Anthropic

View Source

Access Claude models through ReqLLM's unified interface. Supports all Claude 3+ models including extended thinking.

Configuration

ANTHROPIC_API_KEY=sk-ant-...

Provider Options

Passed via :provider_options keyword:

anthropic_top_k

  • Type: 1..40
  • Purpose: Sample from top K options per token
  • Example: provider_options: [anthropic_top_k: 20]

anthropic_version

  • Type: String
  • Default: "2023-06-01"
  • Purpose: API version override
  • Example: provider_options: [anthropic_version: "2023-06-01"]

stop_sequences

  • Type: List of strings
  • Purpose: Custom stop sequences
  • Example: provider_options: [stop_sequences: ["END", "STOP"]]

anthropic_metadata

  • Type: Map
  • Purpose: Request metadata for tracking
  • Example: provider_options: [anthropic_metadata: %{user_id: "123"}]

thinking

  • Type: Map
  • Purpose: Enable extended thinking/reasoning
  • Example: provider_options: [thinking: %{type: "enabled", budget_tokens: 4096}]
  • Access: ReqLLM.Response.thinking(response)

anthropic_prompt_cache

  • Type: Boolean
  • Purpose: Enable prompt caching
  • Example: provider_options: [anthropic_prompt_cache: true]

anthropic_prompt_cache_ttl

  • Type: String (e.g., "1h")
  • Purpose: Cache TTL (default ~5min if omitted)
  • Example: provider_options: [anthropic_prompt_cache_ttl: "1h"]

anthropic_cache_messages

  • Type: Boolean or Integer

  • Purpose: Add cache breakpoint at a specific message position

  • Requires: anthropic_prompt_cache: true

  • Values:

    • -1 or true - last message
    • -2 - second-to-last, -3 - third-to-last, etc.
    • 0 - first message, 1 - second, etc.

  • Examples:

    # Cache entire conversation (breakpoint at last message)
provider_options: [anthropic_prompt_cache: true, anthropic_cache_messages: true]

# Cache up to second-to-last message (before final user input)
provider_options: [anthropic_prompt_cache: true, anthropic_cache_messages: -2]

# Cache only up to first message
provider_options: [anthropic_prompt_cache: true, anthropic_cache_messages: 0]

Note: With anthropic_prompt_cache: true, system messages and tools are cached by default. Use anthropic_cache_messages to also cache conversation history. The offset applies to the messages array (user, assistant, and tool results), not system messages.

Lookback limit: Anthropic only checks up to 20 blocks before each cache breakpoint. If you have many tools or long system prompts, consider where you place message breakpoints.

  • Type: Map

  • Purpose: Enable web search tool with real-time web content access

  • Supported Models: Claude Sonnet 4.5, Claude Sonnet 4, Claude Haiku 4.5, Claude Haiku 3.5, Claude Opus 4.5, Claude Opus 4.1, Claude Opus 4

  • Configuration Options:

    • max_uses - Integer limiting the number of searches per request
    • allowed_domains - List of domains to include in results (e.g., ["wikipedia.org", "britannica.com"])
    • blocked_domains - List of domains to exclude from results (e.g., ["untrustedsource.com"])
    • user_location - Map with keys: :type, :city, :region, :country, :timezone for localized results

  • Pricing: $10 per 1,000 searches plus standard token costs

  • Examples:

    # Basic web search with usage limit
provider_options: [web_search: %{max_uses: 5}]

# Web search with domain filtering
provider_options: [
  web_search: %{
    max_uses: 3,
    allowed_domains: ["wikipedia.org", "britannica.com"]
  }
]

# Web search with blocked domains
provider_options: [
  web_search: %{
    blocked_domains: ["untrustedsource.com"]
  }
]

# Web search with user location for localized results
provider_options: [
  web_search: %{
    max_uses: 5,
    user_location: %{
      type: "approximate",
      city: "San Francisco",
      region: "California",
      country: "US",
      timezone: "America/Los_Angeles"
    }
  }
]

# Combine with regular tools
ReqLLM.chat(
  "What's the weather in NYC and latest tech news?",
  model: "anthropic:claude-sonnet-4-5",
  tools: [my_weather_tool],
  provider_options: [web_search: %{max_uses: 3}]
)

Note: Web search must be enabled by your organization administrator in the Anthropic Console. Domain filters cannot expand beyond organization-level restrictions. Claude automatically decides when to use web search and cites sources in its responses.

Web Search Cost Tracking

Web search usage and costs are tracked in response.usage:

{:ok, response} = ReqLLM.generate_text(
  "anthropic:claude-sonnet-4-5",
  "What are the latest AI announcements?",
  provider_options: [web_search: %{max_uses: 5}]
)

# Access web search usage
response.usage.tool_usage.web_search
#=> %{count: 2, unit: "call"}

# Access cost breakdown
response.usage.cost
#=> %{tokens: 0.001, tools: 0.02, images: 0.0, total: 0.021}

Web search is billed at $10 per 1,000 searches plus standard token costs.

Wire Format Notes

  • Endpoint: /v1/messages
  • Auth: x-api-key header (not Bearer token)
  • System messages: included in messages array
  • Tool calls: content block structure

All differences handled automatically by ReqLLM.

Resources