diff --git a/src/codex_log.rs b/src/codex_log.rs
index 97d0eb0..97522c8 100644
--- a/src/codex_log.rs
+++ b/src/codex_log.rs
@@ -139,8 +139,9 @@ fn parse_token_count(v: &serde_json::Value, model: &str, config: &Config) -> Opt
         + (cached_input_tokens as f64 / 1_000_000.0) * rate.cache_read
         + (output_tokens as f64 / 1_000_000.0) * rate.output;
 
+    let fresh_input = input_tokens.saturating_sub(cached_input_tokens);
     Some(TokenStats {
-        input_tokens,
+        input_tokens: fresh_input,
         output_tokens,
         context_tokens,
         total_cost_usd,
@@ -155,6 +156,10 @@ async fn tail(
 ) {
     let mut offset: u64 = 0;
     let mut model = "unknown".to_string();
+    let mut acc_input: u64 = 0;
+    let mut acc_output: u64 = 0;
+    let mut acc_cost: f64 = 0.0;
+    let mut context_tokens: u64 = 0;
 
     // Scan the first 20 lines (session_meta / first turn_context) for the model.
     if let Ok(content) = tokio::fs::read_to_string(path).await {
@@ -181,6 +186,8 @@ async fn tail(
             break;
         }
 
+        let mut new_stats = false;
+
         if let Ok(file) = tokio::fs::File::open(path).await {
             let mut file = file;
             if file.seek(std::io::SeekFrom::Start(offset)).await.is_ok() {
@@ -220,13 +227,11 @@ async fn tail(
                                 }
                             }
                             if let Some(stats) = parse_token_count(&v, &model, config) {
-                                if tx
-                                    .send(AppEvent::SessionStats { session_id, stats })
-                                    .await
-                                    .is_err()
-                                {
-                                    return;
-                                }
+                                acc_input = stats.input_tokens;
+                                acc_output = stats.output_tokens;
+                                acc_cost = stats.total_cost_usd;
+                                context_tokens = stats.context_tokens;
+                                new_stats = true;
                             }
                         }
                         Err(_) => break,
@@ -235,6 +240,22 @@ async fn tail(
             }
         }
 
+        if new_stats {
+            let stats = TokenStats {
+                input_tokens: acc_input,
+                output_tokens: acc_output,
+                total_cost_usd: acc_cost,
+                context_tokens,
+            };
+            if tx
+                .send(AppEvent::SessionStats { session_id, stats })
+                .await
+                .is_err()
+            {
+                return;
+            }
+        }
+
         sleep(Duration::from_millis(500)).await;
     }
 }
@@ -299,7 +320,7 @@ mod tests {
 
