feat: scaffold ECC 2.0 Rust TUI — agentic IDE control plane

Initial scaffold for ECC 2.0, a terminal-native agentic IDE built with
Ratatui. Compiles to a 3.4MB single binary.

Core modules:
- Session manager with SQLite-backed state store
- TUI dashboard with split-pane layout (sessions, output, metrics)
- Worktree orchestration (auto-create per agent session)
- Observability with tool call risk scoring
- Inter-agent communication via SQLite mailbox
- Background daemon with heartbeat monitoring
- CLI with start/stop/sessions/status/daemon subcommands

Tech stack: Rust + Ratatui + Crossterm + Tokio + rusqlite + git2 + clap

ecc2/src/session/daemon.rs

@@ -0,0 +1,46 @@
+use anyhow::Result;
+use std::time::Duration;
+use tokio::time;
+
+use super::store::StateStore;
+use super::SessionState;
+use crate::config::Config;
+
+/// Background daemon that monitors sessions, handles heartbeats,
+/// and cleans up stale resources.
+pub async fn run(db: StateStore, cfg: Config) -> Result<()> {
+    tracing::info!("ECC daemon started");
+
+    let heartbeat_interval = Duration::from_secs(cfg.heartbeat_interval_secs);
+    let timeout = Duration::from_secs(cfg.session_timeout_secs);
+
+    loop {
+        if let Err(e) = check_sessions(&db, timeout) {
+            tracing::error!("Session check failed: {e}");
+        }
+
+        time::sleep(heartbeat_interval).await;
+    }
+}
+
+fn check_sessions(db: &StateStore, timeout: Duration) -> Result<()> {
+    let sessions = db.list_sessions()?;
+
+    for session in sessions {
+        if session.state != SessionState::Running {
+            continue;
+        }
+
+        let elapsed = chrono::Utc::now()
+            .signed_duration_since(session.updated_at)
+            .to_std()
+            .unwrap_or(Duration::ZERO);
+
+        if elapsed > timeout {
+            tracing::warn!("Session {} timed out after {:?}", session.id, elapsed);
+            db.update_state(&session.id, &SessionState::Failed)?;
+        }
+    }
+
+    Ok(())
+}

ecc2/src/session/manager.rs

@@ -0,0 +1,76 @@
+use anyhow::Result;
+use std::fmt;
+
+use super::{Session, SessionMetrics, SessionState};
+use super::store::StateStore;
+use crate::config::Config;
+use crate::worktree;
+
+pub async fn create_session(
+    db: &StateStore,
+    cfg: &Config,
+    task: &str,
+    agent_type: &str,
+    use_worktree: bool,
+) -> Result<String> {
+    let id = uuid::Uuid::new_v4().to_string()[..8].to_string();
+    let now = chrono::Utc::now();
+
+    let wt = if use_worktree {
+        Some(worktree::create_for_session(&id, cfg)?)
+    } else {
+        None
+    };
+
+    let session = Session {
+        id: id.clone(),
+        task: task.to_string(),
+        agent_type: agent_type.to_string(),
+        state: SessionState::Pending,
+        worktree: wt,
+        created_at: now,
+        updated_at: now,
+        metrics: SessionMetrics::default(),
+    };
+
+    db.insert_session(&session)?;
+    Ok(id)
+}
+
+pub fn list_sessions(db: &StateStore) -> Result<Vec<Session>> {
+    db.list_sessions()
+}
+
+pub fn get_status(db: &StateStore, id: &str) -> Result<SessionStatus> {
+    let session = db
+        .get_session(id)?
+        .ok_or_else(|| anyhow::anyhow!("Session not found: {id}"))?;
+    Ok(SessionStatus(session))
+}
+
+pub async fn stop_session(db: &StateStore, id: &str) -> Result<()> {
+    db.update_state(id, &SessionState::Stopped)?;
+    Ok(())
+}
+
+pub struct SessionStatus(Session);
+
+impl fmt::Display for SessionStatus {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let s = &self.0;
+        writeln!(f, "Session: {}", s.id)?;
+        writeln!(f, "Task:    {}", s.task)?;
+        writeln!(f, "Agent:   {}", s.agent_type)?;
+        writeln!(f, "State:   {}", s.state)?;
+        if let Some(ref wt) = s.worktree {
+            writeln!(f, "Branch:  {}", wt.branch)?;
+            writeln!(f, "Worktree: {}", wt.path.display())?;
+        }
+        writeln!(f, "Tokens:  {}", s.metrics.tokens_used)?;
+        writeln!(f, "Tools:   {}", s.metrics.tool_calls)?;
+        writeln!(f, "Files:   {}", s.metrics.files_changed)?;
+        writeln!(f, "Cost:    ${:.4}", s.metrics.cost_usd)?;
+        writeln!(f, "Created: {}", s.created_at)?;
+        write!(f, "Updated: {}", s.updated_at)
+    }
+}

