fix: reject prompts to blocked agents (#2790)

* fix: reject prompts to blocked agents

refs #2788

* docs: clarify agent prompt timing

refs #2788

---------

Co-authored-by: akbash-bot <300245827+akbash-bot@users.noreply.github.com>

1 files changed, 45 insertions, 0 deletions

diff --git a/src/app/api/agents.rs b/src/app/api/agents.rs
index e5e5525f..1ed13efc 100644
--- a/src/app/api/agents.rs
+++ b/src/app/api/agents.rs
@@ -79,6 +79,16 @@ impl App {
         let Some(terminal) = self.state.terminals.get(&terminal_id) else {
             return agent_not_found(id, &params.target);
         };
+        if terminal.state == crate::detect::AgentState::Blocked {
+            return encode_error(
+                id,
+                "agent_blocked",
+                format!(
+                    "agent {} is blocked and requires interactive input",
+                    params.target
+                ),
+            );
+        }
         let Some(expected_agent) = terminal.effective_known_agent() else {
             return agent_not_ready(id, &params.target);
         };
@@ -407,6 +417,41 @@ mod tests {
     }
 
     #[tokio::test]
+    async fn agent_prompt_rejects_blocked_agent_without_writing() {
+        let mut app = app_with_agent();
+        let pane_id = app.state.workspaces[0].tabs[0].root_pane;
+        let terminal_id = app.state.workspaces[0].tabs[0].panes[&pane_id]
+            .attached_terminal_id
+            .clone();
+        let terminal = app.state.terminals.get_mut(&terminal_id).unwrap();
+        terminal.set_agent_name("reviewer".into());
+        terminal.set_detected_state(Some(Agent::GithubCopilot), AgentState::Blocked);
+        let (runtime, mut rx) = crate::terminal::TerminalRuntime::test_with_channel(80, 24);
+        app.state.insert_test_runtime(pane_id, runtime);
+
+        let response = app.handle_agent_prompt(
+            "req".into(),
+            AgentPromptParams {
+                target: "reviewer".into(),
+                text: "unrelated prompt".into(),
+                wait: None,
+            },
+        );
+
+        let error: crate::api::schema::ErrorResponse = serde_json::from_str(&response).unwrap();
+        assert_eq!(error.error.code, "agent_blocked");
+        assert!(
+            tokio::time::timeout(
+                AGENT_PROMPT_SUBMIT_DELAY + Duration::from_millis(100),
+                rx.recv()
+            )
+            .await
+            .is_err(),
+            "blocked prompt wrote or scheduled terminal input"
+        );
+    }
+
+    #[tokio::test]
     async fn agent_prompt_focuses_copilot_before_submitting() {
         let mut app = app_with_agent();
         let pane_id = app.state.workspaces[0].tabs[0].root_pane;