feat: provider manager, cancellation, session summaries (store+agent)

internal/agent/agent.go

@@ -1,9 +1,12 @@
-// Package agent implements the LLM tool-calling loop.
+// Package agent implements the LLM tool-calling loop, cancellation and
+// summarisation of long sessions.
 package agent
 
 import (
 	"context"
+	"errors"
 	"fmt"
+	"strings"
 	"sync"
 
 	"github.com/crypto/byteclaw/internal/llm"
@@ -11,9 +14,12 @@ import (
 	"github.com/crypto/byteclaw/internal/tools"
 )
 
+// ErrCancelled is returned by Run when the user stopped the answer.
+var ErrCancelled = errors.New("cancelled by user")
+
 // Event is streamed to clients while the agent works.
 type Event struct {
-	Type    string `json:"type"` // delta | tool_call | tool_result | done | error
+	Type    string `json:"type"` // session | delta | tool_call | tool_result | summarized | done | cancelled | error
 	Text    string `json:"text,omitempty"`
 	Tool    string `json:"tool,omitempty"`
 	Args    string `json:"args,omitempty"`
@@ -21,16 +27,29 @@ type Event struct {
 	Session string `json:"session_id,omitempty"`
 }
 
+// SummarizeConfig controls automatic summarisation.
+type SummarizeConfig struct {
+	Enabled     bool
+	MaxMessages int
+	MaxTokens   int
+	KeepRecent  int
+}
+
 type Agent struct {
-	LLM           llm.Provider
+	// LLM is used when Resolve is nil.
+	LLM llm.Provider
+	// Resolve picks the provider for a session (e.g. per-session override).
+	Resolve       func(ctx context.Context, sessionID string) (llm.Provider, error)
 	Tools         *tools.Registry
 	Store         *store.Store
 	SystemPrompt  string
 	MaxIterations int
 	HistoryLimit  int
+	Summarize     SummarizeConfig
 
 	mu    sync.Mutex
 	locks map[string]*sync.Mutex
+	runs  map[string]context.CancelCauseFunc
 }
 
 func (a *Agent) sessionLock(id string) *sync.Mutex {
@@ -47,9 +66,55 @@ func (a *Agent) sessionLock(id string) *sync.Mutex {
 	return l
 }
 
+func (a *Agent) provider(ctx context.Context, sessionID string) (llm.Provider, error) {
+	if a.Resolve != nil {
+		return a.Resolve(ctx, sessionID)
+	}
+	if a.LLM == nil {
+		return nil, errors.New("no LLM provider configured")
+	}
+	return a.LLM, nil
+}
+
+// Cancel stops the running answer of a session. Returns false if none is running.
+func (a *Agent) Cancel(sessionID string) bool {
+	a.mu.Lock()
+	defer a.mu.Unlock()
+	if c, ok := a.runs[sessionID]; ok {
+		c(ErrCancelled)
+		return true
+	}
+	return false
+}
+
+// Running reports whether an answer is in progress for the session.
+func (a *Agent) Running(sessionID string) bool {
+	a.mu.Lock()
+	defer a.mu.Unlock()
+	_, ok := a.runs[sessionID]
+	return ok
+}
+
+func (a *Agent) register(sessionID string, c context.CancelCauseFunc) {
+	a.mu.Lock()
+	defer a.mu.Unlock()
+	if a.runs == nil {
+		a.runs = map[string]context.CancelCauseFunc{}
+	}
+	a.runs[sessionID] = c
+}
+
+func (a *Agent) unregister(sessionID string) {
+	a.mu.Lock()
+	defer a.mu.Unlock()
+	delete(a.runs, sessionID)
+}
+
 // Run appends the user message to the session and loops until the model
-// answers without tool calls. Returns the final assistant text.
+// answers without tool calls. Returns the final assistant text. If the run is
-func (a *Agent) Run(ctx context.Context, sessionID, userText string, emit func(Event)) (string, error) {
+// cancelled via Cancel, the partial answer is stored (marked cancelled) and
+// ErrCancelled is returned together with the partial text.
+func (a *Agent) Run(parent context.Context, sessionID, userText string, emit func(Event)) (string, error) {
 	if emit == nil {
 		emit = func(Event) {}
 	}
@@ -57,26 +122,57 @@ func (a *Agent) Run(ctx context.Context, sessionID, userText string, emit func(E
 	l.Lock()
 	defer l.Unlock()
 
