fix(llm): Opus 4.8 support — adaptive-only thinking, correct headers, pricing verified

- Force adaptive thinking for Opus 4.7+/4.8 (type:"enabled" returns 400)
- Skip interleaved-thinking beta header for adaptive mode (auto-enabled per docs)
- Fix degradeProviderOptions to use adaptive + effort:low for Opus 4.7+
- Fix compat-reasoning opencode-zen path for adaptive-only models
- Fix copilot context windows: opus-4.6/4.7 → 1M, sonnet-4.6 → 1M
- Add isAdaptiveOnly() helper to model-id.ts
- Update provider count tests for NIM provider (21 → 22)

Co-Authored-By: SoulForge <[email protected]>

src/core/llm/compat-reasoning.ts

@@ -4,6 +4,7 @@
  *  Each provider's createModel imports from here directly. */
 
 import type { AppConfig } from "../../types/index.js";
+import { isAdaptiveOnly } from "./model-id.js";
 
 function parseProvider(modelId: string): { provider: string; model: string } {
   const slash = modelId.indexOf("/");
@@ -62,6 +63,10 @@ export function getCompatReasoningBody(
   // Zen's normaliser forwards the OpenAI-compat /v1/chat/completions request
   // to upstream Anthropic which expects { thinking: { type, budget_tokens } }.
   if (isClaude && provider === "opencode-zen") {
+    // Opus 4.7+ only supports adaptive thinking — type:"enabled" returns 400.
+    if (isAdaptiveOnly(base)) {
+      return { thinking: { type: "adaptive" } };
+    }
     const explicitBudget = config.thinking?.budgetTokens;
     const budget =
       explicitBudget ?? { low: 2048, medium: 5000, high: 10000, xhigh: 20000 }[effort] ?? 5000;

src/core/llm/model-id.ts

@@ -40,3 +40,10 @@ export function supportsTemperature(modelId: string): boolean {
   if (!v) return true;
   return v.major < 5 && (v.major < 4 || v.minor < 7);
 }
+/** Opus 4.7+ only supports adaptive thinking — rejects type:"enabled" with budget_tokens. */
+export function isAdaptiveOnly(modelId: string): boolean {
+  const base = extractBaseModel(modelId);
+  const v = parseOpusVersion(base);
+  if (!v) return false;
+  return v.major >= 5 || (v.major === 4 && v.minor >= 7);
+}

src/core/llm/provider-options.ts

@@ -3,6 +3,7 @@ import type { AppConfig, ContextManagementConfig, EffortLevel } from "../../type
 import {
   extractBaseModel as _leafExtractBaseModel,
   getModelId as _leafGetModelId,
+  isAdaptiveOnly as _leafIsAdaptiveOnly,
   parseOpusVersion as _leafParseOpusVersion,
   supportsTemperature as _leafSupportsTemperature,
 } from "./model-id.js";
@@ -10,6 +11,7 @@ import { getModelContextWindow } from "./models.js";
 import { getProvider } from "./providers/index.js";
 
 const parseOpusVersion = _leafParseOpusVersion;
+const isAdaptiveOnly = _leafIsAdaptiveOnly;
 
 export const extractBaseModel = _leafExtractBaseModel;
 export const getModelId = _leafGetModelId;
@@ -647,7 +649,9 @@ async function buildAnthropicOptions(
 
   if (caps.thinking) {
     const mode = config.thinking?.mode ?? "off";
-    if (mode === "auto" || mode === "adaptive") {
+    const adaptiveOnly = isAdaptiveOnly(modelId);
+    if (mode === "auto" || mode === "adaptive" || (mode === "enabled" && adaptiveOnly)) {
+      // Opus 4.7+ only supports adaptive thinking — type:"enabled" returns 400.
       if (caps.adaptiveThinking) {
         opts.thinking = { type: "adaptive" };
         thinkingEnabled = true;
@@ -690,7 +694,9 @@ async function buildAnthropicOptions(
     }
   }
 
-  if (thinkingEnabled && caps.interleavedThinking) {
+  // Interleaved thinking: adaptive mode enables it automatically (no header needed).
+  // Manual mode on Sonnet 4.6 still requires the beta header.
+  if (thinkingEnabled && caps.interleavedThinking && opts.thinking?.type !== "adaptive") {
     headers["anthropic-beta"] = "interleaved-thinking-2025-05-14";
   }
 
