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Sweep 28 Aug 2026 ยท 16:06Z Build v2.1.251 479 read Stable v2.1.236 Latest v2.1.251 Next v2.1.251 Feeds RSS JSON llms.txt

DisclaimerUnofficial, and not affiliated with Anthropic. Nearly all of this is read straight out of what ships: npm bundles, captured prompts, published docs. Anthropic's own notes go in verbatim, marked as theirs. The rest is my reading, and every entry carries the strings behind it. If one looks wrong, vote it down and say why.

One change

thinking-steering-and-cost

build-with-claude/thinking-steering-and-cost

first seen The page's own history The capture it came from

Nearest release: v2.1.251, published 2 hours before this site recorded the change. Shown because the two are within 24 hours of each other. Nothing here says the release caused the edit.

build-with-claude/thinking-steering-and-cost Changed · +22 / -22 lines

from line 57
 
 ```json
 {
-  "model": "claude-opus-4-8",
+  "model": "claude-opus-5",
   "max_tokens": 4096,
   "output_config": { "effort": "medium" },
   "messages": [{ "role": "user", "content": "..." }]
from line 173
       # First request - establish cache
       print("First request - establishing cache")
       response1 = client.messages.create(
-          model="claude-opus-4-8",
+          model="claude-opus-5",
           max_tokens=16000,
           thinking={"type": "adaptive"},
           messages=MESSAGES,
from line 187
       # Second request - same configuration (cache hit expected)
       print("\nSecond request - same configuration (cache hit expected)")
       response2 = client.messages.create(
-          model="claude-opus-4-8",
+          model="claude-opus-5",
           max_tokens=16000,
           thinking={"type": "adaptive"},
           messages=MESSAGES,
from line 201
       # Third request - different effort level (cache miss expected)
       print("\nThird request - different effort level (cache miss expected)")
       response3 = client.messages.create(
-          model="claude-opus-4-8",
+          model="claude-opus-5",
           max_tokens=16000,
           thinking={"type": "adaptive"},
           output_config={"effort": "medium"},
from line 249
       // First request - establish cache
       console.log("First request - establishing cache");
       const response1 = await client.messages.create({
-        model: "claude-opus-4-8",
+        model: "claude-opus-5",
         max_tokens: 16000,
         thinking: { type: "adaptive" },
         messages
from line 265
       // Second request - same configuration (cache hit expected)
       console.log("\nSecond request - same configuration (cache hit expected)");
       const response2 = await client.messages.create({
-        model: "claude-opus-4-8",
+        model: "claude-opus-5",
         max_tokens: 16000,
         thinking: { type: "adaptive" },
         messages
from line 281
       // Third request - different effort level (cache miss expected)
       console.log("\nThird request - different effort level (cache miss expected)");
       const response3 = await client.messages.create({
-        model: "claude-opus-4-8",
+        model: "claude-opus-5",
         max_tokens: 16000,
         thinking: { type: "adaptive" },
         output_config: { effort: "medium" },
from line 303
       Console.WriteLine("First request - establishing cache");
       var parameters1 = new MessageCreateParams
       {
-          Model = Model.ClaudeOpus4_8,
+          Model = Model.ClaudeOpus5,
           MaxTokens = 16000,
           Thinking = new ThinkingConfigAdaptive(),
           Messages =
from line 333
       Console.WriteLine("\nSecond request - same configuration (cache hit expected)");
       var parameters2 = new MessageCreateParams
       {
-          Model = Model.ClaudeOpus4_8,
+          Model = Model.ClaudeOpus5,
           MaxTokens = 16000,
           Thinking = new ThinkingConfigAdaptive(),
           Messages =
from line 373
       Console.WriteLine("\nThird request - different effort level (cache miss expected)");
       var parameters3 = new MessageCreateParams
       {
-          Model = Model.ClaudeOpus4_8,
+          Model = Model.ClaudeOpus5,
           MaxTokens = 16000,
           Thinking = new ThinkingConfigAdaptive(),
           OutputConfig = new OutputConfig
from line 462
