Gemini Url Context

Gemini URL Context Skill

Use Google's Gemini 3.8 Flash model to expand, summarize, and analyze web content directly from URLs, via the gemini-url-context subcommand of agentbox-mcp — a single Rust rmcp binary (services/agentbox-mcp) that also serves the imagemagick and web-summary skills. It replaces the former Python FastMCP server one-for-one: same tool names, parameters, and JSON response shapes.

When to Use This Skill

• URL Expansion: Fetch and summarize content from any URL
• Multi-URL Analysis: Compare or synthesize content from up to 20 URLs
• Document Extraction: Extract structured data from web pages
• Research Aggregation: Gather information from multiple sources
• Content Grounding: Get AI responses grounded in specific web sources

When Not To Use

• For YouTube video transcript extraction -- use the web-summary skill instead (Gemini does not support YouTube)
• For broad web search across many sources -- use the perplexity-research skill instead
• For browser automation, form filling, or interactive page navigation -- use the browser or playwright skills instead
• For summarising content you already have as text -- no URL expansion tool is needed; process it directly
• For pages behind paywalls or requiring authentication -- Gemini URL Context cannot access restricted content

Architecture

┌─────────────────────────────────┐
│  Claude Code / Skill Invocation │
└──────────────┬──────────────────┘
               │ MCP Protocol (stdio)
               ▼
┌─────────────────────────────────┐
│  Gemini URL Context MCP Server  │
│  (agentbox-mcp gemini-url-      │
│   context, Rust rmcp)           │
└──────────────┬──────────────────┘
               │ HTTPS REST API
               ▼
┌─────────────────────────────────┐
│  Google Gemini 3.8 Flash API    │
│  (with url_context tool)        │
└─────────────────────────────────┘

Tools

Examples

# Expand a single URL
expand_url({
    "url": "https://example.com/article",
    "prompt": "Summarize the key points"
})

# Batch expand multiple URLs
expand_urls({
    "urls": [
        "https://example.com/page1",
        "https://example.com/page2"
    ],
    "prompt": "List the main topics from each page"
})

# Compare URLs
compare_urls({
    "urls": [
        "https://site1.com/product",
        "https://site2.com/product"
    ],
    "prompt": "Compare features and pricing"
})

# Extract structured data
extract_from_url({
    "url": "https://example.com/api-docs",
    "schema": {
        "endpoints": "list of API endpoints",
        "auth_method": "authentication method used",
        "rate_limits": "any rate limiting info"
    }
})

Capabilities & Limits

Response Metadata

Responses include urlContextMetadata with:

• retrievedUrl: The URL that was fetched
• urlRetrievalStatus: SUCCESS, FAILED, or PARTIAL

Environment Variables

Setup

# Set API key (add to .env or export)
export GOOGLE_API_KEY="your-api-key"

# Or add to your skills .env
echo 'GOOGLE_API_KEY=your-key' >> "$HOME/.claude/skills/.env"

Troubleshooting

API Key Issues:

# Test API key
curl -s "https://generativelanguage.googleapis.com/v1beta/models?key=$GOOGLE_API_KEY" | jq '.models[0].name'

URL Not Retrieved:

• Check URL is publicly accessible (no paywall)
• Verify URL returns text/HTML/PDF content
• Check content size < 34MB

Integration with Other Skills

Combine with:

• web-summary: For YouTube transcript extraction (Gemini doesn't support YouTube)
• perplexity-research: For broader web search before URL expansion
• playwright: For JavaScript-rendered pages that need browser execution