feat(agent): 新增通用 {{.Now}} 提示词变量(每轮实时渲染)

- 各 agent 渲染路径(chat/worker/mainagent/goals/planner)统一提供 Now(nowStr());
  自定义会话 agent 每次触发都会重新 renderSystem,故 {{.Now}} 每轮实时刷新
- server 端 globalPromptVars + withGlobalVars:在保存校验/变量列表/预览/详情放行
  {{.Now}},否则引用它的自定义提示词会被 validateTemplate 拒绝
- 无 DB 迁移(handler 层注入通用变量,不动 agent_prompt_vars 表)
- 用途:配合固定的开始时间戳相减,判断"已运行多久/是否进入最后N小时"
- 新增 agent/prompt_now_test.go:{{.Now}} 渲染实时时间、未知变量安全回退

agent/chat.go

@@ -58,12 +58,13 @@ func chatWorkDirSpec(workDir string) string {
 // chatSystem renders the DB-managed prompt body for agentKey. Custom agents have
 // no per-key in-code default, so DefaultAssistantPrompt is the render fallback.
 func chatSystem(agentKey, workDir string) string {
-	return renderSystem(agentKey, DefaultAssistantPrompt, chatVars{}) + chatWorkDirSpec(workDir)
+	return renderSystem(agentKey, DefaultAssistantPrompt, chatVars{Now: nowStr()}) + chatWorkDirSpec(workDir)
 }
 
-// chatVars carries no runtime variables today — a custom prompt referencing any
-// {{.X}} simply fails to render and falls back to DefaultAssistantPrompt.
-type chatVars struct{}
+// chatVars carries the runtime variables a custom agent's prompt may reference.
+// Now (server wall-clock, refreshed each turn) is the only one today; any other
+// {{.X}} fails to render and falls back to DefaultAssistantPrompt.
+type chatVars struct{ Now string }
 
 // Chat runs ONE turn of a conversation with the agent identified by agentKey,
 // resuming prior history keyed by sessionID. maxTurns is the per-turn agent step

agent/goals.go

@@ -102,7 +102,7 @@ func DecomposeGoals(ctx context.Context, c Config, goalText, desc string, as *db
 	// Description rides in the user message (same channel as the goal), NOT via the
 	// {{.EngagementDescription}} template var — else a prompt that references the var
 	// would inject the description twice. System prompt stays pure static instructions.
-	sys := renderSystem("goals", goalsDefaultTmpl, GoalsVars{})
+	sys := renderSystem("goals", goalsDefaultTmpl, GoalsVars{Now: nowStr()})
 	tools := []actool.CoreTool{submitTool}
 	// Wire add_task_scope only when we have a real asset store + task to write to.
 	// The scope-extraction tail is appended in lockstep so the prompt never asks for

agent/mainagent.go

@@ -55,7 +55,7 @@ const mainAgentDefaultTmpl = `你是一个授权渗透测试系统的"主 agent"
 不要编造发现；只根据工具返回的真实数据回答。`
 
 func mainAgentSystem(goal, workDir string) string {
-	body := renderSystem("mainagent", mainAgentDefaultTmpl, MainVars{Goal: goal})
+	body := renderSystem("mainagent", mainAgentDefaultTmpl, MainVars{Goal: goal, Now: nowStr()})
 	return body + artifactSpec(workDir)
 }
 

agent/planner.go

@@ -6,7 +6,6 @@ import (
 	"fmt"
 	"strings"
 	"sync"
-	"time"
 
 	"github.com/Autumn-27/artex/db"
 	"github.com/Autumn-27/norma/agentcore"
@@ -160,7 +159,7 @@ const plannerDefaultTmpl = `你是一个授权渗透测试系统的"规划者"
 宁可不生成，也不要重复或硬凑。简洁、克制、高效。`
 
 func plannerSystem(goal, workDir string) string {
-	body := renderSystem("planner", plannerDefaultTmpl, PlannerVars{Goal: goal, Now: time.Now().Format("2006-01-02 15:04:05 MST")})
+	body := renderSystem("planner", plannerDefaultTmpl, PlannerVars{Goal: goal, Now: nowStr()})
 	return body + artifactSpec(workDir)
 }
 

agent/prompt.go

@@ -3,6 +3,7 @@ package agent
 import (
 	"bytes"
 	"text/template"
+	"time"
 )
 
 // PromptOverride, if set, returns the stored system-prompt template for an agent
@@ -15,10 +16,16 @@ var PromptOverride func(agentKey string) (string, bool)
 // user template referencing a catalog variable renders; referencing anything else
 // fails template execution and falls back to the built-in default.
 type PlannerVars struct{ Goal, Scope, AssetSummary, Now string }
-type WorkerVars struct{ ProxyAddr, WorkerName string }
-type MainVars struct{ Goal, AssetSummary, FindingsSummary string }
+type WorkerVars struct{ ProxyAddr, WorkerName, Now string }
+type MainVars struct{ Goal, AssetSummary, FindingsSummary, Now string }
 type GoalsVars struct{ EngagementDescription, Now string }
 