-	if _, err := a.Store.AppendMessage(ctx, sessionID, llm.Message{Role: llm.RoleUser, Content: userText}); err != nil {
+	ctx, cancel := context.WithCancelCause(parent)
+	defer cancel(nil)
+	a.register(sessionID, cancel)
+	defer a.unregister(sessionID)
+	// Writes after a cancellation must still succeed.
+	saveCtx := context.WithoutCancel(ctx)
+
+	if _, err := a.Store.AppendMessage(saveCtx, sessionID, llm.Message{Role: llm.RoleUser, Content: userText}); err != nil {
 		return "", err
 	}
+	prov, err := a.provider(ctx, sessionID)
+	if err != nil {
+		return "", err
+	}
+	if a.Summarize.Enabled {
+		if sm, err := a.summarizeLocked(ctx, prov, sessionID, false); err == nil && sm != nil {
+			emit(Event{Type: "summarized", Text: sm.Content})
+		}
+	}
 	var specs []llm.ToolSpec
 	if a.Tools != nil {
 		specs = a.Tools.Specs()
 	}
+	cancelled := func() bool { return errors.Is(context.Cause(ctx), ErrCancelled) }
 	for i := 0; i < a.MaxIterations; i++ {
-		msgs, err := a.history(ctx, sessionID)
+		if cancelled() {
+			return "", ErrCancelled
+		}
+		msgs, err := a.history(saveCtx, sessionID)
 		if err != nil {
 			return "", err
 		}
-		resp, err := a.LLM.Chat(ctx, llm.Request{Messages: msgs, Tools: specs}, func(t string) {
+		var partial strings.Builder
+		resp, err := prov.Chat(ctx, llm.Request{Messages: msgs, Tools: specs}, func(t string) {
+			partial.WriteString(t)
 			emit(Event{Type: "delta", Text: t})
 		})
 		if err != nil {
+			if cancelled() {
+				text := partial.String()
+				if text != "" {
+					if _, serr := a.Store.AppendMessage(saveCtx, sessionID, llm.Message{Role: llm.RoleAssistant, Content: text, Cancelled: true}); serr != nil {
+						return text, serr
+					}
+				}
+				return text, ErrCancelled
+			}
 			return "", err
 		}
 		asst := llm.Message{Role: llm.RoleAssistant, Content: resp.Content, ToolCalls: resp.ToolCalls}
-		if _, err := a.Store.AppendMessage(ctx, sessionID, asst); err != nil {
+		if _, err := a.Store.AppendMessage(saveCtx, sessionID, asst); err != nil {
 			return "", err
 		}
 		if len(resp.ToolCalls) == 0 {
@@ -84,9 +180,13 @@ func (a *Agent) Run(ctx context.Context, sessionID, userText string, emit func(E
 		}
 		for _, tc := range resp.ToolCalls {
 			emit(Event{Type: "tool_call", Tool: tc.Name, Args: tc.Arguments, CallID: tc.ID})
-			out := a.Tools.Call(ctx, tc.Name, tc.Arguments)
+			out := "error: cancelled by user"
+			if !cancelled() {
+				out = a.Tools.Call(ctx, tc.Name, tc.Arguments)
+			}
 			emit(Event{Type: "tool_result", Tool: tc.Name, Text: clip(out, 2000), CallID: tc.ID})
-			if _, err := a.Store.AppendMessage(ctx, sessionID, llm.Message{Role: llm.RoleTool, ToolCallID: tc.ID, Name: tc.Name, Content: out}); err != nil {
+			// Every tool call gets a result so the history stays valid for the provider.
+			if _, err := a.Store.AppendMessage(saveCtx, sessionID, llm.Message{Role: llm.RoleTool, ToolCallID: tc.ID, Name: tc.Name, Content: out}); err != nil {
 				return "", err
 			}
 		}
@@ -95,7 +195,14 @@ func (a *Agent) Run(ctx context.Context, sessionID, userText string, emit func(E
 }
 
 func (a *Agent) history(ctx context.Context, sessionID string) ([]llm.Message, error) {
-	stored, err := a.Store.Messages(ctx, sessionID, a.HistoryLimit)
+	var after int64
+	summary := ""
+	if sm, err := a.Store.LatestSummary(ctx, sessionID); err == nil {
+		after, summary = sm.UptoMessageID, sm.Content
+	} else if !errors.Is(err, store.ErrNotFound) {
+		return nil, err
+	}
+	stored, err := a.Store.MessagesAfter(ctx, sessionID, after, a.HistoryLimit)
 	if err != nil {
 		return nil, err
 	}
@@ -103,12 +210,17 @@ func (a *Agent) history(ctx context.Context, sessionID string) ([]llm.Message, e
 	for len(stored) > 0 && stored[0].Role == llm.RoleTool {
 		stored = stored[1:]
 	}
-	msgs := make([]llm.Message, 0, len(stored)+1)
+	msgs := make([]llm.Message, 0, len(stored)+2)
 	if a.SystemPrompt != "" {
 		msgs = append(msgs, llm.Message{Role: llm.RoleSystem, Content: a.SystemPrompt})
 	}
+	if summary != "" {
+		msgs = append(msgs, llm.Message{Role: llm.RoleSystem, Content: "Summary of the earlier conversation:\n" + summary})
+	}
 	for _, m := range stored {
-		msgs = append(msgs, m.Message)
+		mm := m.Message
+		mm.Cancelled = false
+		msgs = append(msgs, mm)
 	}
 	return msgs, nil
 }

