diff --git a/agent.go b/agent.go
index 7f2dae1..0810eb5 100644
--- a/agent.go
+++ b/agent.go
@@ -2,60 +2,47 @@ package goba
 
 import (
 	"encoding/json"
+	"fmt"
 	"io"
 
 	"github.com/fumiama/deepinfra"
+	"github.com/fumiama/deepinfra/chat"
 	"github.com/fumiama/deepinfra/model"
 	"github.com/pkg/errors"
 	zero "github.com/wdvxdr1123/ZeroBot"
 )
 
 var (
-	ErrZeroOrNegContextCap = errors.New("ctxcap <= 0")
-	ErrZeroOrNegEventCap   = errors.New("evcap <= 0")
-	ErrPermissionDenied    = errors.New("permission denied")
+	ErrPermissionDenied = errors.New("permission denied")
 )
 
 // Agent is a OneBot event context, it is recommended to create one agent
 // per group or per user.
 type Agent struct {
+	log           chat.Log[fmt.Stringer]
 	id            int64
 	nickname, sex string
 	chars         string
-	ctxcap, evcap int
-	// 64 bits or 32 bits gap
-	ctx  generalctx
-	perm *Perm
+	perm          *Perm
 }
 
-// NewAgent characteristics 最好是 MD 格式
-func NewAgent(id int64, nickname, sex string, characteristics string) Agent {
+// NewAgent characteristics 最好是 MD 格式, defaultprompt 是上下文为空时的默认项, 建议为 Event JSON
+func NewAgent(
+	id int64, batchcap, itemscap int,
+	nickname, sex, characteristics, defaultprompt string,
+) Agent {
 	return Agent{
 		id: id, nickname: nickname, sex: sex, chars: characteristics,
-		ctxcap: 16, evcap: 8,
+		log: chat.NewLog[fmt.Stringer](batchcap, itemscap, "\n", defaultprompt),
 	}
 }
 
-func (ag *Agent) SetContextCap(n int) {
-	if n <= 0 {
-		panic(ErrZeroOrNegContextCap)
-	}
-	ag.ctxcap = n
+func (ag *Agent) AddEvent(grp int64, ev *Event) {
+	ag.log.Add(grp, ev, false)
 }
 
-func (ag *Agent) SetEventCap(n int) {
-	if n <= 0 {
-		panic(ErrZeroOrNegEventCap)
-	}
-	ag.evcap = n
-}
-
-func (ag *Agent) AddEvent(ev *Event) {
-	addctx(&ag.ctx, ev, ag.ctxcap, ag.evcap)
-}
-
-func (ag *Agent) AddRequest(req *zero.APIRequest) {
-	addctx(&ag.ctx, req, ag.ctxcap, ag.evcap)
+func (ag *Agent) AddRequest(grp int64, req *zero.APIRequest) {
+	ag.log.Add(grp, req, true)
 }
 
 // GetAction get OneBot CallAction from LLM and add it to context.
@@ -70,24 +57,15 @@ func (ag *Agent) AddRequest(req *zero.APIRequest) {
 //     with complete req, caller may decide whether to use this req by themselves.
 //     Whatever, this req will not be added into the context. You may call
 //     AddRequest to add it but it is not recommended.
-func (ag *Agent) GetAction(api deepinfra.API, m model.Protocol, role PermRole) (
+func (ag *Agent) GetAction(api deepinfra.API, p model.Protocol, grp int64, role PermRole, isusersystem bool) (
 	req zero.APIRequest, err error,
 ) {
-	p, err := ag.system(role)
+	sysp, err := ag.system(role)
 	if err != nil {
 		return
 	}
-	m.System(p)
 
