Support xhigh only on Claude models that expose it

open-sse/config/providerRegistry.ts

@@ -26,6 +26,7 @@ export interface RegistryModel {
   toolCalling?: boolean;
   supportsReasoning?: boolean;
   supportsVision?: boolean;
+  supportsXHighEffort?: boolean;
   targetFormat?: string;
   unsupportedParams?: readonly string[];
   /** Maximum context window in tokens */
@@ -277,12 +278,20 @@ export const REGISTRY: Record<string, RegistryEntry> = {
       tokenUrl: "https://console.anthropic.com/v1/oauth/token",
     },
     models: [
-      { 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 4.6 Sonnet" },
-      { id: "claude-opus-4-5-20251101", name: "Claude 4.5 Opus" },
-      { id: "claude-sonnet-4-5-20250929", name: "Claude 4.5 Sonnet" },
-      { id: "claude-haiku-4-5-20251001", name: "Claude 4.5 Haiku" },
+      { id: "claude-opus-4-7", name: "Claude Opus 4.7", supportsXHighEffort: true },
+      { id: "claude-opus-4-6", name: "Claude Opus 4.6", supportsXHighEffort: false },
+      { id: "claude-sonnet-4-6", name: "Claude 4.6 Sonnet", supportsXHighEffort: false },
+      { id: "claude-opus-4-5-20251101", name: "Claude 4.5 Opus", supportsXHighEffort: false },
+      {
+        id: "claude-sonnet-4-5-20250929",
+        name: "Claude 4.5 Sonnet",
+        supportsXHighEffort: false,
+      },
+      {
+        id: "claude-haiku-4-5-20251001",
+        name: "Claude 4.5 Haiku",
+        supportsXHighEffort: false,
+      },
     ],
   },
 

open-sse/services/claudeCodeCompatible.ts

@@ -1,6 +1,7 @@
 import { createHash, randomUUID } from "node:crypto";
 
 import { getStainlessTimeoutSeconds } from "@/shared/utils/runtimeTimeouts";
+import { getModelsByProviderId } from "../config/providerModels.ts";
 import { prepareClaudeRequest } from "../translator/helpers/claudeHelper.ts";
 import { signRequestBody } from "./claudeCodeCCH.ts";
 import { computeFingerprint, extractFirstUserMessageText } from "./claudeCodeFingerprint.ts";
@@ -46,6 +47,11 @@ export const CLAUDE_CODE_COMPATIBLE_BILLING_HEADER = `x-anthropic-billing-header
 export const CLAUDE_CODE_COMPATIBLE_STAINLESS_TIMEOUT_SECONDS = getStainlessTimeoutSeconds(
   process.env
 );
+const CLAUDE_XHIGH_SUPPORTED_MODELS = new Set(
+  getModelsByProviderId("claude")
+    .filter((model) => model.supportsXHighEffort)
+    .map((model) => model.id)
+);
 
 type HeaderLike =
   | Headers
@@ -71,6 +77,10 @@ type BuildRequestOptions = {
   preserveCacheControl?: boolean;
 };
 
+function supportsClaudeXHighEffort(model: string | null | undefined): boolean {
+  return typeof model === "string" && CLAUDE_XHIGH_SUPPORTED_MODELS.has(model);
+}
+
 export function isClaudeCodeCompatibleProvider(provider: string | null | undefined): boolean {
   return typeof provider === "string" && provider.startsWith(CLAUDE_CODE_COMPATIBLE_PREFIX);
 }
@@ -331,7 +341,7 @@ export function resolveClaudeCodeCompatibleEffort(
   sourceBody?: Record<string, unknown> | null,
   normalizedBody?: Record<string, unknown> | null,
   model?: string | null
-): "low" | "medium" | "high" {
+): "low" | "medium" | "high" | "xhigh" {
   const raw =
     readNestedString(sourceBody, ["output_config", "effort"]) ||
     readNestedString(sourceBody, ["reasoning", "effort"]) ||
@@ -342,14 +352,16 @@ export function resolveClaudeCodeCompatibleEffort(
     "";
 
