feat: add ecc2 decision log audit trail

ecc2/src/main.rs

@@ -260,6 +260,37 @@ enum Commands {
         #[arg(long)]
         json: bool,
     },
+    /// Log a significant agent decision for auditability
+    LogDecision {
+        /// Session ID or alias. Omit to log against the latest session.
+        session_id: Option<String>,
+        /// The chosen decision or direction
+        #[arg(long)]
+        decision: String,
+        /// Why the agent made this choice
+        #[arg(long)]
+        reasoning: String,
+        /// Alternative considered and rejected; repeat for multiple entries
+        #[arg(long = "alternative")]
+        alternatives: Vec<String>,
+        /// Emit machine-readable JSON instead of the human summary
+        #[arg(long)]
+        json: bool,
+    },
+    /// Show recent decision-log entries
+    Decisions {
+        /// Session ID or alias. Omit to read the latest session.
+        session_id: Option<String>,
+        /// Show decision log entries across all sessions
+        #[arg(long)]
+        all: bool,
+        /// Emit machine-readable JSON instead of the human summary
+        #[arg(long)]
+        json: bool,
+        /// Maximum decision-log entries to return
+        #[arg(long, default_value_t = 20)]
+        limit: usize,
+    },
     /// Export sessions, tool spans, and metrics in OTLP-compatible JSON
     ExportOtel {
         /// Session ID or alias. Omit to export all sessions.
@@ -872,6 +903,45 @@ async fn main() -> Result<()> {
                 println!("{}", format_prune_worktrees_human(&outcome));
             }
         }
+        Some(Commands::LogDecision {
+            session_id,
+            decision,
+            reasoning,
+            alternatives,
+            json,
+        }) => {
+            let resolved_id = resolve_session_id(&db, session_id.as_deref().unwrap_or("latest"))?;
+            let entry = db.insert_decision(&resolved_id, &decision, &alternatives, &reasoning)?;
+            if json {
+                println!("{}", serde_json::to_string_pretty(&entry)?);
+            } else {
+                println!("{}", format_logged_decision_human(&entry));
+            }
+        }
+        Some(Commands::Decisions {
+            session_id,
+            all,
+            json,
+            limit,
+        }) => {
+            if all && session_id.is_some() {
+                return Err(anyhow::anyhow!(
+                    "decisions does not accept a session ID when --all is set"
+                ));
+            }
+            let entries = if all {
+                db.list_decisions(limit)?
+            } else {
+                let resolved_id =
+                    resolve_session_id(&db, session_id.as_deref().unwrap_or("latest"))?;
+                db.list_decisions_for_session(&resolved_id, limit)?
+            };
+            if json {
+                println!("{}", serde_json::to_string_pretty(&entries)?);
+            } else {
+                println!("{}", format_decisions_human(&entries, all));
+            }
+        }
         Some(Commands::ExportOtel { session_id, output }) => {
             sync_runtime_session_metrics(&db, &cfg)?;
             let resolved_session_id = session_id
@@ -1641,6 +1711,63 @@ fn format_prune_worktrees_human(outcome: &session::manager::WorktreePruneOutcome
     lines.join("\n")
 }
 
+fn format_logged_decision_human(entry: &session::DecisionLogEntry) -> String {
+    let mut lines = vec![
+        format!("Logged decision for {}", short_session(&entry.session_id)),
+        format!("Decision: {}", entry.decision),
+        format!("Why: {}", entry.reasoning),
+    ];
+
+    if entry.alternatives.is_empty() {
+        lines.push("Alternatives: none recorded".to_string());
+    } else {
+        lines.push("Alternatives:".to_string());
+        for alternative in &entry.alternatives {
+            lines.push(format!("- {alternative}"));
+        }
+    }
+
+    lines.push(format!(
+        "Recorded at: {}",
+        entry.timestamp.format("%Y-%m-%d %H:%M:%S UTC")
+    ));
+    lines.join("\n")
+}
+
+fn format_decisions_human(entries: &[session::DecisionLogEntry], include_session: bool) -> String {
+    if entries.is_empty() {
+        return if include_session {
+            "No decision-log entries across all sessions yet.".to_string()
+        } else {
+            "No decision-log entries for this session yet.".to_string()
+        };
+    }
+
+    let mut lines = vec![format!("Decision log: {} entries", entries.len())];
+    for entry in entries {
+        let prefix = if include_session {
+            format!("{} | ", short_session(&entry.session_id))
+        } else {
+            String::new()
+        };
+        lines.push(format!(
+            "- [{}] {prefix}{}",
+            entry.timestamp.format("%H:%M:%S"),
+            entry.decision
+        ));
+        lines.push(format!("  why {}", entry.reasoning));
+        if entry.alternatives.is_empty() {
+            lines.push("  alternatives none recorded".to_string());
+        } else {
+            for alternative in &entry.alternatives {
+                lines.push(format!("  alternative {alternative}"));
+            }
+        }
+    }
+
+    lines.join("\n")
+}
+
 fn format_merge_queue_human(report: &session::manager::MergeQueueReport) -> String {
     let mut lines = Vec::new();
     lines.push(format!(
@@ -3259,6 +3386,87 @@ mod tests {
         }
     }
 