       // First request - establish cache
       fmt.Println("First request - establishing cache")
       response1, err := client.Messages.New(context.TODO(), anthropic.MessageNewParams{
-      	Model:     anthropic.ModelClaudeOpus4_8,
+      	Model:     anthropic.ModelClaudeOpus5,
       	MaxTokens: 16000,
       	Thinking: anthropic.ThinkingConfigParamUnion{
       		OfAdaptive: &anthropic.ThinkingConfigAdaptiveParam{},
from line 480
       // Second request - same configuration (cache hit expected)
       fmt.Println("\nSecond request - same configuration (cache hit expected)")
       response2, err := client.Messages.New(context.TODO(), anthropic.MessageNewParams{
-      	Model:     anthropic.ModelClaudeOpus4_8,
+      	Model:     anthropic.ModelClaudeOpus5,
       	MaxTokens: 16000,
       	Thinking: anthropic.ThinkingConfigParamUnion{
       		OfAdaptive: &anthropic.ThinkingConfigAdaptiveParam{},
from line 498
       // Third request - different effort level (cache miss expected)
       fmt.Println("\nThird request - different effort level (cache miss expected)")
       response3, err := client.Messages.New(context.TODO(), anthropic.MessageNewParams{
-      	Model:     anthropic.ModelClaudeOpus4_8,
+      	Model:     anthropic.ModelClaudeOpus5,
       	MaxTokens: 16000,
       	Thinking: anthropic.ThinkingConfigParamUnion{
       		OfAdaptive: &anthropic.ThinkingConfigAdaptiveParam{},
from line 529
           // First request - establishing cache
           IO.println("First request - establishing cache");
           MessageCreateParams params1 = MessageCreateParams.builder()
-              .model(Model.CLAUDE_OPUS_4_8)
+              .model(Model.CLAUDE_OPUS_5)
               .maxTokens(16000L)
               .thinking(ThinkingConfigAdaptive.builder().build())
               .addUserMessageOfBlockParams(List.of(
from line 549
           // Second request - same configuration (cache hit expected)
           IO.println("\nSecond request - same configuration (cache hit expected)");
           MessageCreateParams params2 = MessageCreateParams.builder()
-              .model(Model.CLAUDE_OPUS_4_8)
+              .model(Model.CLAUDE_OPUS_5)
               .maxTokens(16000L)
               .thinking(ThinkingConfigAdaptive.builder().build())
               .addUserMessageOfBlockParams(List.of(
from line 573
           // Third request - different effort level (cache miss expected)
           IO.println("\nThird request - different effort level (cache miss expected)");
           MessageCreateParams params3 = MessageCreateParams.builder()
-              .model(Model.CLAUDE_OPUS_4_8)
+              .model(Model.CLAUDE_OPUS_5)
               .maxTokens(16000L)
               .thinking(ThinkingConfigAdaptive.builder().build())
               .outputConfig(OutputConfig.builder()
from line 645
                   ]
               ]
           ]],
-          model: 'claude-opus-4-8',
+          model: 'claude-opus-5',
           thinking: ['type' => 'adaptive'],
       );
from line 678
                   'content' => 'Analyze the characters in this passage.'
               ]
           ],
-          model: 'claude-opus-4-8',
+          model: 'claude-opus-5',
           thinking: ['type' => 'adaptive'],
       );
from line 719
                   'content' => 'Analyze the setting in this passage.'
               ]
           ],
-          model: 'claude-opus-4-8',
+          model: 'claude-opus-5',
           thinking: ['type' => 'adaptive'],
           outputConfig: ['effort' => 'medium'],
       );
from line 750
 
       puts "First request - establishing cache"
       response1 = client.messages.create(
-        model: "claude-opus-4-8",
+        model: "claude-opus-5",
         max_tokens: 16000,
         thinking: {
           type: "adaptive"
from line 775
 
       puts "\nSecond request - same configuration (cache hit expected)"
       response2 = client.messages.create(
-        model: "claude-opus-4-8",
+        model: "claude-opus-5",
         max_tokens: 16000,
         thinking: {
           type: "adaptive"
from line 810
 
       puts "\nThird request - different effort level (cache miss expected)"
       response3 = client.messages.create(
-        model: "claude-opus-4-8",
+        model: "claude-opus-5",
         max_tokens: 16000,
         thinking: {
           type: "adaptive"