PapiAI Anthropic Provider

Anthropic Claude provider for PapiAI - A simple but powerful PHP library for building AI agents.

Installation

composer require papi-ai/anthropic

Usage

use PapiAI\Core\Agent;
use PapiAI\Anthropic\AnthropicProvider;

$provider = new AnthropicProvider(
    apiKey: $_ENV['ANTHROPIC_API_KEY'],
);

$agent = new Agent(
    provider: $provider,
    model: AnthropicProvider::MODEL_CLAUDE_SONNET_5,
    instructions: 'You are a helpful assistant.',
);

$response = $agent->run('Hello!');
echo $response->text;

Available Models

AnthropicProvider::MODEL_CLAUDE_FABLE_5_1  // 'claude-fable-5-1' (most capable)
AnthropicProvider::MODEL_CLAUDE_OPUS_5     // 'claude-opus-5'
AnthropicProvider::MODEL_CLAUDE_SONNET_5   // 'claude-sonnet-5' (default)
AnthropicProvider::MODEL_CLAUDE_HAIKU_4_5  // 'claude-haiku-4-5' (fastest)
AnthropicProvider::MODEL_CLAUDE_FABLE_5    // 'claude-fable-5'
AnthropicProvider::MODEL_CLAUDE_OPUS_4_8   // 'claude-opus-4-8'
AnthropicProvider::MODEL_CLAUDE_OPUS_4_7   // 'claude-opus-4-7'
AnthropicProvider::MODEL_CLAUDE_OPUS_4_6   // 'claude-opus-4-6'
AnthropicProvider::MODEL_CLAUDE_SONNET_4_6 // 'claude-sonnet-4-6'

All of these are active. Haiku 4.5 is the only one with a retirement floor inside a year: not sooner than 15 October 2026.

The constants alias a ClaudeModel enum, which is the source of truth: it knows each model's thinking API, effort levels, whether a tool can be forced, and its retirement floor. Pass the enum's ->value or the constant, both are the same string.

use PapiAI\Anthropic\ClaudeModel;

ClaudeModel::Haiku45->retiresNotBefore();   // '2026-10-15'
ClaudeModel::Fable51->acceptsForcedTools(); // false
ClaudeModel::tryFrom('claude-opus-6');      // null: unknown IDs are assumed newest, never rejected

Reasoning effort

effort maps to whichever shape the model's generation accepts. Everything from 4.6 on takes adaptive thinking plus an effort level (low to max); Haiku 4.5 takes a token budget carved out of maxTokens; Fable cannot stop thinking, so none narrows to low rather than sending a block the API rejects.

Fable 5.1 does not accept a forced tool choice. toolChoice of required or a named tool throws a ProviderException before any request is made; auto and none work as normal.

Features

• Tool/function calling
• Vision/multimodal support
• Streaming support

License

MIT