+    #[test]
+    fn cli_parses_log_decision_command() {
+        let cli = Cli::try_parse_from([
+            "ecc",
+            "log-decision",
+            "latest",
+            "--decision",
+            "Use sqlite",
+            "--reasoning",
+            "It is already embedded",
+            "--alternative",
+            "json files",
+            "--alternative",
+            "memory only",
+            "--json",
+        ])
+        .expect("log-decision should parse");
+
+        match cli.command {
+            Some(Commands::LogDecision {
+                session_id,
+                decision,
+                reasoning,
+                alternatives,
+                json,
+            }) => {
+                assert_eq!(session_id.as_deref(), Some("latest"));
+                assert_eq!(decision, "Use sqlite");
+                assert_eq!(reasoning, "It is already embedded");
+                assert_eq!(alternatives, vec!["json files", "memory only"]);
+                assert!(json);
+            }
+            _ => panic!("expected log-decision subcommand"),
+        }
+    }
+
+    #[test]
+    fn cli_parses_decisions_command() {
+        let cli = Cli::try_parse_from(["ecc", "decisions", "--all", "--limit", "5", "--json"])
+            .expect("decisions should parse");
+
+        match cli.command {
+            Some(Commands::Decisions {
+                session_id,
+                all,
+                json,
+                limit,
+            }) => {
+                assert!(session_id.is_none());
+                assert!(all);
+                assert!(json);
+                assert_eq!(limit, 5);
+            }
+            _ => panic!("expected decisions subcommand"),
+        }
+    }
+
+    #[test]
+    fn format_decisions_human_renders_details() {
+        let text = format_decisions_human(
+            &[session::DecisionLogEntry {
+                id: 1,
+                session_id: "sess-12345678".to_string(),
+                decision: "Use sqlite for the shared context graph".to_string(),
+                alternatives: vec!["json files".to_string(), "memory only".to_string()],
+                reasoning: "SQLite keeps the audit trail queryable.".to_string(),
+                timestamp: chrono::DateTime::parse_from_rfc3339("2026-04-09T01:02:03Z")
+                    .unwrap()
+                    .with_timezone(&chrono::Utc),
+            }],
+            true,
+        );
+
+        assert!(text.contains("Decision log: 1 entries"));
+        assert!(text.contains("sess-123"));
+        assert!(text.contains("Use sqlite for the shared context graph"));
+        assert!(text.contains("why SQLite keeps the audit trail queryable."));
+        assert!(text.contains("alternative json files"));
+        assert!(text.contains("alternative memory only"));
+    }
+
     #[test]
     fn cli_parses_coordination_status_json_flag() {
         let cli = Cli::try_parse_from(["ecc", "coordination-status", "--json"])

ecc2/src/session/mod.rs

@@ -142,6 +142,16 @@ pub struct FileActivityEntry {
     pub timestamp: DateTime<Utc>,
 }
 
