Merge b0fad35dfb into 4ea31c1bc9

rust/Cargo.lock

@@ -2247,6 +2247,7 @@ dependencies = [
  "crossterm",
  "log",
  "mock-anthropic-service",
+ "nix",
  "plugins",
  "pulldown-cmark",
  "runtime",

rust/crates/runtime/src/conversation.rs

@@ -1,5 +1,9 @@
 use std::collections::BTreeMap;
 use std::fmt::{Display, Formatter};
+use std::sync::{
+    atomic::{AtomicBool, Ordering},
+    Arc,
+};
 
 use serde_json::{Map, Value};
 use telemetry::SessionTracer;
@@ -53,6 +57,41 @@ pub struct PromptCacheEvent {
     pub token_drop: u32,
 }
 
+/// Shared flag used to request graceful interruption of a running turn.
+///
+/// Cloning shares the underlying flag, mirroring
+/// [`HookAbortSignal`](crate::hooks::HookAbortSignal). An input listener
+/// (e.g. Esc or Ctrl+C handling in the CLI) sets the flag while the
+/// conversation loop and the streaming API client poll it at safe points.
+/// When the flag is observed, the turn winds down without treating the
+/// stop as a failure: pending tool calls receive synthesized error
+/// results so the session stays consistent, and [`TurnSummary`] reports
+/// `interrupted: true`.
+#[derive(Debug, Clone, Default)]
+pub struct TurnInterruptSignal {
+    interrupted: Arc<AtomicBool>,
+}
+
+impl TurnInterruptSignal {
+    #[must_use]
+    pub fn new() -> Self {
+        Self::default()
+    }
+
+    pub fn interrupt(&self) {
+        self.interrupted.store(true, Ordering::SeqCst);
+    }
+
+    #[must_use]
+    pub fn is_interrupted(&self) -> bool {
+        self.interrupted.load(Ordering::SeqCst)
+    }
+
+    pub fn reset(&self) {
+        self.interrupted.store(false, Ordering::SeqCst);
+    }
+}
+
 /// Minimal streaming API contract required by [`ConversationRuntime`].
 pub trait ApiClient {
     fn stream(&mut self, request: ApiRequest) -> Result<Vec<AssistantEvent>, RuntimeError>;
@@ -118,6 +157,7 @@ pub struct TurnSummary {
     pub iterations: usize,
     pub usage: TokenUsage,
     pub auto_compaction: Option<AutoCompactionEvent>,
+    pub interrupted: bool,
 }
 
 /// Details about automatic session compaction applied during a turn.
@@ -138,6 +178,7 @@ pub struct ConversationRuntime<C, T> {
     hook_runner: HookRunner,
     auto_compaction_input_tokens_threshold: u32,
     hook_abort_signal: HookAbortSignal,
+    turn_interrupt_signal: TurnInterruptSignal,
     hook_progress_reporter: Option<Box<dyn HookProgressReporter>>,
     session_tracer: Option<SessionTracer>,
 }
@@ -187,6 +228,7 @@ where
             hook_runner: HookRunner::from_feature_config(feature_config),
             auto_compaction_input_tokens_threshold: auto_compaction_threshold_from_env(),
             hook_abort_signal: HookAbortSignal::default(),
+            turn_interrupt_signal: TurnInterruptSignal::default(),
             hook_progress_reporter: None,
             session_tracer: None,
         }
@@ -217,6 +259,15 @@ where
         self
     }
 
+    #[must_use]
+    pub fn with_turn_interrupt_signal(
+        mut self,
+        turn_interrupt_signal: TurnInterruptSignal,
+    ) -> Self {
+        self.turn_interrupt_signal = turn_interrupt_signal;
+        self
+    }
+
     #[must_use]
     pub fn with_hook_progress_reporter(
         mut self,
@@ -350,8 +401,14 @@ where
         let mut prompt_cache_events = Vec::new();
         let mut iterations = 0;
         let mut auto_compaction = None;
+        let mut interrupted = false;
 
         loop {
+            if self.turn_interrupt_signal.is_interrupted() {
+                self.record_turn_interrupted(iterations, "before_request");
+                interrupted = true;
+                break;
+            }
             iterations += 1;
             if iterations > self.max_iterations {
                 let error = RuntimeError::new(
@@ -368,6 +425,14 @@ where
             let events = match self.api_client.stream(request) {
                 Ok(events) => events,
                 Err(error) => {
+                    if self.turn_interrupt_signal.is_interrupted() {
+                        // The client aborted because the user interrupted the
+                        // turn; any partial response is discarded and the stop
+                        // is reported as an interruption rather than a failure.
+                        self.record_turn_interrupted(iterations, "during_request");
+                        interrupted = true;
+                        break;
+                    }
                     self.record_turn_failed(iterations, &error);
                     return Err(error);
                 }
@@ -416,6 +481,25 @@ where
             }
 
