fix: API-scoped gpt-5.4-mini reasoning_effort suppression

chinar-amrutkar · chinar-amrutkar · commit 14f6f57acd23 · 2026-05-03T10:35:44.000+01:00
Only suppress reasoning_effort for gpt-5.4-mini in chat/completions API. Responses API paths retain GPT_52 reasoning efforts since the model supports reasoning in that context. Fixes #76176
diff --git a/src/agents/openai-reasoning-effort.test.ts b/src/agents/openai-reasoning-effort.test.ts
@@ -13,6 +13,18 @@ describe("OpenAI reasoning effort support", () => {
     expect(resolveOpenAIReasoningEffortForModel({ model, effort: "xhigh" })).toBe("xhigh");
   });
 
+  it("omits reasoning_effort for gpt-5.4-mini in chat/completions", () => {
+    const model = { provider: "openai", id: "gpt-5.4-mini", api: "openai-completions" };
+    expect(resolveOpenAISupportedReasoningEfforts(model)).toHaveLength(0);
+    expect(resolveOpenAIReasoningEffortForModel({ model, effort: "medium" })).toBeUndefined();
+  });
+
+  it("preserves reasoning_effort for gpt-5.4-mini in responses API", () => {
+    const model = { provider: "openai", id: "gpt-5.4-mini", api: "openai-responses" };
+    expect(resolveOpenAISupportedReasoningEfforts(model)).toContain("medium");
+    expect(resolveOpenAIReasoningEffortForModel({ model, effort: "medium" })).toBe("medium");
+  });
+
   it("does not downgrade xhigh when Pi compat metadata declares it explicitly", () => {
     const model = {
       provider: "openai-codex",
diff --git a/src/agents/openai-reasoning-effort.ts b/src/agents/openai-reasoning-effort.ts
@@ -80,6 +80,14 @@ export function resolveOpenAISupportedReasoningEfforts(
   if (/^gpt-5\.[2-9](?:\.\d+)?-pro(?:-|$)/u.test(id)) {
     return GPT_PRO_REASONING_EFFORTS;
   }
+  const api = normalizeLowercaseStringOrEmpty(typeof model.api === "string" ? model.api : "");
+  if (api === "openai-responses" || api === "openai-codex-responses") {
+    if (/^gpt-5\.4-mini(?:-|$)/u.test(id)) {
+      return GPT_52_REASONING_EFFORTS;
+    }
+  } else if (/^gpt-5\.4-mini(?:-|$)/u.test(id)) {
+    return [];
+  }
   if (/^gpt-5\.[2-9](?:\.\d+)?(?:-|$)/u.test(id)) {
     return GPT_52_REASONING_EFFORTS;
   }
