1package agent
2
3import (
4 "context"
5 _ "embed"
6 "errors"
7 "fmt"
8 "log/slog"
9 "strings"
10 "sync"
11 "time"
12
13 "github.com/charmbracelet/catwalk/pkg/catwalk"
14 "github.com/charmbracelet/crush/internal/csync"
15 "github.com/charmbracelet/crush/internal/llm/tools"
16 "github.com/charmbracelet/crush/internal/message"
17 "github.com/charmbracelet/crush/internal/permission"
18 "github.com/charmbracelet/crush/internal/session"
19 "github.com/charmbracelet/fantasy/ai"
20 "github.com/charmbracelet/fantasy/anthropic"
21)
22
23//go:embed templates/title.md
24var titlePrompt []byte
25
26//go:embed templates/summary.md
27var summaryPrompt []byte
28
29type SessionAgentCall struct {
30 SessionID string
31 Prompt string
32 ProviderOptions ai.ProviderOptions
33 Attachments []message.Attachment
34 MaxOutputTokens int64
35 Temperature *float64
36 TopP *float64
37 TopK *int64
38 FrequencyPenalty *float64
39 PresencePenalty *float64
40}
41
42type SessionAgent interface {
43 Run(context.Context, SessionAgentCall) (*ai.AgentResult, error)
44 SetModels(large Model, small Model)
45 SetTools(tools []ai.AgentTool)
46 Cancel(sessionID string)
47 CancelAll()
48 IsSessionBusy(sessionID string) bool
49 IsBusy() bool
50 QueuedPrompts(sessionID string) int
51 ClearQueue(sessionID string)
52 Summarize(context.Context, string) error
53}
54
55type Model struct {
56 model ai.LanguageModel
57 config catwalk.Model
58}
59
60type sessionAgent struct {
61 largeModel Model
62 smallModel Model
63 systemPrompt string
64 tools []ai.AgentTool
65 sessions session.Service
66 messages message.Service
67
68 messageQueue *csync.Map[string, []SessionAgentCall]
69 activeRequests *csync.Map[string, context.CancelFunc]
70}
71
72type SessionAgentOption func(*sessionAgent)
73
74func NewSessionAgent(
75 largeModel Model,
76 smallModel Model,
77 systemPrompt string,
78 sessions session.Service,
79 messages message.Service,
80 tools ...ai.AgentTool,
81) SessionAgent {
82 return &sessionAgent{
83 largeModel: largeModel,
84 smallModel: smallModel,
85 systemPrompt: systemPrompt,
86 sessions: sessions,
87 messages: messages,
88 tools: tools,
89 messageQueue: csync.NewMap[string, []SessionAgentCall](),
90 activeRequests: csync.NewMap[string, context.CancelFunc](),
91 }
92}
93
94func (a *sessionAgent) Run(ctx context.Context, call SessionAgentCall) (*ai.AgentResult, error) {
95 if call.Prompt == "" {
96 return nil, ErrEmptyPrompt
97 }
98 if call.SessionID == "" {
99 return nil, ErrSessionMissing
100 }
101
102 // Queue the message if busy
103 if a.IsSessionBusy(call.SessionID) {
104 existing, ok := a.messageQueue.Get(call.SessionID)
105 if !ok {
106 existing = []SessionAgentCall{}
107 }
108 existing = append(existing, call)
109 a.messageQueue.Set(call.SessionID, existing)
110 return nil, nil
111 }
112
113 if len(a.tools) > 0 {
114 // add anthropic caching to the last tool
115 a.tools[len(a.tools)-1].SetProviderOptions(a.getCacheControlOptions())
116 }
117
118 agent := ai.NewAgent(
119 a.largeModel.model,
120 ai.WithSystemPrompt(a.systemPrompt),
121 ai.WithTools(a.tools...),
122 )
123
124 currentSession, err := a.sessions.Get(ctx, call.SessionID)
125 if err != nil {
126 return nil, fmt.Errorf("failed to get session: %w", err)
127 }
128
129 msgs, err := a.getSessionMessages(ctx, currentSession)
130 if err != nil {
131 return nil, fmt.Errorf("failed to get session messages: %w", err)
132 }
133
134 var wg sync.WaitGroup
135 // Generate title if first message
136 if len(msgs) == 0 {
137 wg.Go(func() {
138 a.generateTitle(ctx, currentSession, call.Prompt)
139 })
140 }
141
142 // Add the user message to the session
143 _, err = a.createUserMessage(ctx, call)
144 if err != nil {
145 return nil, err
146 }
147
148 // add the session to the context
149 ctx = context.WithValue(ctx, tools.SessionIDContextKey, call.SessionID)
150
151 genCtx, cancel := context.WithCancel(ctx)
152 a.activeRequests.Set(call.SessionID, cancel)
153
154 defer cancel()
155 defer a.activeRequests.Del(call.SessionID)
156
157 history, files := a.preparePrompt(msgs, call.Attachments...)
