claude_agent/session/state/
mod.rs

1//! Session state management.
2
3mod config;
4mod enums;
5mod ids;
6mod message;
7mod policy;
8
9pub use config::SessionConfig;
10pub use enums::{SessionMode, SessionState, SessionType};
11pub use ids::{MessageId, SessionId};
12pub use message::{MessageMetadata, SessionMessage, ThinkingMetadata, ToolResultMeta};
13pub use policy::{PermissionMode, PermissionPolicy, ToolLimits};
14
15use std::collections::HashMap;
16
17use chrono::{DateTime, Utc};
18use serde::{Deserialize, Serialize};
19
20use crate::session::types::{CompactRecord, Plan, TodoItem, TodoStatus};
21use crate::types::{CacheControl, ContentBlock, Message, Role, TokenUsage, Usage};
22
23const MAX_COMPACT_HISTORY_SIZE: usize = 50;
24
25#[derive(Clone, Debug, Serialize, Deserialize)]
26pub struct Session {
27    pub id: SessionId,
28    pub parent_id: Option<SessionId>,
29    pub session_type: SessionType,
30    pub tenant_id: Option<String>,
31    pub mode: SessionMode,
32    pub state: SessionState,
33    pub config: SessionConfig,
34    pub permission_policy: PermissionPolicy,
35    pub messages: Vec<SessionMessage>,
36    pub current_leaf_id: Option<MessageId>,
37    pub summary: Option<String>,
38    pub total_usage: TokenUsage,
39    #[serde(default)]
40    pub current_input_tokens: u64,
41    pub total_cost_usd: f64,
42    pub static_context_hash: Option<String>,
43    pub created_at: DateTime<Utc>,
44    pub updated_at: DateTime<Utc>,
45    pub expires_at: Option<DateTime<Utc>>,
46    pub error: Option<String>,
47    #[serde(default)]
48    pub todos: Vec<TodoItem>,
49    #[serde(default)]
50    pub current_plan: Option<Plan>,
51    #[serde(default)]
52    pub compact_history: Vec<CompactRecord>,
53}
54
55impl Session {
56    pub fn new(config: SessionConfig) -> Self {
57        Self::with_id(SessionId::new(), config)
58    }
59
60    pub fn with_id(id: SessionId, config: SessionConfig) -> Self {
61        Self::init(id, None, SessionType::Main, config)
62    }
63
64    pub fn new_subagent(
65        parent_id: SessionId,
66        agent_type: impl Into<String>,
67        description: impl Into<String>,
68        config: SessionConfig,
69    ) -> Self {
70        let session_type = SessionType::Subagent {
71            agent_type: agent_type.into(),
72            description: description.into(),
73        };
74        Self::init(SessionId::new(), Some(parent_id), session_type, config)
75    }
76
77    fn init(
78        id: SessionId,
79        parent_id: Option<SessionId>,
80        session_type: SessionType,
81        config: SessionConfig,
82    ) -> Self {
83        let now = Utc::now();
84        let expires_at = config
85            .ttl_secs
86            .map(|ttl| now + chrono::Duration::seconds(ttl as i64));
87
88        Self {
89            id,
90            parent_id,
91            session_type,
92            tenant_id: None,
93            mode: config.mode.clone(),
94            state: SessionState::Created,
95            permission_policy: config.permission_policy.clone(),
96            config,
97            messages: Vec::with_capacity(32),
98            current_leaf_id: None,
99            summary: None,
100            total_usage: TokenUsage::default(),
101            current_input_tokens: 0,
102            total_cost_usd: 0.0,
103            static_context_hash: None,
104            created_at: now,
105            updated_at: now,
106            expires_at,
107            error: None,
108            todos: Vec::with_capacity(8),
109            current_plan: None,
110            compact_history: Vec::new(),
111        }
112    }
113
114    pub fn is_subagent(&self) -> bool {
115        matches!(self.session_type, SessionType::Subagent { .. })
116    }
117
118    pub fn is_running(&self) -> bool {
119        matches!(
120            self.state,
121            SessionState::Active | SessionState::WaitingForTools
122        )
123    }
124
125    pub fn is_terminal(&self) -> bool {
126        matches!(
127            self.state,
128            SessionState::Completed | SessionState::Failed | SessionState::Cancelled
129        )
130    }
131
132    pub fn is_expired(&self) -> bool {
133        self.expires_at.is_some_and(|expires| Utc::now() > expires)
134    }
135
136    pub fn add_message(&mut self, mut message: SessionMessage) {
137        if let Some(leaf) = &self.current_leaf_id {
138            message.parent_id = Some(leaf.clone());
139        }
140        self.current_leaf_id = Some(message.id.clone());
141        if let Some(usage) = &message.usage {
142            self.total_usage.add(usage);
143        }
144        self.messages.push(message);
145        self.updated_at = Utc::now();
146    }
147
148    pub fn get_current_branch(&self) -> Vec<&SessionMessage> {
149        let index: HashMap<&MessageId, &SessionMessage> =
150            self.messages.iter().map(|m| (&m.id, m)).collect();
151
152        let mut result = Vec::new();
153        let mut current_id = self.current_leaf_id.as_ref();