internal/agent/agent_test.go

@@ -2,6 +2,8 @@ package agent
 
 import (
 	"context"
+	"errors"
+	"fmt"
 	"path/filepath"
 	"strings"
 	"testing"
@@ -91,3 +93,116 @@ func TestHistoryDropsOrphanToolMessages(t *testing.T) {
 		t.Fatalf("%+v", h)
 	}
 }
+
+// blocking streams one delta then waits for cancellation, like a slow provider.
+type blocking struct{ started chan struct{} }
+
+func (b *blocking) Chat(ctx context.Context, _ llm.Request, d llm.DeltaFunc) (llm.Response, error) {
+	d("Teil")
+	d("antwort")
+	close(b.started)
+	<-ctx.Done()
+	return llm.Response{}, ctx.Err()
+}
+
+func TestCancelStoresPartialAnswer(t *testing.T) {
+	st := newStore(t)
+	ss, _ := st.CreateSession(context.Background(), "")
+	b := &blocking{started: make(chan struct{})}
+	a := &Agent{LLM: b, Store: st, Tools: tools.NewRegistry(), MaxIterations: 3}
+	if a.Cancel(ss.ID) {
+		t.Fatal("nothing should be running")
+	}
+	go func() {
+		<-b.started
+		if !a.Cancel(ss.ID) {
+			t.Error("cancel should find the run")
+		}
+	}()
+	text, err := a.Run(context.Background(), ss.ID, "erzähl was", nil)
+	if !errors.Is(err, ErrCancelled) || text != "Teilantwort" {
+		t.Fatalf("%q %v", text, err)
+	}
+	msgs, _ := st.Messages(context.Background(), ss.ID, 0)
+	if len(msgs) != 2 || !msgs[1].Cancelled || msgs[1].Content != "Teilantwort" {
+		t.Fatalf("%+v", msgs)
+	}
+	if a.Running(ss.ID) {
+		t.Fatal("run must be unregistered")
+	}
+}
+
+// recorder answers summary requests with "SUMMARY" and normal turns with "ok".
+type recorder struct{ reqs []llm.Request }
+
+func (r *recorder) Chat(_ context.Context, req llm.Request, _ llm.DeltaFunc) (llm.Response, error) {
+	r.reqs = append(r.reqs, req)
+	if strings.Contains(req.Messages[0].Content, "compress chat histories") {
+		return llm.Response{Content: "SUMMARY"}, nil
+	}
+	return llm.Response{Content: "ok"}, nil
+}
+
+func TestAutoSummarize(t *testing.T) {
+	st := newStore(t)
+	ctx := context.Background()
+	ss, _ := st.CreateSession(ctx, "")
+	p := &recorder{}
+	a := &Agent{LLM: p, Store: st, Tools: tools.NewRegistry(), MaxIterations: 2, SystemPrompt: "sys",
+		Summarize: SummarizeConfig{Enabled: true, MaxMessages: 6, KeepRecent: 2}}
+	for i := 0; i < 3; i++ { // 6 messages -> at threshold, no summary yet
+		a.Run(ctx, ss.ID, fmt.Sprintf("frage %d", i), nil)
+	}
+	if _, err := st.LatestSummary(ctx, ss.ID); err == nil {
+		t.Fatal("summary created too early")
+	}
+	var events []string
+	a.Run(ctx, ss.ID, "frage 3", func(e Event) { events = append(events, e.Type) })
+	sm, err := st.LatestSummary(ctx, ss.ID)
+	if err != nil || sm.Content != "SUMMARY" {
+		t.Fatalf("%+v %v", sm, err)
+	}
+	if events[0] != "summarized" {
+		t.Fatalf("%v", events)
+	}
+	last := p.reqs[len(p.reqs)-1].Messages
+	if last[1].Role != llm.RoleSystem || !strings.Contains(last[1].Content, "SUMMARY") {
+		t.Fatalf("summary not in context: %+v", last)
+	}
+	// the verbatim tail starts at a user message and older messages are not sent
+	if last[2].Role != llm.RoleUser || strings.Contains(fmt.Sprint(last), "frage 0") {
+		t.Fatalf("bad window: %+v", last)
+	}
+	if all, _ := st.Messages(ctx, ss.ID, 0); len(all) != 8 {
+		t.Fatalf("originals must be kept, got %d", len(all))
+	}
+}
+
+func TestAutoSummarizeByTokens(t *testing.T) {
+	st := newStore(t)
+	ctx := context.Background()
+	ss, _ := st.CreateSession(ctx, "")
+	a := &Agent{LLM: &recorder{}, Store: st, Tools: tools.NewRegistry(), MaxIterations: 2,
+		Summarize: SummarizeConfig{Enabled: true, MaxMessages: 1000, MaxTokens: 50, KeepRecent: 1}}
+	a.Run(ctx, ss.ID, strings.Repeat("lang ", 100), nil)
+	a.Run(ctx, ss.ID, "kurz", nil)
+	if _, err := st.LatestSummary(ctx, ss.ID); err != nil {
+		t.Fatal("token threshold should trigger summary")
+	}
+}
+
+func TestSummarizeNowManual(t *testing.T) {
+	st := newStore(t)
+	ctx := context.Background()
+	ss, _ := st.CreateSession(ctx, "")
+	a := &Agent{LLM: &recorder{}, Store: st, Tools: tools.NewRegistry(), MaxIterations: 2, Summarize: SummarizeConfig{KeepRecent: 2}}
+	if sm, err := a.SummarizeNow(ctx, ss.ID); err != nil || sm != nil {
+		t.Fatalf("empty session: %v %v", sm, err)
+	}
+	a.Run(ctx, ss.ID, "eins", nil)
+	a.Run(ctx, ss.ID, "zwei", nil)
+	sm, err := a.SummarizeNow(ctx, ss.ID)
+	if err != nil || sm == nil || sm.Content != "SUMMARY" {
+		t.Fatalf("%v %v", sm, err)
+	}
+}

internal/agent/summarize.go

@@ -0,0 +1,105 @@
+package agent
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"strings"
+
+	"github.com/crypto/byteclaw/internal/llm"
+	"github.com/crypto/byteclaw/internal/store"
+)
+
+const summarizePrompt = `You compress chat histories. Write a concise summary of the conversation below so an assistant can continue it.
+Keep facts, user preferences, decisions, results of tool calls and open tasks. Use the language of the conversation. No preamble.`
+
+// estimateTokens is a cheap approximation (≈4 characters per token).
+func estimateTokens(msgs []store.StoredMessage) int {
+	n := 0
+	for _, m := range msgs {
+		n += len(m.Content) / 4
+		for _, tc := range m.ToolCalls {
+			n += len(tc.Arguments) / 4
+		}
+	}
+	return n
+}
+
+// SummarizeNow summarises the session regardless of thresholds (manual trigger).
+// Returns nil summary if there is nothing old enough to summarise.
+func (a *Agent) SummarizeNow(ctx context.Context, sessionID string) (*store.Summary, error) {
+	l := a.sessionLock(sessionID)
+	l.Lock()
+	defer l.Unlock()
+	prov, err := a.provider(ctx, sessionID)
+	if err != nil {
+		return nil, err
+	}
+	return a.summarizeLocked(ctx, prov, sessionID, true)
+}
+
+func (a *Agent) summarizeLocked(ctx context.Context, prov llm.Provider, sessionID string, force bool) (*store.Summary, error) {
+	var after int64
+	prev := ""
+	if sm, err := a.Store.LatestSummary(ctx, sessionID); err == nil {
+		after, prev = sm.UptoMessageID, sm.Content
+	} else if !errors.Is(err, store.ErrNotFound) {
+		return nil, err
+	}
+	msgs, err := a.Store.MessagesAfter(ctx, sessionID, after, 0)
+	if err != nil {
+		return nil, err
+	}
+	cfg := a.Summarize
+	if !force && len(msgs) <= cfg.MaxMessages && (cfg.MaxTokens <= 0 || estimateTokens(msgs) <= cfg.MaxTokens) {
+		return nil, nil
+	}
+	keep := cfg.KeepRecent
+	if keep < 1 {
+		keep = 1
+	}
+	cut := len(msgs) - keep
+	// The verbatim tail must start at a user message so tool call/result pairs stay together.
+	for cut > 0 && cut < len(msgs) && msgs[cut].Role != llm.RoleUser {
+		cut--
+	}
+	if cut <= 0 {
+		return nil, nil
+	}
+	var b strings.Builder
+	if prev != "" {
+		b.WriteString("Previous summary:\n" + prev + "\n\n")
+	}
+	b.WriteString("Conversation:\n")
+	for _, m := range msgs[:cut] {
+		switch {
+		case m.Role == llm.RoleTool:
+			fmt.Fprintf(&b, "tool %s result: %s\n", m.Name, clip(m.Content, 500))
+		case len(m.ToolCalls) > 0:
+			for _, tc := range m.ToolCalls {
+				fmt.Fprintf(&b, "assistant called %s(%s)\n", tc.Name, clip(tc.Arguments, 200))
+			}
+			if m.Content != "" {
+				fmt.Fprintf(&b, "assistant: %s\n", m.Content)
+			}
+		default:
+			fmt.Fprintf(&b, "%s: %s\n", m.Role, m.Content)
+		}
+	}
+	resp, err := prov.Chat(ctx, llm.Request{Messages: []llm.Message{
+		{Role: llm.RoleSystem, Content: summarizePrompt},
+		{Role: llm.RoleUser, Content: b.String()},
+	}}, nil)
+	if err != nil {
+		return nil, fmt.Errorf("summarize: %w", err)
+	}
+	text := strings.TrimSpace(resp.Content)
+	if text == "" {
+		return nil, errors.New("summarize: empty summary")
+	}
+	sm, err := a.Store.AddSummary(context.WithoutCancel(ctx), sessionID, msgs[cut-1].ID, text)
+	if err != nil {
+		return nil, err
+	}
+	return &sm, nil
+}