+#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
+pub struct DecisionLogEntry {
+    pub id: i64,
+    pub session_id: String,
+    pub decision: String,
+    pub alternatives: Vec<String>,
+    pub reasoning: String,
+    pub timestamp: DateTime<Utc>,
+}
+
 #[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
 #[serde(rename_all = "snake_case")]
 pub enum FileActivityAction {

ecc2/src/session/store.rs

@@ -13,8 +13,9 @@ use crate::observability::{ToolCallEvent, ToolLogEntry, ToolLogPage};
 
 use super::output::{OutputLine, OutputStream, OUTPUT_BUFFER_LIMIT};
 use super::{
-    default_project_label, default_task_group_label, normalize_group_label, FileActivityAction,
-    FileActivityEntry, Session, SessionMessage, SessionMetrics, SessionState, WorktreeInfo,
+    default_project_label, default_task_group_label, normalize_group_label, DecisionLogEntry,
+    FileActivityAction, FileActivityEntry, Session, SessionMessage, SessionMetrics, SessionState,
+    WorktreeInfo,
 };
 
 pub struct StateStore {
@@ -193,6 +194,15 @@ impl StateStore {
                 timestamp TEXT NOT NULL
             );
 
+            CREATE TABLE IF NOT EXISTS decision_log (
+                id INTEGER PRIMARY KEY AUTOINCREMENT,
+                session_id TEXT NOT NULL REFERENCES sessions(id) ON DELETE CASCADE,
+                decision TEXT NOT NULL,
+                alternatives_json TEXT NOT NULL DEFAULT '[]',
+                reasoning TEXT NOT NULL,
+                timestamp TEXT NOT NULL
+            );
+
             CREATE TABLE IF NOT EXISTS pending_worktree_queue (
                 session_id TEXT PRIMARY KEY REFERENCES sessions(id) ON DELETE CASCADE,
                 repo_root TEXT NOT NULL,
@@ -225,12 +235,11 @@ impl StateStore {
 
             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 UNIQUE INDEX IF NOT EXISTS idx_tool_log_hook_event
-                ON tool_log(hook_event_id)
-                WHERE hook_event_id IS NOT NULL;
             CREATE INDEX IF NOT EXISTS idx_messages_to ON messages(to_session, read);
             CREATE INDEX IF NOT EXISTS idx_session_output_session
                 ON session_output(session_id, id);
+            CREATE INDEX IF NOT EXISTS idx_decision_log_session
+                ON decision_log(session_id, timestamp, id);
             CREATE INDEX IF NOT EXISTS idx_pending_worktree_queue_requested_at
                 ON pending_worktree_queue(requested_at, session_id);
 
@@ -1423,6 +1432,84 @@ impl StateStore {
             .map_err(Into::into)
     }
 
+    pub fn insert_decision(
+        &self,
+        session_id: &str,
+        decision: &str,
+        alternatives: &[String],
+        reasoning: &str,
+    ) -> Result<DecisionLogEntry> {
+        let timestamp = chrono::Utc::now();
+        let alternatives_json = serde_json::to_string(alternatives)
+            .context("Failed to serialize decision alternatives")?;
+
+        self.conn.execute(
+            "INSERT INTO decision_log (session_id, decision, alternatives_json, reasoning, timestamp)
+             VALUES (?1, ?2, ?3, ?4, ?5)",
+            rusqlite::params![
+                session_id,
+                decision,
+                alternatives_json,
+                reasoning,
+                timestamp.to_rfc3339(),
+            ],
+        )?;
+
+        Ok(DecisionLogEntry {
+            id: self.conn.last_insert_rowid(),
+            session_id: session_id.to_string(),
+            decision: decision.to_string(),
+            alternatives: alternatives.to_vec(),
+            reasoning: reasoning.to_string(),
+            timestamp,
+        })
+    }
+
+    pub fn list_decisions_for_session(
+        &self,
+        session_id: &str,
+        limit: usize,
+    ) -> Result<Vec<DecisionLogEntry>> {
+        let mut stmt = self.conn.prepare(
+            "SELECT id, session_id, decision, alternatives_json, reasoning, timestamp
+             FROM (
+                 SELECT id, session_id, decision, alternatives_json, reasoning, timestamp
+                 FROM decision_log
+                 WHERE session_id = ?1
+                 ORDER BY timestamp DESC, id DESC
+                 LIMIT ?2
+             )
+             ORDER BY timestamp ASC, id ASC",
+        )?;
+
+        let entries = stmt
+            .query_map(rusqlite::params![session_id, limit as i64], |row| {
+                map_decision_log_entry(row)
+            })?
+            .collect::<Result<Vec<_>, _>>()?;
+
+        Ok(entries)
+    }
+
+    pub fn list_decisions(&self, limit: usize) -> Result<Vec<DecisionLogEntry>> {
+        let mut stmt = self.conn.prepare(
+            "SELECT id, session_id, decision, alternatives_json, reasoning, timestamp
+             FROM (
+                 SELECT id, session_id, decision, alternatives_json, reasoning, timestamp
+                 FROM decision_log
+                 ORDER BY timestamp DESC, id DESC
+                 LIMIT ?1
+             )
+             ORDER BY timestamp ASC, id ASC",
+        )?;
+
+        let entries = stmt
+            .query_map(rusqlite::params![limit as i64], map_decision_log_entry)?
+            .collect::<Result<Vec<_>, _>>()?;
+
+        Ok(entries)
+    }
+
     pub fn daemon_activity(&self) -> Result<DaemonActivity> {
         self.conn
             .query_row(
@@ -2037,6 +2124,34 @@ fn session_state_supports_overlap(state: &SessionState) -> bool {
     )
 }
 