154
155        while let Some(id) = current_id {
156            if let Some(&msg) = index.get(id) {
157                result.push(msg);
158                current_id = msg.parent_id.as_ref();
159            } else {
160                break;
161            }
162        }
163
164        result.reverse();
165        result
166    }
167
168    pub fn to_api_messages(&self) -> Vec<Message> {
169        self.to_api_messages_with_cache(true)
170    }
171
172    pub fn to_api_messages_with_cache(&self, cache_enabled: bool) -> Vec<Message> {
173        let branch = self.get_current_branch();
174        if branch.is_empty() {
175            return Vec::new();
176        }
177
178        let mut messages: Vec<Message> = branch.iter().map(|m| m.to_api_message()).collect();
179
180        if cache_enabled {
181            self.apply_cache_breakpoint(&mut messages);
182        }
183
184        messages
185    }
186
187    fn apply_cache_breakpoint(&self, messages: &mut [Message]) {
188        let last_user_idx = messages
189            .iter()
190            .enumerate()
191            .rev()
192            .find(|(_, m)| m.role == Role::User)
193            .map(|(i, _)| i);
194
195        if let Some(idx) = last_user_idx {
196            messages[idx].set_cache_on_last_block(CacheControl::ephemeral());
197        }
198    }
199
200    pub fn branch_length(&self) -> usize {
201        self.get_current_branch().len()
202    }
203
204    pub fn set_state(&mut self, state: SessionState) {
205        self.state = state;
206        self.updated_at = Utc::now();
207    }
208
209    pub fn set_todos(&mut self, todos: Vec<TodoItem>) {
210        self.todos = todos;
211        self.updated_at = Utc::now();
212    }
213
214    pub fn todos_in_progress_count(&self) -> usize {
215        self.todos
216            .iter()
217            .filter(|t| t.status == TodoStatus::InProgress)
218            .count()
219    }
220
221    pub fn enter_plan_mode(&mut self, name: Option<String>) -> &Plan {
222        let mut plan = Plan::new(self.id);
223        if let Some(n) = name {
224            plan = plan.with_name(n);
225        }
226        self.current_plan = Some(plan);
227        self.updated_at = Utc::now();
228        self.current_plan.as_ref().expect("plan was just set")
229    }
230
231    pub fn update_plan_content(&mut self, content: String) {
232        if let Some(ref mut plan) = self.current_plan {
233            plan.content = content;
234            self.updated_at = Utc::now();
235        }
236    }
237
238    pub fn exit_plan_mode(&mut self) -> Option<Plan> {
239        if let Some(ref mut plan) = self.current_plan {
240            plan.approve();
241            self.updated_at = Utc::now();
242        }
243        self.current_plan.take()
244    }
245
246    pub fn cancel_plan(&mut self) -> Option<Plan> {
247        if let Some(ref mut plan) = self.current_plan {
248            plan.cancel();
249            self.updated_at = Utc::now();
250        }
251        self.current_plan.take()
252    }
253
254    pub fn is_in_plan_mode(&self) -> bool {
255        self.current_plan
256            .as_ref()
257            .is_some_and(|p| !p.status.is_terminal())
258    }
259
260    pub fn record_compact(&mut self, record: CompactRecord) {
261        if self.compact_history.len() >= MAX_COMPACT_HISTORY_SIZE {
262            self.compact_history.remove(0);
263        }
264        self.compact_history.push(record);
265        self.updated_at = Utc::now();
266    }
267
268    pub fn update_summary(&mut self, summary: impl Into<String>) {
269        self.summary = Some(summary.into());
270        self.updated_at = Utc::now();
271    }
272
273    pub fn add_user_message(&mut self, content: impl Into<String>) {
274        let msg = SessionMessage::user(vec![ContentBlock::text(content.into())]);
275        self.add_message(msg);
276    }
277
278    pub fn add_assistant_message(&mut self, content: Vec<ContentBlock>, usage: Option<Usage>) {
279        let mut msg = SessionMessage::assistant(content);
280        if let Some(u) = usage {
281            msg = msg.with_usage(TokenUsage {
282                input_tokens: u.input_tokens as u64,
283                output_tokens: u.output_tokens as u64,
284                cache_read_input_tokens: u.cache_read_input_tokens.unwrap_or(0) as u64,
285                cache_creation_input_tokens: u.cache_creation_input_tokens.unwrap_or(0) as u64,
286            });
287        }
288        self.add_message(msg);
289    }
290
291    pub fn add_tool_results(&mut self, results: Vec<crate::types::ToolResultBlock>) {
292        let content: Vec<ContentBlock> =
293            results.into_iter().map(ContentBlock::ToolResult).collect();
294        let msg = SessionMessage::user(content);
295        self.add_message(msg);
296    }
297
298    pub fn current_tokens(&self) -> u64 {
299        self.current_input_tokens
300    }
301
302    pub fn should_compact(&self, max_tokens: u64, threshold: f32, keep_messages: usize) -> bool {
