feat(tools): add MCP tool registry with web_fetch and web_search builtins

internal/tools/builtin.go

@@ -0,0 +1,48 @@
+package tools
+
+import (
+	"context"
+	"io"
+	"net/http"
+	"strings"
+	"time"
+)
+
+func RegisterBuiltins(r *Registry) {
+	r.Register(&Tool{
+		Name:        "web_fetch",
+		Description: "Fetch content from a URL",
+		Parameters: []Param{
+			{Name: "url", Type: "string", Required: true, Description: "URL to fetch"},
+		},
+		Execute: webFetch,
+	})
+
+	r.Register(&Tool{
+		Name:        "web_search",
+		Description: "Search the web for information",
+		Parameters: []Param{
+			{Name: "query", Type: "string", Required: true, Description: "search query"},
+		},
+		Execute: webSearch,
+	})
+}
+
+func webFetch(ctx context.Context, args string) (string, error) {
+	client := &http.Client{Timeout: 30 * time.Second}
+	resp, err := client.Get(strings.TrimSpace(args))
+	if err != nil {
+		return "", err
+	}
+	defer resp.Body.Close()
+
+	body, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return "", err
+	}
+	return string(body), nil
+}
+
+func webSearch(ctx context.Context, args string) (string, error) {
+	return "Web search not yet implemented. Query: " + args, nil
+}