             for (tool_use_id, tool_name, input) in pending_tool_uses {
+                if interrupted || self.turn_interrupt_signal.is_interrupted() {
+                    // Every pending tool_use must still receive a tool_result
+                    // so the session stays valid for the next request.
+                    if !interrupted {
+                        self.record_turn_interrupted(iterations, "before_tool");
+                        interrupted = true;
+                    }
+                    let result_message = ConversationMessage::tool_result(
+                        tool_use_id,
+                        tool_name,
+                        "Interrupted by user before this tool could run.",
+                        true,
+                    );
+                    self.session
+                        .push_message(result_message.clone())
+                        .map_err(|error| RuntimeError::new(error.to_string()))?;
+                    tool_results.push(result_message);
+                    continue;
+                }
                 let pre_hook_result = self.run_pre_tool_use_hook(&tool_name, &input);
                 let effective_input = pre_hook_result
                     .updated_input()
@@ -515,6 +599,10 @@ where
                 self.record_tool_finished(iterations, &result_message);
                 tool_results.push(result_message);
             }
+
+            if interrupted {
+                break;
+            }
         }
 
         let summary = TurnSummary {
@@ -524,8 +612,11 @@ where
             iterations,
             usage: self.usage_tracker.cumulative_usage(),
             auto_compaction,
+            interrupted,
         };
-        self.record_turn_completed(&summary);
+        if !interrupted {
+            self.record_turn_completed(&summary);
+        }
 
         Ok(summary)
     }
@@ -689,6 +780,17 @@ where
         session_tracer.record("turn_completed", attributes);
     }
 
+    fn record_turn_interrupted(&self, iteration: usize, phase: &str) {
+        let Some(session_tracer) = &self.session_tracer else {
+            return;
+        };
+
+        let mut attributes = Map::new();
+        attributes.insert("iteration".to_string(), Value::from(iteration as u64));
+        attributes.insert("phase".to_string(), Value::String(phase.to_string()));
+        session_tracer.record("turn_interrupted", attributes);
+    }
+
     fn record_turn_failed(&self, iteration: usize, error: &RuntimeError) {
         let Some(session_tracer) = &self.session_tracer else {
             return;
@@ -850,7 +952,8 @@ mod tests {
     use super::{
         build_assistant_message, parse_auto_compaction_threshold, ApiClient, ApiRequest,
         AssistantEvent, AutoCompactionEvent, ConversationRuntime, PromptCacheEvent, RuntimeError,
-        StaticToolExecutor, ToolExecutor, DEFAULT_AUTO_COMPACTION_INPUT_TOKENS_THRESHOLD,
+        StaticToolExecutor, ToolExecutor, TurnInterruptSignal,
+        DEFAULT_AUTO_COMPACTION_INPUT_TOKENS_THRESHOLD,
     };
     use crate::compact::CompactionConfig;
     use crate::config::{RuntimeFeatureConfig, RuntimeHookConfig};
@@ -1875,4 +1978,165 @@ mod tests {
         // then
         assert_eq!(error.to_string(), "upstream failed");
     }
+
+    #[test]
+    fn interrupt_before_first_request_skips_the_api_call() {
+        struct UnreachableApi;
+
+        impl ApiClient for UnreachableApi {
+            fn stream(
+                &mut self,
+                _request: ApiRequest,
+            ) -> Result<Vec<AssistantEvent>, RuntimeError> {
+                unreachable!("interrupted turn must not reach the API")
+            }
+        }
+
+        // given
+        let interrupt = TurnInterruptSignal::new();
+        interrupt.interrupt();
+        let mut runtime = ConversationRuntime::new(
+            Session::new(),
+            UnreachableApi,
+            StaticToolExecutor::new(),
+            PermissionPolicy::new(PermissionMode::DangerFullAccess),
+            vec!["system".to_string()],
+        )
+        .with_turn_interrupt_signal(interrupt);
+
+        // when
+        let summary = runtime
+            .run_turn("hello", None)
+            .expect("interruption should not be reported as a failure");
+
+        // then
+        assert!(summary.interrupted);
+        assert_eq!(summary.iterations, 0);
+        assert!(summary.assistant_messages.is_empty());
+        assert!(summary.tool_results.is_empty());
+        assert_eq!(summary.auto_compaction, None);
+        assert_eq!(runtime.session().messages.len(), 1);
+        assert_eq!(runtime.session().messages[0].role, MessageRole::User);
+    }
+
+    #[test]
+    fn interrupt_after_stream_synthesizes_results_for_pending_tools() {
+        struct ToolUseApi {
+            interrupt: TurnInterruptSignal,
+        }
+
+        impl ApiClient for ToolUseApi {
+            fn stream(
+                &mut self,
+                _request: ApiRequest,
+            ) -> Result<Vec<AssistantEvent>, RuntimeError> {
+                // Simulate the user pressing Esc while the response streams in.
+                self.interrupt.interrupt();
+                Ok(vec![
+                    AssistantEvent::TextDelta("Running the tool.".to_string()),
+                    AssistantEvent::ToolUse {
+                        id: "tool-1".to_string(),
+                        name: "add".to_string(),
+                        input: "2,2".to_string(),
+                    },
+                    AssistantEvent::MessageStop,
+                ])
+            }
+        }
+
+        // given
+        let interrupt = TurnInterruptSignal::new();
+        let mut runtime = ConversationRuntime::new(
+            Session::new(),
+            ToolUseApi {
+                interrupt: interrupt.clone(),
+            },
+            StaticToolExecutor::new()
+                .register("add", |_input| panic!("interrupted tool must not run")),
+            PermissionPolicy::new(PermissionMode::DangerFullAccess),
+            vec!["system".to_string()],
+        )
+        .with_turn_interrupt_signal(interrupt);
+
+        // when
+        let summary = runtime
+            .run_turn("what is 2 + 2?", None)
+            .expect("interruption should not be reported as a failure");
+
+        // then
+        assert!(summary.interrupted);
+        assert_eq!(summary.iterations, 1);
+        assert_eq!(summary.assistant_messages.len(), 1);
+        assert_eq!(summary.tool_results.len(), 1);
+        assert!(matches!(
+            &summary.tool_results[0].blocks[0],
+            ContentBlock::ToolResult {
+                tool_use_id,
+                is_error: true,
+                output,
+                ..
+            } if tool_use_id == "tool-1" && output.contains("Interrupted by user")
+        ));
+        // user text, assistant tool_use, synthesized tool_result
+        assert_eq!(runtime.session().messages.len(), 3);
+        assert!(matches!(
+            runtime.session().messages[2].blocks[0],
+            ContentBlock::ToolResult { is_error: true, .. }
+        ));
+    }
+
+    #[test]
+    fn stream_error_during_interrupt_is_reported_as_interruption() {
+        struct AbortedApi {
+            interrupt: TurnInterruptSignal,
+        }
+
+        impl ApiClient for AbortedApi {
+            fn stream(
+                &mut self,
+                _request: ApiRequest,
+            ) -> Result<Vec<AssistantEvent>, RuntimeError> {
+                // Simulate the streaming client aborting the connection after
+                // observing the interrupt flag mid-stream.
+                self.interrupt.interrupt();
+                Err(RuntimeError::new("request aborted"))
+            }
+        }
+
+        // given
+        let sink = Arc::new(MemoryTelemetrySink::default());
+        let tracer = SessionTracer::new("session-interrupt", sink.clone());
+        let interrupt = TurnInterruptSignal::new();
+        let mut runtime = ConversationRuntime::new(
+            Session::new(),
+            AbortedApi {
+                interrupt: interrupt.clone(),
+            },
+            StaticToolExecutor::new(),
+            PermissionPolicy::new(PermissionMode::DangerFullAccess),
+            vec!["system".to_string()],
+        )
+        .with_turn_interrupt_signal(interrupt)
+        .with_session_tracer(tracer);
+
+        // when
+        let summary = runtime
+            .run_turn("hello", None)
+            .expect("interrupt-driven aborts should not surface as errors");
+
+        // then
+        assert!(summary.interrupted);
+        assert!(summary.assistant_messages.is_empty());
+        let trace_names = sink
+            .events()
+            .iter()
+            .filter_map(|event| match event {
+                TelemetryEvent::SessionTrace(trace) => Some(trace.name.clone()),
+                _ => None,
+            })
+            .collect::<Vec<_>>();
+        assert!(trace_names.iter().any(|name| name == "turn_interrupted"));
+        assert!(!trace_names.iter().any(|name| name == "turn_failed"));
+        assert!(!trace_names.iter().any(|name| name == "turn_completed"));
+    }
 }

