feat: handle Elicitation and ElicitationResult hook events (#223)

Parses [Elicitation Hook] and [ElicitationResult Hook] from Claude Code
stderr, emits claude:elicitation and claude:elicitation-result Tauri
events, and renders an ElicitationModal for MCP server input requests.

src-tauri/src/types.rs

@@ -280,6 +280,26 @@ pub struct UserQuestionEvent {
     pub conversation_id: Option<String>,
 }
 
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct ElicitationEvent {
+    pub message: String,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub server_name: Option<String>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub request_id: Option<String>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub conversation_id: Option<String>,
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct ElicitationResultEvent {
+    pub action: String,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub request_id: Option<String>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub conversation_id: Option<String>,
+}
+
 #[derive(Debug, Clone, Serialize, Deserialize)]
 pub struct AgentStartEvent {
     pub tool_use_id: String,
@@ -566,4 +586,63 @@ mod tests {
             panic!("Expected RateLimitEvent variant");
         }
     }
+
+    #[test]
+    fn test_elicitation_event_serialization() {
+        let event = ElicitationEvent {
+            message: "Please provide the API endpoint".to_string(),
+            server_name: Some("my-server".to_string()),
+            request_id: Some("req-123".to_string()),
+            conversation_id: Some("conv-abc".to_string()),
+        };
+
+        let serialized = serde_json::to_string(&event).unwrap();
+        assert!(serialized.contains("\"message\":\"Please provide the API endpoint\""));
+        assert!(serialized.contains("\"server_name\":\"my-server\""));
+        assert!(serialized.contains("\"request_id\":\"req-123\""));
+        assert!(serialized.contains("\"conversation_id\":\"conv-abc\""));
+    }
+
+    #[test]
+    fn test_elicitation_event_omits_none_fields() {
+        let event = ElicitationEvent {
+            message: "Enter your token".to_string(),
+            server_name: None,
+            request_id: None,
+            conversation_id: None,
+        };
+
+        let serialized = serde_json::to_string(&event).unwrap();
+        assert!(serialized.contains("\"message\":\"Enter your token\""));
+        assert!(!serialized.contains("server_name"));
+        assert!(!serialized.contains("request_id"));
+        assert!(!serialized.contains("conversation_id"));
+    }
+
+    #[test]
+    fn test_elicitation_result_event_serialization() {
+        let event = ElicitationResultEvent {
+            action: "accept".to_string(),
+            request_id: Some("req-123".to_string()),
+            conversation_id: Some("conv-abc".to_string()),
+        };
+
+        let serialized = serde_json::to_string(&event).unwrap();
+        assert!(serialized.contains("\"action\":\"accept\""));
+        assert!(serialized.contains("\"request_id\":\"req-123\""));
+    }
+
+    #[test]
+    fn test_elicitation_result_event_cancel_omits_none_fields() {
+        let event = ElicitationResultEvent {
+            action: "cancel".to_string(),
+            request_id: None,
+            conversation_id: None,
+        };
+
+        let serialized = serde_json::to_string(&event).unwrap();
+        assert!(serialized.contains("\"action\":\"cancel\""));
+        assert!(!serialized.contains("request_id"));
+        assert!(!serialized.contains("conversation_id"));
+    }
 }

src-tauri/src/wsl_bridge.rs

@@ -15,9 +15,10 @@ use crate::process_ext::HideWindow;
 use crate::stats::{calculate_cost, StatsUpdateEvent, UsageStats};
 use crate::types::{
     AgentEndEvent, AgentStartEvent, CharacterState, ClaudeMessage, ConnectionEvent,
-    ConnectionStatus, ContentBlock, MessageCost, OutputEvent, PermissionPromptEvent,
-    PermissionPromptEventItem, QuestionOption, SessionEvent, StateChangeEvent, TodoItem,
-    TodoUpdateEvent, UserQuestionEvent, WorkingDirectoryEvent, WorktreeEvent, WorktreeInfo,
+    ConnectionStatus, ContentBlock, ElicitationEvent, ElicitationResultEvent, MessageCost,
+    OutputEvent, PermissionPromptEvent, PermissionPromptEventItem, QuestionOption, SessionEvent,
+    StateChangeEvent, TodoItem, TodoUpdateEvent, UserQuestionEvent, WorkingDirectoryEvent,
+    WorktreeEvent, WorktreeInfo,
 };
 use parking_lot::RwLock;
 use std::cell::RefCell;
@@ -1051,11 +1052,15 @@ fn handle_stderr(
                 // Hook events are informational — emit with distinct types instead of error
                 let is_worktree_create = line.contains("[WorktreeCreate Hook]");
                 let is_worktree_remove = line.contains("[WorktreeRemove Hook]");
+                let is_elicitation = line.contains("[Elicitation Hook]");
+                let is_elicitation_result = line.contains("[ElicitationResult Hook]");
 
