feat(tools): add getToolExplanation() method with XML examples for LLM tool calling

Each tool now provides comprehensive documentation including parameter
schemas and concrete <tool_call> XML examples. This helps smaller LLMs
understand the exact format required for tool invocation.

ts/smartagent.tools.http.ts

@@ -180,6 +180,84 @@ export class HttpTool extends BaseToolWrapper {
     }
   }
 
+  public getToolExplanation(): string {
+    return `## Tool: http
+Make HTTP requests to web APIs and services.
+
+### Actions:
+
+**get** - Make a GET request
+Parameters:
+  - url (required): URL to request
+  - headers (optional): Request headers (key-value object)
+  - query (optional): Query parameters (key-value object)
+  - timeout (optional): Timeout in milliseconds
+
+Example:
+<tool_call>
+  <tool>http</tool>
+  <action>get</action>
+  <params>{"url": "https://api.example.com/data", "headers": {"Authorization": "Bearer token123"}}</params>
+</tool_call>
+
+**post** - Make a POST request with JSON body
+Parameters:
+  - url (required): URL to request
+  - body (optional): JSON body to send
+  - headers (optional): Request headers (key-value object)
+  - query (optional): Query parameters (key-value object)
+  - timeout (optional): Timeout in milliseconds
+
+Example:
+<tool_call>
+  <tool>http</tool>
+  <action>post</action>
+  <params>{"url": "https://api.example.com/submit", "body": {"name": "test", "value": 123}}</params>
+</tool_call>
+
+**put** - Make a PUT request with JSON body
+Parameters:
+  - url (required): URL to request
+  - body (required): JSON body to send
+  - headers (optional): Request headers (key-value object)
+  - timeout (optional): Timeout in milliseconds
+
+Example:
+<tool_call>
+  <tool>http</tool>
+  <action>put</action>
+  <params>{"url": "https://api.example.com/resource/1", "body": {"name": "updated"}}</params>
+</tool_call>
+
+**patch** - Make a PATCH request with JSON body
+Parameters:
+  - url (required): URL to request
+  - body (required): JSON body to send
+  - headers (optional): Request headers (key-value object)
+  - timeout (optional): Timeout in milliseconds
+
+Example:
+<tool_call>
+  <tool>http</tool>
+  <action>patch</action>
+  <params>{"url": "https://api.example.com/resource/1", "body": {"status": "active"}}</params>
+</tool_call>
+
+**delete** - Make a DELETE request
+Parameters:
+  - url (required): URL to request
+  - headers (optional): Request headers (key-value object)
+  - timeout (optional): Timeout in milliseconds
+
+Example:
+<tool_call>
+  <tool>http</tool>
+  <action>delete</action>
+  <params>{"url": "https://api.example.com/resource/1"}</params>
+</tool_call>
+`;
+  }
+
   public getCallSummary(action: string, params: Record<string, unknown>): string {
     const method = action.toUpperCase();
     let summary = `${method} request to "${params.url}"`;