@@ -846,7 +852,9 @@ export function degradeProviderOptions(modelId: string, level: number): Provider
 
   if (caps.anthropicOptions && caps.thinking) {
     // biome-ignore lint/suspicious/noExplicitAny: ProviderOptions inner shape is parsed by Zod at runtime
-    const opts: Record<string, any> = { thinking: { type: "enabled", budgetTokens: 5_000 } };
+    const opts: Record<string, any> = isAdaptiveOnly(modelId)
+      ? { thinking: { type: "adaptive" }, effort: "low" }
+      : { thinking: { type: "enabled", budgetTokens: 5_000 } };
     providerOptions.anthropic = opts;
   }
 
@@ -873,9 +881,9 @@ export function degradeProviderOptions(modelId: string, level: number): Provider
   }
 
   if (caps.bedrockOptions && caps.thinking) {
-    providerOptions.bedrock = {
-      reasoningConfig: { type: "enabled", budgetTokens: 5_000 },
-    };
+    providerOptions.bedrock = isAdaptiveOnly(modelId)
+      ? { reasoningConfig: { type: "adaptive", maxReasoningEffort: "low" } }
+      : { reasoningConfig: { type: "enabled", budgetTokens: 5_000 } };
   }
 
   return {

src/core/llm/providers/anthropic.ts

@@ -52,6 +52,7 @@ export const anthropic: ProviderDefinition = {
   },
 
   fallbackModels: [
+    { id: "claude-opus-4-8", name: "Claude Opus 4.8" },
     { id: "claude-opus-4-7", name: "Claude Opus 4.7" },
     { id: "claude-opus-4-6", name: "Claude Opus 4.6" },
     { id: "claude-sonnet-4-6", name: "Claude Sonnet 4.6" },
@@ -63,6 +64,7 @@ export const anthropic: ProviderDefinition = {
   ],
 
   contextWindows: [
+    ["claude-opus-4-8", 1_000_000],
     ["claude-opus-4-7", 1_000_000],
     ["claude-opus-4-6", 1_000_000],
     ["claude-sonnet-4-6", 1_000_000],

src/core/llm/providers/bedrock.ts

@@ -31,6 +31,7 @@ export const bedrock: ProviderDefinition = {
   },
 
   fallbackModels: [
+    { id: "anthropic.claude-opus-4-8", name: "Claude Opus 4.8" },
     { id: "anthropic.claude-sonnet-4-20250514-v1:0", name: "Claude Sonnet 4" },
     { id: "anthropic.claude-haiku-4-5-20251001-v1:0", name: "Claude Haiku 4.5" },
     { id: "us.amazon.nova-pro-v1:0", name: "Amazon Nova Pro" },
@@ -39,6 +40,10 @@ export const bedrock: ProviderDefinition = {
   ],
 
   contextWindows: [
+    ["claude-opus-4-8", 1_000_000],
+    ["claude-opus-4-7", 1_000_000],
+    ["claude-opus-4-6", 1_000_000],
+    ["claude-sonnet-4-6", 1_000_000],
     ["claude-sonnet-4", 200_000],
     ["claude-opus-4", 200_000],
     ["claude-haiku-4", 200_000],

src/core/llm/providers/copilot.ts

@@ -209,8 +209,10 @@ export const copilot: ProviderDefinition = {
   },
 
   fallbackModels: [
-    { id: "claude-opus-4.6", name: "Claude Opus 4.6", contextWindow: 200_000 },
-    { id: "claude-sonnet-4.6", name: "Claude Sonnet 4.6", contextWindow: 200_000 },
+    { id: "claude-opus-4.8", name: "Claude Opus 4.8", contextWindow: 1_000_000 },
+    { id: "claude-opus-4.7", name: "Claude Opus 4.7", contextWindow: 1_000_000 },
+    { id: "claude-opus-4.6", name: "Claude Opus 4.6", contextWindow: 1_000_000 },
+    { id: "claude-sonnet-4.6", name: "Claude Sonnet 4.6", contextWindow: 1_000_000 },
     { id: "claude-sonnet-4", name: "Claude Sonnet 4", contextWindow: 128_000 },
     { id: "claude-opus-4.5", name: "Claude Opus 4.5", contextWindow: 200_000 },
     { id: "claude-sonnet-4.5", name: "Claude Sonnet 4.5", contextWindow: 200_000 },
@@ -226,8 +228,10 @@ export const copilot: ProviderDefinition = {
   ],
 