303        self.messages.len() > keep_messages
304            && self.current_input_tokens as f32 > max_tokens as f32 * threshold
305    }
306
307    pub fn update_usage(&mut self, usage: &Usage) {
308        self.current_input_tokens = usage.input_tokens as u64;
309        self.total_usage.input_tokens += usage.input_tokens as u64;
310        self.total_usage.output_tokens += usage.output_tokens as u64;
311        if let Some(cache_read) = usage.cache_read_input_tokens {
312            self.total_usage.cache_read_input_tokens += cache_read as u64;
313        }
314        if let Some(cache_creation) = usage.cache_creation_input_tokens {
315            self.total_usage.cache_creation_input_tokens += cache_creation as u64;
316        }
317    }
318
319    pub async fn compact(
320        &mut self,
321        client: &crate::Client,
322        keep_messages: usize,
323    ) -> crate::Result<crate::types::CompactResult> {
324        use crate::client::ModelType;
325        use crate::client::messages::CreateMessageRequest;
326        use crate::types::CompactResult;
327
328        if self.messages.len() <= keep_messages {
329            return Ok(CompactResult::NotNeeded);
330        }
331
332        let tokens_before = self.current_input_tokens;
333        let split_point = self.messages.len() - keep_messages;
334        let to_summarize: Vec<_> = self.messages[..split_point].to_vec();
335        let to_keep: Vec<_> = self.messages[split_point..].to_vec();
336
337        let summary_prompt = Self::format_for_summary(&to_summarize);
338        let model = client.adapter().model(ModelType::Small).to_string();
339        let request = CreateMessageRequest::new(&model, vec![Message::user(&summary_prompt)])
340            .with_max_tokens(2000);
341        let response = client.send(request).await?;
342        let summary = response.text();
343
344        let original_count = self.messages.len();
345
346        self.messages.clear();
347        self.current_leaf_id = None;
348
349        let summary_msg = SessionMessage::user(vec![ContentBlock::text(format!(
350            "[Previous conversation summary]\n{}",
351            summary
352        ))])
353        .as_compact_summary();
354        self.add_message(summary_msg);
355
356        for mut msg in to_keep {
357            msg.parent_id = self.current_leaf_id.clone();
358            self.current_leaf_id = Some(msg.id.clone());
359            self.messages.push(msg);
360        }
361
362        // Reset to 0: actual value will be set by next API call's update_usage().
363        // This also prevents immediate re-compaction since should_compact() returns false when 0.
364        self.current_input_tokens = 0;
365        self.summary = Some(summary.clone());
366        self.updated_at = Utc::now();
367
368        let record = CompactRecord::new(self.id)
369            .with_counts(original_count, self.messages.len())
370            .with_summary(summary.clone())
371            .with_saved_tokens(tokens_before as usize);
372        self.record_compact(record);
373
374        Ok(CompactResult::Compacted {
375            original_count,
376            new_count: self.messages.len(),
377            saved_tokens: tokens_before as usize,
378            summary,
379        })
380    }
381
382    fn format_for_summary(messages: &[SessionMessage]) -> String {
383        let estimated_capacity = messages.len() * 500 + 200;
384        let mut formatted = String::with_capacity(estimated_capacity.min(32768));
385        formatted.push_str(
386            "Summarize this conversation concisely. \
387             Preserve key decisions, code changes, file paths, and important context:\n\n",
388        );
389
390        for msg in messages {
391            let role = match msg.role {
392                Role::User => "User",
393                Role::Assistant => "Assistant",
394            };
395            formatted.push_str(role);
396            formatted.push_str(":\n");
397
398            for block in &msg.content {
399                if let Some(text) = block.as_text() {
400                    if text.len() > 800 {
401                        formatted.push_str(&text[..800]);
402                        formatted.push_str("... [truncated]\n");
403                    } else {
404                        formatted.push_str(text);
405                        formatted.push('\n');
406                    }
407                }
408            }
409            formatted.push('\n');
410        }
411
412        formatted
413    }
414
415    pub fn clear_messages(&mut self) {
416        self.messages.clear();
417        self.current_leaf_id = None;
418        self.updated_at = Utc::now();
419    }
420}
421
422#[cfg(test)]
423mod tests {
424    use super::*;
425    use crate::types::{ContentBlock, Role};
426
427    #[test]
428    fn test_session_creation() {
429        let config = SessionConfig::default();
430        let session = Session::new(config);
431
