fix(kiro): add Claude Sonnet 5 model support (#2264)

Co-authored-by: Cursor <cursoragent@cursor.com>

tests/__baseline__/known-fails.txt

@@ -1,6 +1,5 @@
 tests/unit/antigravity-mitm.test.js :: Antigravity MITM model handling flags the out-of-box agent/Default model mandatory
 tests/unit/claude-header-forwarding.test.js :: proxyAwareFetch — api.anthropic.com routing routes api.anthropic.com to gotScraping (non-streaming) and returns ok response
-tests/unit/kiro-model-slots.test.js :: Kiro MITM model slots offers a mappable slot for the agent default model id 'auto'
 tests/unit/oauth-cursor-auto-import.test.js :: GET /api/oauth/cursor/auto-import extracts tokens using exact keys
 tests/unit/oauth-cursor-auto-import.test.js :: GET /api/oauth/cursor/auto-import falls back to fuzzy key matching on macOS when exact keys are missing
 tests/unit/oauth-cursor-auto-import.test.js :: GET /api/oauth/cursor/auto-import linux uses single hardcoded path and original error message
@@ -23,4 +22,4 @@ tests/unit/rtk.test.js :: compressMessages (enabled) skips when body has no mess
 tests/unit/translator-request-normalization.test.js :: request normalization claudeToOpenAIRequest flattens text-only content arrays into string
 tests/unit/translator-request-normalization.test.js :: request normalization filterToOpenAIFormat flattens text-only arrays to string
 tests/unit/translator-request-normalization.test.js :: request normalization parseSSELine supports provider raw NDJSON stream lines
-tests/unit/translator-request-normalization.test.js :: request normalization translateRequest keeps /v1/messages Claude->OpenAI text payloads string-safe
+tests/unit/translator-request-normalization.test.js :: request normalization translateRequest keeps /v1/messages Claude->OpenAI text payloads string-safe

tests/unit/capabilities.test.js

@@ -2,6 +2,15 @@ import { describe, expect, it } from "vitest";
 import { getCapabilitiesForModel } from "../../open-sse/providers/capabilities.js";
 
 describe("getCapabilitiesForModel", () => {
+  const claudeSonnet5Expected = {
+    contextWindow: 1000000,
+    maxOutput: 128000,
+    thinkingFormat: "claude-adaptive",
+    reasoning: true,
+    vision: true,
+    search: true,
+  };
+
   it("reports Kiro Claude Opus 4.8 as a 1M context model", () => {
     expect(getCapabilitiesForModel("kiro", "claude-opus-4.8").contextWindow).toBe(1000000);
     expect(getCapabilitiesForModel("kiro", "anthropic/claude-opus-4.8").contextWindow).toBe(1000000);
@@ -9,4 +18,12 @@ describe("getCapabilitiesForModel", () => {
     expect(getCapabilitiesForModel("kiro", "claude-opus-4.8-thinking").contextWindow).toBe(1000000);
     expect(getCapabilitiesForModel("kiro", "claude-opus-4-8-thinking").contextWindow).toBe(1000000);
   });
+
+  it("reports Kiro Claude Sonnet 5 as a 1M adaptive-thinking model", () => {
+    expect(getCapabilitiesForModel("kiro", "claude-sonnet-5")).toMatchObject(claudeSonnet5Expected);
+    expect(getCapabilitiesForModel("kiro", "anthropic/claude-sonnet-5")).toMatchObject(claudeSonnet5Expected);
+    expect(getCapabilitiesForModel("kiro", "claude-sonnet-5-thinking")).toMatchObject(claudeSonnet5Expected);
+    expect(getCapabilitiesForModel("kiro", "claude-sonnet-5-agentic")).toMatchObject(claudeSonnet5Expected);
+    expect(getCapabilitiesForModel("kiro", "claude-sonnet-5-thinking-agentic")).toMatchObject(claudeSonnet5Expected);
+  });
 });

tests/unit/kiro-model-slots.test.js

@@ -1,12 +1,10 @@
 import { describe, expect, it } from "vitest";
+import { PROVIDER_MODELS } from "../../open-sse/config/providerModels.js";
 import { MITM_TOOLS } from "../../src/shared/constants/cliTools.js";
 
-// Guards the fix in commit 356607c: Kiro's agent/"vibe" mode sends modelId
-// "auto" for the main turn and "simple-task" for background sub-tasks. Both
-// need a mappable defaultModels slot — otherwise getMappedModel (src/mitm/server.js)
-// returns null and the /generateAssistantResponse call is passed through to AWS
-// instead of being routed to the user's chosen provider (surfacing as Kiro's
-// "monthly usage limit" once the AWS quota is gone).
+// Guards Kiro model ids that still need mappable defaultModels slots. Without
+// a slot, getMappedModel (src/mitm/server.js) returns null and the request is
+// passed through to AWS instead of being routed to the user's chosen provider.
 describe("Kiro MITM model slots", () => {
   const kiro = MITM_TOOLS.kiro;
 
@@ -16,10 +14,10 @@ describe("Kiro MITM model slots", () => {
     expect(Array.isArray(kiro.defaultModels)).toBe(true);
   });
 
-  it("offers a mappable slot for the agent default model id 'auto'", () => {
-    const auto = kiro.defaultModels.find((m) => m.id === "auto");
-    expect(auto).toBeTruthy();
-    expect(auto.alias).toBe("auto");
+  it("offers a mappable slot for Claude Sonnet 5", () => {
+    const sonnet5 = kiro.defaultModels.find((m) => m.id === "claude-sonnet-5");
+    expect(sonnet5).toBeTruthy();
+    expect(sonnet5.alias).toBe("claude-sonnet-5");
   });
 
   it("offers a mappable slot for the background sub-task model id 'simple-task'", () => {
@@ -28,3 +26,15 @@ describe("Kiro MITM model slots", () => {
     expect(simpleTask.alias).toBe("simple-task");
   });
 });
+
+describe("Kiro static provider models", () => {
+  it("includes Claude Sonnet 5 and its synthetic Kiro variants", () => {
+    const ids = (PROVIDER_MODELS.kr || []).map((model) => model.id);
+    expect(ids).toEqual(expect.arrayContaining([
+      "claude-sonnet-5",
+      "claude-sonnet-5-thinking",
+      "claude-sonnet-5-agentic",
+      "claude-sonnet-5-thinking-agentic",
+    ]));
+  });
+});