open-vision-mcp

open-vision-mcp

Provider-neutral Vision MCP Server — image analysis via 10 inference providers through a single MCP server.

⚠️ Validation status: This server is engineering-validated (163/163 unit/integration tests pass) but live provider validation is pending. No provider has been tested end-to-end with real API credentials yet. Cerebras vision support is specifically unverified. See the Validation Status section below.

What It Does

A Model Context Protocol (MCP) server that gives AI agents the ability to see and understand images using any of 9 supported inference providers. All providers are accessed through a single code path with per-provider configuration.

Perfect for screenshots, photos, diagrams, webpage analysis, and mobile app UI review.

Supported Providers

Provider	PROVIDER	Default baseUrl	Suggested vision model	MODEL required?	Notes
OpenRouter	openrouter	https://openrouter.ai/api/v1	google/gemini-2.0-flash-exp:free	No (default: anthropic/claude-3.5-sonnet)	Sends HTTP-Referer/X-Title ranking headers
OpenAI	openai	https://api.openai.com/v1	gpt-4o	No	—
Together	together	https://api.together.xyz/v1	(check Together's model catalog)	Yes	Multi-model aggregator
DeepInfra	deepinfra	https://api.deepinfra.com/v1/openai	(check DeepInfra's catalog)	Yes	Multi-model aggregator
Fireworks	fireworks	https://api.fireworks.ai/inference/v1	(check Fireworks' catalog)	Yes	Multi-model aggregator
Groq	groq	https://api.groq.com/openai/v1	llama-3.2-90b-vision-preview	No	Fast inference
Chutes	chutes	https://llm.chutes.ai/v1	(check Chutes' /models for supported_features)	Yes	Per-model capability preflight
Cerebras	cerebras	https://api.cerebras.ai/v1	llama-4-scout-17b-16e-instruct	No	⚠️ Vision support unverified
Azure OpenAI	azure	(user-supplied deployment URL)	(deployment-configured)	No (ignored)	Requires BASE_URL with ?api-version=; uses api-key header
Ollama	ollama	http://localhost:11434	llama3.2-vision	No	Local (default) or Cloud (BASE_URL=https://api.ollama.com); uses native /api/chat endpoint

Quick Start

Prerequisites

• Node.js 18+
• An API key for at least one provider above

Option 1: Use with npx (recommended)

# Set your provider, API key, and model
export PROVIDER=openrouter
export API_KEY=sk-or-v1-your-api-key-here
export MODEL=google/gemini-2.0-flash-exp:free

# Run the server
npx open-vision-mcp

Option 2: Install globally

npm install -g open-vision-mcp
open-vision-mcp

Option 3: Clone and build

git clone https://github.com/abyssbugg/open-vision-mcp.git
cd open-vision-mcp
npm install
npm run build
node dist/index.js

Configuration

All configuration is via environment variables.

Environment Variables

Variable	Required?	Default	Purpose
PROVIDER	No	openrouter	Provider discriminator (one of the 9 above)
API_KEY	Yes	—	API key for the selected provider
MODEL	Depends	Per-provider default	Model id (required for together, deepinfra, fireworks, chutes; ignored by azure)
BASE_URL	No (yes for azure)	Per-provider default	Full-prefix base URL (must include /v1 or /api/v1 as appropriate). Azure requires the full deployment URL with ?api-version=.
EXTRA_HEADERS	No	Per-provider default	JSON object string of extra HTTP headers (e.g., OpenRouter's HTTP-Referer/X-Title)
LOG_LEVEL	No	info	Log level: debug, info, warn, error
MAX_IMAGE_SIZE	No	10485760 (10MB)	Maximum image size in bytes
RETRY_ATTEMPTS	No	3	(Reserved — not yet implemented)
PORT	No	3000	(Reserved — not used by stdio transport)

Legacy Environment Variables (backwards compatible)

If the new variables above are unset, the server falls back to the legacy OpenRouter variables:

Legacy variable	Maps to
OPENROUTER_API_KEY	API_KEY
OPENROUTER_MODEL	MODEL
OPENROUTER_BASE_URL	BASE_URL

Resolution precedence: new variable > legacy variable > per-provider default.

Existing OpenRouter users with only OPENROUTER_API_KEY set continue to work with zero config changes. The server defaults to PROVIDER=openrouter and lifts the legacy variables into the new fields.

Azure OpenAI Configuration

Azure is the only provider that requires BASE_URL (no per-provider default). The BASE_URL must be the full deployment URL including the api-version query parameter:

export PROVIDER=azure
export API_KEY=your-azure-resource-key
export BASE_URL=https://your-resource.openai.azure.com/openai/deployments/your-deployment?api-version=2024-02-15-preview

For Azure, MODEL is ignored — the deployment name is in BASE_URL. Azure uses the api-key header (not Authorization: Bearer). Azure has no /models endpoint; testConnection and validateModel return true without making HTTP calls (the first analyze_image call is the real health check).