158
159 var currentAssistant *message.Message
160 result, err := agent.Stream(genCtx, ai.AgentStreamCall{
161 Prompt: call.Prompt,
162 Files: files,
163 Messages: history,
164 ProviderOptions: call.ProviderOptions,
165 MaxOutputTokens: &call.MaxOutputTokens,
166 TopP: call.TopP,
167 Temperature: call.Temperature,
168 PresencePenalty: call.PresencePenalty,
169 TopK: call.TopK,
170 FrequencyPenalty: call.FrequencyPenalty,
171 // Before each step create the new assistant message
172 PrepareStep: func(options ai.PrepareStepFunctionOptions) (prepared ai.PrepareStepResult, err error) {
173 var assistantMsg message.Message
174 assistantMsg, err = a.messages.Create(genCtx, call.SessionID, message.CreateMessageParams{
175 Role: message.Assistant,
176 Parts: []message.ContentPart{},
177 Model: a.largeModel.model.Model(),
178 Provider: a.largeModel.model.Provider(),
179 })
180 if err != nil {
181 return prepared, err
182 }
183
184 currentAssistant = &assistantMsg
185
186 prepared.Messages = options.Messages
187
188 queuedCalls, _ := a.messageQueue.Get(call.SessionID)
189 a.messageQueue.Del(call.SessionID)
190 for _, queued := range queuedCalls {
191 userMessage, createErr := a.createUserMessage(genCtx, queued)
192 if createErr != nil {
193 return prepared, createErr
194 }
195 prepared.Messages = append(prepared.Messages, userMessage.ToAIMessage()...)
196 }
197
198 lastSystemRoleInx := 0
199 systemMessageUpdated := false
200 for i, msg := range prepared.Messages {
201 // only add cache control to the last message
202 if msg.Role == ai.MessageRoleSystem {
203 lastSystemRoleInx = i
204 } else if !systemMessageUpdated {
205 prepared.Messages[lastSystemRoleInx].ProviderOptions = a.getCacheControlOptions()
206 systemMessageUpdated = true
207 }
208 // than add cache control to the last 2 messages
209 if i > len(msgs)-3 {
210 prepared.Messages[i].ProviderOptions = a.getCacheControlOptions()
211 }
212 }
213 return prepared, err
214 },
215 OnReasoningDelta: func(id string, text string) error {
216 currentAssistant.AppendReasoningContent(text)
217 return a.messages.Update(genCtx, *currentAssistant)
218 },
219 OnReasoningEnd: func(id string, reasoning ai.ReasoningContent) error {
220 // handle anthropic signature
221 if anthropicData, ok := reasoning.ProviderMetadata[anthropic.Name]; ok {
222 if reasoning, ok := anthropicData.(*anthropic.ReasoningOptionMetadata); ok {
223 currentAssistant.AppendReasoningSignature(reasoning.Signature)
224 }
225 }
226 currentAssistant.FinishThinking()
227 return a.messages.Update(genCtx, *currentAssistant)
228 },
229 OnTextDelta: func(id string, text string) error {
230 currentAssistant.AppendContent(text)
231 return a.messages.Update(genCtx, *currentAssistant)
232 },
233 OnToolInputStart: func(id string, toolName string) error {
234 toolCall := message.ToolCall{
235 ID: id,
236 Name: toolName,
237 ProviderExecuted: false,
238 Finished: false,
239 }
240 currentAssistant.AddToolCall(toolCall)
241 return a.messages.Update(genCtx, *currentAssistant)
242 },
243 OnRetry: func(err *ai.APICallError, delay time.Duration) {
244 // TODO: implement
245 },
246 OnToolResult: func(result ai.ToolResultContent) error {
247 var resultContent string
248 isError := false
249 switch result.Result.GetType() {
250 case ai.ToolResultContentTypeText:
251 r, ok := ai.AsToolResultOutputType[ai.ToolResultOutputContentText](result.Result)
252 if ok {
253 resultContent = r.Text
254 }
255 case ai.ToolResultContentTypeError:
256 r, ok := ai.AsToolResultOutputType[ai.ToolResultOutputContentError](result.Result)
257 if ok {
