AltText.ai MCP Server

AltText.ai MCP Server

An MCP server that lets AI assistants generate alt text, manage image libraries, and audit web pages for accessibility using the AltText.ai API.

Works with Claude Desktop, Claude Code, Cursor, Windsurf, and any MCP-compatible client.

Verify this package

This server runs npx -y @alttext_ai/alttext-mcp, which downloads and executes code with your API key in its environment. That's worth a moment of verification before you install — by you or by an AI agent doing the setup. Everything below should match:

| Signal | Value | |--------|-------| | npm package | @alttext_ai/alttext-mcp | | Source repository | github.com/alttextai/alttext-mcp | | Publisher | AltText.ai | | Provenance | Published from this repo's CI with npm provenance — npm shows a verified build badge linking the package to this exact commit |

The npm scope is @alttext_ai (with an underscore), while the GitHub org is alttextai (no underscore). This is intentional, not a typosquat: the @alttextai npm scope was already taken, so we publish under @alttext_ai. The two names refer to the same official AltText.ai package.

To cryptographically verify the published package was built by this repo's CI — not just trust the metadata — run:

npm audit signatures

from a project where the package is installed. This validates the registry signature and the npm provenance attestation, which links the tarball to a specific commit and GitHub Actions build. A counterfeit package can forge repository.url and other metadata, but it cannot forge the provenance attestation — so this is the check that actually matters.

(For a quick, weaker cross-reference of the claimed source you can run npm view @alttext_ai/alttext-mcp repository.url, but note that field is publisher-controlled metadata and proves nothing on its own.)

Pinning a version

The setup snippet uses npx -y @alttext_ai/alttext-mcp, which always resolves to the latest published version and re-runs it on every launch. That keeps you current, but it also means a future release runs automatically without review. If you want a reproducible, audited install, pin a specific version:

"args": ["-y", "@alttext_ai/alttext-mcp@1.0.2"]

Run npm audit signatures against the pinned version, and bump it deliberately when you're ready to take a new release.

Setup

Requirements: Node.js 18+ and an AltText.ai API key

Add the server to your MCP client configuration:

{
  "mcpServers": {
    "alttext-ai": {
      "command": "npx",
      "args": ["-y", "@alttext_ai/alttext-mcp"],
      "env": {
        "ALTTEXT_API_KEY": "your-api-key"
      }
    }
  }
}

Where to add this:

| Client | Config file | |--------|-------------| | Claude Desktop | claude_desktop_config.json | | Claude Code | .mcp.json in your project root | | Cursor | MCP settings in the Cursor preferences | | Windsurf | MCP settings in the Windsurf preferences |

Tools

Account Management

| Tool | Description | |------|-------------| | get_account | Check your credit balance, usage, and account settings. | | update_account | Update account name, webhook URL, or notification email. |

Generate Alt Text

| Tool | Description | |------|-------------| | generate_alt_text | Generate alt text for an image URL. Supports multilingual output, custom prompts, keywords, and character limits. Costs 1 credit. | | generate_alt_text_from_file | Generate alt text from a local image file. Automatically base64-encodes and uploads. Costs 1 credit. | | translate_image | Add alt text in a new language for an existing image (by asset_id). Costs 1 credit. |

Manage Image Library

| Tool | Description | |------|-------------| | list_images | List images in your library with pagination. | | search_images | Search your image library by alt text content. | | get_image | Get details for a specific image by asset ID. | | update_image | Update alt text, tags, or metadata for an image. | | delete_image | Delete an image from your library. |

Bulk Operations

| Tool | Description | |------|-------------| | bulk_create | Bulk generate alt text from a CSV file with image URLs and optional metadata. | | scrape_page | Scan a web page, find images missing alt text, and queue generation. Results are async -- use list_images to check progress. |

Example Prompts

Once configured, just ask your AI assistant:

Account & Credits

• "How many credits do I have left?"
• "Update my webhook URL to https://example.com/webhook"

Generate Alt Text

• "Generate alt text for https://example.com/photo.jpg"
• "Generate alt text for this image" (with local file)
• "Generate alt text in French and Spanish for this image"
• "Translate image abc123 to German"

Manage Library

• "Search my images for 'product photo'"
• "List my images"
• "Get details for image abc123"
• "Update the alt text for asset abc123"
• "Delete image xyz789"

Bulk Operations

• "Scan https://example.com for images missing alt text"
• "Process this CSV file of image URLs" (bulk_create)

Environment Variables

| Variable | Required | Description | |----------|----------|-------------| | ALTTEXT_API_KEY | Yes | Your AltText.ai API key | | ALTTEXT_API_BASE_URL | No | Override the API base URL (default: https://alttext.ai/api/v1) |

Development

npm install
npm run build
npm test
npm run lint

Tests use mocked fetch calls -- no API key or network access needed.

License

MIT