internal/config/config.go

@@ -20,12 +20,32 @@ type LLM struct {
 	Model       string  `yaml:"model" json:"model"`
 	TimeoutSec  int     `yaml:"timeout_sec" json:"timeout_sec"`
 	Temperature float64 `yaml:"temperature" json:"temperature"`
+	// Providers holds optional per-preset settings (keys stay server-side) so the
+	// active provider can be switched at runtime, e.g. providers: {dahl: {api_key: ...}}.
+	Providers map[string]ProviderOverride `yaml:"providers" json:"providers"`
+}
+
+type ProviderOverride struct {
+	BaseURL string `yaml:"base_url" json:"base_url"`
+	APIKey  string `yaml:"api_key" json:"api_key"`
+	Model   string `yaml:"model" json:"model"`
 }
 
 type Agent struct {
-	SystemPrompt  string `yaml:"system_prompt" json:"system_prompt"`
+	SystemPrompt  string    `yaml:"system_prompt" json:"system_prompt"`
-	MaxIterations int    `yaml:"max_iterations" json:"max_iterations"`
+	MaxIterations int       `yaml:"max_iterations" json:"max_iterations"`
-	HistoryLimit  int    `yaml:"history_limit" json:"history_limit"`
+	HistoryLimit  int       `yaml:"history_limit" json:"history_limit"`
+	Summarize     Summarize `yaml:"summarize" json:"summarize"`
+}
+
+// Summarize controls automatic summarisation of long sessions.
+type Summarize struct {
+	Enabled bool `yaml:"enabled" json:"enabled"`
+	// Summarise when unsummarised messages exceed MaxMessages or ~MaxTokens (chars/4).
+	MaxMessages int `yaml:"max_messages" json:"max_messages"`
+	MaxTokens   int `yaml:"max_tokens" json:"max_tokens"`
+	// KeepRecent newest messages always stay verbatim.
+	KeepRecent int `yaml:"keep_recent" json:"keep_recent"`
 }
 
 type WebFetch struct {
@@ -80,6 +100,7 @@ func Default() Config {
 			SystemPrompt:  "You are ByteClaw, a concise and helpful self-hosted assistant. Use tools when they help.",
 			MaxIterations: 8,
 			HistoryLimit:  50,
+			Summarize:     Summarize{Enabled: true, MaxMessages: 40, MaxTokens: 12000, KeepRecent: 10},
 		},
 		Tools: Tools{
 			WebFetch:     WebFetch{Enabled: true, MaxBytes: 512 * 1024, TimeoutSec: 15},

internal/llm/llm.go

@@ -24,6 +24,8 @@ type Message struct {
 	ToolCalls  []ToolCall `json:"tool_calls,omitempty"`
 	ToolCallID string     `json:"tool_call_id,omitempty"`
 	Name       string     `json:"name,omitempty"`
+	// Cancelled marks a partial assistant answer that was stopped by the user.
+	Cancelled bool `json:"cancelled,omitempty"`
 }
 
 // ToolSpec describes a callable tool using JSON Schema parameters.

