commit

README.md

@@ -25,9 +25,9 @@ The full screen clears are 35x larger than incremental line clears - these are t
 claude-chill sits between your terminal and Claude Code:
 
 1. **Intercepts sync blocks** - Catches those massive atomic updates
-2. **Truncates output** - Sends only the last N lines (default: 100) to your terminal
+2. **Truncates full screen clears** - Only the 45% that are full redraws (94.5 KB avg) get truncated to the last N lines (default: 100). The 55% incremental updates (2.7 KB avg) pass through unchanged.
-3. **Preserves history** - Stores the full content in a buffer
+3. **Preserves history** - Accumulates content in a buffer. Clears on full screen clear, accumulates otherwise.
-4. **Enables lookback** - Press a key to dump the buffer, then scroll up
+4. **Enables lookback** - Press a key to pause Claude and view the full history buffer
 
 ## Installation
 
@@ -43,9 +43,16 @@ claude-chill -- claude --verbose   # Use -- for command flags
 claude-chill -l 50 -- claude       # Set max lines to 50
 ```
 
-## Lookback
+## Lookback Mode
 
-Press `Ctrl+Shift+J` to dump the history buffer to terminal. Scroll up to see it. The next update from Claude will resume normal display.
+Press `Ctrl+Shift+J` (or your configured key) to enter lookback mode:
+
+1. **Claude pauses** - Output from Claude is cached, input is blocked
+2. **History dumps** - The full history buffer is written to your terminal
+3. **Scroll freely** - Use your terminal's scrollback to review everything
+4. **Exit** - Press the lookback key again or `Ctrl+C` to resume
+
+When you exit lookback mode, any cached output is processed and the current state is displayed.
 
 ## Configuration
 

crates/claude-chill/src/proxy.rs

@@ -57,6 +57,8 @@ pub struct Proxy {
     history: LineBuffer,
     sync_buffer: Vec<u8>,
     in_sync_block: bool,
+    in_lookback_mode: bool,
+    lookback_cache: Vec<u8>,
     input_buffer: Vec<u8>,
     output_buffer: Vec<u8>,
     sync_start_finder: memmem::Finder<'static>,
@@ -114,6 +116,8 @@ impl Proxy {
             original_termios,
             sync_buffer: Vec::with_capacity(SYNC_BUFFER_CAPACITY),
             in_sync_block: false,
+            in_lookback_mode: false,
+            lookback_cache: Vec::new(),
             input_buffer: Vec::with_capacity(INPUT_BUFFER_CAPACITY),
             output_buffer: Vec::with_capacity(OUTPUT_BUFFER_CAPACITY),
             sync_start_finder: memmem::Finder::new(SYNC_START),
@@ -197,6 +201,11 @@ impl Proxy {
     }
 
     fn process_output(&mut self, data: &[u8], stdout_fd: i32) -> Result<()> {
+        if self.in_lookback_mode {
+            self.lookback_cache.extend_from_slice(data);
+            return Ok(());
+        }
+
         let mut pos = 0;
 
         while pos < data.len() {
@@ -261,36 +270,81 @@ impl Proxy {
 
     fn process_input(&mut self, data: &[u8], stdout_fd: i32) -> Result<()> {
         let master_fd = self.pty_master.as_raw_fd();
+
         for &byte in data {
+            if self.in_lookback_mode && byte == 0x03 {
+                self.input_buffer.clear();
+                self.exit_lookback_mode(stdout_fd)?;
+                continue;
+            }
+
             self.input_buffer.push(byte);
 
             if self.input_buffer.len() > self.config.lookback_sequence.len() {
                 let excess = self.input_buffer.len() - self.config.lookback_sequence.len();
+                if !self.in_lookback_mode {
                     write_all_raw(master_fd, &self.input_buffer[..excess])?;
+                }
                 self.input_buffer.drain(..excess);
             }
 
             if self.input_buffer == self.config.lookback_sequence {
-                self.enter_lookback_mode(stdout_fd)?;
                 self.input_buffer.clear();
+                if self.in_lookback_mode {
+                    self.exit_lookback_mode(stdout_fd)?;
+                } else {
+                    self.enter_lookback_mode()?;
+                }
             } else if !self
                 .config
                 .lookback_sequence
                 .starts_with(&self.input_buffer)
             {
+                if !self.in_lookback_mode {
                     write_all_raw(master_fd, &self.input_buffer)?;
+                }
                 self.input_buffer.clear();
             }
         }
         Ok(())
     }
 
-    fn enter_lookback_mode(&mut self, stdout_fd: i32) -> Result<()> {
+    fn enter_lookback_mode(&mut self) -> Result<()> {
-        let header = b"\x1b[7m--- LOOKBACK: scroll up to see history ---\x1b[0m\r\n";
+        self.in_lookback_mode = true;
-        write_all_raw(stdout_fd, header)?;
+        self.lookback_cache.clear();
+
         self.output_buffer.clear();
         self.history.append_all(&mut self.output_buffer);
+
+        let stdout_fd = io::stdout().as_raw_fd();
+        write_all_raw(stdout_fd, CLEAR_SCREEN)?;
+        write_all_raw(stdout_fd, CURSOR_HOME)?;
         write_all_raw(stdout_fd, &self.output_buffer)?;
+
+        let exit_msg = format!(
+            "\r\n\x1b[7m--- LOOKBACK MODE: press {} or Ctrl+C to exit ---\x1b[0m\r\n",
+            self.config.lookback_key
+        );
+        write_all_raw(stdout_fd, exit_msg.as_bytes())?;
+
+        Ok(())
+    }
+
+    fn exit_lookback_mode(&mut self, stdout_fd: i32) -> Result<()> {
+        self.in_lookback_mode = false;
+
+        let cached = std::mem::take(&mut self.lookback_cache);
+        if !cached.is_empty() {
+            self.process_output(&cached, stdout_fd)?;
+        }
+
+        self.output_buffer.clear();
+        self.history.append_all(&mut self.output_buffer);
+
+        write_all_raw(stdout_fd, CLEAR_SCREEN)?;
+        write_all_raw(stdout_fd, CURSOR_HOME)?;
+        write_all_raw(stdout_fd, &self.output_buffer)?;
+
         Ok(())
     }