258 isError = true
259 resultContent = r.Error.Error()
260 }
261 case ai.ToolResultContentTypeMedia:
262 // TODO: handle this message type
263 }
264 toolResult := message.ToolResult{
265 ToolCallID: result.ToolCallID,
266 Name: result.ToolName,
267 Content: resultContent,
268 IsError: isError,
269 Metadata: result.ClientMetadata,
270 }
271 a.messages.Create(context.Background(), currentAssistant.SessionID, message.CreateMessageParams{
272 Role: message.Tool,
273 Parts: []message.ContentPart{
274 toolResult,
275 },
276 })
277 return a.messages.Update(genCtx, *currentAssistant)
278 },
279 OnStepFinish: func(stepResult ai.StepResult) error {
280 finishReason := message.FinishReasonUnknown
281 switch stepResult.FinishReason {
282 case ai.FinishReasonLength:
283 finishReason = message.FinishReasonMaxTokens
284 case ai.FinishReasonStop:
285 finishReason = message.FinishReasonEndTurn
286 case ai.FinishReasonToolCalls:
287 finishReason = message.FinishReasonToolUse
288 }
289 currentAssistant.AddFinish(finishReason, "", "")
290 a.updateSessionUsage(a.largeModel, ¤tSession, stepResult.Usage)
291 return a.messages.Update(genCtx, *currentAssistant)
292 },
293 })
294 if err != nil {
295 isCancelErr := errors.Is(err, context.Canceled)
296 isPermissionErr := errors.Is(err, permission.ErrorPermissionDenied)
297 if currentAssistant == nil {
298 return result, err
299 }
300 toolCalls := currentAssistant.ToolCalls()
301 toolResults := currentAssistant.ToolResults()
302 for _, tc := range toolCalls {
303 if !tc.Finished {
304 tc.Finished = true
305 tc.Input = "{}"
306 }
307 currentAssistant.AddToolCall(tc)
308 found := false
309 for _, tr := range toolResults {
310 if tr.ToolCallID == tc.ID {
311 found = true
312 break
313 }
314 }
315 if !found {
316 content := "There was an error while executing the tool"
317 if isCancelErr {
318 content = "Tool execution canceled by user"
319 } else if isPermissionErr {
320 content = "Permission denied"
321 }
322 currentAssistant.AddToolResult(message.ToolResult{
323 ToolCallID: tc.ID,
324 Name: tc.Name,
325 Content: content,
326 IsError: true,
327 })
328 }
329 }
330 if isCancelErr {
331 currentAssistant.AddFinish(message.FinishReasonCanceled, "Request cancelled", "")
332 } else if isPermissionErr {
333 currentAssistant.AddFinish(message.FinishReasonPermissionDenied, "Permission denied", "")
334 } else {
335 currentAssistant.AddFinish(message.FinishReasonError, "API Error", err.Error())
336 }
337 // INFO: we use the parent context here because the genCtx might have been cancelled
338 updateErr := a.messages.Update(ctx, *currentAssistant)
339 if updateErr != nil {
340 return nil, updateErr
341 }
342 }
343 if err != nil {
344 return nil, err
345 }
346 wg.Wait()
347
348 queuedMessages, ok := a.messageQueue.Get(call.SessionID)
349 if !ok || len(queuedMessages) == 0 {
350 return result, err
351 }
352 // there are queued messages restart the loop
353 firstQueuedMessage := queuedMessages[0]
354 a.messageQueue.Set(call.SessionID, queuedMessages[1:])
355 return a.Run(genCtx, firstQueuedMessage)
356}
357
358func (a *sessionAgent) Summarize(ctx context.Context, sessionID string) error {
359 if a.IsSessionBusy(sessionID) {
360 return ErrSessionBusy
361 }
362
363 currentSession, err := a.sessions.Get(ctx, sessionID)
364 if err != nil {
365 return fmt.Errorf("failed to get session: %w", err)
366 }
367 msgs, err := a.getSessionMessages(ctx, currentSession)
368 if err != nil {
369 return err
370 }
371 if len(msgs) == 0 {
372 // nothing to summarize
373 return nil
374 }
375
376 aiMsgs, _ := a.preparePrompt(msgs)
