diff --git a/crates/tui/src/core/engine/approval.rs b/crates/tui/src/core/engine/approval.rs
index ac04900b4..b0f866cc1 100644
--- a/crates/tui/src/core/engine/approval.rs
+++ b/crates/tui/src/core/engine/approval.rs
@@ -5,10 +5,14 @@
 //! or whenever a tool requests live user input (`await_user_input`). Channels
 //! and engine state stay private to the parent module.
 
+use std::time::Duration;
+
 use crate::core::events::Event;
 use crate::tools::spec::ToolError;
 use crate::tools::user_input::{UserInputRequest, UserInputResponse};
 
+const USER_INPUT_TIMEOUT: Duration = Duration::from_secs(300);
+
 use super::Engine;
 
 #[derive(Debug, Clone)]
@@ -123,22 +127,43 @@ impl Engine {
                         format!("Request cancelled while awaiting user input{suffix}"),
                     ));
                 }
-                decision = self.rx_user_input.recv() => {
-                    let Some(decision) = decision else {
-                        return Err(ToolError::execution_failed(
-                            "User input channel closed".to_string(),
-                        ));
-                    };
-                    match decision {
-                        UserInputDecision::Submitted { id, response } if id == tool_id => {
-                            return Ok(response);
+                result = tokio::time::timeout(USER_INPUT_TIMEOUT, self.rx_user_input.recv()) => {
+                    match result {
+                        Ok(Some(decision)) => {
+                            match decision {
+                                UserInputDecision::Submitted { id, response } if id == tool_id => {
+                                    return Ok(response);
+                                }
+                                UserInputDecision::Cancelled { id } if id == tool_id => {
+                                    return Err(ToolError::execution_failed(
+                                        "User input cancelled".to_string(),
+                                    ));
+                                }
+                                _ => continue,
+                            }
                         }
-                        UserInputDecision::Cancelled { id } if id == tool_id => {
+                        Ok(None) => {
                             return Err(ToolError::execution_failed(
-                                "User input cancelled".to_string(),
+                                "User input channel closed".to_string(),
+                            ));
+                        }
+                        Err(_) => {
+                            let _ = self
+                                .tx_event
+                                .send(Event::Status {
+                                    message: format!(
+                                        "User input timed out after {}s",
+                                        USER_INPUT_TIMEOUT.as_secs()
+                                    ),
+                                })
+                                .await;
+                            return Err(ToolError::execution_failed(
+                                format!(
+                                    "User input timed out after {}s",
+                                    USER_INPUT_TIMEOUT.as_secs()
+                                ),
                             ));
                         }
-                        _ => continue,
                     }
                 }
             }
diff --git a/crates/tui/src/runtime_api.rs b/crates/tui/src/runtime_api.rs
index 20110cc45..da316accd 100644
--- a/crates/tui/src/runtime_api.rs
+++ b/crates/tui/src/runtime_api.rs
@@ -296,6 +296,25 @@ struct DecideApprovalResponse {
     delivered: bool,
 }
 
+#[derive(Debug, Deserialize)]
+struct SubmitUserInputBody {
+    answers: Vec<UserInputAnswerBody>,
+}
+
+#[derive(Debug, Deserialize)]
+struct UserInputAnswerBody {
+    id: String,
+    label: String,
+    value: String,
+}
+
+#[derive(Debug, Serialize)]
+struct SubmitUserInputResponse {
+    ok: bool,
+    input_id: String,
+    delivered: bool,
+}
+
 #[derive(Debug, Serialize)]
 struct RuntimeInfoResponse {
     bind_host: String,
@@ -500,6 +519,10 @@ pub fn build_router(state: RuntimeApiState) -> Router {
         .route("/v1/threads/{id}/compact", post(compact_thread))
         .route("/v1/threads/{id}/events", get(stream_thread_events))
         .route("/v1/approvals/{approval_id}", post(decide_approval))
+        .route(
+            "/v1/user-input/{thread_id}/{input_id}",
+            post(submit_user_input),
+        )
         .route("/v1/tasks", get(list_tasks).post(create_task))
         .route("/v1/tasks/{id}", get(get_task))
         .route("/v1/tasks/{id}/cancel", post(cancel_task))
@@ -984,6 +1007,34 @@ async fn decide_approval(
     }))
 }
 
+async fn submit_user_input(
+    State(state): State<RuntimeApiState>,
+    Path((thread_id, input_id)): Path<(String, String)>,
+    Json(req): Json<SubmitUserInputBody>,
+) -> Result<Json<SubmitUserInputResponse>, ApiError> {
+    use crate::tools::user_input::{UserInputAnswer, UserInputResponse};
+    let answers: Vec<UserInputAnswer> = req
+        .answers
+        .into_iter()
+        .map(|a| UserInputAnswer {
+            id: a.id,
+            label: a.label,
+            value: a.value,
+        })
+        .collect();
+    let response = UserInputResponse { answers };
+    let delivered = state
+        .runtime_threads
+        .submit_user_input(&thread_id, &input_id, response)
+        .await
+        .map_err(map_thread_err)?;
+    Ok(Json(SubmitUserInputResponse {
+        ok: true,
+        input_id,
+        delivered,
+    }))
+}
+
 async fn runtime_info(State(state): State<RuntimeApiState>) -> Json<RuntimeInfoResponse> {
     Json(RuntimeInfoResponse {
         bind_host: state.bind_host.clone(),
diff --git a/crates/tui/src/runtime_threads.rs b/crates/tui/src/runtime_threads.rs
index 1a08473d6..1058dda77 100644
--- a/crates/tui/src/runtime_threads.rs
+++ b/crates/tui/src/runtime_threads.rs
@@ -833,6 +833,30 @@ impl RuntimeThreadManager {
         }
     }
 
+    pub async fn submit_user_input(
+        &self,
+        thread_id: &str,
+        input_id: &str,
+        response: crate::tools::user_input::UserInputResponse,
+    ) -> Result<bool> {
+        let active = self.active.lock().await;
+        let Some(state) = active.engines.get(thread_id) else {
+            bail!("thread '{thread_id}' not found");
+        };
+        state.engine.submit_user_input(input_id, response).await?;
+        Ok(true)
+    }
+
+    #[allow(dead_code)]
+    pub async fn cancel_user_input(&self, thread_id: &str, input_id: &str) -> Result<bool> {
+        let active = self.active.lock().await;
+        let Some(state) = active.engines.get(thread_id) else {
+            bail!("thread '{thread_id}' not found");
+        };
+        state.engine.cancel_user_input(input_id).await?;
+        Ok(true)
+    }
+
     #[allow(dead_code)]
     pub fn pending_approvals_count(&self) -> usize {
         self.pending_approvals
@@ -2782,6 +2806,19 @@ impl RuntimeThreadManager {
                         }
                     }
                 }
+                EngineEvent::UserInputRequired { id, request } => {
+                    self.emit_event(
+                        &thread_id,
+                        Some(&turn_id),
+                        None,
+                        "user_input.required",
+                        json!({
+                            "id": id,
+                            "request": request,
+                        }),
+                    )
+                    .await?;
+                }
                 EngineEvent::Status { message } => {
                     let item = TurnItemRecord {
                         schema_version: CURRENT_RUNTIME_SCHEMA_VERSION,