         let config = crate::config::Config::default();
         let stats = parse_token_count(&v, "unknown", &config).unwrap();
-        assert_eq!(stats.input_tokens, 99975);
+        assert_eq!(stats.input_tokens, 41223); // fresh input: 99975 - 58752 cached
         assert_eq!(stats.output_tokens, 1358);
         assert_eq!(stats.context_tokens, 31619);
         // "unknown" model rate is 0.0, so cost should be 0.
@@ -435,4 +456,62 @@ mod tests {
         let dir = sessions_dir(Some("/opt/codex-personal")).unwrap();
         assert_eq!(dir, PathBuf::from("/opt/codex-personal/sessions"));
     }
+
+    fn make_codex_token_event(input: u64, cached: u64, output: u64) -> serde_json::Value {
+        serde_json::json!({
+            "type": "event_msg",
+            "payload": {
+                "type": "token_count",
+                "info": {
+                    "total_token_usage": {
+                        "input_tokens": input,
+                        "cached_input_tokens": cached,
+                        "output_tokens": output
+                    },
+                    "last_token_usage": {
+                        "input_tokens": input - cached
+                    }
+                }
+            }
+        })
+    }
+
+    #[test]
+    fn cumulative_token_counts_not_inflated_by_naive_sum() {
+        let entry1 = make_codex_token_event(10_000, 2_000, 3_000);
+        let entry2 = make_codex_token_event(30_000, 8_000, 8_000);
+        let entry3 = make_codex_token_event(50_000, 15_000, 12_000);
+
+        let config = Config::default();
+
+        let stats1 = parse_token_count(&entry1, "gpt-5", &config).unwrap();
+        let _stats2 = parse_token_count(&entry2, "gpt-5", &config).unwrap();
+        let stats3 = parse_token_count(&entry3, "gpt-5", &config).unwrap();
+
+        assert_eq!(stats1.input_tokens, 8_000); // 10k - 2k cached = 8k fresh
+        assert_eq!(stats3.input_tokens, 35_000); // 50k - 15k cached = 35k fresh
+        assert_eq!(stats3.output_tokens, 12_000);
+
+        let naive_sum_input = stats1.input_tokens + _stats2.input_tokens + stats3.input_tokens;
+        assert!(
+            naive_sum_input > stats3.input_tokens,
+            "naive sum ({}) exceeds correct total",
+            naive_sum_input
+        );
+    }
+
+    #[test]
+    fn cached_input_excluded_from_fresh_input_count() {
+        let v = make_codex_token_event(100_000, 60_000, 5_000);
+        let config = Config::default();
+        let stats = parse_token_count(&v, "gpt-5.4-mini", &config).unwrap();
+
+        assert_eq!(stats.input_tokens, 40_000); // only fresh (non-cached) input
+        assert_eq!(stats.output_tokens, 5_000);
+        assert!(stats.total_cost_usd > 0.0); // cost still includes cache pricing
+
+        let v2 = make_codex_token_event(10_000, 0, 500);
+        let stats2 = parse_token_count(&v2, "gpt-5.4-mini", &config).unwrap();
+        assert_eq!(stats2.input_tokens, 10_000);
+    }
 }
diff --git a/src/patterns.rs b/src/patterns.rs
index b307296..7bd2c5d 100644
--- a/src/patterns.rs
+++ b/src/patterns.rs
@@ -57,7 +57,9 @@ impl PatternMatcher {
             )
             .unwrap(),
             generic_waiting: Regex::new(r"\[y/n\]|\[Y/n\]|\(yes/no\)|Press Enter").unwrap(),
-            generic_error: Regex::new(r"(?i)error:|failed:|panic!|fatal:|command not found")
+            generic_error: Regex::new(
+                r"(?i)^error[:\[]|^failed[:\[]|^panic!|^[Ff]atal:|command not found",
+            )
                 .unwrap(),
 
             nctx_re: Regex::new(r"\bn_ctx\s*=\s*(\d+)").unwrap(),
@@ -96,7 +98,9 @@ impl PatternMatcher {
         if self.generic_waiting.is_match(line) {
             return Some(SessionState::Waiting);
         }
-        if self.generic_error.is_match(line) {
+        // Generic error detection only for shell/custom sessions — agents
+        // report ERROR via process exit, JSONL records, or IPC.
+        if matches!(base, BaseKind::Other) && self.generic_error.is_match(line) {
             return Some(SessionState::Error);
         }
         match base {
@@ -294,16 +298,47 @@ mod tests {
     fn generic_waiting_and_error_take_precedence_for_all_session_kinds() {
         let matcher = PatternMatcher::new();
 
+        // Generic waiting applies to all kinds
         for base in [BaseKind::Claude, BaseKind::Codex, BaseKind::Other] {
             assert_eq!(
                 matcher.infer_state("Press Enter to continue", base),
                 Some(SessionState::Waiting)
             );
-            assert_eq!(
-                matcher.infer_state("fatal: command not found", base),
-                Some(SessionState::Error)
-            );
         }
+
+        // Generic error detection only applies to Other (shell/custom)
+        assert_eq!(
+            matcher.infer_state("fatal: command not found", BaseKind::Other),
+            Some(SessionState::Error)
+        );
+
+        // Agents do NOT trigger Error from screen-scraped "error" text
+        assert_ne!(
+            matcher.infer_state("fatal: command not found", BaseKind::Claude),
+            Some(SessionState::Error)
+        );
+        assert_ne!(
+            matcher.infer_state("fatal: command not found", BaseKind::Codex),
+            Some(SessionState::Error)
+        );
+
+        // Codex discussing an error file is just Running, not Error
+        assert_eq!(
+            matcher.infer_state("fixed the error in ucp_tag_send.c", BaseKind::Codex),
+            Some(SessionState::Running)
+        );
+
+        // Shell session: anchored "Error:" at start of line -> Error
+        assert_eq!(
+            matcher.infer_state("Error: connection refused", BaseKind::Other),
+            Some(SessionState::Error)
+        );
+
+        // Shell session: bare "error" mid-line does NOT match
+        assert_ne!(
+            matcher.infer_state("no error here", BaseKind::Other),
+            Some(SessionState::Error)
+        );
     }
 
     #[test]
diff --git a/src/session.rs b/src/session.rs
index 7f4428e..7bf238b 100644
--- a/src/session.rs
+++ b/src/session.rs
@@ -92,6 +92,12 @@ impl SessionKind {
                 .unwrap_or(false)
     }
 
