From ccd0677dc1fd4a31cc75013c417f53b6b0bdeff6 Mon Sep 17 00:00:00 2001
From: Amirsalar Sojoudi <amirsalaar@gmail.com>
Date: Thu, 1 Oct 2026 10:06:58 +0700
Subject: [PATCH] fix(claude): resolve Sonnet 5.x to adaptive thinking so no
 forged thinking placeholders are sent

---
 open-sse/providers/capabilities.js         |  1 +
 tests/unit/capabilities-sonnet-5-5.test.js | 21 +++++++++++++++++++++
 2 files changed, 22 insertions(+)
 create mode 100644 tests/unit/capabilities-sonnet-5-5.test.js

diff --git a/open-sse/providers/capabilities.js b/open-sse/providers/capabilities.js
index 1e4240c8..39d116ee 100644
--- a/open-sse/providers/capabilities.js
+++ b/open-sse/providers/capabilities.js
@@ -286,6 +286,7 @@ PROVIDER_CAPABILITIES.cx = PROVIDER_CAPABILITIES.codex;
 export const PATTERN_CAPABILITIES = [
   // ── Claude (4.6+ = adaptive thinking; older/haiku = budget) ──────
   { pattern: "*claude*opus-5*",     caps: { vision: true, reasoning: true, search: true, thinkingFormat: "claude-adaptive", contextWindow: 1000000, maxOutput: 128000 } },
+  { pattern: "*claude*sonnet-5*",   caps: { vision: true, reasoning: true, search: true, thinkingFormat: "claude-adaptive", contextWindow: 1000000, maxOutput: 128000 } },
   { pattern: "*claude*opus-4.6*",   caps: { vision: true, reasoning: true, search: true, thinkingFormat: "claude-adaptive" } },
   { pattern: "*claude*opus-4.7*",   caps: { vision: true, reasoning: true, search: true, thinkingFormat: "claude-adaptive" } },
   { pattern: "*claude*opus-4.8*",   caps: { vision: true, reasoning: true, search: true, thinkingFormat: "claude-adaptive" } },
diff --git a/tests/unit/capabilities-sonnet-5-5.test.js b/tests/unit/capabilities-sonnet-5-5.test.js
new file mode 100644
index 00000000..824bc309
--- /dev/null
+++ b/tests/unit/capabilities-sonnet-5-5.test.js
@@ -0,0 +1,21 @@
+import { describe, expect, it } from "vitest";
+
+import { getCapabilitiesForModel } from "../../open-sse/providers/capabilities.js";
+
+// claude-sonnet-5-5 has no exact entry and matched only the generic *claude*sonnet*
+// pattern (claude-budget). That sent thinking.type "enabled" and made the translator
+// forge signed thinking placeholders on every tool_use turn; Sonnet 5.5 answered
+// large Codex conversations with stop_reason "refusal". It must resolve like the
+// rest of the 5.x family: adaptive thinking, 1M context.
+describe("Claude Sonnet 5.5 capabilities", () => {
+  for (const model of ["claude-sonnet-5-5", "claude-sonnet-5.5", "anthropic/claude-sonnet-5-5"]) {
+    it(`${model} resolves to adaptive thinking + 1M context`, () => {
+      expect(getCapabilitiesForModel("claude", model)).toMatchObject({
+        thinkingFormat: "claude-adaptive",
+        contextWindow: 1000000,
+        maxOutput: 128000,
+        reasoning: true,
+      });
+    });
+  }
+});