Initial commit: Cyrene Plugins SDK + Plugin Manager

Extracted from Cyrene main repo (backend/pkg/plugins + backend/plugin-manager).
Contains SDK interfaces (Plugin/Tool/HostAPI), 13 built-in plugins,
ToolRegistry with call log ring buffer, and Plugin Manager REST API service.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

web_fetch/plugin.go

@@ -0,0 +1,113 @@
+package webfetch
+
+import (
+	"context"
+	"fmt"
+	"io"
+	"net/http"
+	"strings"
+	"time"
+
+	"git.yeij.top/AskaEth/Cyrene-Plugins/sdk"
+)
+
+type WebFetchPlugin struct {
+	sdk.BasePlugin
+	client *http.Client
+}
+
+func NewWebFetchPlugin() *WebFetchPlugin {
+	return &WebFetchPlugin{client: &http.Client{Timeout: 15 * time.Second}}
+}
+
+func (p *WebFetchPlugin) Metadata() sdk.PluginMetadata {
+	return sdk.PluginMetadata{
+		Name: "web_fetch", DisplayName: "Web Fetch", Version: "1.0.0",
+		Description: "Fetch and extract text content from URLs",
+		Category: "network", Author: sdk.PluginAuthor{Name: "Cyrene Team"},
+	}
+}
+
+func (p *WebFetchPlugin) Tools() []sdk.Tool { return []sdk.Tool{&WebFetchTool{client: p.client}} }
+
+type WebFetchTool struct {
+	sdk.BaseTool
+	client *http.Client
+}
+
+func (t *WebFetchTool) Definition() sdk.ToolDefinition {
+	return sdk.ToolDefinition{
+		ID: "web_fetch", Name: "web_fetch", DisplayName: "Web Fetch",
+		Description: "Fetch content of a specified URL. Returns plain text summary (first 2000 characters). HTTP/HTTPS only.",
+		Category: "network", Complexity: sdk.ComplexitySimple,
+		Parameters: map[string]interface{}{
+			"type": "object",
+			"properties": map[string]interface{}{"url": map[string]interface{}{"type": "string"}},
+			"required": []string{"url"},
+		},
+	}
+}
+
+func (t *WebFetchTool) Validate(args map[string]interface{}) error {
+	if _, ok := args["url"]; !ok {
+		return fmt.Errorf("missing required parameter: url")
+	}
+	return nil
+}
+
+func (t *WebFetchTool) Execute(_ context.Context, args map[string]interface{}) (*sdk.ToolResult, error) {
+	urlStr, _ := args["url"].(string)
+	if !strings.HasPrefix(urlStr, "http://") && !strings.HasPrefix(urlStr, "https://") {
+		return &sdk.ToolResult{ToolName: "web_fetch", Success: false, Error: "only http/https URLs allowed"}, nil
+	}
+
+	req, _ := http.NewRequest("GET", urlStr, nil)
+	req.Header.Set("User-Agent", "CyreneBot/1.0")
+	resp, err := t.client.Do(req)
+	if err != nil {
+		return &sdk.ToolResult{ToolName: "web_fetch", Success: false, Error: err.Error()}, nil
+	}
+	defer resp.Body.Close()
+
+	bodyBytes, _ := io.ReadAll(io.LimitReader(resp.Body, 100*1024))
+	text := stripHTMLFull(string(bodyBytes))
+	text = removeBlankLines(text)
+	runes := []rune(text)
+	if len(runes) > 2000 {
+		text = string(runes[:2000]) + "..."
+	}
+	return &sdk.ToolResult{ToolName: "web_fetch", Success: true, Output: fmt.Sprintf(
+		"URL: %s\nStatus: %d\nContent-Type: %s\n\n%s",
+		urlStr, resp.StatusCode, resp.Header.Get("Content-Type"), text)}, nil
+}
+
+func stripHTMLFull(s string) string {
+	result := make([]rune, 0, len([]rune(s)))
+	inTag := false
+	for _, r := range s {
+		if r == '<' {
+			inTag = true
+			continue
+		}
+		if r == '>' {
+			inTag = false
+			continue
+		}
+		if !inTag {
+			result = append(result, r)
+		}
+	}
+	return string(result)
+}
+
+func removeBlankLines(s string) string {
+	lines := strings.Split(s, "\n")
+	var result []string
+	for _, line := range lines {
+		trimmed := strings.TrimSpace(line)
+		if trimmed != "" {
+			result = append(result, trimmed)
+		}
+	}
+	return strings.Join(result, "\n")
+}