diff --git a/.osc-metadata/sync.json b/.osc-metadata/sync.json
new file mode 100644
index 00000000..62fdbcaa
--- /dev/null
+++ b/.osc-metadata/sync.json
@@ -0,0 +1,5 @@
+{
+  "fork_synced_at": "2026-07-12T08:08:26.930714+00:00",
+  "commits_behind_before_sync": 0,
+  "action_taken": "noop"
+}
\ No newline at end of file
diff --git a/app/api/chat/route.ts b/app/api/chat/route.ts
index c7de122e..446ace2d 100644
--- a/app/api/chat/route.ts
+++ b/app/api/chat/route.ts
@@ -16,6 +16,7 @@ import {
     getAIModel,
     SINGLE_SYSTEM_PROVIDERS,
     supportsPromptCaching,
+    supportsTemperature,
 } from "@/lib/ai-providers"
 import { findCachedResponse } from "@/lib/cached-responses"
 import {
@@ -254,6 +255,16 @@ async function handleChatRequest(req: Request): Promise<Response> {
         `[Prompt Caching] ${shouldCache ? "ENABLED" : "DISABLED"} for model: ${modelId}`,
     )
 
+    const configuredTemperature = process.env.TEMPERATURE
+    const temperature = supportsTemperature(modelId)
+        ? configuredTemperature
+        : undefined
+    if (configuredTemperature !== undefined && temperature === undefined) {
+        console.log(
+            `[Temperature] SKIPPED for model: ${modelId} (parameter is not supported)`,
+        )
+    }
+
     // Get the appropriate system prompt based on model (extended for Opus/Haiku 4.5)
     const systemMessage = getSystemPrompt(modelId, minimalStyle)
     const finalSystemMessage = customSystemMessage
@@ -762,8 +773,8 @@ Call this tool to get shape names and usage syntax for a specific library.`,
                 },
             },
         },
-        ...(process.env.TEMPERATURE !== undefined && {
-            temperature: parseFloat(process.env.TEMPERATURE),
+        ...(temperature !== undefined && {
+            temperature: parseFloat(temperature),
         }),
     })
 
diff --git a/env.example b/env.example
index d1fafb5c..d59ee91e 100644
--- a/env.example
+++ b/env.example
@@ -118,7 +118,8 @@ AI_MODEL=global.anthropic.claude-sonnet-4-5-20250929-v1:0
 
 # Temperature (Optional)
 # Controls randomness in AI responses. Lower = more deterministic.
-# Leave unset for models that don't support temperature (e.g., GPT-5.1 reasoning models)
+# Automatically ignored for Claude Opus 4.7/4.8 models that deprecate temperature.
+# Leave unset for other models that don't support it (e.g., GPT-5.1 reasoning models)
 # TEMPERATURE=0
 
 # Access Control (Optional)
diff --git a/lib/ai-providers.ts b/lib/ai-providers.ts
index 61e19e7b..07f7b2fe 100644
--- a/lib/ai-providers.ts
+++ b/lib/ai-providers.ts
@@ -1440,6 +1440,15 @@ export function supportsPromptCaching(modelId: string): boolean {
     )
 }
 
+/**
+ * Check if a model supports the temperature sampling parameter.
+ * Claude Opus 4.7 and 4.8 reject sampling parameters entirely.
+ */
+export function supportsTemperature(modelId: string): boolean {
+    // Match plain, Bedrock inference-profile, and version-suffixed model IDs.
+    return !/claude-opus-4[.-](?:7|8)(?=$|[-.:])/i.test(modelId)
+}
+
 /**
  * Get the AI model for diagram validation.
  * Uses VALIDATION_MODEL env var if set, otherwise falls back to AI_MODEL.
diff --git a/tests/unit/ai-providers.test.ts b/tests/unit/ai-providers.test.ts
index 826cbb00..293dc440 100644
--- a/tests/unit/ai-providers.test.ts
+++ b/tests/unit/ai-providers.test.ts
@@ -4,6 +4,7 @@ import {
     isAihubmixStandardBaseURL,
     resolveBaseURL,
     supportsPromptCaching,
+    supportsTemperature,
 } from "@/lib/ai-providers"
 import { extractAihubmixModelIds } from "@/lib/aihubmix-models"
 
@@ -182,6 +183,30 @@ describe("supportsPromptCaching", () => {
     })
 })
 
+describe("supportsTemperature", () => {
+    it.each([
+        "claude-opus-4-7-20260416",
+        "anthropic.claude-opus-4-7-v1:0",
+        "us.anthropic.claude-opus-4-8-20260528-v1:0",
+        "global.anthropic.claude-opus-4-8",
+        "anthropic/claude-opus-4.7",
+        "anthropic/claude-opus-4.8",
+    ])("returns false for Claude Opus models without temperature (%s)", (modelId) => {
+        expect(supportsTemperature(modelId)).toBe(false)
+    })
+
+    it.each([
+        "claude-sonnet-4-5",
+        "anthropic.claude-3-5-sonnet-20241022-v2:0",
+        "gpt-4o",
+        "gemini-2.0-flash",
+        "",
+        "unknown-model",
+    ])("returns true for models that may support temperature (%s)", (modelId) => {
+        expect(supportsTemperature(modelId)).toBe(true)
+    })
+})
+
 vi.mock("ollama-ai-provider-v2", () => {
     const mockModel = { modelId: "test-model" }
     const mockProviderFn = vi.fn(() => mockModel)