432        assert_eq!(session.state, SessionState::Created);
433        assert!(session.messages.is_empty());
434        assert!(session.current_leaf_id.is_none());
435    }
436
437    #[test]
438    fn test_add_message() {
439        let mut session = Session::new(SessionConfig::default());
440
441        let msg1 = SessionMessage::user(vec![ContentBlock::text("Hello")]);
442        session.add_message(msg1);
443
444        assert_eq!(session.messages.len(), 1);
445        assert!(session.current_leaf_id.is_some());
446    }
447
448    #[test]
449    fn test_message_tree() {
450        let mut session = Session::new(SessionConfig::default());
451
452        let user_msg = SessionMessage::user(vec![ContentBlock::text("Hello")]);
453        session.add_message(user_msg);
454
455        let assistant_msg = SessionMessage::assistant(vec![ContentBlock::text("Hi there!")]);
456        session.add_message(assistant_msg);
457
458        let branch = session.get_current_branch();
459        assert_eq!(branch.len(), 2);
460        assert_eq!(branch[0].role, Role::User);
461        assert_eq!(branch[1].role, Role::Assistant);
462    }
463
464    #[test]
465    fn test_session_expiry() {
466        let config = SessionConfig {
467            ttl_secs: Some(0),
468            ..Default::default()
469        };
470        let session = Session::new(config);
471
472        std::thread::sleep(std::time::Duration::from_millis(10));
473        assert!(session.is_expired());
474    }
475
476    #[test]
477    fn test_token_usage_accumulation() {
478        let mut session = Session::new(SessionConfig::default());
479
480        let msg1 = SessionMessage::assistant(vec![ContentBlock::text("Response 1")]).with_usage(
481            TokenUsage {
482                input_tokens: 100,
483                output_tokens: 50,
484                ..Default::default()
485            },
486        );
487        session.add_message(msg1);
488
489        let msg2 = SessionMessage::assistant(vec![ContentBlock::text("Response 2")]).with_usage(
490            TokenUsage {
491                input_tokens: 150,
492                output_tokens: 75,
493                ..Default::default()
494            },
495        );
496        session.add_message(msg2);
497
498        assert_eq!(session.total_usage.input_tokens, 250);
499        assert_eq!(session.total_usage.output_tokens, 125);
500    }
501
502    #[test]
503    fn test_compact_history_limit() {
504        let mut session = Session::new(SessionConfig::default());
505
506        for i in 0..MAX_COMPACT_HISTORY_SIZE + 10 {
507            let record = CompactRecord::new(session.id).with_summary(format!("Summary {}", i));
508            session.record_compact(record);
509        }
510
511        assert_eq!(session.compact_history.len(), MAX_COMPACT_HISTORY_SIZE);
512        assert!(session.compact_history[0].summary.contains("10"));
513    }
514
515    #[test]
516    fn test_exit_plan_mode_takes_ownership() {
517        let mut session = Session::new(SessionConfig::default());
518        session.enter_plan_mode(Some("Test Plan".to_string()));
519
520        let plan = session.exit_plan_mode();
521        assert!(plan.is_some());
522        assert!(session.current_plan.is_none());
523    }
524
525    #[test]
526    fn test_message_caching_applies_to_last_user_turn() {
527        let mut session = Session::new(SessionConfig::default());
528
529        session.add_user_message("First question");
530        session.add_message(SessionMessage::assistant(vec![ContentBlock::text(
531            "First answer",
532        )]));
533        session.add_user_message("Second question");
534
535        let messages = session.to_api_messages();
536
537        assert_eq!(messages.len(), 3);
538        assert!(!messages[0].has_cache_control());
539        assert!(!messages[1].has_cache_control());
540        assert!(messages[2].has_cache_control());
541    }
542
543    #[test]
544    fn test_message_caching_disabled() {
545        let mut session = Session::new(SessionConfig::default());
546
547        session.add_user_message("Question");
548
549        let messages = session.to_api_messages_with_cache(false);
550
551        assert_eq!(messages.len(), 1);
552        assert!(!messages[0].has_cache_control());
553    }
554
555    #[test]
556    fn test_message_caching_empty_session() {
557        let session = Session::new(SessionConfig::default());
558        let messages = session.to_api_messages();
559        assert!(messages.is_empty());
560    }
561
562    #[test]
563    fn test_message_caching_assistant_only() {
564        let mut session = Session::new(SessionConfig::default());
565        session.add_message(SessionMessage::assistant(vec![ContentBlock::text("Hi")]));
566
567        let messages = session.to_api_messages();
568
569        assert_eq!(messages.len(), 1);
570        assert!(!messages[0].has_cache_control());
571    }
572}
claude_agent/session/state/mod.rs

claude_agent/session/state/
mod.rs