ecc2/src/session/mod.rs

@@ -0,0 +1,59 @@
+pub mod daemon;
+pub mod manager;
+pub mod store;
+
+use chrono::{DateTime, Utc};
+use serde::{Deserialize, Serialize};
+use std::fmt;
+use std::path::PathBuf;
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct Session {
+    pub id: String,
+    pub task: String,
+    pub agent_type: String,
+    pub state: SessionState,
+    pub worktree: Option<WorktreeInfo>,
+    pub created_at: DateTime<Utc>,
+    pub updated_at: DateTime<Utc>,
+    pub metrics: SessionMetrics,
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
+pub enum SessionState {
+    Pending,
+    Running,
+    Idle,
+    Completed,
+    Failed,
+    Stopped,
+}
+
+impl fmt::Display for SessionState {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            SessionState::Pending => write!(f, "pending"),
+            SessionState::Running => write!(f, "running"),
+            SessionState::Idle => write!(f, "idle"),
+            SessionState::Completed => write!(f, "completed"),
+            SessionState::Failed => write!(f, "failed"),
+            SessionState::Stopped => write!(f, "stopped"),
+        }
+    }
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct WorktreeInfo {
+    pub path: PathBuf,
+    pub branch: String,
+    pub base_branch: String,
+}
+
+#[derive(Debug, Clone, Default, Serialize, Deserialize)]
+pub struct SessionMetrics {
+    pub tokens_used: u64,
+    pub tool_calls: u64,
+    pub files_changed: u32,
+    pub duration_secs: u64,
+    pub cost_usd: f64,
+}