MCP Client Configuration

Claude Code

Add to ~/.claude.json:

{
  "mcp": {
    "servers": {
      "vision": {
        "command": "npx",
        "args": ["open-vision-mcp"],
        "env": {
          "PROVIDER": "openrouter",
          "API_KEY": "sk-or-v1-your-key-here",
          "MODEL": "google/gemini-2.0-flash-exp:free"
        }
      }
    }
  }
}

Claude Desktop

Add to ~/Library/Application Support/Claude/claude_desktop_config.json:

{
  "mcpServers": {
    "vision": {
      "command": "npx",
      "args": ["open-vision-mcp"],
      "env": {
        "PROVIDER": "openai",
        "API_KEY": "sk-your-key-here",
        "MODEL": "gpt-4o"
      }
    }
  }
}

Other MCP Clients

• Cursor: ~/.cursor/mcp.json
• Cline: ~/.cline/mcp.json
• Windsurf: MCP settings file
• Check your agent's MCP documentation

Switching Providers

Change only the env vars — no code changes:

# Switch from OpenRouter to Groq
export PROVIDER=groq
export API_KEY=gsk-your-groq-key
export MODEL=llama-3.2-90b-vision-preview

npx open-vision-mcp

Tools

The server exposes 3 MCP tools. Tool names and schemas are identical for all providers.

analyze_image

General image analysis. Supports base64, file paths, and URLs.

Parameters:

• type — base64 | file | url
• data — image data (base64 string, file path, or URL)
• mimeType — MIME type (required for base64)
• prompt — custom analysis prompt (optional)
• format — text | json (default: text)
• maxTokens — max response tokens (default: 4000)
• temperature — sampling temperature 0–2 (default: 0.1)

analyze_webpage_screenshot

Webpage screenshot specialist. Extracts content, layout, navigation, forms, and accessibility info.

Additional parameters:

• focusArea — layout | content | navigation | forms | interactive | accessibility
• includeAccessibility — include accessibility analysis (default: true)
• format — text | json (default: json)

analyze_mobile_app_screenshot

Mobile app screenshot specialist. UI design, UX, platform conventions, accessibility.

Additional parameters:

• platform — ios | android | auto-detect (default: auto-detect)
• focusArea — ui-design | user-experience | navigation | accessibility | performance | onboarding
• includeUXHeuristics — include Nielsen's 10 heuristics (default: true)
• format — text | json (default: json)

Validation Status

Engineering Validation: COMPLETE

• 163/163 unit + integration tests pass (JSON reporter; npm test)
• npm run build exit 0 — TypeScript strict mode, zero errors
• npm run lint exit 0 — ESLint, zero errors
• Sentinel 8/8 — black-box MCP protocol test over stdio
• Phase 2B.5 Stage 1: 10/10 mandatory gates passed — keyless validation (configuration, request construction, auth headers, error handling, image processing, timeouts, capabilities, base URLs, logging)
• MCP contract byte-identical to baseline — tool names, schemas, and output format unchanged from the original upstream
• Backwards compatibility verified — legacy OPENROUTER_API_KEY env var fallback works end-to-end

Operational Validation: PENDING

• Live provider validation (Stage 2): paused pending valid API credentials. No provider has been tested end-to-end through analyze_image with a real key. Stage 2 may be executed at any future time when credentials become available.
• Cerebras vision support: UNVERIFIED. The llama-4-scout-17b-16e-instruct model is configured as the default, but whether it accepts multimodal (image) input has not been confirmed. If it doesn't support vision, the user gets a clear provider-aware error at runtime.
• Provider response shapes: unit tests mock axios and assert the request/response shape. Live APIs have not been confirmed to match the mocked shapes, though all providers are OpenAI-compatible per their official documentation.

What This Means for Users

The server is architecturally sound and thoroughly unit-tested. The provider abstraction, configuration resolution, request construction, error handling, and MCP protocol are all verified. However, no live API call has been made against any provider. Users should be aware that:

• The request body shape is correct per provider documentation (verified in Phase 2A research), but not confirmed against a live 200 response.
• Cerebras may not support vision input — use a different provider if vision is critical.
• If a provider's API has changed since the Phase 2A research (conducted June 2026), the server may need a config update.

Supported Image Formats

Format	Extension	MIME Type	Status
JPEG	.jpg, .jpeg	image/jpeg	✅
PNG	.png	image/png	✅
WebP	.webp	image/webp	✅
GIF	.gif	image/gif	✅
Max size	—	—	10MB (configurable via MAX_IMAGE_SIZE)

MIME type detection is signature-based (no native dependencies).

Development

# Install dependencies
npm install

# Build
npm run build

# Run in development mode
npm run dev

# Run tests
npm test                          # all tests (JSON reporter for counts)
npx vitest run test/unit          # unit tests only
npx vitest run test/integration   # integration tests only

# Lint and format
npm run lint
npm run format

# Clean
npm run clean

Troubleshooting

"API_KEY environment variable is required"

Set API_KEY (or the legacy OPENROUTER_API_KEY) to your provider's API key.

"MODEL environment variable is required for provider 'together'"

The together, deepinfra, fireworks, and chutes providers are multi-model aggregators with no default model. Set MODEL to a vision-capable model id from the provider's catalog.

"Unknown PROVIDER 'xyz'"

The PROVIDER value must be one of: openrouter, openai, together, deepinfra, fireworks, groq, chutes, cerebras, azure.

"BASE_URL is required for provider 'azure'"

Azure requires BASE_URL to be the full deployment URL including ?api-version=. There is no per-provider default.

" API Error: ..."

The error message includes the provider id (e.g., openai API Error: Invalid API key). This confirms the provider-aware error handling is working. Check your API key and model id.

Ollama: connection refused (local)

Ensure Ollama is running locally (ollama serve or ollama pull <model>). The default BASE_URL is http://localhost:11434. For Ollama Cloud, set BASE_URL=https://api.ollama.com and API_KEY=<cloud-token>.

Attribution

This project is a fork of JonathanJude/openrouter-image-mcp (MIT license), refactored to be provider-neutral with support for 10 inference providers.

License

MIT — see LICENSE.