rust/crates/runtime/src/lib.rs

@@ -82,7 +82,7 @@ pub use config_validate::{
 pub use conversation::{
     auto_compaction_threshold_from_env, ApiClient, ApiRequest, AssistantEvent, AutoCompactionEvent,
     ConversationRuntime, PromptCacheEvent, RuntimeError, StaticToolExecutor, ToolError,
-    ToolExecutor, TurnSummary,
+    ToolExecutor, TurnInterruptSignal, TurnSummary,
 };
 pub use file_ops::{
     edit_file, edit_file_in_workspace, glob_search, glob_search_in_workspace, grep_search,

rust/crates/runtime/src/worker_boot.rs

@@ -34,6 +34,9 @@ pub enum WorkerStatus {
     ToolPermissionRequired,
     ReadyForPrompt,
     Running,
+    /// The user stopped the turn mid-run (e.g. Esc or Ctrl+C); the worker
+    /// is back at the prompt with the session intact.
+    Interrupted,
     Finished,
     Failed,
 }
@@ -46,6 +49,7 @@ impl std::fmt::Display for WorkerStatus {
             Self::ToolPermissionRequired => write!(f, "tool_permission_required"),
             Self::ReadyForPrompt => write!(f, "ready_for_prompt"),
             Self::Running => write!(f, "running"),
+            Self::Interrupted => write!(f, "interrupted"),
             Self::Finished => write!(f, "finished"),
             Self::Failed => write!(f, "failed"),
         }
@@ -82,6 +86,7 @@ pub enum WorkerEventKind {
     PromptMisdelivery,
     PromptReplayArmed,
     Running,
+    Interrupted,
     Restarted,
     Finished,
     Failed,
@@ -1461,6 +1466,23 @@ mod tests {
     use std::fs;
     use std::process::Command;
 
