<!--
name: 'Data: Claude API reference — PHP'
description: PHP SDK reference
ccVersion: 2.1.73
-->
# Claude API — PHP

> **Note:** The PHP SDK is the official Anthropic SDK for PHP. Tool runner and Agent SDK are not available. Bedrock, Vertex AI, and Foundry clients are supported.

## Installation

\`\`\`bash
composer require "anthropic-ai/sdk"
\`\`\`

## Client Initialization

\`\`\`php
use Anthropic\\Client;

// Using API key from environment variable
$client = new Client(apiKey: getenv("ANTHROPIC_API_KEY"));
\`\`\`

### Amazon Bedrock

\`\`\`php
use Anthropic\\Bedrock;

// Constructor is private — use the static factory. Reads AWS credentials from env.
$client = Bedrock\\Client::fromEnvironment(region: 'us-east-1');
\`\`\`

### Google Vertex AI

\`\`\`php
use Anthropic\\Vertex;

// Constructor is private. Parameter is \`location\`, not \`region\`.
$client = Vertex\\Client::fromEnvironment(
    location: 'us-east5',
    projectId: 'my-project-id',
);
\`\`\`

### Anthropic Foundry

\`\`\`php
use Anthropic\\Foundry;

// Constructor is private. baseUrl or resource is required.
$client = Foundry\\Client::withCredentials(
    authToken: getenv('ANTHROPIC_FOUNDRY_AUTH_TOKEN'),
    baseUrl: 'https://<resource>.services.ai.azure.com/anthropic',
);
\`\`\`

---

## Basic Message Request

\`\`\`php
$message = $client->messages->create(
    model: '{{OPUS_ID}}',
    maxTokens: 1024,
    messages: [
        ['role' => 'user', 'content' => 'What is the capital of France?'],
    ],
);

// content is an array of polymorphic blocks (TextBlock, ToolUseBlock,
// ThinkingBlock). Accessing ->text on content[0] without checking the block
// type will throw if the first block is not a TextBlock (e.g., when extended
// thinking is enabled and a ThinkingBlock comes first). Always guard:
foreach ($message->content as $block) {
    if ($block->type === 'text') {
        echo $block->text;
    }
}
\`\`\`

If you only want the first text block:

\`\`\`php
foreach ($message->content as $block) {
    if ($block->type === 'text') {
        echo $block->text;
        break;
    }
}
\`\`\`

---

## Streaming

> **Requires SDK v0.5.0+.** v0.4.0 and earlier used a single \`$params\` array; calling with named parameters throws \`Unknown named parameter $model\`. Upgrade: \`composer require "anthropic-ai/sdk:^0.6"\`

\`\`\`php
use Anthropic\\Messages\\RawContentBlockDeltaEvent;
use Anthropic\\Messages\\TextDelta;

$stream = $client->messages->createStream(
    model: '{{OPUS_ID}}',
    maxTokens: 1024,
    messages: [
        ['role' => 'user', 'content' => 'Write a haiku'],
    ],
);

foreach ($stream as $event) {
    if ($event instanceof RawContentBlockDeltaEvent && $event->delta instanceof TextDelta) {
        echo $event->delta->text;
    }
}
\`\`\`

---

## Tool Use (Manual Loop)

Tools are passed as arrays. **The SDK uses camelCase keys** (\`inputSchema\`, \`toolUseID\`, \`stopReason\`) and auto-maps to the API's snake_case on the wire — since v0.5.0. See [shared tool use concepts](../shared/tool-use-concepts.md) for the loop pattern.