+fn map_decision_log_entry(row: &rusqlite::Row<'_>) -> rusqlite::Result<DecisionLogEntry> {
+    let alternatives_json = row
+        .get::<_, Option<String>>(3)?
+        .unwrap_or_else(|| "[]".to_string());
+    let alternatives = serde_json::from_str(&alternatives_json).map_err(|error| {
+        rusqlite::Error::FromSqlConversionFailure(3, rusqlite::types::Type::Text, Box::new(error))
+    })?;
+    let timestamp = row.get::<_, String>(5)?;
+    let timestamp = chrono::DateTime::parse_from_rfc3339(&timestamp)
+        .map(|value| value.with_timezone(&chrono::Utc))
+        .map_err(|error| {
+            rusqlite::Error::FromSqlConversionFailure(
+                5,
+                rusqlite::types::Type::Text,
+                Box::new(error),
+            )
+        })?;
+
+    Ok(DecisionLogEntry {
+        id: row.get(0)?,
+        session_id: row.get(1)?,
+        decision: row.get(2)?,
+        alternatives,
+        reasoning: row.get(4)?,
+        timestamp,
+    })
+}
+
 fn file_overlap_is_relevant(current: &FileActivityEntry, other: &FileActivityEntry) -> bool {
     current.path == other.path
         && !(matches!(current.action, FileActivityAction::Read)
@@ -2467,6 +2582,151 @@ mod tests {
         Ok(())
     }
 
