AI Provider Configuration

AI Alt Text supports multiple AI providers with vision capabilities. This document provides detailed configuration instructions for each provider.

Table of Contents

• Configuration Priority
• OpenAI
• Azure OpenAI
• Anthropic Claude
• Google Gemini
• Ollama (Self-Hosted)
• Grok (xAI)
• Environment Variables Reference
• Constants Reference
• Troubleshooting

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Configuration Priority

Settings are resolved in the following priority order:

1. PHP Constants (wp-config.php) - Highest priority
2. Environment Variables - Second priority
3. Database Settings (Admin UI) - Third priority
4. Default Values - Fallback

When a setting is defined via constant or environment variable, the admin UI field becomes read-only and shows the source.

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OpenAI

Requirements

• OpenAI API account with billing enabled
• API key from OpenAI Platform

Recommended Models

Model	Description	Cost
gpt-4o	Best quality, multimodal (recommended)	$$$
gpt-4o-mini	Good quality, lower cost	$$
gpt-4-turbo	High quality, vision capable	$$$

Configuration via wp-config.php

define( 'AI_ALT_TEXT_AI_PROVIDER', 'openai' );
define( 'AI_ALT_TEXT_OPENAI_KEY', 'sk-proj-xxxxxxxxxxxxxxxxxxxx' );
define( 'AI_ALT_TEXT_OPENAI_MODEL', 'gpt-4o' );
define( 'AI_ALT_TEXT_OPENAI_TYPE', 'openai' ); // 'openai' or 'azure'

Configuration via Environment Variables

AI_ALT_TEXT_AI_PROVIDER=openai
AI_ALT_TEXT_OPENAI_KEY=sk-proj-xxxxxxxxxxxxxxxxxxxx
AI_ALT_TEXT_OPENAI_MODEL=gpt-4o
AI_ALT_TEXT_OPENAI_TYPE=openai

API Endpoint

POST https://api.openai.com/v1/chat/completions

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Azure OpenAI

Requirements

• Azure subscription
• Azure OpenAI Service resource
• Deployed GPT-4o or GPT-4 Vision model

Setup Steps

1. Create an Azure OpenAI resource in the Azure Portal
2. Deploy a vision-capable model (e.g., gpt-4o)
3. Copy the endpoint URL and API key

Configuration via wp-config.php

define( 'AI_ALT_TEXT_AI_PROVIDER', 'openai' );
define( 'AI_ALT_TEXT_OPENAI_TYPE', 'azure' );
define( 'AI_ALT_TEXT_OPENAI_KEY', 'your-azure-api-key' );
define( 'AI_ALT_TEXT_OPENAI_MODEL', 'your-deployment-name' ); // Deployment name, not model name
define( 'AI_ALT_TEXT_AZURE_ENDPOINT', 'https://your-resource.openai.azure.com' );
define( 'AI_ALT_TEXT_AZURE_API_VERSION', '2024-02-15-preview' );

Configuration via Environment Variables

AI_ALT_TEXT_AI_PROVIDER=openai
AI_ALT_TEXT_OPENAI_TYPE=azure
AI_ALT_TEXT_OPENAI_KEY=your-azure-api-key
AI_ALT_TEXT_OPENAI_MODEL=your-deployment-name
AI_ALT_TEXT_AZURE_ENDPOINT=https://your-resource.openai.azure.com
AI_ALT_TEXT_AZURE_API_VERSION=2024-02-15-preview

API Endpoint Format

POST {endpoint}/openai/deployments/{deployment}/chat/completions?api-version={api-version}

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Anthropic Claude

Requirements

• Anthropic Console account
• API key from Anthropic Console

Recommended Models

Model	Description	Cost
claude-sonnet-4-20250514	Best balance of quality and speed	$$$
claude-3-5-sonnet-20241022	Previous generation, still excellent	$$
claude-3-haiku-20240307	Fastest, lower cost	$

Configuration via wp-config.php

define( 'AI_ALT_TEXT_AI_PROVIDER', 'anthropic' );
define( 'AI_ALT_TEXT_ANTHROPIC_KEY', 'sk-ant-xxxxxxxxxxxxxxxxxxxx' );
define( 'AI_ALT_TEXT_ANTHROPIC_MODEL', 'claude-sonnet-4-20250514' );

