From 4f02ace7de3f83a4c07db06d7656ed802f8a003e Mon Sep 17 00:00:00 2001
From: YeonGyu-Kim <code.yeon.gyu@gmail.com>
Date: Sun, 12 Apr 2026 02:28:36 +0900
Subject: [PATCH] fix(shared): guard maxOutputTokens <= 0 in model settings
 compatibility (#3305)
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When model metadata reports maxOutputTokens as 0 or negative, the
clamp logic would set maxTokens to 0 and break generation. Added
a positive-value guard so invalid metadata is ignored and the
user-requested maxTokens is preserved.

🤖 Generated with OhMyOpenCode assistance
https://github.com/code-yeongyu/oh-my-opencode
---
 .../model-settings-compatibility.test.ts      | 24 +++++++++++++++++++
 src/shared/model-settings-compatibility.ts    |  1 +
 2 files changed, 25 insertions(+)

diff --git a/src/shared/model-settings-compatibility.test.ts b/src/shared/model-settings-compatibility.test.ts
index d9b8a455d..6e7a7b590 100644
--- a/src/shared/model-settings-compatibility.test.ts
+++ b/src/shared/model-settings-compatibility.test.ts
@@ -486,6 +486,30 @@ describe("resolveCompatibleModelSettings", () => {
     ])
   })
 
+  test("#given capabilities.maxOutputTokens is 0 #then maxTokens preserved unchanged", () => {
+    const result = resolveCompatibleModelSettings({
+      providerID: "openai",
+      modelID: "gpt-5.4",
+      desired: { maxTokens: 200_000 },
+      capabilities: { maxOutputTokens: 0 },
+    })
+
+    expect(result.maxTokens).toBe(200_000)
+    expect(result.changes).toEqual([])
+  })
+
+  test("#given capabilities.maxOutputTokens is -1 #then maxTokens preserved unchanged", () => {
+    const result = resolveCompatibleModelSettings({
+      providerID: "openai",
+      modelID: "gpt-5.4",
+      desired: { maxTokens: 200_000 },
+      capabilities: { maxOutputTokens: -1 },
+    })
+
+    expect(result.maxTokens).toBe(200_000)
+    expect(result.changes).toEqual([])
+  })
+
   // Passthrough: undefined desired values produce no changes
   test("no-op when desired settings are empty", () => {
     const result = resolveCompatibleModelSettings({
diff --git a/src/shared/model-settings-compatibility.ts b/src/shared/model-settings-compatibility.ts
index f39875f43..974d75619 100644
--- a/src/shared/model-settings-compatibility.ts
+++ b/src/shared/model-settings-compatibility.ts
@@ -165,6 +165,7 @@ export function resolveCompatibleModelSettings(
   if (
     maxTokens !== undefined &&
     input.capabilities?.maxOutputTokens !== undefined &&
+    input.capabilities.maxOutputTokens > 0 &&
     maxTokens > input.capabilities.maxOutputTokens
   ) {
     changes.push({