+    #[test]
+    fn open_migrates_legacy_tool_log_before_creating_hook_event_index() -> Result<()> {
+        let tempdir = TestDir::new("store-legacy-hook-event")?;
+        let db_path = tempdir.path().join("state.db");
+        let conn = Connection::open(&db_path)?;
+        conn.execute_batch(
+            "
+            CREATE TABLE sessions (
+                id TEXT PRIMARY KEY,
+                task TEXT NOT NULL,
+                agent_type TEXT NOT NULL,
+                state TEXT NOT NULL DEFAULT 'pending',
+                created_at TEXT NOT NULL,
+                updated_at TEXT NOT NULL
+            );
+
+            CREATE TABLE tool_log (
+                id INTEGER PRIMARY KEY AUTOINCREMENT,
+                session_id TEXT NOT NULL,
+                tool_name TEXT NOT NULL,
+                input_summary TEXT,
+                output_summary TEXT,
+                duration_ms INTEGER,
+                risk_score REAL DEFAULT 0.0,
+                timestamp TEXT NOT NULL
+            );
+            ",
+        )?;
+        drop(conn);
+
+        let db = StateStore::open(&db_path)?;
+        assert!(db.has_column("tool_log", "hook_event_id")?);
+
+        let conn = Connection::open(&db_path)?;
+        let index_count: i64 = conn.query_row(
+            "SELECT COUNT(*)
+             FROM sqlite_master
+             WHERE type = 'index' AND name = 'idx_tool_log_hook_event'",
+            [],
+            |row| row.get(0),
+        )?;
+        assert_eq!(index_count, 1);
+
+        Ok(())
+    }
+
+    #[test]
+    fn insert_and_list_decisions_for_session() -> Result<()> {
+        let tempdir = TestDir::new("store-decisions")?;
+        let db = StateStore::open(&tempdir.path().join("state.db"))?;
+        let now = Utc::now();
+
+        db.insert_session(&Session {
+            id: "session-1".to_string(),
+            task: "architect".to_string(),
+            project: "workspace".to_string(),
+            task_group: "general".to_string(),
+            agent_type: "claude".to_string(),
+            working_dir: PathBuf::from("/tmp"),
+            state: SessionState::Running,
+            pid: None,
+            worktree: None,
+            created_at: now,
+            updated_at: now,
+            last_heartbeat_at: now,
+            metrics: SessionMetrics::default(),
+        })?;
+
+        db.insert_decision(
+            "session-1",
+            "Use sqlite for the shared context graph",
+            &["json files".to_string(), "memory only".to_string()],
+            "SQLite keeps the audit trail queryable from both CLI and TUI.",
+        )?;
+        db.insert_decision(
+            "session-1",
+            "Keep decision logging append-only",
+            &["mutable edits".to_string()],
+            "Append-only history preserves operator trust and timeline integrity.",
+        )?;
+
+        let entries = db.list_decisions_for_session("session-1", 10)?;
+        assert_eq!(entries.len(), 2);
+        assert_eq!(entries[0].session_id, "session-1");
+        assert_eq!(
+            entries[0].decision,
+            "Use sqlite for the shared context graph"
+        );
+        assert_eq!(
+            entries[0].alternatives,
+            vec!["json files".to_string(), "memory only".to_string()]
+        );
+        assert_eq!(entries[1].decision, "Keep decision logging append-only");
+        assert_eq!(
+            entries[1].reasoning,
+            "Append-only history preserves operator trust and timeline integrity."
+        );
+
+        Ok(())
+    }
+
+    #[test]
+    fn list_recent_decisions_across_sessions_returns_latest_subset_in_order() -> Result<()> {
+        let tempdir = TestDir::new("store-decisions-all")?;
+        let db = StateStore::open(&tempdir.path().join("state.db"))?;
+        let now = Utc::now();
+
+        for session_id in ["session-a", "session-b", "session-c"] {
+            db.insert_session(&Session {
+                id: session_id.to_string(),
+                task: "decision log".to_string(),
+                project: "workspace".to_string(),
+                task_group: "general".to_string(),
+                agent_type: "claude".to_string(),
+                working_dir: PathBuf::from("/tmp"),
+                state: SessionState::Running,
+                pid: None,
+                worktree: None,
+                created_at: now,
+                updated_at: now,
+                last_heartbeat_at: now,
+                metrics: SessionMetrics::default(),
+            })?;
+        }
+
+        db.insert_decision("session-a", "Oldest", &[], "first")?;
+        std::thread::sleep(std::time::Duration::from_millis(2));
+        db.insert_decision("session-b", "Middle", &[], "second")?;
+        std::thread::sleep(std::time::Duration::from_millis(2));
+        db.insert_decision("session-c", "Newest", &[], "third")?;
+
+        let entries = db.list_decisions(2)?;
+        assert_eq!(
+            entries
+                .iter()
+                .map(|entry| entry.decision.as_str())
+                .collect::<Vec<_>>(),
+            vec!["Middle", "Newest"]
+        );
+        assert_eq!(entries[0].session_id, "session-b");
+        assert_eq!(entries[1].session_id, "session-c");
+
+        Ok(())
+    }
+
     #[test]
     fn refresh_session_durations_updates_running_and_terminal_sessions() -> Result<()> {
         let tempdir = TestDir::new("store-duration-metrics")?;

ecc2/src/tui/dashboard.rs

@@ -22,7 +22,9 @@ use crate::session::output::{
     OutputEvent, OutputLine, OutputStream, SessionOutputStore, OUTPUT_BUFFER_LIMIT,
 };
 use crate::session::store::{DaemonActivity, FileActivityOverlap, StateStore};
-use crate::session::{FileActivityEntry, Session, SessionGrouping, SessionMessage, SessionState};
+use crate::session::{
+    DecisionLogEntry, FileActivityEntry, Session, SessionGrouping, SessionMessage, SessionState,
+};
 use crate::worktree;
 
 #[cfg(test)]
@@ -215,6 +217,7 @@ enum TimelineEventFilter {
     Messages,
     ToolCalls,
     FileChanges,
+    Decisions,
 }
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
@@ -257,6 +260,7 @@ enum TimelineEventType {
     Message,
     ToolCall,
     FileChange,
+    Decision,
 }
 