Configuration via Environment Variables

AI_ALT_TEXT_AI_PROVIDER=anthropic
AI_ALT_TEXT_ANTHROPIC_KEY=sk-ant-xxxxxxxxxxxxxxxxxxxx
AI_ALT_TEXT_ANTHROPIC_MODEL=claude-sonnet-4-20250514

API Endpoint

POST https://api.anthropic.com/v1/messages

Notes

• Claude requires images to be sent as base64-encoded data
• The plugin automatically handles image encoding

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Google Gemini

Requirements

• Google account
• API key from Google AI Studio

Recommended Models

Model	Description	Cost
gemini-2.0-flash	Latest, fastest multimodal	Free tier available
gemini-1.5-flash	Fast, good quality	Free tier available
gemini-1.5-pro	Highest quality	$$

Configuration via wp-config.php

define( 'AI_ALT_TEXT_AI_PROVIDER', 'gemini' );
define( 'AI_ALT_TEXT_GEMINI_KEY', 'AIzaSyxxxxxxxxxxxxxxxxxxxx' );
define( 'AI_ALT_TEXT_GEMINI_MODEL', 'gemini-2.0-flash' );

Configuration via Environment Variables

AI_ALT_TEXT_AI_PROVIDER=gemini
AI_ALT_TEXT_GEMINI_KEY=AIzaSyxxxxxxxxxxxxxxxxxxxx
AI_ALT_TEXT_GEMINI_MODEL=gemini-2.0-flash

API Endpoint Format

POST https://generativelanguage.googleapis.com/v1beta/models/{model}:generateContent?key={api_key}

Notes

• Gemini has a generous free tier (60 requests per minute)
• Images are sent as base64-encoded data

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Ollama (Self-Hosted)

Requirements

• Ollama installed locally or on a server
• A vision-capable model pulled (e.g., llava)

Installation

# macOS
brew install ollama

# Linux
curl -fsSL https://ollama.ai/install.sh | sh

# Start Ollama server
ollama serve

# Pull a vision model
ollama pull llava

Recommended Models

Model	Description	Size
llava	LLaVA 7B, good quality	4.7 GB
llava:13b	LLaVA 13B, better quality	8.0 GB
bakllava	BakLLaVA, alternative	4.7 GB
llava-llama3	LLaVA with Llama 3	5.5 GB

Configuration via wp-config.php

define( 'AI_ALT_TEXT_AI_PROVIDER', 'ollama' );
define( 'AI_ALT_TEXT_OLLAMA_ENDPOINT', 'http://localhost:11434' );
define( 'AI_ALT_TEXT_OLLAMA_MODEL', 'llava' );

Configuration via Environment Variables

AI_ALT_TEXT_AI_PROVIDER=ollama
AI_ALT_TEXT_OLLAMA_ENDPOINT=http://localhost:11434
AI_ALT_TEXT_OLLAMA_MODEL=llava

API Endpoint Format

POST {endpoint}/api/generate

Notes

• Free - No API costs, runs entirely locally
• Requires local installation of Ollama
• Processing speed depends on your hardware (GPU recommended)
• For Docker deployments, use http://host.docker.internal:11434

Running Ollama on a Remote Server

If WordPress runs on a different server than Ollama:

define( 'AI_ALT_TEXT_OLLAMA_ENDPOINT', 'http://your-server-ip:11434' );

Make sure the Ollama server is accessible from your WordPress server.

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Grok (xAI)

Requirements

• xAI account
• API key from xAI Console

Recommended Models

Model	Description	Cost
grok-2-vision-1212	Vision-capable Grok 2	$$
grok-vision-beta	Beta vision model	$$

Configuration via wp-config.php

define( 'AI_ALT_TEXT_AI_PROVIDER', 'grok' );
define( 'AI_ALT_TEXT_GROK_KEY', 'xai-xxxxxxxxxxxxxxxxxxxx' );
define( 'AI_ALT_TEXT_GROK_MODEL', 'grok-2-vision-1212' );

Configuration via Environment Variables

AI_ALT_TEXT_AI_PROVIDER=grok
AI_ALT_TEXT_GROK_KEY=xai-xxxxxxxxxxxxxxxxxxxx
AI_ALT_TEXT_GROK_MODEL=grok-2-vision-1212

