Quick start

The advisor tool is in beta. Include the beta header advisor-tool-2026-03-01 in your requests.

curl https://api.anthropic.com/v1/messages \
  -H "x-api-key: $ANTHROPIC_API_KEY" \
  -H "anthropic-version: 2023-06-01" \
  -H "anthropic-beta: advisor-tool-2026-03-01" \
  -H "content-type: application/json" \
  -d '{
    "model": "claude-sonnet-5",
    "max_tokens": 4096,
    "tools": [
      {
        "type": "advisor_20260301",
        "name": "advisor",
        "model": "claude-opus-5"
      }
    ],
    "messages": [{
      "role": "user",
      "content": "Build a concurrent worker pool in Go with graceful shutdown."
    }]
  }'

ant beta:messages create --beta advisor-tool-2026-03-01 <<'YAML'
model: claude-sonnet-5
max_tokens: 4096
tools:
  - type: advisor_20260301
    name: advisor
    model: claude-opus-5
messages:
  - role: user
    content: Build a concurrent worker pool in Go with graceful shutdown.
YAML

client = anthropic.Anthropic()

response = client.beta.messages.create(
    model="claude-sonnet-5",
    max_tokens=4096,
    betas=["advisor-tool-2026-03-01"],
    tools=[
        {
            "type": "advisor_20260301",
            "name": "advisor",
            "model": "claude-opus-5",
        }
    ],
    messages=[
        {
            "role": "user",
            "content": "Build a concurrent worker pool in Go with graceful shutdown.",
        }
    ],
)

print(response)

const client = new Anthropic();

const response = await client.beta.messages.create({
  model: "claude-sonnet-5",
  max_tokens: 4096,
  betas: ["advisor-tool-2026-03-01"],
  tools: [
    {
      type: "advisor_20260301",
      name: "advisor",
      model: "claude-opus-5"
    }
  ],
  messages: [
    {
      role: "user",
      content: "Build a concurrent worker pool in Go with graceful shutdown."
    }
  ]
});

console.log(response);

using Anthropic.Models.Beta.Messages;
using Messages = Anthropic.Models.Messages;

var client = new AnthropicClient();

var parameters = new MessageCreateParams
{
    Model = Messages::Model.ClaudeSonnet5,
    MaxTokens = 4096,
    Tools = new BetaToolUnion[]
    {
        new BetaAdvisorTool20260301
        {
            Model = Messages::Model.ClaudeOpus5
        }
    },
    Messages =
    [
        new BetaMessageParam
        {
            Role = Role.User,
            Content = "Build a concurrent worker pool in Go with graceful shutdown."
        }
    ],
    Betas = ["advisor-tool-2026-03-01"]
};

var response = await client.Beta.Messages.Create(parameters);
Console.WriteLine(response);

client := anthropic.NewClient()

response, err := client.Beta.Messages.New(context.TODO(), anthropic.BetaMessageNewParams{
	Model:     anthropic.ModelClaudeSonnet5,
	MaxTokens: 4096,
	Tools: []anthropic.BetaToolUnionParam{
		{OfAdvisorTool20260301: &anthropic.BetaAdvisorTool20260301Param{
			Model: anthropic.ModelClaudeOpus5,
		}},
	},
	Messages: []anthropic.BetaMessageParam{
		anthropic.NewBetaUserMessage(anthropic.NewBetaTextBlock("Build a concurrent worker pool in Go with graceful shutdown.")),
	},
	Betas: []anthropic.AnthropicBeta{
		anthropic.AnthropicBetaAdvisorTool2026_03_01,
	},
})
if err != nil {
	log.Fatal(err)
}
fmt.Println(response)

import com.anthropic.models.beta.messages.BetaAdvisorTool20260301;
import com.anthropic.models.beta.messages.BetaMessage;
import com.anthropic.models.beta.messages.MessageCreateParams;
import com.anthropic.models.messages.Model;

void main() {
    AnthropicClient client = AnthropicOkHttpClient.fromEnv();

    MessageCreateParams params = MessageCreateParams.builder()
        .model(Model.CLAUDE_SONNET_5)
        .maxTokens(4096L)
        .addTool(BetaAdvisorTool20260301.builder()
            .model(Model.CLAUDE_OPUS_5)
            .build())
        .addUserMessage("Build a concurrent worker pool in Go with graceful shutdown.")
        .addBeta("advisor-tool-2026-03-01")
        .build();

    BetaMessage response = client.beta().messages().create(params);
    IO.println(response);
}

$client = new Client();

$response = $client->beta->messages->create(
    maxTokens: 4096,
    messages: [
        [
            'role' => 'user',
            'content' => 'Build a concurrent worker pool in Go with graceful shutdown.',
        ],
    ],
    model: 'claude-sonnet-5',
    tools: [
        [
            'type' => 'advisor_20260301',
            'name' => 'advisor',
            'model' => 'claude-opus-5',
        ],
    ],
    betas: ['advisor-tool-2026-03-01'],
);

echo $response;

client = Anthropic::Client.new

response = client.beta.messages.create(
  model: "claude-sonnet-5",
  max_tokens: 4096,
  tools: [
    {
      type: "advisor_20260301",
      name: "advisor",
      model: "claude-opus-5"
    }
  ],
  messages: [
    {
      role: "user",
      content: "Build a concurrent worker pool in Go with graceful shutdown."
    }
  ],
  betas: ["advisor-tool-2026-03-01"]
)

puts response

The response content includes an advisor_tool_result block carrying the advisor's guidance. With claude-opus-5 as the advisor, as in this quick start, the block's content field is an advisor_redacted_result variant (encrypted; the executor reads it server-side, but your client does not). To see the advice text directly in your response, use claude-opus-4-8 as the advisor model instead, which returns the plaintext advisor_result variant. See Result variants for both shapes side by side and which advisor models return which, and Model compatibility for the full list of valid pairs.