 #[derive(Debug, Clone)]
@@ -1025,6 +1029,11 @@ impl Dashboard {
                 TimelineEventFilter::FileChanges,
                 OutputTimeFilter::AllTime,
             ) => "No file-change events across all sessions yet.",
+            (
+                SearchScope::AllSessions,
+                TimelineEventFilter::Decisions,
+                OutputTimeFilter::AllTime,
+            ) => "No decision-log events across all sessions yet.",
             (SearchScope::AllSessions, TimelineEventFilter::All, _) => {
                 "No timeline events across all sessions in the selected time range."
             }
@@ -1040,6 +1049,9 @@ impl Dashboard {
             (SearchScope::AllSessions, TimelineEventFilter::FileChanges, _) => {
                 "No file-change events across all sessions in the selected time range."
             }
+            (SearchScope::AllSessions, TimelineEventFilter::Decisions, _) => {
+                "No decision-log events across all sessions in the selected time range."
+            }
             (SearchScope::SelectedSession, TimelineEventFilter::All, OutputTimeFilter::AllTime) => {
                 "No timeline events for this session yet."
             }
@@ -1063,6 +1075,11 @@ impl Dashboard {
                 TimelineEventFilter::FileChanges,
                 OutputTimeFilter::AllTime,
             ) => "No file-change events for this session yet.",
+            (
+                SearchScope::SelectedSession,
+                TimelineEventFilter::Decisions,
+                OutputTimeFilter::AllTime,
+            ) => "No decision-log events for this session yet.",
             (SearchScope::SelectedSession, TimelineEventFilter::All, _) => {
                 "No timeline events in the selected time range."
             }
@@ -1078,6 +1095,9 @@ impl Dashboard {
             (SearchScope::SelectedSession, TimelineEventFilter::FileChanges, _) => {
                 "No file-change events in the selected time range."
             }
+            (SearchScope::SelectedSession, TimelineEventFilter::Decisions, _) => {
+                "No decision-log events in the selected time range."
+            }
         }
     }
 
@@ -4926,6 +4946,18 @@ impl Dashboard {
             }
         }));
 
+        let decisions = self
+            .db
+            .list_decisions_for_session(&session.id, 32)
+            .unwrap_or_default();
+        events.extend(decisions.into_iter().map(|entry| TimelineEvent {
+            occurred_at: entry.timestamp,
+            session_id: session.id.clone(),
+            event_type: TimelineEventType::Decision,
+            summary: decision_log_summary(&entry),
+            detail_lines: decision_log_detail_lines(&entry),
+        }));
+
         let tool_logs = self
             .db
             .query_tool_logs(&session.id, 1, 128)
@@ -5613,6 +5645,23 @@ impl Dashboard {
                     }
                 }
             }
+            let recent_decisions = self
+                .db
+                .list_decisions_for_session(&session.id, 5)
+                .unwrap_or_default();
+            if !recent_decisions.is_empty() {
+                lines.push("Recent decisions".to_string());
+                for entry in recent_decisions {
+                    lines.push(format!(
+                        "- {} {}",
+                        self.short_timestamp(&entry.timestamp.to_rfc3339()),
+                        decision_log_summary(&entry)
+                    ));
+                    for detail in decision_log_detail_lines(&entry).into_iter().take(3) {
+                        lines.push(format!("  {}", detail));
+                    }
+                }
+            }
             let file_overlaps = self
                 .db
                 .list_file_overlaps(&session.id, 3)
@@ -6361,7 +6410,8 @@ impl TimelineEventFilter {
             Self::Lifecycle => Self::Messages,
             Self::Messages => Self::ToolCalls,
             Self::ToolCalls => Self::FileChanges,
-            Self::FileChanges => Self::All,
+            Self::FileChanges => Self::Decisions,
+            Self::Decisions => Self::All,
         }
     }
 
@@ -6372,6 +6422,7 @@ impl TimelineEventFilter {
             Self::Messages => event_type == TimelineEventType::Message,
             Self::ToolCalls => event_type == TimelineEventType::ToolCall,
             Self::FileChanges => event_type == TimelineEventType::FileChange,
+            Self::Decisions => event_type == TimelineEventType::Decision,
         }
     }
 
