Class WebSearchTool

Namespace: LMKit.Agents.Tools.BuiltIn.Net

Assembly: LM-Kit.NET.dll

A built-in tool for performing web searches using various search providers.

Enables agents to search the web for information using DuckDuckGo, Brave Search, SearXNG, Tavily, Serper, or custom search providers.

Production note: the default DuckDuckGo provider scrapes the public no-JavaScript HTML endpoint and is rate-limited aggressively by anti-bot protections. It is suitable for local development and ad-hoc queries only. For production agent workloads, use Brave, Tavily, or Serper (all offer free tiers and require an API key).

public sealed class WebSearchTool : IBuiltInTool, ITool, IToolMetadata, IDisposable

Inheritance: object

WebSearchTool

Implements: IBuiltInTool

ITool

IToolMetadata

IDisposable

Inherited Members: object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.ReferenceEquals(object, object)

object.ToString()

Examples

Example: Basic usage with DuckDuckGo (no API key)

// DuckDuckGo - no API key required
var webSearch = new WebSearchTool();
registry.Register(webSearch);
// Agent can now search the web

Example: Using Brave Search with API key

var webSearch = new WebSearchTool(new WebSearchTool.Options
{
    SearchProvider = WebSearchTool.Provider.Brave,
    ApiKey = "your-brave-api-key"
});
registry.Register(webSearch);

Example: Using self-hosted SearXNG

var webSearch = new WebSearchTool(new WebSearchTool.Options
{
    SearchProvider = WebSearchTool.Provider.SearXNG,
    BaseUrl = "https://your-searxng-instance.com"
});
registry.Register(webSearch);

Example: Using Tavily for AI-optimized search

var webSearch = new WebSearchTool(new WebSearchTool.Options
{
    SearchProvider = WebSearchTool.Provider.Tavily,
    ApiKey = Environment.GetEnvironmentVariable("TAVILY_API_KEY")
});
registry.Register(webSearch);

Remarks

Provider Overview:

Provider	Features
DuckDuckGo	Free, no API key required. HTML scraping based. Suitable for local development only; returns blocking errors after a small number of queries from any single IP.
Brave	Free tier available (2000 queries/month). High quality results. Requires API key.
SearXNG	Self-hosted meta-search engine. Privacy-focused. Aggregates multiple sources.
Tavily	AI-optimized search API. Excellent for RAG applications. Requires API key.
Serper	Google search results via API. High accuracy. Requires API key.
Custom	Bring your own search endpoint. Flexible integration.

Security Considerations:
This tool makes real network requests. Consider security implications when enabling it, especially with untrusted input.

Constructors

WebSearchTool(): Initializes a new instance with default settings (DuckDuckGo provider, no API key required).

WebSearchTool(Options): Initializes a new instance with custom options.

WebSearchTool(Provider, string): Initializes a new instance with the specified provider and API key.

WebSearchTool(HttpClient, Options): Initializes a new instance with an existing HttpClient.

Properties

Description: Gets a concise description of what the tool does.

InputSchema: Gets the JSON Schema defining the expected input arguments.

Name: Gets the stable, unique identifier for this tool.

SearchProvider: Gets the current search provider.

Methods

Dispose()

InvokeAsync(string, CancellationToken): Executes the tool with the specified JSON arguments.

Events

RawContentReceived

Occurs when raw content is received from a search provider.

This event allows interception of the raw HTML or JSON response before parsing. Useful for logging, caching, or custom processing of full page content.

ResultProcessing

Occurs before a result is processed and added to the response.

Allows inspection or modification of individual results before they are included. Set Cancel to true to exclude a result.

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