\`\`\`php
use Anthropic\\Messages\\ToolUseBlock;

$tools = [
    [
        'name' => 'get_weather',
        'description' => 'Get the current weather in a given location',
        'inputSchema' => [  // camelCase, not input_schema
            'type' => 'object',
            'properties' => [
                'location' => ['type' => 'string', 'description' => 'City and state'],
            ],
            'required' => ['location'],
        ],
    ],
];

$messages = [['role' => 'user', 'content' => 'What is the weather in SF?']];

$response = $client->messages->create(
    model: '{{OPUS_ID}}',
    maxTokens: 1024,
    tools: $tools,
    messages: $messages,
);

while ($response->stopReason === 'tool_use') {  // camelCase property
    $toolResults = [];
    foreach ($response->content as $block) {
        if ($block instanceof ToolUseBlock) {
            // $block->name  : string               — tool name to dispatch on
            // $block->input : array<string,mixed>  — parsed JSON input
            // $block->id    : string               — pass back as toolUseID
            $result = executeYourTool($block->name, $block->input);
            $toolResults[] = [
                'type' => 'tool_result',
                'toolUseID' => $block->id,  // camelCase, not tool_use_id
                'content' => $result,
            ];
        }
    }

    // Append assistant turn + user turn with tool results
    $messages[] = ['role' => 'assistant', 'content' => $response->content];
    $messages[] = ['role' => 'user', 'content' => $toolResults];

    $response = $client->messages->create(
        model: '{{OPUS_ID}}',
        maxTokens: 1024,
        tools: $tools,
        messages: $messages,
    );
}

// Final text response
foreach ($response->content as $block) {
    if ($block->type === 'text') {
        echo $block->text;
    }
}
\`\`\`

\`$block->type === 'tool_use'\` also works; \`instanceof ToolUseBlock\` narrows for PHPStan.


---

## Extended Thinking

**Adaptive thinking is the recommended mode for Claude 4.6+ models.** Claude decides dynamically when and how much to think.

\`\`\`php
use Anthropic\\Messages\\ThinkingBlock;

$message = $client->messages->create(
    model: '{{OPUS_ID}}',
    maxTokens: 16000,
    thinking: ['type' => 'adaptive'],
    messages: [
        ['role' => 'user', 'content' => 'Solve: 27 * 453'],
    ],
);

// ThinkingBlock(s) precede TextBlock in content
foreach ($message->content as $block) {
    if ($block instanceof ThinkingBlock) {
        echo "Thinking:\\n{$block->thinking}\\n\\n";
        // $block->signature is an opaque string — preserve verbatim if
        // passing thinking blocks back in multi-turn conversations
    } elseif ($block->type === 'text') {
        echo "Answer: {$block->text}\\n";
    }
}
\`\`\`

> **Deprecated:** \`['type' => 'enabled', 'budgetTokens' => N]\` (fixed-budget extended thinking) still works on Claude 4.6 but is deprecated. Use adaptive thinking above.

\`$block->type === 'thinking'\` also works for the check; \`instanceof\` narrows for PHPStan.

---

## Beta Features & Server-Side Tools

**\`betas:\` is NOT a param on \`$client->messages->create()\`** — it only exists on the beta namespace. Use it for features that need an explicit opt-in header:

\`\`\`php
use Anthropic\\Beta\\Messages\\BetaRequestMCPServerURLDefinition;

$response = $client->beta->messages->create(
    model: '{{OPUS_ID}}',
    maxTokens: 1024,
    mcpServers: [
        BetaRequestMCPServerURLDefinition::with(
            name: 'my-server',
            url: 'https://example.com/mcp',
        ),
    ],
    betas: ['mcp-client-2025-11-20'],  // only valid on ->beta->messages
    messages: [['role' => 'user', 'content' => 'Use the MCP tools']],
);
\`\`\`

**Server-side tools** (bash, web_search, text_editor, code_execution) are GA and work on both paths — \`Anthropic\\Messages\\ToolBash20250124\` / \`WebSearchTool20260209\` / \`ToolTextEditor20250728\` / \`CodeExecutionTool20260120\` for non-beta, \`Anthropic\\Beta\\Messages\\BetaToolBash20250124\` / \`BetaWebSearchTool20260209\` / \`BetaToolTextEditor20250728\` / \`BetaCodeExecutionTool20260120\` for beta. No \`betas:\` header needed for these.