                 let line_type = if is_worktree_create || is_worktree_remove {
                     "worktree"
                 } else if line.contains("[ConfigChange Hook]") {
                     "config-change"
+                } else if is_elicitation || is_elicitation_result {
+                    "elicitation"
                 } else {
                     "error"
                 };
@@ -1097,6 +1102,57 @@ fn handle_stderr(
                             parent_tool_use_id: None,
                         },
                     );
+                } else if is_elicitation {
+                    let data = parse_elicitation_hook(&line);
+                    let friendly_content =
+                        format!("MCP server requesting input: {}", data.message);
+
+                    let _ = app.emit(
+                        "claude:elicitation",
+                        ElicitationEvent {
+                            message: data.message,
+                            server_name: data.server_name,
+                            request_id: data.request_id,
+                            conversation_id: conversation_id.clone(),
+                        },
+                    );
+
+                    let _ = app.emit(
+                        "claude:output",
+                        OutputEvent {
+                            line_type: "elicitation".to_string(),
+                            content: friendly_content,
+                            tool_name: None,
+                            conversation_id: conversation_id.clone(),
+                            cost: None,
+                            parent_tool_use_id: None,
+                        },
+                    );
+                } else if is_elicitation_result {
+                    let data = parse_elicitation_result_hook(&line);
+                    let friendly_content =
+                        format!("MCP elicitation completed: {}", data.action);
+
+                    let _ = app.emit(
+                        "claude:elicitation-result",
+                        ElicitationResultEvent {
+                            action: data.action,
+                            request_id: data.request_id,
+                            conversation_id: conversation_id.clone(),
+                        },
+                    );
+
+                    let _ = app.emit(
+                        "claude:output",
+                        OutputEvent {
+                            line_type: "elicitation".to_string(),
+                            content: friendly_content,
+                            tool_name: None,
+                            conversation_id: conversation_id.clone(),
+                            cost: None,
+                            parent_tool_use_id: None,
+                        },
+                    );
                 } else {
                     let _ = app.emit(
                         "claude:output",
@@ -1235,6 +1291,73 @@ fn parse_subagent_stop_hook(line: &str) -> Option<SubagentStopData> {
     })
 }
 