-	ag.ctx.mu.Lock()
-	for i, evs := range ag.ctx.ctx {
-		if i%2 == 0 { // is user input
-			m.User(evs.String())
-		} else { // is agent callback
-			m.Assistant(evs.String())
-		}
-	}
-	ag.ctx.mu.Unlock()
+	m := ag.log.Modelize(p, grp, sysp, isusersystem)
 
 	resp, err := api.Request(m)
 	if err != nil {
@@ -101,7 +79,8 @@ func (ag *Agent) GetAction(api deepinfra.API, m model.Protocol, role PermRole) (
 	if !ag.perm.allow(role, req.Action) {
 		err = errors.Wrap(ErrPermissionDenied, req.Action)
 	} else {
-		ag.AddRequest(&req)
+		ag.AddRequest(grp, &req)
 	}
+
 	return
 }
diff --git a/ctx.go b/ctx.go
deleted file mode 100644
index a98360f..0000000
--- a/ctx.go
+++ /dev/null
@@ -1,72 +0,0 @@
-package goba
-
-import (
-	"reflect"
-	"sync"
-
-	"github.com/pkg/errors"
-	zero "github.com/wdvxdr1123/ZeroBot"
-)
-
-var (
-	ErrInvalidFirstContextType = errors.New("invalid first context type")
-)
-
-var (
-	eventType = reflect.TypeOf(Event{})
-	// requestType = reflect.TypeOf(zero.APIRequest{})
-)
-
-type generalctx struct {
-	mu  sync.Mutex
-	ctx []events
-}
-
-func addctx[T Event | zero.APIRequest](
-	ctx *generalctx, v *T, ctxcap, evcap int,
-) {
-	ctx.mu.Lock()
-	defer ctx.mu.Unlock()
-
-	typ := reflect.TypeOf(v).Elem()
-
-	if len(ctx.ctx) == 0 {
-		// must triggered by event
-		if !typ.AssignableTo(eventType) {
-			panic(errors.Wrap(ErrInvalidFirstContextType, typ.String()))
-		}
-
-		// ctxcap & evcap must > 0, no need to check
-		evs := make(events, 1, evcap)
-		evs[0] = v
-		ctx.ctx = make([]events, 1, ctxcap)
-		ctx.ctx[0] = evs
-		return
-	}
-	// Get the last events slice
-	lastEvents := &ctx.ctx[len(ctx.ctx)-1]
-
-	// Check if the type matches the first element of the last events
-	firstElemType := reflect.TypeOf((*lastEvents)[0]).Elem()
-	if typ.AssignableTo(firstElemType) {
-		// Same type, add to the last events
-		if len(*lastEvents) >= evcap {
-			// Shift elements forward by 1 (discard first element)
-			copy((*lastEvents)[:], (*lastEvents)[1:])
-			(*lastEvents)[len(*lastEvents)-1] = any(v)
-		} else {
-			*lastEvents = append(*lastEvents, any(v))
-		}
-		return
-	}
-
-	// Different type or empty last events, create new events slice
-	if len(ctx.ctx) >= ctxcap {
-		// Shift elements forward by 2 (user-assistant pair)
-		copy(ctx.ctx[:], ctx.ctx[2:])
-		ctx.ctx = ctx.ctx[:len(ctx.ctx)-2]
-	}
-	evs := make(events, 1, evcap)
-	evs[0] = v
-	ctx.ctx = append(ctx.ctx, evs)
-}
diff --git a/go.mod b/go.mod
index 424ad81..d8b521c 100644
--- a/go.mod
+++ b/go.mod
@@ -4,9 +4,9 @@ go 1.20
 
 require (
 	github.com/RomiChan/syncx v0.0.0-20240418144900-b7402ffdebc7
-	github.com/fumiama/deepinfra v0.0.0-20250910144855-27a4e697106d
+	github.com/fumiama/deepinfra v0.0.0-20250920170049-e3d1b92cc3a1
 	github.com/pkg/errors v0.9.1
-	github.com/wdvxdr1123/ZeroBot v1.8.2-0.20250919145948-e8ffbbc995ac
+	github.com/wdvxdr1123/ZeroBot v1.8.2-0.20250921063512-13752a73d444
 	gopkg.in/yaml.v3 v3.0.1
 )
 
