beta-headers changedapi/beta-headers
Nearest release: v2.1.280, published under an hour 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.
Recorded here
Lines+9added
Lines−9removed
From line
34
where the diff opens
First seen
14 Aug 2026
this site's first read of the page
Recorded edits18to this page, all time
The whole hunk
from line 34, old and new numbered
/
from line 34
3434 -H "anthropic-beta: context-management-2025-06-27" \
3535 -H "content-type: application/json" \
3636 -d '{
37 "model": "claude-opus-5",
37 "model": "claude-opus-5-5",
3838 "max_tokens": 1024,
3939 "messages": [
4040 {"role": "user", "content": "Hello, Claude"}
from line 45
4545 ```bash CLI
4646 ant beta:messages create \
4747 --beta context-management-2025-06-27 \
48 --model claude-opus-5 \
48 --model claude-opus-5-5 \
4949 --max-tokens 1024 \
5050 --message '{role: user, content: "Hello, Claude"}'
5151 ```
from line 54
5454 client = Anthropic()
5555
5656 response = client.beta.messages.create(
57 model="claude-opus-5",
57 model="claude-opus-5-5",
5858 max_tokens=1024,
5959 messages=[{"role": "user", "content": "Hello, Claude"}],
6060 betas=["context-management-2025-06-27"],
from line 67
6767 const client = new Anthropic();
6868
6969 const msg = await client.beta.messages.create({
70 model: "claude-opus-5",
70 model: "claude-opus-5-5",
7171 max_tokens: 1024,
7272 messages: [{ role: "user", content: "Hello, Claude" }],
7373 betas: ["context-management-2025-06-27"]
from line 82
8282 var message = await client.Beta.Messages.Create(
8383 new MessageCreateParams
8484 {
85 Model = "claude-opus-5",
85 Model = "claude-opus-5-5",
8686 MaxTokens = 1024,
8787 Messages = [new() { Role = Role.User, Content = "Hello, Claude" }],
8888 Betas = ["context-management-2025-06-27"],
from line 96
9696 client := anthropic.NewClient()
9797
9898 message, err := client.Beta.Messages.New(context.TODO(), anthropic.BetaMessageNewParams{
99 Model: anthropic.ModelClaudeOpus5,
99 Model: anthropic.ModelClaudeOpus5_5,
100100 MaxTokens: 1024,
101101 Messages: []anthropic.BetaMessageParam{
102102 anthropic.NewBetaUserMessage(anthropic.NewBetaTextBlock("Hello, Claude")),
from line 114
114114 AnthropicClient client = AnthropicOkHttpClient.fromEnv();
115115
116116 MessageCreateParams params = MessageCreateParams.builder()
117 .model(Model.CLAUDE_OPUS_5)
117 .model(Model.CLAUDE_OPUS_5_5)
118118 .maxTokens(1024)
119119 .addUserMessage("Hello, Claude")
120120 .addBeta(AnthropicBeta.CONTEXT_MANAGEMENT_2025_06_27)
from line 130
130130 $message = $client->beta->messages->create(
131131 maxTokens: 1024,
132132 messages: [['role' => 'user', 'content' => 'Hello, Claude']],
133 model: 'claude-opus-5',
133 model: 'claude-opus-5-5',
134134 betas: ['context-management-2025-06-27'],
135135 );
136136
from line 141
141141 client = Anthropic::Client.new
142142
143143 message = client.beta.messages.create(
144 model: "claude-opus-5",
144 model: "claude-opus-5-5",
145145 max_tokens: 1024,
146146 messages: [{role: "user", content: "Hello, Claude"}],
147147 betas: ["context-management-2025-06-27"]
No line in this hunk matches that.