Claude Search Skill

Use Anthropic Claude's web search tool via the Messages API to perform read-only web research with citations.

When to Use

• The user asks for current docs, best practices, or library comparisons
• The user needs up-to-date troubleshooting or security guidance
• The user requests sources, links, or citations
• The topic is time-sensitive (news, releases, versions, policies)

Prerequisites

• ANTHROPIC_API_KEY is set
• Web search is enabled for the org/project in the Anthropic Console
• Use a model that supports web search (check Anthropic docs for the current list)

Basic Usage

Step 1: Frame the Research Query

• Be specific about the goal and scope
• Prefer official documentation and authoritative sources
• Add date constraints when recency matters

Step 2: Call the Messages API with the Web Search Tool

curl https://api.anthropic.com/v1/messages \
  -H "x-api-key: $ANTHROPIC_API_KEY" \
  -H "anthropic-version: 2023-06-01" \
  -H "content-type: application/json" \
  -d '{
    "model": "MODEL_NAME",
    "max_tokens": 1000,
    "messages": [
      {"role": "user", "content": "Research: [QUERY]. Provide a concise answer and cite sources."}
    ],
    "tools": [
      {
        "type": "web_search_20250305",
        "name": "web_search",
        "max_uses": 3,
        "allowed_domains": ["example.com"]
      }
    ]
  }'

Step 3: Present Results with Citations

• Summary: direct answer in 2-3 sentences
• Key findings: bullet points with citations
• Sources: list of URLs referenced

Domain Filtering and Location

• Use allowed_domains or blocked_domains to constrain sources
• Use user_location to bias results toward a region when needed
• Increase max_uses for broader coverage (keep it minimal to reduce cost)

Best Practices

• Prefer official docs, standards bodies, and vendor sources
• Request dates in the response for time-sensitive info
• Ask for alternative approaches if multiple options exist
• Keep the prompt explicit about citation requirements

Error Handling

• If web search is not enabled, ask the user to enable it in the Anthropic Console
• If the model lacks web search support, switch to a supported model
• If results are thin, broaden the query or remove domain filters

Related Skills

• codex-search for OpenAI Codex CLI web search
• claude-ask for read-only codebase understanding
• claude-exec for code modifications