   contextWindows: [
-    ["claude-opus-4.6", 200_000],
-    ["claude-sonnet-4.6", 200_000],
+    ["claude-opus-4.8", 1_000_000],
+    ["claude-opus-4.7", 1_000_000],
+    ["claude-opus-4.6", 1_000_000],
+    ["claude-sonnet-4.6", 1_000_000],
     ["claude-opus-4.5", 200_000],
     ["claude-sonnet-4.5", 200_000],
     ["claude-sonnet-4", 128_000],

src/core/llm/providers/llmgateway.ts

@@ -33,6 +33,7 @@ export const llmgateway: ProviderDefinition = {
   },
 
   fallbackModels: [
+    { id: "claude-opus-4-8", name: "Claude Opus 4.8" },
     { id: "claude-opus-4-7", name: "Claude Opus 4.7" },
     { id: "claude-opus-4-6", name: "Claude Opus 4.6" },
     { id: "claude-sonnet-4-6", name: "Claude Sonnet 4.6" },
@@ -63,6 +64,7 @@ export const llmgateway: ProviderDefinition = {
   // Specific overrides first → shared patterns → generic catch-alls last.
   contextWindows: [
     // Claude (LLM Gateway uses hyphens: claude-opus-4-6)
+    ["claude-opus-4-8", 1_000_000],
     ["claude-opus-4-7", 1_000_000],
     ["claude-opus-4-6", 1_000_000],
     ["claude-sonnet-4-6", 200_000],

src/core/llm/providers/opencode-zen.ts

@@ -72,6 +72,7 @@ export const opencodeZen: ProviderDefinition = {
     { id: "gpt-5", name: "GPT 5" },
     { id: "gpt-5-codex", name: "GPT 5 Codex" },
     { id: "gpt-5-nano", name: "GPT 5 Nano" },
+    { id: "claude-opus-4-8", name: "Claude Opus 4.8" },
     { id: "claude-opus-4-7", name: "Claude Opus 4.7" },
     { id: "claude-opus-4-6", name: "Claude Opus 4.6" },
     { id: "claude-opus-4-5", name: "Claude Opus 4.5" },
@@ -133,6 +134,7 @@ export const opencodeZen: ProviderDefinition = {
     ["gpt-5-codex", 400_000],
     ["gpt-5-nano", 400_000],
     // Claude (hyphen-style on Zen)
+    ["claude-opus-4-8", 1_000_000],
     ["claude-opus-4-7", 1_000_000],
     ["claude-opus-4-6", 1_000_000],
     ["claude-opus-4-5", 200_000],
@@ -142,6 +144,7 @@ export const opencodeZen: ProviderDefinition = {
     ["claude-sonnet-4", 200_000],
     ["claude-haiku-4-5", 200_000],
     // also tolerate dot-style if returned
+    ["claude-opus-4.8", 1_000_000],
     ["claude-opus-4.6", 1_000_000],
     ["claude-sonnet-4.6", 1_000_000],
     ["claude-sonnet-4.5", 1_000_000],

src/core/llm/providers/openrouter.ts

@@ -28,6 +28,7 @@ export const openrouter: ProviderDefinition = {
   },
 
   fallbackModels: [
+    { id: "anthropic/claude-opus-4.8", name: "Claude Opus 4.8" },
     { id: "anthropic/claude-opus-4.7", name: "Claude Opus 4.7" },
     { id: "anthropic/claude-opus-4.6", name: "Claude Opus 4.6" },
     { id: "anthropic/claude-sonnet-4.6", name: "Claude Sonnet 4.6" },
@@ -68,6 +69,8 @@ export const openrouter: ProviderDefinition = {
   // Specific overrides must NOT be substrings of shared patterns (ordering matters).
   contextWindows: [
     // Claude (OpenRouter uses dots: claude-opus-4.6)
+    ["claude-opus-4.8", 1_000_000],
+    ["claude-opus-4.7", 1_000_000],
     ["claude-opus-4.6", 1_000_000],
     ["claude-sonnet-4.6", 1_000_000],
     ["claude-sonnet-4.5", 1_000_000],

src/core/llm/providers/proxy.ts

@@ -66,6 +66,7 @@ export const proxy: ProviderDefinition = {
   },
 
   fallbackModels: [
+    { id: "claude-opus-4-8", name: "Claude Opus 4.8" },
     { id: "claude-opus-4-7", name: "Claude Opus 4.7" },
     { id: "claude-opus-4-6", name: "Claude Opus 4.6" },
     { id: "claude-sonnet-4-6", name: "Claude Sonnet 4.6" },
@@ -79,6 +80,8 @@ export const proxy: ProviderDefinition = {
   // Specific overrides first → shared patterns → generic catch-alls last.
   contextWindows: [
     // Claude (both dot/hyphen styles)
+    ["claude-opus-4-8", 1_000_000],
+    ["claude-opus-4.8", 1_000_000],
     ["claude-opus-4-7", 1_000_000],
     ["claude-opus-4.7", 1_000_000],
     ["claude-opus-4-6", 1_000_000],