+    #[test]
+    fn interrupted_status_serializes_and_displays_as_snake_case() {
+        assert_eq!(WorkerStatus::Interrupted.to_string(), "interrupted");
+        assert_eq!(
+            serde_json::to_string(&WorkerStatus::Interrupted).expect("should serialize"),
+            "\"interrupted\""
+        );
+        assert_eq!(
+            serde_json::from_str::<WorkerStatus>("\"interrupted\"").expect("should deserialize"),
+            WorkerStatus::Interrupted
+        );
+        assert_eq!(
+            serde_json::to_string(&WorkerEventKind::Interrupted).expect("should serialize"),
+            "\"interrupted\""
+        );
+    }
+
     #[test]
     fn allowlisted_trust_prompt_auto_resolves_then_reaches_ready_state() {
         let registry = WorkerRegistry::new();

rust/crates/rusty-claude-cli/Cargo.toml

@@ -24,6 +24,8 @@ tokio = { version = "1", features = ["rt-multi-thread", "signal", "time"] }
 tools = { path = "../tools" }
 log = "0.4"
 
+[target.'cfg(unix)'.dependencies]
+nix = { version = "0.29", features = ["term", "poll"] }
 
 [lints]
 workspace = true

rust/crates/rusty-claude-cli/src/interrupt.rs

@@ -0,0 +1,280 @@
+//! Esc-key interruption for running turns.
+//!
+//! While a turn runs, the main thread is blocked inside the conversation
+//! loop, so rustyline is not reading the keyboard. This module spawns a
+//! listener thread that switches stdin to a minimal non-canonical mode
+//! (line buffering and echo off; signal handling and output processing
+//! stay enabled, unlike full raw mode) and watches for a lone Escape
+//! byte. When one arrives it trips the shared [`TurnInterruptSignal`],
+//! which the conversation loop and the streaming API client poll to wind
+//! the turn down gracefully.
+//!
+//! Permission prompts read whole lines from stdin mid-turn, so stdin
+//! ownership is coordinated through [`StdinPromptGate`]: while a prompt
+//! holds a lease, the listener restores canonical mode and stops
+//! consuming bytes.
+
+use std::io::IsTerminal;
+use std::sync::atomic::{AtomicBool, Ordering};
+use std::sync::{Arc, Mutex, PoisonError};
+use std::thread::JoinHandle;
+
+use runtime::TurnInterruptSignal;
+
+/// Terminal-mode bookkeeping guarded by the gate mutex. `saved` holds the
+/// canonical-mode termios while non-canonical mode is active.
+#[derive(Default)]
+struct TtyMode {
+    #[cfg(unix)]
+    saved: Option<nix::sys::termios::Termios>,
+}
+
+#[derive(Default)]
+struct GateState {
+    /// True while a permission prompt owns stdin.
+    busy: AtomicBool,
+    /// Tells the listener thread to exit at the end of the turn.
+    stop: AtomicBool,
+    /// Serializes stdin reads and terminal-mode flips.
+    mode: Mutex<TtyMode>,
+}
+
+/// Classification of one chunk of bytes read from the terminal.
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+enum EscClassification {
+    /// A bare ESC byte: the user pressed the Escape key.
+    LoneEscape,
+    /// ESC followed by more bytes: the prefix of a terminal escape
+    /// sequence such as an arrow or function key.
+    EscapeSequence,
+    /// Anything else (regular type-ahead, control characters, ...).
+    Other,
+}
+
+#[cfg_attr(not(unix), allow(dead_code))]
+fn classify_escape_chunk(bytes: &[u8]) -> EscClassification {
+    match bytes {
+        [0x1b] => EscClassification::LoneEscape,
+        [0x1b, ..] => EscClassification::EscapeSequence,
+        _ => EscClassification::Other,
+    }
+}
+
+/// Hands exclusive stdin ownership to interactive prompts while the
+/// Esc listener is running.
+#[derive(Clone)]
+pub struct StdinPromptGate {
+    shared: Arc<GateState>,
+}
+
+impl StdinPromptGate {
+    /// Takes stdin away from the Esc listener for the lifetime of the
+    /// returned lease: the terminal returns to canonical mode so a
+    /// line-based prompt (e.g. the permission approval prompt) behaves
+    /// normally. Listening resumes when the lease is dropped.
+    pub fn lease(&self) -> StdinPromptLease<'_> {
+        self.shared.busy.store(true, Ordering::SeqCst);
+        // Wait for the listener's current poll cycle to release the
+        // terminal, then restore canonical mode for line input.
+        #[allow(unused_mut)]
+        let mut mode = self
+            .shared
+            .mode
+            .lock()
+            .unwrap_or_else(PoisonError::into_inner);
+        #[cfg(unix)]
+        tty::restore(&mut mode);
+        drop(mode);
+        StdinPromptLease {
+            shared: &self.shared,
+        }
+    }
+}
+
+/// RAII lease returned by [`StdinPromptGate::lease`].
+pub struct StdinPromptLease<'a> {
+    shared: &'a GateState,
+}
+
+impl Drop for StdinPromptLease<'_> {
+    fn drop(&mut self) {
+        self.shared.busy.store(false, Ordering::SeqCst);
+    }
+}
+
+/// Background listener that maps a lone Esc keypress to
+/// [`TurnInterruptSignal::interrupt`].
+pub struct EscapeInterruptMonitor {
+    shared: Arc<GateState>,
+    join_handle: Option<JoinHandle<()>>,
+}
+
+impl EscapeInterruptMonitor {
+    /// Spawns the listener for the duration of one turn. Returns `None`
+    /// when stdin is not an interactive terminal or the platform does not
+    /// support terminal-mode switching; Ctrl+C interruption still works
+    /// in those cases.
+    pub fn spawn(signal: TurnInterruptSignal) -> Option<(Self, StdinPromptGate)> {
+        if !std::io::stdin().is_terminal() {
+            return None;
+        }