internal/providers/providers.go

@@ -0,0 +1,255 @@
+// Package providers manages the set of configured LLM providers and which one
+// is active (globally or per session). API keys never leave this package.
+package providers
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+	"net/http"
+	"sort"
+	"strings"
+	"sync"
+	"time"
+
+	"github.com/crypto/byteclaw/internal/config"
+	"github.com/crypto/byteclaw/internal/llm"
+	"github.com/crypto/byteclaw/internal/store"
+)
+
+var ErrUnknown = errors.New("unknown provider")
+var ErrNotConfigured = errors.New("provider has no API key configured")
+
+const settingKey = "active_provider"
+
+type entry struct {
+	name, baseURL, model, apiKey string
+	keyless                      bool
+}
+
+// Info is the public view of a provider (no secrets).
+type Info struct {
+	Name         string `json:"name"`
+	BaseURL      string `json:"base_url"`
+	DefaultModel string `json:"default_model"`
+	Configured   bool   `json:"configured"`
+	Active       bool   `json:"active"`
+}
+
+type Active struct {
+	Provider string `json:"provider"`
+	Model    string `json:"model"`
+}
+
+type Manager struct {
+	mu          sync.RWMutex
+	entries     map[string]*entry
+	active      Active
+	store       *store.Store
+	timeout     time.Duration
+	temperature float64
+	HTTP        *http.Client
+	// New builds a provider; replaceable in tests.
+	New func(baseURL, apiKey, model string) llm.Provider
+}
+
+// New builds the manager from config: every preset (key from llm.providers.<name>
+// or the preset's env var) plus the provider configured in llm.*.
+func New(cfg config.LLM, getenv func(string) string, st *store.Store) *Manager {
+	m := &Manager{entries: map[string]*entry{}, store: st, timeout: time.Duration(cfg.TimeoutSec) * time.Second,
+		temperature: cfg.Temperature, HTTP: &http.Client{Timeout: 15 * time.Second}}
+	m.New = func(baseURL, apiKey, model string) llm.Provider {
+		return llm.NewOpenAI(baseURL, apiKey, model, m.temperature, m.timeout)
+	}
+	for name, p := range config.Presets {
+		e := &entry{name: name, baseURL: p.BaseURL, model: p.DefaultModel, keyless: p.KeyEnv == ""}
+		if p.KeyEnv != "" {
+			e.apiKey = getenv(p.KeyEnv)
+		}
+		m.entries[name] = e
+	}
+	for name, o := range cfg.Providers {
+		name = strings.ToLower(name)
+		e, ok := m.entries[name]
+		if !ok {
+			e = &entry{name: name}
+			m.entries[name] = e
+		}
+		if o.BaseURL != "" {
+			e.baseURL = o.BaseURL
+		}
+		if o.APIKey != "" {
+			e.apiKey = o.APIKey
+		}
+		if o.Model != "" {
+			e.model = o.Model
+		}
+	}
+	// The primary llm.* settings win for the configured provider.
+	e, ok := m.entries[cfg.Provider]
+	if !ok {
+		e = &entry{name: cfg.Provider, keyless: true}
+		m.entries[cfg.Provider] = e
+	}
+	e.baseURL, e.model = cfg.BaseURL, cfg.Model
+	if cfg.APIKey != "" {
+		e.apiKey = cfg.APIKey
+	}
+	m.active = Active{Provider: cfg.Provider, Model: cfg.Model}
+	if st != nil {
+		if raw, err := st.GetSetting(context.Background(), settingKey); err == nil {
+			var a Active
+			if json.Unmarshal([]byte(raw), &a) == nil && m.usable(a.Provider) == nil {
+				m.active = a
+			}
+		}
+	}
+	return m
+}
+
+func (m *Manager) usable(name string) error {
+	e, ok := m.entries[name]
+	if !ok || e.baseURL == "" {
+		return fmt.Errorf("%w: %q", ErrUnknown, name)
+	}
+	if e.apiKey == "" && !e.keyless {
+		return fmt.Errorf("%w: %q", ErrNotConfigured, name)
+	}
+	return nil
+}
+
+func (m *Manager) List() []Info {
+	m.mu.RLock()
+	defer m.mu.RUnlock()
+	out := make([]Info, 0, len(m.entries))
+	for _, e := range m.entries {
+		if e.baseURL == "" {
+			continue
+		}
+		out = append(out, Info{Name: e.name, BaseURL: e.baseURL, DefaultModel: e.model,
+			Configured: m.usable(e.name) == nil, Active: e.name == m.active.Provider})
+	}
+	sort.Slice(out, func(i, j int) bool { return out[i].Name < out[j].Name })
+	return out
+}
+
+func (m *Manager) Active() Active {
+	m.mu.RLock()
+	defer m.mu.RUnlock()
+	return m.active
+}
+
+func (m *Manager) BaseURL(name string) string {
+	m.mu.RLock()
+	defer m.mu.RUnlock()
+	if e, ok := m.entries[name]; ok {
+		return e.baseURL
+	}
+	return ""
+}
+
+// Validate checks provider/model and fills the default model.
+func (m *Manager) Validate(name, model string) (Active, error) {
+	m.mu.RLock()
+	defer m.mu.RUnlock()
+	name = strings.ToLower(strings.TrimSpace(name))
+	if err := m.usable(name); err != nil {
+		return Active{}, err
+	}
+	if model = strings.TrimSpace(model); model == "" {
+		model = m.entries[name].model
+	}
+	if model == "" {
+		return Active{}, errors.New("model required")
+	}
+	return Active{Provider: name, Model: model}, nil
+}
+
+// SetActive switches the server-wide default and persists it.
+func (m *Manager) SetActive(ctx context.Context, name, model string) (Active, error) {
+	a, err := m.Validate(name, model)
+	if err != nil {
+		return a, err
+	}
+	m.mu.Lock()
+	m.active = a
+	m.mu.Unlock()
+	if m.store != nil {
+		b, _ := json.Marshal(a)
+		if err := m.store.SetSetting(ctx, settingKey, string(b)); err != nil {
+			return a, err
+		}
+	}
+	return a, nil
+}
+
+// Build returns a provider client for name/model.
+func (m *Manager) Build(name, model string) (llm.Provider, error) {
+	a, err := m.Validate(name, model)
+	if err != nil {
+		return nil, err
+	}
+	m.mu.RLock()
+	e := *m.entries[a.Provider]
+	m.mu.RUnlock()
+	return m.New(e.baseURL, e.apiKey, a.Model), nil
+}
+
+// ForSession resolves the provider for a session (session override, else active).
+func (m *Manager) ForSession(ctx context.Context, sessionID string) (llm.Provider, Active, error) {
+	a := m.Active()
+	if m.store != nil && sessionID != "" {
+		if ss, err := m.store.GetSession(ctx, sessionID); err == nil && ss.Provider != "" {
+			a = Active{Provider: ss.Provider, Model: ss.Model}
+		}
+	}
+	p, err := m.Build(a.Provider, a.Model)
+	return p, a, err
+}
+
+// Models lists model ids from the provider's OpenAI-compatible GET /models (key added server-side).
+func (m *Manager) Models(ctx context.Context, name string) ([]string, error) {
+	m.mu.RLock()
+	e, ok := m.entries[strings.ToLower(name)]
+	var ec entry
+	if ok {
+		ec = *e
+	}
+	m.mu.RUnlock()
+	if !ok || ec.baseURL == "" {
+		return nil, fmt.Errorf("%w: %q", ErrUnknown, name)
+	}
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, strings.TrimRight(ec.baseURL, "/")+"/models", nil)
+	if err != nil {
+		return nil, err
+	}
+	if ec.apiKey != "" {
+		req.Header.Set("Authorization", "Bearer "+ec.apiKey)
+	}
+	resp, err := m.HTTP.Do(req)
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+	if resp.StatusCode/100 != 2 {
+		return nil, fmt.Errorf("models endpoint returned HTTP %d", resp.StatusCode)
+	}
+	var body struct {
+		Data []struct {
+			ID string `json:"id"`
+		} `json:"data"`
+	}
+	if err := json.NewDecoder(io.LimitReader(resp.Body, 4<<20)).Decode(&body); err != nil {
+		return nil, fmt.Errorf("decode models: %w", err)
+	}
+	ids := make([]string, 0, len(body.Data))
+	for _, d := range body.Data {
+		if d.ID != "" {
+			ids = append(ids, d.ID)
+		}
+	}
+	sort.Strings(ids)
+	return ids, nil
+}