ecc2/src/session/store.rs

@@ -0,0 +1,190 @@
+use anyhow::Result;
+use rusqlite::Connection;
+use std::path::Path;
+
+use super::{Session, SessionMetrics, SessionState};
+
+pub struct StateStore {
+    conn: Connection,
+}
+
+impl StateStore {
+    pub fn open(path: &Path) -> Result<Self> {
+        let conn = Connection::open(path)?;
+        let store = Self { conn };
+        store.init_schema()?;
+        Ok(store)
+    }
+
+    fn init_schema(&self) -> Result<()> {
+        self.conn.execute_batch(
+            "
+            CREATE TABLE IF NOT EXISTS sessions (
+                id TEXT PRIMARY KEY,
+                task TEXT NOT NULL,
+                agent_type TEXT NOT NULL,
+                state TEXT NOT NULL DEFAULT 'pending',
+                worktree_path TEXT,
+                worktree_branch TEXT,
+                worktree_base TEXT,
+                tokens_used INTEGER DEFAULT 0,
+                tool_calls INTEGER DEFAULT 0,
+                files_changed INTEGER DEFAULT 0,
+                duration_secs INTEGER DEFAULT 0,
+                cost_usd REAL DEFAULT 0.0,
+                created_at TEXT NOT NULL,
+                updated_at TEXT NOT NULL
+            );
+
+            CREATE TABLE IF NOT EXISTS tool_log (
+                id INTEGER PRIMARY KEY AUTOINCREMENT,
+                session_id TEXT NOT NULL REFERENCES sessions(id),
+                tool_name TEXT NOT NULL,
+                input_summary TEXT,
+                output_summary TEXT,
+                duration_ms INTEGER,
+                risk_score REAL DEFAULT 0.0,
+                timestamp TEXT NOT NULL
+            );
+
+            CREATE TABLE IF NOT EXISTS messages (
+                id INTEGER PRIMARY KEY AUTOINCREMENT,
+                from_session TEXT NOT NULL,
+                to_session TEXT NOT NULL,
+                content TEXT NOT NULL,
+                msg_type TEXT NOT NULL DEFAULT 'info',
+                read INTEGER DEFAULT 0,
+                timestamp TEXT NOT NULL
+            );
+
+            CREATE INDEX IF NOT EXISTS idx_sessions_state ON sessions(state);
+            CREATE INDEX IF NOT EXISTS idx_tool_log_session ON tool_log(session_id);
+            CREATE INDEX IF NOT EXISTS idx_messages_to ON messages(to_session, read);
+            ",
+        )?;
+        Ok(())
+    }
+
+    pub fn insert_session(&self, session: &Session) -> Result<()> {
+        self.conn.execute(
+            "INSERT INTO sessions (id, task, agent_type, state, worktree_path, worktree_branch, worktree_base, created_at, updated_at)
+             VALUES (?1, ?2, ?3, ?4, ?5, ?6, ?7, ?8, ?9)",
+            rusqlite::params![
+                session.id,
+                session.task,
+                session.agent_type,
+                session.state.to_string(),
+                session.worktree.as_ref().map(|w| w.path.to_string_lossy().to_string()),
+                session.worktree.as_ref().map(|w| w.branch.clone()),
+                session.worktree.as_ref().map(|w| w.base_branch.clone()),
+                session.created_at.to_rfc3339(),
+                session.updated_at.to_rfc3339(),
+            ],
+        )?;
+        Ok(())
+    }
+
+    pub fn update_state(&self, session_id: &str, state: &SessionState) -> Result<()> {
+        self.conn.execute(
+            "UPDATE sessions SET state = ?1, updated_at = ?2 WHERE id = ?3",
+            rusqlite::params![
+                state.to_string(),
+                chrono::Utc::now().to_rfc3339(),
+                session_id,
+            ],
+        )?;
+        Ok(())
+    }
+
+    pub fn update_metrics(&self, session_id: &str, metrics: &SessionMetrics) -> Result<()> {
+        self.conn.execute(
+            "UPDATE sessions SET tokens_used = ?1, tool_calls = ?2, files_changed = ?3, duration_secs = ?4, cost_usd = ?5, updated_at = ?6 WHERE id = ?7",
+            rusqlite::params![
+                metrics.tokens_used,
+                metrics.tool_calls,
+                metrics.files_changed,
+                metrics.duration_secs,
+                metrics.cost_usd,
+                chrono::Utc::now().to_rfc3339(),
+                session_id,
+            ],
+        )?;
+        Ok(())
+    }
+
+    pub fn list_sessions(&self) -> Result<Vec<Session>> {
+        let mut stmt = self.conn.prepare(
+            "SELECT id, task, agent_type, state, worktree_path, worktree_branch, worktree_base,
+                    tokens_used, tool_calls, files_changed, duration_secs, cost_usd,
+                    created_at, updated_at
+             FROM sessions ORDER BY updated_at DESC",
+        )?;
+
+        let sessions = stmt
+            .query_map([], |row| {
+                let state_str: String = row.get(3)?;
+                let state = match state_str.as_str() {
+                    "running" => SessionState::Running,
+                    "idle" => SessionState::Idle,
+                    "completed" => SessionState::Completed,
+                    "failed" => SessionState::Failed,
+                    "stopped" => SessionState::Stopped,
+                    _ => SessionState::Pending,
+                };
+
+                let worktree_path: Option<String> = row.get(4)?;
+                let worktree = worktree_path.map(|p| super::WorktreeInfo {
+                    path: std::path::PathBuf::from(p),
+                    branch: row.get::<_, String>(5).unwrap_or_default(),
+                    base_branch: row.get::<_, String>(6).unwrap_or_default(),
+                });
+
+                let created_str: String = row.get(12)?;
+                let updated_str: String = row.get(13)?;
+
+                Ok(Session {
+                    id: row.get(0)?,
+                    task: row.get(1)?,
+                    agent_type: row.get(2)?,
+                    state,
+                    worktree,
+                    created_at: chrono::DateTime::parse_from_rfc3339(&created_str)
+                        .unwrap_or_default()
+                        .with_timezone(&chrono::Utc),
+                    updated_at: chrono::DateTime::parse_from_rfc3339(&updated_str)
+                        .unwrap_or_default()
+                        .with_timezone(&chrono::Utc),
+                    metrics: SessionMetrics {
+                        tokens_used: row.get(7)?,
+                        tool_calls: row.get(8)?,
+                        files_changed: row.get(9)?,
+                        duration_secs: row.get(10)?,
+                        cost_usd: row.get(11)?,
+                    },
+                })
+            })?
+            .collect::<Result<Vec<_>, _>>()?;
+
+        Ok(sessions)
+    }
+
+    pub fn get_session(&self, id: &str) -> Result<Option<Session>> {
+        let sessions = self.list_sessions()?;
+        Ok(sessions.into_iter().find(|s| s.id == id || s.id.starts_with(id)))
+    }
+
+    pub fn send_message(
+        &self,
+        from: &str,
+        to: &str,
+        content: &str,
+        msg_type: &str,
+    ) -> Result<()> {
+        self.conn.execute(
+            "INSERT INTO messages (from_session, to_session, content, msg_type, timestamp)
+             VALUES (?1, ?2, ?3, ?4, ?5)",
+            rusqlite::params![from, to, content, msg_type, chrono::Utc::now().to_rfc3339()],
+        )?;
+        Ok(())
+    }
+}