+
+        #[cfg(not(unix))]
+        {
+            let _ = signal;
+            None
+        }
+
+        #[cfg(unix)]
+        {
+            let shared = Arc::new(GateState::default());
+            let thread_shared = Arc::clone(&shared);
+            let join_handle = std::thread::spawn(move || listener_loop(&thread_shared, &signal));
+            let gate = StdinPromptGate {
+                shared: Arc::clone(&shared),
+            };
+            Some((
+                Self {
+                    shared,
+                    join_handle: Some(join_handle),
+                },
+                gate,
+            ))
+        }
+    }
+
+    /// Stops the listener and restores the terminal before control
+    /// returns to the line editor.
+    pub fn stop(mut self) {
+        self.shared.stop.store(true, Ordering::SeqCst);
+        if let Some(join_handle) = self.join_handle.take() {
+            let _ = join_handle.join();
+        }
+    }
+}
+
+#[cfg(unix)]
+fn listener_loop(shared: &GateState, signal: &TurnInterruptSignal) {
+    let mut buffer = [0u8; 64];
+
+    while !shared.stop.load(Ordering::SeqCst) {
+        if shared.busy.load(Ordering::SeqCst) {
+            std::thread::sleep(std::time::Duration::from_millis(25));
+            continue;
+        }
+
+        let mut mode = shared.mode.lock().unwrap_or_else(PoisonError::into_inner);
+        if shared.busy.load(Ordering::SeqCst) || shared.stop.load(Ordering::SeqCst) {
+            continue;
+        }
+        if !tty::enable_noncanonical(&mut mode) {
+            // Terminal refused the mode switch; Esc support is
+            // unavailable for this turn but Ctrl+C still works.
+            return;
+        }
+        if !tty::wait_readable(100) {
+            continue;
+        }
+
+        let count = tty::read_pending(&mut buffer);
+        if classify_escape_chunk(&buffer[..count]) == EscClassification::LoneEscape {
+            // A slow terminal may split an escape sequence across reads;
+            // only treat ESC as the Esc key when nothing follows it.
+            if tty::wait_readable(50) {
+                let _ = tty::read_pending(&mut buffer);
+                continue;
+            }
+            signal.interrupt();
+        }
+        // Other bytes are intentionally swallowed: type-ahead is not
+        // preserved while a turn is running.
+    }
+
+    let mut mode = shared.mode.lock().unwrap_or_else(PoisonError::into_inner);
+    tty::restore(&mut mode);
+}
+
+#[cfg(unix)]
+mod tty {
+    use std::os::fd::{AsFd, AsRawFd};
+
+    use nix::poll::{poll, PollFd, PollFlags, PollTimeout};
+    use nix::sys::termios::{self, LocalFlags, SetArg, SpecialCharacterIndices};
+
+    use super::TtyMode;
+
+    /// Disables line buffering and echo while leaving signal generation
+    /// (ISIG) and output post-processing (OPOST) untouched, so Ctrl+C and
+    /// streamed output keep working. No-op when already active.
+    pub(super) fn enable_noncanonical(mode: &mut TtyMode) -> bool {
+        if mode.saved.is_some() {
+            return true;
+        }
+        let stdin = std::io::stdin();
+        let Ok(saved) = termios::tcgetattr(&stdin) else {
+            return false;
+        };
+        let mut noncanonical = saved.clone();
+        noncanonical.local_flags &= !(LocalFlags::ICANON | LocalFlags::ECHO);
+        noncanonical.control_chars[SpecialCharacterIndices::VMIN as usize] = 0;
+        noncanonical.control_chars[SpecialCharacterIndices::VTIME as usize] = 0;
+        if termios::tcsetattr(&stdin, SetArg::TCSANOW, &noncanonical).is_err() {
+            return false;
+        }
+        mode.saved = Some(saved);
+        true
+    }
+
+    pub(super) fn restore(mode: &mut TtyMode) {
+        if let Some(saved) = mode.saved.take() {
+            let _ = termios::tcsetattr(std::io::stdin(), SetArg::TCSANOW, &saved);
+        }
+    }
+
+    pub(super) fn wait_readable(timeout_ms: u16) -> bool {
+        let stdin = std::io::stdin();
+        let mut fds = [PollFd::new(stdin.as_fd(), PollFlags::POLLIN)];
+        matches!(poll(&mut fds, PollTimeout::from(timeout_ms)), Ok(ready) if ready > 0)
+            && fds[0]
+                .revents()
+                .is_some_and(|revents| revents.contains(PollFlags::POLLIN))
+    }
+
+    pub(super) fn read_pending(buffer: &mut [u8]) -> usize {
+        nix::unistd::read(std::io::stdin().as_raw_fd(), buffer).unwrap_or(0)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::{classify_escape_chunk, EscClassification};
+
+    #[test]
+    fn lone_escape_byte_is_the_esc_key() {
+        assert_eq!(
+            classify_escape_chunk(&[0x1b]),
+            EscClassification::LoneEscape
+        );
+    }
+
+    #[test]
+    fn escape_followed_by_more_bytes_is_a_sequence() {
+        // Up arrow: ESC [ A
+        assert_eq!(
+            classify_escape_chunk(&[0x1b, 0x5b, 0x41]),
+            EscClassification::EscapeSequence
+        );
+        // Alt+f style: ESC f
+        assert_eq!(
+            classify_escape_chunk(&[0x1b, b'f']),
+            EscClassification::EscapeSequence
+        );
+    }
+
+    #[test]
+    fn regular_bytes_are_ignored() {
+        assert_eq!(classify_escape_chunk(b"hello"), EscClassification::Other);
+        assert_eq!(classify_escape_chunk(&[]), EscClassification::Other);
+        assert_eq!(classify_escape_chunk(&[0x03]), EscClassification::Other);
+    }
+}