internal/providers/providers_test.go

@@ -0,0 +1,100 @@
+package providers
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"net/http"
+	"net/http/httptest"
+	"path/filepath"
+	"testing"
+
+	"github.com/crypto/byteclaw/internal/config"
+	"github.com/crypto/byteclaw/internal/llm"
+	"github.com/crypto/byteclaw/internal/store"
+)
+
+type fake struct{ base, key, model string }
+
+func (fake) Chat(context.Context, llm.Request, llm.DeltaFunc) (llm.Response, error) {
+	return llm.Response{}, nil
+}
+
+func newMgr(t *testing.T, env map[string]string) (*Manager, *store.Store) {
+	st, err := store.Open(filepath.Join(t.TempDir(), "p.db"))
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Cleanup(func() { st.Close() })
+	cfg := config.LLM{Provider: "openai", BaseURL: "https://api.openai.com/v1", Model: "gpt-4o-mini", APIKey: "sk-openai",
+		Providers: map[string]config.ProviderOverride{"gonkarouter": {APIKey: "sk-gonka"}}}
+	m := New(cfg, func(k string) string { return env[k] }, st)
+	m.New = func(b, k, mo string) llm.Provider { return fake{b, k, mo} }
+	return m, st
+}
+
+func TestListAndSwitch(t *testing.T) {
+	m, st := newMgr(t, map[string]string{"DAHL_API_KEY": "dahl_k"})
+	got := map[string]Info{}
+	for _, i := range m.List() {
+		got[i.Name] = i
+	}
+	if !got["openai"].Active || !got["dahl"].Configured || !got["gonkarouter"].Configured || got["openrouter"].Configured || !got["ollama"].Configured {
+		t.Fatalf("%+v", got)
+	}
+	if _, err := m.SetActive(context.Background(), "openrouter", ""); !errors.Is(err, ErrNotConfigured) {
+		t.Fatalf("want not configured, got %v", err)
+	}
+	if _, err := m.SetActive(context.Background(), "nope", ""); !errors.Is(err, ErrUnknown) {
+		t.Fatal(err)
+	}
+	a, err := m.SetActive(context.Background(), "Dahl", "")
+	if err != nil || a.Provider != "dahl" || a.Model != "MiniMaxAI/MiniMax-M2.7" {
+		t.Fatalf("%+v %v", a, err)
+	}
+	p, _ := m.Build("dahl", "zai-org/GLM-5.3-Flash")
+	if f := p.(fake); f.key != "dahl_k" || f.base != "https://inference.dahl.global/v1" || f.model != "zai-org/GLM-5.3-Flash" {
+		t.Fatalf("%+v", f)
+	}
+	// persisted across restarts
+	m2 := New(config.LLM{Provider: "openai", BaseURL: "x", Model: "y"}, func(k string) string { return map[string]string{"DAHL_API_KEY": "dahl_k"}[k] }, st)
+	if m2.Active().Provider != "dahl" {
+		t.Fatalf("not persisted: %+v", m2.Active())
+	}
+}
+
+func TestSessionOverride(t *testing.T) {
+	m, st := newMgr(t, nil)
+	ctx := context.Background()
+	ss, _ := st.CreateSession(ctx, "")
+	st.SetSessionProvider(ctx, ss.ID, "gonkarouter", "MiniMaxAI/MiniMax-M2.7")
+	p, a, err := m.ForSession(ctx, ss.ID)
+	if err != nil || a.Provider != "gonkarouter" || p.(fake).key != "sk-gonka" {
+		t.Fatalf("%+v %v", a, err)
+	}
+	other, _ := st.CreateSession(ctx, "")
+	if _, a, _ := m.ForSession(ctx, other.ID); a.Provider != "openai" {
+		t.Fatalf("%+v", a)
+	}
+}
+
+func TestModelsUsesServerSideKey(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.URL.Path != "/v1/models" || r.Header.Get("Authorization") != "Bearer sk-gonka" {
+			http.Error(w, "no", 401)
+			return
+		}
+		fmt.Fprint(w, `{"data":[{"id":"b-model"},{"id":"a-model"}]}`)
+	}))
+	defer srv.Close()
+	m, _ := newMgr(t, nil)
+	m.entries["gonkarouter"].baseURL = srv.URL + "/v1"
+	ids, err := m.Models(context.Background(), "gonkarouter")
+	if err != nil || len(ids) != 2 || ids[0] != "a-model" {
+		t.Fatalf("%v %v", ids, err)
+	}
+	m.entries["gonkarouter"].apiKey = "wrong"
+	if _, err := m.Models(context.Background(), "gonkarouter"); err == nil {
+		t.Fatal("expected error")
+	}
+}

internal/store/store.go

@@ -18,8 +18,11 @@ import (
 var ErrNotFound = errors.New("not found")
 
 type Session struct {
-	ID        string    `json:"id"`
+	ID    string `json:"id"`
-	Title     string    `json:"title"`
+	Title string `json:"title"`
+	// Provider/Model override the server-wide active provider for this session (empty = default).
+	Provider  string    `json:"provider,omitempty"`
+	Model     string    `json:"model,omitempty"`
 	CreatedAt time.Time `json:"created_at"`
 	UpdatedAt time.Time `json:"updated_at"`
 }
@@ -45,15 +48,46 @@ CREATE TABLE IF NOT EXISTS messages(
   tool_calls TEXT NOT NULL DEFAULT '', tool_call_id TEXT NOT NULL DEFAULT '',
   name TEXT NOT NULL DEFAULT '', created_at INTEGER NOT NULL);
 CREATE INDEX IF NOT EXISTS idx_messages_session ON messages(session_id, id);
+CREATE TABLE IF NOT EXISTS summaries(
+  id INTEGER PRIMARY KEY AUTOINCREMENT,
+  session_id TEXT NOT NULL REFERENCES sessions(id) ON DELETE CASCADE,
+  upto_message_id INTEGER NOT NULL, content TEXT NOT NULL, created_at INTEGER NOT NULL);
+CREATE INDEX IF NOT EXISTS idx_summaries_session ON summaries(session_id, id);
+CREATE TABLE IF NOT EXISTS settings(key TEXT PRIMARY KEY, value TEXT NOT NULL);
 `
 
