly empty reasoning options", () => {
     expect(ProviderTransform.reasoningVariants(model([]), target("@ai-sdk/openai"))).toEqual({})
@@ -3119,6 +3125,19 @@ describe("ProviderTransform.reasoningVariants", () => {
     ).toEqual({ max: { effort: "max" } })
   })
 
+  test("maps Kimi effort metadata to adaptive thinking", () => {
+    expect(
+      ProviderTransform.reasoningVariants(
+        model([{ type: "effort", values: ["low", "high", "max"] }]),
+        target("@ai-sdk/anthropic", "kimi-k3"),
+      ),
+    ).toEqual({
+      low: { thinking: { type: "adaptive", display: "summarized" }, effort: "low" },
+      high: { thinking: { type: "adaptive", display: "summarized" }, effort: "high" },
+      max: { thinking: { type: "adaptive", display: "summarized" }, effort: "max" },
+    })
+  })
+
   test("uses adaptive reasoning config for Anthropic models on Bedrock", () => {
     expect(
       ProviderTransform.reasoningVariants(
@@ -5136,3 +5155,95 @@ describe("ProviderTransform.providerOptions - ai-gateway-provider", () => {
     expect(result).toEqual({ openaiCompatible: { reasoningEffort: "high" } })
   })
 })
+
+describe("ProviderTransform.options - kimi family adaptive thinking", () => {
+  const createModel = (overrides: Record<string, any> = {}) =>
+    ({
+      id: "moonshotai/kimi-k2-thinking",
+      providerID: "moonshotai",
+      api: {
+        id: "kimi-k2-thinking",
+        url: "https://api.moonshot.ai/anthropic",
+        npm: "@ai-sdk/anthropic",
+      },
+      name: "Kimi K2 Thinking",
+      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: 0.001, output: 0.002, cache: { read: 0.0001, write: 0.0002 } },
+      limit: { context: 262144, output: 262144 },
+      status: "active",
+      options: {},
+      headers: {},
+      ...overrides,
+    }) as any
+
+  test("uses adaptive thinking with effort instead of budget tokens", () => {
+    const result = ProviderTransform.options({ model: createModel(), sessionID: "s1", providerOptions: {} })
+    expect(result.thinking).toEqual({ type: "adaptive", display: "summarized" })
+    expect(result.effort).toBe("high")
+    expect(JSON.stringify(result)).not.toContain("budgetTokens")
+  })
+
+  test("uses adaptive thinking through Google Vertex Anthropic", () => {
+    const model = createModel()
+    model.api.npm = "@ai-sdk/google-vertex/anthropic"
+    const result = ProviderTransform.options({ model, sessionID: "s1", providerOptions: {} })
+    expect(result.thinking).toEqual({ type: "adaptive", display: "summarized" })
+    expect(result.effort).toBe("high")
+  })
+
+  test("provides adaptive effort variants without models.dev metadata", () => {
+    expect(ProviderTransform.variants(createModel())).toEqual(
+      Object.fromEntries(
+        ["low", "medium", "high", "xhigh", "max"].map((effort) => [
+          effort,
+          { thinking: { type: "adaptive", display: "summarized" }, effort },
+        ]),
+      ),
+    )
+
+    const model = createModel()
+    model.api.npm = "@ai-sdk/openai-compatible"
+    expect(ProviderTransform.variants(model)).toEqual({})
+  })
+
+  test("does not enable thinking for kimi models without reasoning capability", () => {
+    const model = createModel()
+    model.capabilities.reasoning = false
+    const result = ProviderTransform.options({ model, sessionID: "s1", providerOptions: {} })
+    expect(result.thinking).toBeUndefined()
+  })
+
+  test("does not set thinking defaults for non-kimi anthropic models", () => {
+    const model = createModel({
+      id: "anthropic/claude-sonnet-4-5",
+      providerID: "anthropic",
+      api: {
+        id: "claude-sonnet-4-5",
+        url: "https://api.anthropic.com",
+        npm: "@ai-sdk/anthropic",
+      },
+    })
+    const result = ProviderTransform.options({ model, sessionID: "s1", providerOptions: {} })
+    expect(result.thinking).toBeUndefined()
+    expect(result.effort).toBeUndefined()
+  })
+
+  test("does not set adaptive thinking for kimi on openai-compatible", () => {
+    const model = createModel()
+    model.api = {
+      id: "kimi-k2-thinking",
+      url: "https://api.moonshot.ai/v1",
+      npm: "@ai-sdk/openai-compatible",
+    }
+    const result = ProviderTransform.options({ model, sessionID: "s1", providerOptions: {} })
+    expect(result.thinking).toBeUndefined()
+  })
+})