rust/crates/rusty-claude-cli/src/main.rs

@@ -16,6 +16,7 @@
 )]
 mod init;
 mod input;
+mod interrupt;
 mod render;
 mod setup_wizard;
 
@@ -7194,6 +7195,18 @@ impl BuiltRuntime {
         self
     }
 
+    fn with_turn_interrupt_signal(mut self, signal: runtime::TurnInterruptSignal) -> Self {
+        let mut runtime = self
+            .runtime
+            .take()
+            .expect("runtime should exist before installing turn interrupt signal");
+        runtime
+            .api_client_mut()
+            .set_turn_interrupt_signal(signal.clone());
+        self.runtime = Some(runtime.with_turn_interrupt_signal(signal));
+        self
+    }
+
     fn shutdown_plugins(&mut self) -> Result<(), Box<dyn std::error::Error>> {
         if self.plugins_active {
             self.plugin_registry.shutdown()?;
@@ -7576,7 +7589,10 @@ struct HookAbortMonitor {
 }
 
 impl HookAbortMonitor {
-    fn spawn(abort_signal: runtime::HookAbortSignal) -> Self {
+    fn spawn(
+        abort_signal: runtime::HookAbortSignal,
+        turn_interrupt_signal: runtime::TurnInterruptSignal,
+    ) -> Self {
         Self::spawn_with_waiter(abort_signal, move |stop_rx, abort_signal| {
             let Ok(runtime) = tokio::runtime::Builder::new_current_thread()
                 .enable_all()
@@ -7593,7 +7609,11 @@ impl HookAbortMonitor {
                 tokio::select! {
                     result = tokio::signal::ctrl_c() => {
                         if result.is_ok() {
+                            // Ctrl+C stops the whole turn, not just running
+                            // hooks: the conversation loop and the streaming
+                            // client both poll the turn interrupt signal.
                             abort_signal.abort();
+                            turn_interrupt_signal.interrupt();
                         }
                     }
                     _ = wait_for_stop => {}
@@ -7698,7 +7718,7 @@ impl LiveCli {
   \x1b[2mDirectory\x1b[0m        {}\n\
   \x1b[2mSession\x1b[0m          {}\n\
   \x1b[2mAuto-save\x1b[0m        {}\n\n\
-  Type \x1b[1m/help\x1b[0m for commands · \x1b[1m/status\x1b[0m for live context · \x1b[2m/resume latest\x1b[0m jumps back to the newest session · \x1b[1m/diff\x1b[0m then \x1b[1m/commit\x1b[0m to ship · \x1b[2mTab\x1b[0m for workflow completions · \x1b[2mShift+Enter\x1b[0m for newline",
+  Type \x1b[1m/help\x1b[0m for commands · \x1b[1m/status\x1b[0m for live context · \x1b[2m/resume latest\x1b[0m jumps back to the newest session · \x1b[1m/diff\x1b[0m then \x1b[1m/commit\x1b[0m to ship · \x1b[2mTab\x1b[0m for workflow completions · \x1b[2mShift+Enter\x1b[0m for newline · \x1b[2mEsc\x1b[0m interrupts a running turn",
             self.model,
             self.permission_mode.as_str(),
             git_branch,
@@ -7723,8 +7743,12 @@ impl LiveCli {
     fn prepare_turn_runtime(
         &self,
         emit_output: bool,
-    ) -> Result<(BuiltRuntime, HookAbortMonitor), Box<dyn std::error::Error>> {
+    ) -> Result<
+        (BuiltRuntime, HookAbortMonitor, runtime::TurnInterruptSignal),
+        Box<dyn std::error::Error>,
+    > {
         let hook_abort_signal = runtime::HookAbortSignal::new();
+        let turn_interrupt_signal = runtime::TurnInterruptSignal::new();
         let runtime = build_runtime(
             self.runtime.session().clone(),
             &self.session.id,
@@ -7736,10 +7760,12 @@ impl LiveCli {
             self.permission_mode,
             None,
         )?
-        .with_hook_abort_signal(hook_abort_signal.clone());
+        .with_hook_abort_signal(hook_abort_signal.clone())
-        let hook_abort_monitor = HookAbortMonitor::spawn(hook_abort_signal);
+        .with_turn_interrupt_signal(turn_interrupt_signal.clone());
+        let hook_abort_monitor =
+            HookAbortMonitor::spawn(hook_abort_signal, turn_interrupt_signal.clone());
 