+// migrations add columns to databases created by older versions.
+var migrations = []struct{ table, column, ddl string }{
+	{"sessions", "provider", "ALTER TABLE sessions ADD COLUMN provider TEXT NOT NULL DEFAULT ''"},
+	{"sessions", "model", "ALTER TABLE sessions ADD COLUMN model TEXT NOT NULL DEFAULT ''"},
+	{"messages", "cancelled", "ALTER TABLE messages ADD COLUMN cancelled INTEGER NOT NULL DEFAULT 0"},
+}
+
+func migrate(db *sql.DB) error {
+	if _, err := db.Exec(schema); err != nil {
+		return err
+	}
+	for _, m := range migrations {
+		var n int
+		if err := db.QueryRow(`SELECT COUNT(*) FROM pragma_table_info(?) WHERE name=?`, m.table, m.column).Scan(&n); err != nil {
+			return err
+		}
+		if n == 0 {
+			if _, err := db.Exec(m.ddl); err != nil {
+				return err
+			}
+		}
+	}
+	return nil
+}
+
 func Open(path string) (*Store, error) {
 	db, err := sql.Open("sqlite", "file:"+path+"?_pragma=busy_timeout(5000)")
 	if err != nil {
 		return nil, err
 	}
 	db.SetMaxOpenConns(1) // SQLite: serialize writers, avoids SQLITE_BUSY
-	if _, err := db.Exec(schema); err != nil {
+	if err := migrate(db); err != nil {
 		db.Close()
 		return nil, fmt.Errorf("migrate: %w", err)
 	}
@@ -79,7 +113,7 @@ func (s *Store) CreateSession(ctx context.Context, title string) (Session, error
 func (s *Store) GetSession(ctx context.Context, id string) (Session, error) {
 	var ss Session
 	var c, u int64
-	err := s.db.QueryRowContext(ctx, `SELECT id,title,created_at,updated_at FROM sessions WHERE id=?`, id).Scan(&ss.ID, &ss.Title, &c, &u)
+	err := s.db.QueryRowContext(ctx, `SELECT id,title,provider,model,created_at,updated_at FROM sessions WHERE id=?`, id).Scan(&ss.ID, &ss.Title, &ss.Provider, &ss.Model, &c, &u)
 	if errors.Is(err, sql.ErrNoRows) {
 		return ss, ErrNotFound
 	}
@@ -88,7 +122,7 @@ func (s *Store) GetSession(ctx context.Context, id string) (Session, error) {
 }
 
 func (s *Store) ListSessions(ctx context.Context, limit int) ([]Session, error) {
-	rows, err := s.db.QueryContext(ctx, `SELECT id,title,created_at,updated_at FROM sessions ORDER BY updated_at DESC LIMIT ?`, limit)
+	rows, err := s.db.QueryContext(ctx, `SELECT id,title,provider,model,created_at,updated_at FROM sessions ORDER BY updated_at DESC LIMIT ?`, limit)
 	if err != nil {
 		return nil, err
 	}
@@ -97,7 +131,7 @@ func (s *Store) ListSessions(ctx context.Context, limit int) ([]Session, error)
 	for rows.Next() {
 		var ss Session
 		var c, u int64
-		if err := rows.Scan(&ss.ID, &ss.Title, &c, &u); err != nil {
+		if err := rows.Scan(&ss.ID, &ss.Title, &ss.Provider, &ss.Model, &c, &u); err != nil {
 			return nil, err
 		}
 		ss.CreatedAt, ss.UpdatedAt = time.UnixMilli(c).UTC(), time.UnixMilli(u).UTC()
@@ -138,8 +172,8 @@ func (s *Store) AppendMessage(ctx context.Context, sessionID string, m llm.Messa
 		return 0, err
 	}
 	defer tx.Rollback()
-	res, err := tx.ExecContext(ctx, `INSERT INTO messages(session_id,role,content,tool_calls,tool_call_id,name,created_at) VALUES(?,?,?,?,?,?,?)`,
+	res, err := tx.ExecContext(ctx, `INSERT INTO messages(session_id,role,content,tool_calls,tool_call_id,name,cancelled,created_at) VALUES(?,?,?,?,?,?,?,?)`,
-		sessionID, string(m.Role), m.Content, tc, m.ToolCallID, m.Name, now)
+		sessionID, string(m.Role), m.Content, tc, m.ToolCallID, m.Name, m.Cancelled, now)
 	if err != nil {
 		return 0, err
 	}
@@ -152,11 +186,16 @@ func (s *Store) AppendMessage(ctx context.Context, sessionID string, m llm.Messa
 