src/stores/statusbar.ts

@@ -47,6 +47,7 @@ const MODEL_PRICING: Record<string, ModelPricing> = {
   // cacheWrite = 5-min TTL (1.25× base). 1h TTL would be 2× base; SDK doesn't
   // expose which TTL was used, and we always request the 5m default.
   // cacheRead = 0.1× base input.
+  "claude-opus-4-8": { input: 5, cacheWrite: 6.25, cacheRead: 0.5, output: 25 },
   "claude-opus-4-7": { input: 5, cacheWrite: 6.25, cacheRead: 0.5, output: 25 },
   "claude-opus-4-6": { input: 5, cacheWrite: 6.25, cacheRead: 0.5, output: 25 },
   "claude-opus-4-5": { input: 5, cacheWrite: 6.25, cacheRead: 0.5, output: 25 },
@@ -186,9 +187,14 @@ const COPILOT_PRICING: Record<string, ModelPricing> = {
   "claude-opus-4.6": M3,
   // multiplier 7.5
   "claude-opus-4.7": M75,
+  "claude-opus-4.8": M75,
+  // multiplier 7.5
   "gpt-5.5": M75,
-  // multiplier 30 (Opus 4.6 fast mode preview)
+  // multiplier 10 (Opus 4.8 fast mode)
+  "claude-opus-4.8-fast": { input: 20, cacheWrite: 20, cacheRead: 2, output: 100 },
+  // multiplier 30 (Opus 4.6/4.7 fast mode)
   "claude-opus-4.6-fast": M30,
+  "claude-opus-4.7-fast": M30,
 };
 
 function matchCopilotPricing(model: string): ModelPricing | undefined {
@@ -269,7 +275,7 @@ function matchPricing(modelId: string): ModelPricing {
     if (id.includes(key)) return pricing;
   }
   // Fallback heuristics for unknown variants / OpenRouter prefixed IDs
-  if (id.includes("opus")) return MODEL_PRICING["claude-opus-4-6"] ?? DEFAULT_PRICING;
+  if (id.includes("opus")) return MODEL_PRICING["claude-opus-4-8"] ?? DEFAULT_PRICING;
   if (id.includes("sonnet")) return DEFAULT_PRICING;
   if (id.includes("haiku")) return MODEL_PRICING["claude-haiku-4-5"] ?? DEFAULT_PRICING;
   if (id.includes("gemini")) return MODEL_PRICING["gemini-2.5-flash"] ?? DEFAULT_PRICING;

tests/codex-provider.test.ts

@@ -23,7 +23,7 @@ const BASE_OPTIONS: LanguageModelV2CallOptions = {
 describe("codex provider", () => {
   test("is registered as a builtin provider", () => {
     expect(getProvider("codex")).toBeDefined();
-    expect(getAllProviders().filter((provider) => !provider.custom)).toHaveLength(21);
+    expect(getAllProviders().filter((provider) => !provider.custom)).toHaveLength(22);
   });
 
   test("has provider metadata, fallback models, and shared auth hook", () => {

tests/local-providers.test.ts

@@ -14,9 +14,9 @@ describe("local providers registration", () => {
 		expect(getProvider("lmstudio")!.custom).toBeUndefined();
 	});
 
-	test("total builtin count is 21", () => {
+	test("total builtin count is 22", () => {
 		const builtins = getAllProviders().filter((p) => !p.custom);
-		expect(builtins.length).toBe(21);
+		expect(builtins.length).toBe(22);
 	});
 
 	test("ollama has required fields", () => {

tests/new-providers.test.ts

@@ -37,8 +37,8 @@ describe("new providers registration", () => {
 
 	test("total builtin count increased by 5", () => {
 		const builtins = getAllProviders().filter((p) => !p.custom);
-		// Was 13, then 18 after the previous provider batch, now 21 with Codex + OpenCode.
-		expect(builtins.length).toBe(21);
+		// Was 13, then 18 after the previous provider batch, now 22 with Codex + OpenCode + NIM.
+		expect(builtins.length).toBe(22);
 	});
 });