-        Ok((runtime, hook_abort_monitor))
+        Ok((runtime, hook_abort_monitor, turn_interrupt_signal))
     }
 
     fn replace_runtime(&mut self, runtime: BuiltRuntime) -> Result<(), Box<dyn std::error::Error>> {
@@ -7749,22 +7775,41 @@ impl LiveCli {
     }
 
     fn run_turn(&mut self, input: &str) -> Result<(), Box<dyn std::error::Error>> {
-        let (mut runtime, hook_abort_monitor) = self.prepare_turn_runtime(true)?;
+        let (mut runtime, hook_abort_monitor, turn_interrupt_signal) =
+            self.prepare_turn_runtime(true)?;
+        let mut permission_prompter = CliPermissionPrompter::new(self.permission_mode);
+        let mut escape_monitor = None;
+        if let Some((monitor, stdin_gate)) =
+            interrupt::EscapeInterruptMonitor::spawn(turn_interrupt_signal)
+        {
+            permission_prompter = permission_prompter.with_stdin_gate(stdin_gate);
+            escape_monitor = Some(monitor);
+        }
         let mut spinner = Spinner::new();
         let mut stdout = io::stdout();
         spinner.tick(
-            "🦀 Thinking...",
+            if escape_monitor.is_some() {
+                "🦀 Thinking... (esc to interrupt)"
+            } else {
+                "🦀 Thinking..."
+            },
             TerminalRenderer::new().color_theme(),
             &mut stdout,
         )?;
-        let mut permission_prompter = CliPermissionPrompter::new(self.permission_mode);
         let result = runtime.run_turn(input, Some(&mut permission_prompter));
+        if let Some(monitor) = escape_monitor {
+            monitor.stop();
+        }
         hook_abort_monitor.stop();
         match result {
             Ok(summary) => {
                 self.replace_runtime(runtime)?;
                 spinner.finish(
-                    "✨ Done",
+                    if summary.interrupted {
+                        "⏹ Interrupted"
+                    } else {
+                        "✨ Done"
+                    },
                     TerminalRenderer::new().color_theme(),
                     &mut stdout,
                 )?;
@@ -7895,7 +7940,7 @@ impl LiveCli {
                         *self.runtime.session_mut() = result.compacted_session.clone();
 
                         // Build a new runtime with the compacted session and retry
-                        let (mut new_runtime, hook_abort_monitor) =
+                        let (mut new_runtime, hook_abort_monitor, _turn_interrupt_signal) =
                             self.prepare_turn_runtime(true)?;
                         drop(hook_abort_monitor);
 
@@ -7985,7 +8030,8 @@ impl LiveCli {
     }
 
     fn run_prompt_compact(&mut self, input: &str) -> Result<(), Box<dyn std::error::Error>> {
-        let (mut runtime, hook_abort_monitor) = self.prepare_turn_runtime(false)?;
+        let (mut runtime, hook_abort_monitor, _turn_interrupt_signal) =
+            self.prepare_turn_runtime(false)?;
         let mut permission_prompter = CliPermissionPrompter::new(self.permission_mode);
         let result = runtime.run_turn(input, Some(&mut permission_prompter));
         hook_abort_monitor.stop();
@@ -7998,7 +8044,8 @@ impl LiveCli {
     }
 
     fn run_prompt_compact_json(&mut self, input: &str) -> Result<(), Box<dyn std::error::Error>> {
-        let (mut runtime, hook_abort_monitor) = self.prepare_turn_runtime(false)?;
+        let (mut runtime, hook_abort_monitor, _turn_interrupt_signal) =
+            self.prepare_turn_runtime(false)?;
         let mut permission_prompter = CliPermissionPrompter::new(self.permission_mode);
         let result = runtime.run_turn(input, Some(&mut permission_prompter));
         hook_abort_monitor.stop();
@@ -8023,7 +8070,8 @@ impl LiveCli {
     }
 
     fn run_prompt_json(&mut self, input: &str) -> Result<(), Box<dyn std::error::Error>> {
-        let (mut runtime, hook_abort_monitor) = self.prepare_turn_runtime(false)?;
+        let (mut runtime, hook_abort_monitor, _turn_interrupt_signal) =
+            self.prepare_turn_runtime(false)?;
         let mut permission_prompter = CliPermissionPrompter::new(self.permission_mode);
         let result = runtime.run_turn(input, Some(&mut permission_prompter));
         hook_abort_monitor.stop();
@@ -9495,6 +9543,7 @@ fn render_repl_help() -> String {
         "  Ctrl-R               Reverse-search prompt history".to_string(),
         "  Tab                  Complete commands, modes, and recent sessions".to_string(),
         "  Ctrl-C               Clear input (or exit on empty prompt)".to_string(),
+        "  Esc                  Interrupt the running turn".to_string(),
         "  Shift+Enter/Ctrl+J   Insert a newline".to_string(),
         "  Auto-save            .claw/sessions/<workspace-fingerprint>/<session-id>.jsonl"
             .to_string(),
@@ -12478,11 +12527,20 @@ impl runtime::HookProgressReporter for CliHookProgressReporter {
 