377
378 genCtx, cancel := context.WithCancel(ctx)
379 a.activeRequests.Set(sessionID, cancel)
380 defer a.activeRequests.Del(sessionID)
381 defer cancel()
382
383 agent := ai.NewAgent(a.largeModel.model,
384 ai.WithSystemPrompt(string(summaryPrompt)),
385 )
386 summaryMessage, err := a.messages.Create(ctx, sessionID, message.CreateMessageParams{
387 Role: message.Assistant,
388 Model: a.largeModel.model.Model(),
389 Provider: a.largeModel.model.Provider(),
390 })
391 if err != nil {
392 return err
393 }
394
395 resp, err := agent.Stream(ctx, ai.AgentStreamCall{
396 Prompt: "Provide a detailed summary of our conversation above.",
397 Messages: aiMsgs,
398 OnReasoningDelta: func(id string, text string) error {
399 summaryMessage.AppendReasoningContent(text)
400 return a.messages.Update(ctx, summaryMessage)
401 },
402 OnReasoningEnd: func(id string, reasoning ai.ReasoningContent) error {
403 // handle anthropic signature
404 if anthropicData, ok := reasoning.ProviderMetadata["anthropic"]; ok {
405 if signature, ok := anthropicData.(*anthropic.ReasoningOptionMetadata); ok && signature.Signature != "" {
406 summaryMessage.AppendReasoningSignature(signature.Signature)
407 }
408 }
409 summaryMessage.FinishThinking()
410 return a.messages.Update(ctx, summaryMessage)
411 },
412 OnTextDelta: func(id, text string) error {
413 summaryMessage.AppendContent(text)
414 return a.messages.Update(ctx, summaryMessage)
415 },
416 })
417 if err != nil {
418 return err
419 }
420
421 summaryMessage.AddFinish(message.FinishReasonEndTurn, "", "")
422 err = a.messages.Update(genCtx, summaryMessage)
423 if err != nil {
424 return err
425 }
426
427 a.updateSessionUsage(a.largeModel, ¤tSession, resp.TotalUsage)
428
429 // just in case get just the last usage
430 usage := resp.Response.Usage
431 currentSession.SummaryMessageID = summaryMessage.ID
432 currentSession.CompletionTokens = usage.OutputTokens
433 currentSession.PromptTokens = 0
434 _, err = a.sessions.Save(genCtx, currentSession)
435 return err
436}
437
438func (a *sessionAgent) getCacheControlOptions() ai.ProviderOptions {
439 return ai.ProviderOptions{
440 anthropic.Name: &anthropic.ProviderCacheControlOptions{
441 CacheControl: anthropic.CacheControl{Type: "ephemeral"},
442 },
443 }
444}
445
446func (a *sessionAgent) createUserMessage(ctx context.Context, call SessionAgentCall) (message.Message, error) {
447 var attachmentParts []message.ContentPart
448 for _, attachment := range call.Attachments {
449 attachmentParts = append(attachmentParts, message.BinaryContent{Path: attachment.FilePath, MIMEType: attachment.MimeType, Data: attachment.Content})
450 }
451 parts := []message.ContentPart{message.TextContent{Text: call.Prompt}}
452 parts = append(parts, attachmentParts...)
453 msg, err := a.messages.Create(ctx, call.SessionID, message.CreateMessageParams{
454 Role: message.User,
455 Parts: parts,
456 })
457 if err != nil {
458 return message.Message{}, fmt.Errorf("failed to create user message: %w", err)
459 }
460 return msg, nil
461}
462
463func (a *sessionAgent) preparePrompt(msgs []message.Message, attachments ...message.Attachment) ([]ai.Message, []ai.FilePart) {
464 var history []ai.Message
465 for _, m := range msgs {
466 if len(m.Parts) == 0 {
467 continue
468 }
469 // Assistant message without content or tool calls (cancelled before it returned anything)
470 if m.Role == message.Assistant && len(m.ToolCalls()) == 0 && m.Content().Text == "" && m.ReasoningContent().String() == "" {
471 continue
472 }
473 history = append(history, m.ToAIMessage()...)