+    /// True for TUI-based agent sessions whose transcript is useful as scrollback.
+    /// Full-repaint dashboards (htop, btop) would spew garbage if enabled here.
+    pub fn captures_alt_scrollback(&self) -> bool {
+        matches!(self, SessionKind::Claude | SessionKind::Codex)
+    }
+
     pub(crate) fn custom_base_name_pub(&self) -> Option<&str> {
         self.custom_base_name()
     }
@@ -360,8 +366,51 @@ impl Session {
     /// for full-screen TUIs that repaint with byte-identical output.
     pub fn process_bytes(&mut self, data: &[u8]) -> bool {
         use std::hash::{Hash, Hasher};
+
+        // Capture top-line snapshot BEFORE processing, if this session kind
+        // supports alt-screen scrollback capture and we're on the alternate screen.
+        let prev_top =
+            if self.kind.captures_alt_scrollback() && self.screen.screen().alternate_screen() {
+                self.screen
+                    .screen()
+                    .contents()
+                    .lines()
+                    .next()
+                    .map(|s| s.trim_end().trim_end_matches('\t').to_string())
+            } else {
+                None
+            };
+
         self.bytes_since_last_tick += data.len();
         self.screen.process(data);
+
+        // After processing, check if content scrolled (top row changed)
+        if let Some(ref prev) = prev_top {
+            let current_top: Option<String> = self
+                .screen
+                .screen()
+                .contents()
+                .lines()
+                .next()
+                .map(|s| s.trim_end().trim_end_matches('\t').to_string());
+
+            // If the top line changed, content scrolled upward. The old top row
+            // was pushed off-screen — capture it for scrollback.
+            if let Some(cur) = current_top {
+                if cur != *prev && !prev.is_empty() {
+                    // Dedupe: skip if identical to last appended line
+                    let dominated = self.output_lines.back().is_some_and(|last| *last == *prev);
+                    if !dominated {
+                        self.push_output_line(prev.clone());
+                    }
+                }
+            } else {
+                // Screen is now empty (left alternate screen?), capture the old top
+                if !prev.is_empty() && self.output_lines.back().is_none_or(|last| *last != *prev) {
+                    self.push_output_line(prev.clone());
+                }
+            }
+        }
         // contents_formatted is exactly what the display path renders from, so
         // an unchanged hash means the next frame would be pixel-identical.
         let mut hasher = std::collections::hash_map::DefaultHasher::new();
@@ -965,4 +1014,64 @@ mod tests {
             );
         }
     }
+
+    #[test]
+    fn alt_screen_scrolled_lines_captured_in_output_lines() {
+        let mut s = Session::new(
+            1,
+            "codex".into(),
+            SessionKind::Codex,
+            "/tmp".into(),
+            5,
+            80,
+            100,
+        );
+        s.process_bytes(b"\x1b[?1049h\x1b[HLine A\r\nLine B\r\nLine C\r\nLine D\r\nLine E");
+        assert!(s.output_lines.is_empty());
+
+        // Scroll up by 1: Line A leaves the top, everything shifts up
+        s.process_bytes(b"\x1b[1S");
+
+        assert_eq!(s.output_lines.len(), 1);
+        assert_eq!(s.output_lines.front().unwrap(), "Line A");
+
+        // Scroll up by 1 more: Line B leaves the top
+        s.process_bytes(b"\x1b[1S");
+
+        assert_eq!(s.output_lines.len(), 2);
+        assert_eq!(s.output_lines.get(1).unwrap(), "Line B");
+    }
+
+    #[test]
+    fn alt_screen_scrollback_deduplicates_identical_repaint() {
+        let mut s = Session::new(
+            0,
+            "codex".into(),
+            SessionKind::Codex,
+            "/tmp".into(),
+            3,
+            80,
+            100,
+        );
+        s.process_bytes(b"\x1b[?1049h\x1b[HHeader\r\nBody 1\r\nFooter");
+
+        // Repaint with same top line (TUI re-rendering) — should NOT add to output_lines
+        s.process_bytes(b"\x1b[HHeader\r\nBody 1\r\nFooter");
+        assert!(s.output_lines.is_empty());
+    }
+
+    #[test]
+    fn shell_session_no_alt_scrollback() {
+        let mut s = Session::new(
+            0,
+            "shell".into(),
+            SessionKind::Shell,
+            "/tmp".into(),
+            3,
+            80,
+            100,
+        );
+        s.process_bytes(b"hello world\n");
+        assert!(s.output_lines.is_empty());
+    }
 }