> ## Documentation Index > Fetch the complete documentation index at: https://openrouter-d02e98a0-mintlify-5b6e02fd.mintlify.site/llms.txt > Use this file to discover all available pages before exploring further. # WebSearchServerTool - Go SDK > WebSearchServerTool type definition The Go SDK and docs are currently in beta. Report issues on [GitHub](https://github.com/OpenRouterTeam/go-sdk/issues). Web search tool configuration (2025-08-26 version) ## Fields | Field | Type | Required | Description | Example | | ------------------- | ---------------------------------------------------------------------------------------------------------------------------------- | -------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------- | | `Engine` | [\*components.WebSearchEngineEnum](/client-sdks/go/api-reference/models/websearchengineenum) | :heavy\_minus\_sign: | Which search engine to use. "auto" (default) uses native if the provider supports it, otherwise Exa. "native" forces the provider's built-in search. "exa" forces the Exa search API. "firecrawl" uses Firecrawl (requires BYOK). "parallel" uses the Parallel search API. | auto | | `Filters` | optionalnullable.OptionalNullable\[[components.WebSearchDomainFilter](/client-sdks/go/api-reference/models/websearchdomainfilter)] | :heavy\_minus\_sign: | N/A | `{"allowed_domains": ["example.com"],"excluded_domains": ["spam.com"]}` | | `MaxResults` | `*int64` | :heavy\_minus\_sign: | Maximum number of search results to return per search call. Defaults to 5. Applies to Exa, Firecrawl, and Parallel engines; ignored with native provider search. | 5 | | `SearchContextSize` | [\*components.SearchContextSizeEnum](/client-sdks/go/api-reference/models/searchcontextsizeenum) | :heavy\_minus\_sign: | Size of the search context for web search tools | medium | | `Type` | [components.WebSearchServerToolType](/client-sdks/go/api-reference/models/websearchservertooltype) | :heavy\_check\_mark: | N/A | | | `UserLocation` | optionalnullable.OptionalNullable\[[components.WebSearchUserLocation](/client-sdks/go/api-reference/models/websearchuserlocation)] | :heavy\_minus\_sign: | User location information for web search | `{"city": "San Francisco","country": "USA","region": "California","timezone": "America/Los_Angeles","type": "approximate"}` |