 // Messages returns the last `limit` messages of a session in chronological order (limit<=0: all).
 func (s *Store) Messages(ctx context.Context, sessionID string, limit int) ([]StoredMessage, error) {
+	return s.MessagesAfter(ctx, sessionID, 0, limit)
+}
+
+// MessagesAfter returns the last `limit` messages with id > afterID (limit<=0: all), oldest first.
+func (s *Store) MessagesAfter(ctx context.Context, sessionID string, afterID int64, limit int) ([]StoredMessage, error) {
 	if limit <= 0 {
 		limit = -1
 	}
-	rows, err := s.db.QueryContext(ctx, `SELECT * FROM (SELECT id,role,content,tool_calls,tool_call_id,name,created_at
+	rows, err := s.db.QueryContext(ctx, `SELECT * FROM (SELECT id,role,content,tool_calls,tool_call_id,name,cancelled,created_at
-		FROM messages WHERE session_id=? ORDER BY id DESC LIMIT ?) ORDER BY id ASC`, sessionID, limit)
+		FROM messages WHERE session_id=? AND id>? ORDER BY id DESC LIMIT ?) ORDER BY id ASC`, sessionID, afterID, limit)
 	if err != nil {
 		return nil, err
 	}
@@ -166,7 +205,7 @@ func (s *Store) Messages(ctx context.Context, sessionID string, limit int) ([]St
 		var m StoredMessage
 		var role, tc string
 		var c int64
-		if err := rows.Scan(&m.ID, &role, &m.Content, &tc, &m.ToolCallID, &m.Name, &c); err != nil {
+		if err := rows.Scan(&m.ID, &role, &m.Content, &tc, &m.ToolCallID, &m.Name, &m.Cancelled, &c); err != nil {
 			return nil, err
 		}
 		m.Role, m.CreatedAt = llm.Role(role), time.UnixMilli(c).UTC()
@@ -179,3 +218,58 @@ func (s *Store) Messages(ctx context.Context, sessionID string, limit int) ([]St
 	}
 	return out, rows.Err()
 }
+
+func (s *Store) SetSessionProvider(ctx context.Context, id, provider, model string) error {
+	res, err := s.db.ExecContext(ctx, `UPDATE sessions SET provider=?, model=? WHERE id=?`, provider, model, id)
+	return affected(res, err)
+}
+
+// ---- summaries
+
+type Summary struct {
+	ID            int64     `json:"id"`
+	SessionID     string    `json:"session_id"`
+	UptoMessageID int64     `json:"upto_message_id"`
+	Content       string    `json:"content"`
+	CreatedAt     time.Time `json:"created_at"`
+}
+
+func (s *Store) AddSummary(ctx context.Context, sessionID string, upto int64, content string) (Summary, error) {
+	now := time.Now().UTC()
+	res, err := s.db.ExecContext(ctx, `INSERT INTO summaries(session_id,upto_message_id,content,created_at) VALUES(?,?,?,?)`,
+		sessionID, upto, content, now.UnixMilli())
+	if err != nil {
+		return Summary{}, err
+	}
+	id, _ := res.LastInsertId()
+	return Summary{ID: id, SessionID: sessionID, UptoMessageID: upto, Content: content, CreatedAt: now}, nil
+}
+
+// LatestSummary returns the newest summary of a session or ErrNotFound.
+func (s *Store) LatestSummary(ctx context.Context, sessionID string) (Summary, error) {
+	var sm Summary
+	var c int64
+	err := s.db.QueryRowContext(ctx, `SELECT id,session_id,upto_message_id,content,created_at FROM summaries
+		WHERE session_id=? ORDER BY id DESC LIMIT 1`, sessionID).Scan(&sm.ID, &sm.SessionID, &sm.UptoMessageID, &sm.Content, &c)
+	if errors.Is(err, sql.ErrNoRows) {
+		return sm, ErrNotFound
+	}
+	sm.CreatedAt = time.UnixMilli(c).UTC()
+	return sm, err
+}
+
+// ---- settings (key/value)
+
+func (s *Store) GetSetting(ctx context.Context, key string) (string, error) {
+	var v string
+	err := s.db.QueryRowContext(ctx, `SELECT value FROM settings WHERE key=?`, key).Scan(&v)
+	if errors.Is(err, sql.ErrNoRows) {
+		return "", ErrNotFound
+	}
+	return v, err
+}
+
+func (s *Store) SetSetting(ctx context.Context, key, value string) error {
+	_, err := s.db.ExecContext(ctx, `INSERT INTO settings(key,value) VALUES(?,?) ON CONFLICT(key) DO UPDATE SET value=excluded.value`, key, value)
+	return err
+}

internal/store/store_test.go

@@ -48,3 +48,43 @@ func TestStoreRoundTrip(t *testing.T) {
 		t.Fatal("cascade delete failed")
 	}
 }
+
+func TestSummariesSettingsProviderAndCancelled(t *testing.T) {
+	s, err := Open(filepath.Join(t.TempDir(), "t.db"))
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer s.Close()
+	ctx := context.Background()
+	ss, _ := s.CreateSession(ctx, "x")
+	if _, err := s.LatestSummary(ctx, ss.ID); !errors.Is(err, ErrNotFound) {
+		t.Fatal(err)
+	}
+	id1, _ := s.AppendMessage(ctx, ss.ID, llm.Message{Role: llm.RoleUser, Content: "a"})
+	s.AppendMessage(ctx, ss.ID, llm.Message{Role: llm.RoleAssistant, Content: "part", Cancelled: true})
+	s.AddSummary(ctx, ss.ID, id1, "old")
+	s.AddSummary(ctx, ss.ID, id1, "new")
+	sm, _ := s.LatestSummary(ctx, ss.ID)
+	if sm.Content != "new" || sm.UptoMessageID != id1 {
+		t.Fatalf("%+v", sm)
+	}
+	after, _ := s.MessagesAfter(ctx, ss.ID, id1, 0)
+	if len(after) != 1 || !after[0].Cancelled || after[0].Content != "part" {
+		t.Fatalf("%+v", after)
+	}
+	if all, _ := s.Messages(ctx, ss.ID, 0); len(all) != 2 {
+		t.Fatal("original messages must be kept")
+	}
+	if err := s.SetSessionProvider(ctx, ss.ID, "dahl", "m"); err != nil {
+		t.Fatal(err)
+	}
+	got, _ := s.GetSession(ctx, ss.ID)
+	if got.Provider != "dahl" || got.Model != "m" {
+		t.Fatalf("%+v", got)
+	}
+	s.SetSetting(ctx, "k", "v1")
+	s.SetSetting(ctx, "k", "v2")
+	if v, _ := s.GetSetting(ctx, "k"); v != "v2" {
+		t.Fatal(v)
+	}
+}

internal/tools/shell.go

@@ -107,14 +107,14 @@ func (s *Shell) Parse(line string) ([]step, error) {
 		}
 	}
 	var (
-		steps   []step
+		steps  []step
-		cur     []string // current command tokens
+		cur    []string // current command tokens
-		pipe    [][]string
+		pipe   [][]string
-		tok     strings.Builder
+		tok    strings.Builder
-		inTok   bool
+		inTok  bool
-		quote   rune
+		quote  rune
-		nextOp  = ""
+		nextOp = ""
-		runes   = []rune(line)
+		runes  = []rune(line)
 	)
 	flushTok := func() {
 		if inTok {
@@ -258,7 +258,9 @@ func (s *Shell) env() []string {
 }
 
 func (s *Shell) Call(ctx context.Context, raw json.RawMessage) (string, error) {
-	var a struct{ Command string `json:"command"` }
+	var a struct {
+		Command string `json:"command"`
+	}
 	if err := json.Unmarshal(raw, &a); err != nil {
 		return "", err
 	}