474 }
475
476 var files []ai.FilePart
477 for _, attachment := range attachments {
478 files = append(files, ai.FilePart{
479 Filename: attachment.FileName,
480 Data: attachment.Content,
481 MediaType: attachment.MimeType,
482 })
483 }
484
485 return history, files
486}
487
488func (a *sessionAgent) getSessionMessages(ctx context.Context, session session.Session) ([]message.Message, error) {
489 msgs, err := a.messages.List(ctx, session.ID)
490 if err != nil {
491 return nil, fmt.Errorf("failed to list messages: %w", err)
492 }
493
494 if session.SummaryMessageID != "" {
495 summaryMsgInex := -1
496 for i, msg := range msgs {
497 if msg.ID == session.SummaryMessageID {
498 summaryMsgInex = i
499 break
500 }
501 }
502 if summaryMsgInex != -1 {
503 msgs = msgs[summaryMsgInex:]
504 msgs[0].Role = message.User
505 }
506 }
507 return msgs, nil
508}
509
510func (a *sessionAgent) generateTitle(ctx context.Context, session session.Session, prompt string) {
511 if prompt == "" {
512 return
513 }
514
515 agent := ai.NewAgent(a.smallModel.model,
516 ai.WithSystemPrompt(string(titlePrompt)),
517 ai.WithMaxOutputTokens(40),
518 )
519
520 resp, err := agent.Stream(ctx, ai.AgentStreamCall{
521 Prompt: fmt.Sprintf("Generate a concise title for the following content:\n\n%s", prompt),
522 })
523 if err != nil {
524 slog.Error("error generating title", "err", err)
525 return
526 }
527
528 title := resp.Response.Content.Text()
529
530 title = strings.ReplaceAll(title, "\n", " ")
531
532 // remove thinking tags if present
533 if idx := strings.Index(title, "</think>"); idx > 0 {
534 title = title[idx+len("</think>"):]
535 }
536
537 title = strings.TrimSpace(title)
538 if title == "" {
539 slog.Warn("failed to generate title", "warn", "empty title")
540 return
541 }
542
543 session.Title = title
544 a.updateSessionUsage(a.smallModel, &session, resp.TotalUsage)
545 _, saveErr := a.sessions.Save(ctx, session)
546 if saveErr != nil {
547 slog.Error("failed to save session title & usage", "error", saveErr)
548 return
549 }
550}
551
552func (a *sessionAgent) updateSessionUsage(model Model, session *session.Session, usage ai.Usage) {
553 modelConfig := model.config
554 cost := modelConfig.CostPer1MInCached/1e6*float64(usage.CacheCreationTokens) +
555 modelConfig.CostPer1MOutCached/1e6*float64(usage.CacheReadTokens) +
556 modelConfig.CostPer1MIn/1e6*float64(usage.InputTokens) +
557 modelConfig.CostPer1MOut/1e6*float64(usage.OutputTokens)
558 session.Cost += cost
559 session.CompletionTokens = usage.OutputTokens + usage.CacheReadTokens
560 session.PromptTokens = usage.InputTokens + usage.CacheCreationTokens
561}
562
563func (a *sessionAgent) Cancel(sessionID string) {
564 // Cancel regular requests
565 if cancel, ok := a.activeRequests.Take(sessionID); ok && cancel != nil {
566 slog.Info("Request cancellation initiated", "session_id", sessionID)
567 cancel()
568 }
569
570 // Also check for summarize requests
571 if cancel, ok := a.activeRequests.Take(sessionID + "-summarize"); ok && cancel != nil {
572 slog.Info("Summarize cancellation initiated", "session_id", sessionID)
573 cancel()
574 }
575
576 if a.QueuedPrompts(sessionID) > 0 {
577 slog.Info("Clearing queued prompts", "session_id", sessionID)
578 a.messageQueue.Del(sessionID)
579 }
580}
581
582func (a *sessionAgent) ClearQueue(sessionID string) {
583 if a.QueuedPrompts(sessionID) > 0 {
584 slog.Info("Clearing queued prompts", "session_id", sessionID)
585 a.messageQueue.Del(sessionID)
586 }
587}
588
589func (a *sessionAgent) CancelAll() {
590 if !a.IsBusy() {
591 return
592 }
593 for key := range a.activeRequests.Seq2() {
594 a.Cancel(key) // key is sessionID
595 }
596
597 timeout := time.After(5 * time.Second)
598 for a.IsBusy() {
599 select {
600 case <-timeout:
601 return
602 default:
603 time.Sleep(200 * time.Millisecond)
604 }
605 }
606}
607
608func (a *sessionAgent) IsBusy() bool {
609 var busy bool
610 for cancelFunc := range a.activeRequests.Seq() {
611 if cancelFunc != nil {
612 busy = true
613 break
614 }
615 }
616 return busy
617}
618
619func (a *sessionAgent) IsSessionBusy(sessionID string) bool {
620 _, busy := a.activeRequests.Get(sessionID)
621 return busy
622}
623
624func (a *sessionAgent) QueuedPrompts(sessionID string) int {
625 l, ok := a.messageQueue.Get(sessionID)
626 if !ok {
627 return 0
628 }
629 return len(l)
630}
631
632func (a *sessionAgent) SetModels(large Model, small Model) {
633 a.largeModel = large
634 a.smallModel = small
635}
636
637func (a *sessionAgent) SetTools(tools []ai.AgentTool) {
638 a.tools = tools
639}