API Endpoint

POST https://api.x.ai/v1/chat/completions

Notes

• Grok uses an OpenAI-compatible API format
• Vision capabilities are available in Grok 2

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Environment Variables Reference

Variable	Description	Default
AI_ALT_TEXT_AI_PROVIDER	Provider: openai, anthropic, gemini, ollama, grok	openai
AI_ALT_TEXT_AUTO_GENERATE	Auto-generate on upload: 1 or 0	1
AI_ALT_TEXT_OPENAI_TYPE	OpenAI type: openai or azure	openai
AI_ALT_TEXT_OPENAI_KEY	OpenAI/Azure API key	(none)
AI_ALT_TEXT_OPENAI_MODEL	OpenAI model or Azure deployment name	gpt-4o
AI_ALT_TEXT_AZURE_ENDPOINT	Azure OpenAI endpoint URL	(none)
AI_ALT_TEXT_AZURE_API_VERSION	Azure API version	2024-02-15-preview
AI_ALT_TEXT_ANTHROPIC_KEY	Anthropic API key	(none)
AI_ALT_TEXT_ANTHROPIC_MODEL	Anthropic model name	claude-3-5-sonnet-20241022
AI_ALT_TEXT_GEMINI_KEY	Google AI API key	(none)
AI_ALT_TEXT_GEMINI_MODEL	Gemini model name	gemini-1.5-flash
AI_ALT_TEXT_OLLAMA_ENDPOINT	Ollama server URL	http://localhost:11434
AI_ALT_TEXT_OLLAMA_MODEL	Ollama model name	llava
AI_ALT_TEXT_GROK_KEY	xAI API key	(none)
AI_ALT_TEXT_GROK_MODEL	Grok model name	grok-2-vision-1212

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Constants Reference

All environment variables can also be defined as PHP constants in wp-config.php using the same names:

// Example: Full configuration for OpenAI
define( 'AI_ALT_TEXT_AI_PROVIDER', 'openai' );
define( 'AI_ALT_TEXT_AUTO_GENERATE', '1' );
define( 'AI_ALT_TEXT_OPENAI_KEY', 'sk-proj-xxxx' );
define( 'AI_ALT_TEXT_OPENAI_MODEL', 'gpt-4o' );

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Troubleshooting

Common Issues

”Configuration is incomplete”

• Ensure you’ve set both the API key and model for your chosen provider
• Check that constants/environment variables are spelled correctly

”Unknown AI provider”

• Valid providers: openai, anthropic, gemini, ollama, grok
• Check for typos in the provider name

”Failed to fetch image”

• Ensure the image URL is accessible
• For local images, check file permissions
• For remote images, ensure the server allows external requests

Azure: “Resource not found”

• Verify the endpoint URL is correct (no trailing slash)
• Ensure the deployment name matches exactly
• Check the API version is supported

Ollama: “Connection refused”

• Ensure Ollama is running: ollama serve
• Check the endpoint URL (default: http://localhost:11434)
• Verify the model is pulled: ollama list

Enable Debug Logging

Add to wp-config.php:

define( 'WP_DEBUG', true );
define( 'WP_DEBUG_LOG', true );
define( 'WP_DEBUG_DISPLAY', false );

Logs are written to wp-content/debug.log.

Testing API Connection

The plugin validates your configuration when you save settings. If there’s an error, you’ll see a warning message with details.

You can also test manually with curl:

# Test OpenAI
curl https://api.openai.com/v1/models \
  -H "Authorization: Bearer sk-proj-xxxx"

# Test Anthropic
curl https://api.anthropic.com/v1/messages \
  -H "x-api-key: sk-ant-xxxx" \
  -H "anthropic-version: 2023-06-01"

# Test Ollama
curl http://localhost:11434/api/tags

# Test Gemini
curl "https://generativelanguage.googleapis.com/v1beta/models?key=AIzaSy-xxxx"

# Test Grok
curl https://api.x.ai/v1/models \
  -H "Authorization: Bearer xai-xxxx"

📦 Source: soderlind/ai-alt-text · Edit on GitHub