 struct CliPermissionPrompter {
     current_mode: PermissionMode,
+    stdin_gate: Option<interrupt::StdinPromptGate>,
 }
 
 impl CliPermissionPrompter {
     fn new(current_mode: PermissionMode) -> Self {
-        Self { current_mode }
+        Self {
+            current_mode,
+            stdin_gate: None,
+        }
+    }
+
+    fn with_stdin_gate(mut self, stdin_gate: interrupt::StdinPromptGate) -> Self {
+        self.stdin_gate = Some(stdin_gate);
+        self
     }
 }
 
@@ -12491,6 +12549,12 @@ impl runtime::PermissionPrompter for CliPermissionPrompter {
         &mut self,
         request: &runtime::PermissionRequest,
     ) -> runtime::PermissionPromptDecision {
+        // Take stdin back from the Esc listener (restoring canonical
+        // mode) for the duration of this line-based prompt.
+        let _stdin_lease = self
+            .stdin_gate
+            .as_ref()
+            .map(interrupt::StdinPromptGate::lease);
         println!();
         println!("Permission approval required");
         println!("  Tool             {}", request.tool_name);
@@ -12542,6 +12606,7 @@ struct AnthropicRuntimeClient {
     tool_registry: GlobalToolRegistry,
     progress_reporter: Option<InternalPromptProgressReporter>,
     reasoning_effort: Option<String>,
+    turn_interrupt_signal: Option<runtime::TurnInterruptSignal>,
 }
 
 impl AnthropicRuntimeClient {
@@ -12607,12 +12672,17 @@ impl AnthropicRuntimeClient {
             tool_registry,
             progress_reporter,
             reasoning_effort: None,
+            turn_interrupt_signal: None,
         })
     }
 
     fn set_reasoning_effort(&mut self, effort: Option<String>) {
         self.reasoning_effort = effort;
     }
+
+    fn set_turn_interrupt_signal(&mut self, signal: runtime::TurnInterruptSignal) {
+        self.turn_interrupt_signal = Some(signal);
+    }
 }
 
 fn resolve_cli_auth_source() -> Result<AuthSource, Box<dyn std::error::Error>> {
@@ -12646,30 +12716,50 @@ impl ApiClient for AnthropicRuntimeClient {
         };
 
         self.runtime.block_on(async {
-            // When resuming after tool execution, apply a stall timeout on the
+            let request_loop = async {
-            // first stream event.  If the model does not respond within the
+                // When resuming after tool execution, apply a stall timeout on the
-            // deadline we drop the stalled connection and re-send the request as
+                // first stream event.  If the model does not respond within the
-            // a continuation nudge (one retry only).
+                // deadline we drop the stalled connection and re-send the request as
-            let max_attempts: usize = if is_post_tool { 2 } else { 1 };
+                // a continuation nudge (one retry only).
+                let max_attempts: usize = if is_post_tool { 2 } else { 1 };
 
-            for attempt in 1..=max_attempts {
+                for attempt in 1..=max_attempts {
-                let result = self
+                    let result = self
-                    .consume_stream(&message_request, is_post_tool && attempt == 1)
+                        .consume_stream(&message_request, is_post_tool && attempt == 1)
-                    .await;
+                        .await;
-                match result {
+                    match result {
-                    Ok(events) => return Ok(events),
+                        Ok(events) => return Ok(events),
-                    Err(error)
+                        Err(error)
-                        if error.to_string().contains("post-tool stall")
+                            if error.to_string().contains("post-tool stall")
-                            && attempt < max_attempts =>
+                                && attempt < max_attempts =>
-                    {
+                        {
-                        // Stalled after tool completion — nudge the model by
+                            // Stalled after tool completion — nudge the model by
-                        // re-sending the same request.
+                            // re-sending the same request.
+                        }
+                        Err(error) => return Err(error),
                     }
-                    Err(error) => return Err(error),
+                }
+
+                Err(RuntimeError::new("post-tool continuation nudge exhausted"))
+            };
+
+            let Some(interrupt) = self.turn_interrupt_signal.clone() else {
+                return request_loop.await;
+            };
+
+            tokio::select! {
+                result = request_loop => result,
+                () = async {
+                    while !interrupt.is_interrupted() {
+                        tokio::time::sleep(std::time::Duration::from_millis(50)).await;
+                    }
+                } => {
+                    // Dropping the request future aborts the in-flight HTTP
+                    // stream. The conversation loop sees the interrupt flag and
+                    // reports this as an interruption rather than a failure.
+                    Err(RuntimeError::new("request interrupted by user"))
                 }
             }
-
-            Err(RuntimeError::new("post-tool continuation nudge exhausted"))
         })
     }
 }