   const normalizedEffort = raw.toLowerCase();
-  void model;
 
   if (!normalizedEffort) return "high";
   if (normalizedEffort === "low") return "low";
   if (normalizedEffort === "medium") return "medium";
   if (normalizedEffort === "high") return "high";
   if (normalizedEffort === "none" || normalizedEffort === "disabled") return "low";
-  if (normalizedEffort === "max" || normalizedEffort === "xhigh") {
+  if (normalizedEffort === "xhigh") {
+    return supportsClaudeXHighEffort(model) ? "xhigh" : "high";
+  }
+  if (normalizedEffort === "max") {
     return "high";
   }
   return "high";

tests/unit/cc-compatible-provider.test.ts

@@ -142,6 +142,23 @@ test("buildClaudeCodeCompatibleRequest keeps prior role history while dropping t
   assert.equal(JSON.parse(payload.metadata.user_id).session_id, "session-1");
 });
 
+test("buildClaudeCodeCompatibleRequest preserves xhigh for Claude models that support it", () => {
+  const payload = buildClaudeCodeCompatibleRequest({
+    sourceBody: {
+      reasoning_effort: "xhigh",
+    },
+    normalizedBody: {
+      messages: [{ role: "user", content: "u1" }],
+    },
+    model: "claude-opus-4-7",
+    cwd: "/tmp/work",
+    now: new Date("2026-04-01T12:00:00.000Z"),
+  });
+
+  assert.equal(payload.output_config.effort, "xhigh");
+  assert.equal(payload.thinking.type, "adaptive");
+});
+
 test("buildClaudeCodeCompatibleRequest preserves Claude cache markers when requested", () => {
   const payload = buildClaudeCodeCompatibleRequest({
     sourceBody: {

tests/unit/claude-code-compatible-request.test.ts

@@ -11,6 +11,7 @@ const {
   resolveClaudeCodeCompatibleMaxTokens,
   buildClaudeCodeCompatibleRequest,
 } = await import("../../open-sse/services/claudeCodeCompatible.ts");
+const { getModelsByProviderId } = await import("../../open-sse/config/providerModels.ts");
 
 test("Claude Code compatible URL helpers cover empty values, version trimming and legacy session headers", () => {
   assert.equal(stripClaudeCodeCompatibleEndpointSuffix(""), "");
@@ -33,9 +34,33 @@ test("Claude Code compatible URL helpers cover empty values, version trimming an
 });
 
 test("Claude Code compatible effort and max token helpers cover priority fallbacks", () => {
+  const claudeModels = getModelsByProviderId("claude");
+  assert.equal(
+    claudeModels.find((model) => model.id === "claude-opus-4-7")?.supportsXHighEffort,
+    true
+  );
+  assert.equal(
+    claudeModels.find((model) => model.id === "claude-opus-4-6")?.supportsXHighEffort,
+    false
+  );
   assert.equal(resolveClaudeCodeCompatibleEffort({ reasoning_effort: "medium" }), "medium");
   assert.equal(resolveClaudeCodeCompatibleEffort({ reasoning: { effort: "none" } }), "low");
-  assert.equal(resolveClaudeCodeCompatibleEffort({ output_config: { effort: "xhigh" } }), "high");
+  assert.equal(
+    resolveClaudeCodeCompatibleEffort(
+      { output_config: { effort: "xhigh" } },
+      null,
+      "claude-opus-4-7"
+    ),
+    "xhigh"
+  );
+  assert.equal(
+    resolveClaudeCodeCompatibleEffort(
+      { output_config: { effort: "xhigh" } },
+      null,
+      "claude-opus-4-6"
+    ),
+    "high"
+  );
   assert.equal(
     resolveClaudeCodeCompatibleEffort({ output_config: { effort: "unexpected" } }),
     "high"