diff --git a/go.sum b/go.sum
index 0afc1e7..327dd5c 100644
--- a/go.sum
+++ b/go.sum
@@ -5,8 +5,8 @@ github.com/RomiChan/syncx v0.0.0-20240418144900-b7402ffdebc7/go.mod h1:vD7Ra3Q9o
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
-github.com/fumiama/deepinfra v0.0.0-20250910144855-27a4e697106d h1:iGxnST620IHrJ47DXkjzrZJ2rskBogWze+UyvnAxT6g=
-github.com/fumiama/deepinfra v0.0.0-20250910144855-27a4e697106d/go.mod h1:wW05PQSn8mo1mZIoa6LBUE+3xIBjkoONvnfPTV5ZOhY=
+github.com/fumiama/deepinfra v0.0.0-20250920170049-e3d1b92cc3a1 h1:6PglFpNVm3DalGyRldacW2/v4jGWwn3v3q1tr2PhbVQ=
+github.com/fumiama/deepinfra v0.0.0-20250920170049-e3d1b92cc3a1/go.mod h1:wW05PQSn8mo1mZIoa6LBUE+3xIBjkoONvnfPTV5ZOhY=
 github.com/pkg/errors v0.9.1 h1:FEBLx1zS214owpjy7qsBeixbURkuhQAwrK5UwLGTwt4=
 github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
@@ -22,8 +22,8 @@ github.com/tidwall/match v1.1.1 h1:+Ho715JplO36QYgwN9PGYNhgZvoUSc9X2c80KVTi+GA=
 github.com/tidwall/match v1.1.1/go.mod h1:eRSPERbgtNPcGhD8UCthc6PmLEQXEWd3PRB5JTxsfmM=
 github.com/tidwall/pretty v1.2.0 h1:RWIZEg2iJ8/g6fDDYzMpobmaoGh5OLl4AXtGUGPcqCs=
 github.com/tidwall/pretty v1.2.0/go.mod h1:ITEVvHYasfjBbM0u2Pg8T2nJnzm8xPwvNhhsoaGGjNU=
-github.com/wdvxdr1123/ZeroBot v1.8.2-0.20250919145948-e8ffbbc995ac h1:XWpJQrUg75qUMwyKZX1jjK4ZziS5R4m/yVv5JCee3/s=
-github.com/wdvxdr1123/ZeroBot v1.8.2-0.20250919145948-e8ffbbc995ac/go.mod h1:C86nQ0gIdAri4K2vg8IIQIslt08zzrKMcqYt8zhkx1M=
+github.com/wdvxdr1123/ZeroBot v1.8.2-0.20250921063512-13752a73d444 h1:7aYFXzvVr2zuxBvqrGaJb24Z4W12aXBdW8DuE1mteE4=
+github.com/wdvxdr1123/ZeroBot v1.8.2-0.20250921063512-13752a73d444/go.mod h1:C86nQ0gIdAri4K2vg8IIQIslt08zzrKMcqYt8zhkx1M=
 golang.org/x/sys v0.0.0-20220715151400-c0bba94af5f8 h1:0A+M6Uqn+Eje4kHMK80dtF3JCXC4ykBgQG4Fe06QRhQ=
 golang.org/x/sys v0.0.0-20220715151400-c0bba94af5f8/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
diff --git a/types.go b/types.go
index fb0f966..4e5625d 100644
--- a/types.go
+++ b/types.go
@@ -8,19 +8,6 @@ import (
 	zero "github.com/wdvxdr1123/ZeroBot"
 )
 
-type events []any
-
-func (evs events) String() string {
-	sb := strings.Builder{}
-	for _, ev := range evs {
-		err := json.NewEncoder(&sb).Encode(ev) // has been terminated with '\n'
-		if err != nil {
-			panic(errors.Wrap(err, "unexpected"))
-		}
-	}
-	return strings.TrimSpace(sb.String())
-}
-
 // Event is the simplified OneBot event that dumped to the agent in JSON format
 type Event struct {
 	Time        int64           `json:"time"`         // 事件发生的时间戳
@@ -41,3 +28,12 @@ type Event struct {
 	Sender      *zero.User      `json:"sender,omitempty"`  // 事件发送者个人信息
 	Message     json.RawMessage `json:"message,omitempty"` // JSON 格式的消息内容
 }
+
+func (ev *Event) String() string {
+	sb := strings.Builder{}
+	err := json.NewEncoder(&sb).Encode(ev)
+	if err != nil {
+		panic(errors.Wrap(err, "unexpected"))
+	}
+	return strings.TrimSpace(sb.String())
+}