@@ -6382,6 +6433,7 @@ impl TimelineEventFilter {
             Self::Messages => "messages",
             Self::ToolCalls => "tool calls",
             Self::FileChanges => "file changes",
+            Self::Decisions => "decisions",
         }
     }
 
@@ -6392,6 +6444,7 @@ impl TimelineEventFilter {
             Self::Messages => " messages",
             Self::ToolCalls => " tool calls",
             Self::FileChanges => " file changes",
+            Self::Decisions => " decisions",
         }
     }
 }
@@ -6403,6 +6456,7 @@ impl TimelineEventType {
             Self::Message => "message",
             Self::ToolCall => "tool",
             Self::FileChange => "file-change",
+            Self::Decision => "decision",
         }
     }
 }
@@ -7332,6 +7386,28 @@ fn file_overlap_summary(entry: &FileActivityOverlap, timestamp: &str) -> String
     )
 }
 
+fn decision_log_summary(entry: &DecisionLogEntry) -> String {
+    format!("decided {}", truncate_for_dashboard(&entry.decision, 72))
+}
+
+fn decision_log_detail_lines(entry: &DecisionLogEntry) -> Vec<String> {
+    let mut lines = vec![format!(
+        "why {}",
+        truncate_for_dashboard(&entry.reasoning, 72)
+    )];
+    if entry.alternatives.is_empty() {
+        lines.push("alternatives none recorded".to_string());
+    } else {
+        for alternative in entry.alternatives.iter().take(3) {
+            lines.push(format!(
+                "alternative {}",
+                truncate_for_dashboard(alternative, 72)
+            ));
+        }
+    }
+    lines
+}
+
 fn tool_log_detail_lines(entry: &ToolLogEntry) -> Vec<String> {
     let mut lines = Vec::new();
     if !entry.trigger_summary.trim().is_empty() {
@@ -8994,6 +9070,61 @@ diff --git a/src/lib.rs b/src/lib.rs\n\
         Ok(())
     }
 
+    #[test]
+    fn timeline_and_metrics_render_decision_log_entries() -> Result<()> {
+        let now = Utc::now();
+        let mut session = sample_session(
+            "focus-12345678",
+            "planner",
+            SessionState::Running,
+            Some("ecc/focus"),
+            256,
+            7,
+        );
+        session.created_at = now - chrono::Duration::hours(1);
+        session.updated_at = now - chrono::Duration::minutes(2);
+
+        let mut dashboard = test_dashboard(vec![session.clone()], 0);
+        dashboard.db.insert_session(&session)?;
+        dashboard.db.insert_decision(
+            &session.id,
+            "Use sqlite for the shared context graph",
+            &["json files".to_string(), "memory only".to_string()],
+            "SQLite keeps the audit trail queryable from CLI and TUI.",
+        )?;
+
+        dashboard.toggle_timeline_mode();
+        let rendered = dashboard.rendered_output_text(180, 30);
+        assert!(rendered.contains("decision"));
+        assert!(rendered.contains("decided Use sqlite for the shared context graph"));
+        assert!(rendered.contains("why SQLite keeps the audit trail queryable"));
+        assert!(rendered.contains("alternative json files"));
+        assert!(rendered.contains("alternative memory only"));
+
+        let metrics_text = dashboard.selected_session_metrics_text();
+        assert!(metrics_text.contains("Recent decisions"));
+        assert!(metrics_text.contains("decided Use sqlite for the shared context graph"));
+        assert!(metrics_text.contains("alternative json files"));
+
+        dashboard.cycle_timeline_event_filter();
+        dashboard.cycle_timeline_event_filter();
+        dashboard.cycle_timeline_event_filter();
+        dashboard.cycle_timeline_event_filter();
+        dashboard.cycle_timeline_event_filter();
+
+        assert_eq!(
+            dashboard.timeline_event_filter,
+            TimelineEventFilter::Decisions
+        );
+        assert_eq!(
+            dashboard.operator_note.as_deref(),
+            Some("timeline filter set to decisions")
+        );
+        assert_eq!(dashboard.output_title(), " Timeline decisions ");
+
+        Ok(())
+    }
+
     #[test]
     fn timeline_time_filter_hides_old_events() {
         let now = Utc::now();