+// nowStr is the server-local wall-clock string exposed as the universal {{.Now}}
+// prompt variable. renderSystem runs on every agent turn/round, so this is fresh
+// each run — a prompt can subtract it from a fixed start stamp to reason about
+// elapsed time (e.g. a timed benchmark's "last N hours" window).
+func nowStr() string { return time.Now().Format("2006-01-02 15:04:05 MST") }
+
 // renderSystem returns the rendered system-prompt BODY (段 [A]) for agentKey.
 // Precedence: the DB-stored template (if any) over the built-in default template
 // (def). BOTH are Go templates now — the built-in default is seeded into the DB

agent/prompt_now_test.go

@@ -0,0 +1,50 @@
+package agent
+
+import (
+	"strings"
+	"testing"
+	"time"
+)
+
+// TestChatNowVarRenders verifies the universal {{.Now}} runtime variable: a custom
+// (chat) agent prompt referencing it renders the live server time each turn, rather
+// than failing template execution and falling back to DefaultAssistantPrompt.
+func TestChatNowVarRenders(t *testing.T) {
+	prev := PromptOverride
+	defer func() { PromptOverride = prev }()
+
+	PromptOverride = func(key string) (string, bool) {
+		if key == "tec_benchmark" {
+			return "当前时间：{{.Now}}", true
+		}
+		return "", false
+	}
+
+	out := chatSystem("tec_benchmark", "/tmp/x")
+	if !strings.Contains(out, "当前时间：") {
+		t.Fatalf("custom prompt body missing, likely fell back to default: %q", out)
+	}
+	year := time.Now().Format("2006")
+	if !strings.Contains(out, year) {
+		t.Fatalf("{{.Now}} did not render the live time (want year %s): %q", year, out)
+	}
+}
+
+// TestChatUnknownVarFallsBack verifies an out-of-catalog {{.X}} still degrades
+// safely to the default assistant prompt (never a half-rendered prompt).
+func TestChatUnknownVarFallsBack(t *testing.T) {
+	prev := PromptOverride
+	defer func() { PromptOverride = prev }()
+
+	PromptOverride = func(key string) (string, bool) {
+		return "引用了不存在的变量：{{.Bogus}}", true
+	}
+
+	out := chatSystem("whatever", "/tmp/x")
+	if strings.Contains(out, "引用了不存在的变量") {
+		t.Fatalf("broken template should have fallen back, got custom body: %q", out)
+	}
+	if !strings.Contains(out, DefaultAssistantPrompt) {
+		t.Fatalf("expected fallback to DefaultAssistantPrompt, got: %q", out)
+	}
+}

agent/worker.go

@@ -184,7 +184,7 @@ func ensureRunDir(base string, taskID, intentID int64) string {
 func cmdOutDir(dir string) string { return filepath.Join(dir, "cmd-output") }
 
 func workerSystem(proxyAddr, runDir string) string {
-	body := renderSystem("worker", workerDefaultTmpl, WorkerVars{ProxyAddr: proxyAddr})
+	body := renderSystem("worker", workerDefaultTmpl, WorkerVars{ProxyAddr: proxyAddr, Now: nowStr()})
 	return body + workerTrafficBlock(proxyAddr) + workerArtifactSpec(runDir)
 }
 

server/server_mgmt.go

@@ -303,6 +303,7 @@ func (s *Server) pgGetAgent(w http.ResponseWriter, r *http.Request) {
 	}
 	cur, _ := pg.CurrentPrompt(a.ID)
 	vars, _ := pg.PromptVars(a.ID)
+	vars = withGlobalVars(vars)
 	vers, _ := pg.ListPromptVersions(a.ID)
 	if vers == nil {
 		vers = []db.PromptVersion{}
@@ -339,7 +340,7 @@ func (s *Server) pgSavePrompt(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 	vars, _ := pg.PromptVars(a.ID)
-	if bad := validateTemplate(body.Template, vars); bad != "" {
+	if bad := validateTemplate(body.Template, withGlobalVars(vars)); bad != "" {
 		writeErr(w, 400, bad)
 		return
 	}
@@ -495,7 +496,7 @@ func (s *Server) pgPromptVars(w http.ResponseWriter, r *http.Request) {
 		writeErr(w, 500, err.Error())
 		return
 	}
-	writeJSON(w, 200, map[string]any{"variables": vars})
+	writeJSON(w, 200, map[string]any{"variables": withGlobalVars(vars)})
 }
 
 func (s *Server) pgPreviewPrompt(w http.ResponseWriter, r *http.Request) {
@@ -512,7 +513,7 @@ func (s *Server) pgPreviewPrompt(w http.ResponseWriter, r *http.Request) {
 	if body.Template == "" {
 		body.Template, _ = pg.CurrentPrompt(a.ID)
 	}
-	rendered, err := renderPrompt(body.Template, vars, body.Sample)
+	rendered, err := renderPrompt(body.Template, withGlobalVars(vars), body.Sample)
 	if err != nil {
 		writeJSON(w, 200, map[string]any{"rendered": "", "error": err.Error()})
 		return
@@ -1706,6 +1707,20 @@ func (s *Server) pgListModels(w http.ResponseWriter, r *http.Request) {
 
 // --- prompt template helpers (Go text/template + catalog 白名单) ---
 
+// globalPromptVars are runtime variables available to EVERY agent (built-in and
+// custom) regardless of its per-agent catalog. Each agent's render path fills them
+// (see agent.nowStr, rendered fresh each turn), so a prompt may always reference
+// {{.Now}} — e.g. subtract it from a fixed start stamp to reason about elapsed time.
+var globalPromptVars = []db.PromptVar{
+	{Name: "Now", Description: "服务端当前时间（每次运行实时刷新；可与固定起始时间相减判断已用时长）", Example: "2026-08-11 14:30:00 CST", Source: "runtime"},
+}
+
+// withGlobalVars appends the universal runtime vars onto an agent's own catalog,
+// so validation / the UI variable list / preview all recognize {{.Now}} etc.
+func withGlobalVars(vars []db.PromptVar) []db.PromptVar {
+	return append(append([]db.PromptVar{}, vars...), globalPromptVars...)
+}
+
 // validateTemplate parses the template and rejects any {{.Var}} not in the catalog.
 // Returns "" if valid, otherwise an error message.
 func validateTemplate(tmpl string, catalog []db.PromptVar) string {