Add go-llm v2: redesigned API for simpler LLM abstraction

v2 is a new Go module (v2/) with a dramatically simpler API:
- Unified Message type (no more Input marker interface)
- Define[T] for ergonomic tool creation with standard context.Context
- Chat session with automatic tool-call loop (agent loop)
- Streaming via pull-based StreamReader
- MCP one-call connect (MCPStdioServer, MCPHTTPServer, MCPSSEServer)
- Middleware support (logging, retry, timeout, usage tracking)
- Decoupled JSON Schema (map[string]any, no provider coupling)
- Sample tools: WebSearch, Browser, Exec, ReadFile, WriteFile, HTTP
- Providers: OpenAI, Anthropic, Google (all with streaming)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

v2/tools/http.go

@@ -0,0 +1,75 @@
+package tools
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+
+	llm "gitea.stevedudenhoeffer.com/steve/go-llm/v2"
+)
+
+// HTTPParams defines parameters for the HTTP request tool.
+type HTTPParams struct {
+	Method  string            `json:"method" description:"HTTP method" enum:"GET,POST,PUT,DELETE,PATCH,HEAD"`
+	URL     string            `json:"url" description:"Request URL"`
+	Headers map[string]string `json:"headers,omitempty" description:"Request headers"`
+	Body    *string           `json:"body,omitempty" description:"Request body"`
+}
+
+// HTTP creates an HTTP request tool.
+//
+// Example:
+//
+//	tools := llm.NewToolBox(tools.HTTP())
+func HTTP() llm.Tool {
+	return llm.Define[HTTPParams]("http_request", "Make an HTTP request and return the response",
+		func(ctx context.Context, p HTTPParams) (string, error) {
+			var bodyReader io.Reader
+			if p.Body != nil {
+				bodyReader = bytes.NewBufferString(*p.Body)
+			}
+
+			req, err := http.NewRequestWithContext(ctx, p.Method, p.URL, bodyReader)
+			if err != nil {
+				return "", fmt.Errorf("creating request: %w", err)
+			}
+
+			for k, v := range p.Headers {
+				req.Header.Set(k, v)
+			}
+
+			resp, err := http.DefaultClient.Do(req)
+			if err != nil {
+				return "", fmt.Errorf("request failed: %w", err)
+			}
+			defer resp.Body.Close()
+
+			// Limit to 1MB
+			limited := io.LimitReader(resp.Body, 1<<20)
+			body, err := io.ReadAll(limited)
+			if err != nil {
+				return "", fmt.Errorf("reading response: %w", err)
+			}
+
+			headers := map[string]string{}
+			for k, v := range resp.Header {
+				if len(v) > 0 {
+					headers[k] = v[0]
+				}
+			}
+
+			result := map[string]any{
+				"status":      resp.StatusCode,
+				"status_text": resp.Status,
+				"headers":     headers,
+				"body":        string(body),
+			}
+
+			out, _ := json.MarshalIndent(result, "", "  ")
+			return string(out), nil
+		},
+	)
+}