+#[derive(Debug)]
+struct ElicitationData {
+    message: String,
+    server_name: Option<String>,
+    request_id: Option<String>,
+}
+
+fn parse_elicitation_hook(line: &str) -> ElicitationData {
+    let message = extract_quoted_value(line, "message").unwrap_or_else(|| {
+        line.split("[Elicitation Hook]")
+            .nth(1)
+            .unwrap_or("")
+            .trim()
+            .to_string()
+    });
+
+    let server_name = extract_debug_string_value(line, "server_name");
+    let request_id = extract_debug_string_value(line, "request_id");
+
+    ElicitationData { message, server_name, request_id }
+}
+
+#[derive(Debug)]
+struct ElicitationResultData {
+    action: String,
+    request_id: Option<String>,
+}
+
+fn parse_elicitation_result_hook(line: &str) -> ElicitationResultData {
+    let action =
+        extract_quoted_value(line, "action").unwrap_or_else(|| "unknown".to_string());
+
+    let request_id = extract_debug_string_value(line, "request_id");
+
+    ElicitationResultData { action, request_id }
+}
+
+/// Extracts a double-quoted string value from a `key="value"` pair in a hook line.
+/// Handles escape sequences within the quoted value.
+fn extract_quoted_value(line: &str, key: &str) -> Option<String> {
+    let prefix = format!("{}=\"", key);
+    let start_idx = line.find(&prefix)? + prefix.len();
+    let rest = &line[start_idx..];
+
+    let mut result = String::new();
+    let mut chars = rest.chars();
+    loop {
+        match chars.next() {
+            Some('"') => return Some(result),
+            Some('\\') => match chars.next() {
+                Some('n') => result.push('\n'),
+                Some('t') => result.push('\t'),
+                Some('"') => result.push('"'),
+                Some('\\') => result.push('\\'),
+                Some(c) => {
+                    result.push('\\');
+                    result.push(c);
+                }
+                None => break,
+            },
+            Some(c) => result.push(c),
+            None => break,
+        }
+    }
+    None
+}
+
 /// Extract text content from a ToolResult's `content` field.
 /// The content may be a JSON string or an array of typed content blocks.
 fn extract_tool_result_text(content: &serde_json::Value) -> Option<String> {
@@ -3191,4 +3314,68 @@ mod tests {
         let result = build_combined_settings_arg(Some(""), None);
         assert_eq!(result, "{}");
     }
+
+    #[test]
+    fn test_extract_quoted_value_basic() {
+        let line = r#"[Elicitation Hook] message="Hello world", server_name=Some("srv")"#;
+        let result = extract_quoted_value(line, "message");
+        assert_eq!(result, Some("Hello world".to_string()));
+    }
+
+    #[test]
+    fn test_extract_quoted_value_with_escapes() {
+        let line = r#"[Elicitation Hook] message="Line one\nLine two", request_id=Some("r1")"#;
+        let result = extract_quoted_value(line, "message");
+        assert_eq!(result, Some("Line one\nLine two".to_string()));
+    }
+
+    #[test]
+    fn test_extract_quoted_value_missing() {
+        let line = r#"[Elicitation Hook] server_name=Some("srv")"#;
+        let result = extract_quoted_value(line, "message");
+        assert_eq!(result, None);
+    }
+
+    #[test]
+    fn test_parse_elicitation_hook_with_all_fields() {
+        let line = r#"[Elicitation Hook] message="Please enter your API key", server_name=Some("my-mcp"), request_id=Some("req-456")"#;
+        let data = parse_elicitation_hook(line);
+        assert_eq!(data.message, "Please enter your API key");
+        assert_eq!(data.server_name, Some("my-mcp".to_string()));
+        assert_eq!(data.request_id, Some("req-456".to_string()));
+    }
+
+    #[test]
+    fn test_parse_elicitation_hook_missing_optional_fields() {
+        let line = r#"[Elicitation Hook] message="What is the endpoint?", server_name=None, request_id=None"#;
+        let data = parse_elicitation_hook(line);
+        assert_eq!(data.message, "What is the endpoint?");
+        assert_eq!(data.server_name, None);
+        assert_eq!(data.request_id, None);
+    }
+
+    #[test]
+    fn test_parse_elicitation_hook_invalid_line() {
+        let line = "[Elicitation Hook] some unstructured data";
+        let data = parse_elicitation_hook(line);
+        assert_eq!(data.message, "some unstructured data");
+        assert_eq!(data.server_name, None);
+        assert_eq!(data.request_id, None);
+    }
+
+    #[test]
+    fn test_parse_elicitation_result_hook_accept() {
+        let line = r#"[ElicitationResult Hook] action="accept", request_id=Some("req-789")"#;
+        let data = parse_elicitation_result_hook(line);
+        assert_eq!(data.action, "accept");
+        assert_eq!(data.request_id, Some("req-789".to_string()));
+    }
+
+    #[test]
+    fn test_parse_elicitation_result_hook_cancel() {
+        let line = r#"[ElicitationResult Hook] action="cancel", request_id=None"#;
+        let data = parse_elicitation_result_hook(line);
+        assert_eq!(data.action, "cancel");
+        assert_eq!(data.request_id, None);
+    }
 }