story-kit: merge 267_story_mcp_update_story_tool_should_support_front_matter_fields

server/src/http/mcp.rs

@@ -19,6 +19,7 @@ use poem::web::Data;
 use poem::{Body, Request, Response};
 use serde::{Deserialize, Serialize};
 use serde_json::{json, Value};
+use std::collections::HashMap;
 use std::fs;
 use std::sync::Arc;
 
@@ -638,7 +639,7 @@ fn handle_tools_list(id: Option<Value>) -> JsonRpcResponse {
                 },
                 {
                     "name": "update_story",
-                    "description": "Update the user story text and/or description of an existing story file. Replaces the content of the '## User Story' and/or '## Description' section in place. Auto-commits via the filesystem watcher.",
+                    "description": "Update an existing story file. Can replace the '## User Story' and/or '## Description' section content, and/or set YAML front matter fields (e.g. agent, manual_qa). Auto-commits via the filesystem watcher.",
                     "inputSchema": {
                         "type": "object",
                         "properties": {
@@ -653,6 +654,17 @@ fn handle_tools_list(id: Option<Value>) -> JsonRpcResponse {
                             "description": {
                                 "type": "string",
                                 "description": "New description text to replace the '## Description' section content"
+                            },
+                            "agent": {
+                                "type": "string",
+                                "description": "Set or change the 'agent' YAML front matter field"
+                            },
+                            "front_matter": {
+                                "type": "object",
+                                "description": "Arbitrary YAML front matter key-value pairs to set or update",
+                                "additionalProperties": {
+                                    "type": "string"
+                                }
                             }
                         },
                         "required": ["story_id"]
@@ -1544,8 +1556,24 @@ fn tool_update_story(args: &Value, ctx: &AppContext) -> Result<String, String> {
     let user_story = args.get("user_story").and_then(|v| v.as_str());
     let description = args.get("description").and_then(|v| v.as_str());
 
+    // Collect front matter fields: explicit `agent` param + arbitrary `front_matter` object.
+    let mut front_matter: HashMap<String, String> = HashMap::new();
+    if let Some(agent) = args.get("agent").and_then(|v| v.as_str()) {
+        front_matter.insert("agent".to_string(), agent.to_string());
+    }
+    if let Some(obj) = args.get("front_matter").and_then(|v| v.as_object()) {
+        for (k, v) in obj {
+            let val = match v {
+                Value::String(s) => s.clone(),
+                other => other.to_string(),
+            };
+            front_matter.insert(k.clone(), val);
+        }
+    }
+    let front_matter_opt = if front_matter.is_empty() { None } else { Some(&front_matter) };
+
     let root = ctx.state.get_project_root()?;
-    update_story_in_file(&root, story_id, user_story, description)?;
+    update_story_in_file(&root, story_id, user_story, description, front_matter_opt)?;
 
     Ok(format!("Updated story '{story_id}'."))
 }

server/src/http/workflow.rs

@@ -1,6 +1,6 @@
 use crate::agents::AgentStatus;
 use crate::http::context::AppContext;
-use crate::io::story_metadata::{parse_front_matter, write_coverage_baseline};
+use crate::io::story_metadata::{parse_front_matter, set_front_matter_field, write_coverage_baseline};
 use crate::workflow::{StoryTestResults, TestCaseResult, TestStatus};
 use serde::Serialize;
 use std::collections::HashMap;
@@ -706,10 +706,13 @@ pub fn update_story_in_file(
     story_id: &str,
     user_story: Option<&str>,
     description: Option<&str>,
+    front_matter: Option<&HashMap<String, String>>,
 ) -> Result<(), String> {
-    if user_story.is_none() && description.is_none() {
+    let has_front_matter_updates = front_matter.map(|m| !m.is_empty()).unwrap_or(false);
+    if user_story.is_none() && description.is_none() && !has_front_matter_updates {
         return Err(
-            "At least one of 'user_story' or 'description' must be provided.".to_string(),
+            "At least one of 'user_story', 'description', or 'front_matter' must be provided."
+                .to_string(),
         );
     }
 
@@ -717,6 +720,13 @@ pub fn update_story_in_file(
     let mut contents = fs::read_to_string(&filepath)
         .map_err(|e| format!("Failed to read story file: {e}"))?;
 
+    if let Some(fields) = front_matter {
+        for (key, value) in fields {
+            let yaml_value = format!("\"{}\"", value.replace('"', "\\\"").replace('\n', " ").replace('\r', ""));
+            contents = set_front_matter_field(&contents, key, &yaml_value);
+        }
+    }
+
     if let Some(us) = user_story {
         contents = replace_section_content(&contents, "User Story", us)?;
     }
@@ -1597,7 +1607,7 @@ mod tests {
         let content = "---\nname: T\n---\n\n## User Story\n\nOld text\n\n## Acceptance Criteria\n\n- [ ] AC\n";
         fs::write(&filepath, content).unwrap();
 
-        update_story_in_file(tmp.path(), "20_test", Some("New user story text"), None).unwrap();
+        update_story_in_file(tmp.path(), "20_test", Some("New user story text"), None, None).unwrap();
 
         let result = fs::read_to_string(&filepath).unwrap();
         assert!(result.contains("New user story text"), "new text should be present");
@@ -1614,7 +1624,7 @@ mod tests {
         let content = "---\nname: T\n---\n\n## Description\n\nOld description\n\n## Acceptance Criteria\n\n- [ ] AC\n";
         fs::write(&filepath, content).unwrap();
 
-        update_story_in_file(tmp.path(), "21_test", None, Some("New description")).unwrap();
+        update_story_in_file(tmp.path(), "21_test", None, Some("New description"), None).unwrap();
 
         let result = fs::read_to_string(&filepath).unwrap();
         assert!(result.contains("New description"), "new description present");
@@ -1628,7 +1638,7 @@ mod tests {
         fs::create_dir_all(&current).unwrap();
         fs::write(current.join("22_test.md"), "---\nname: T\n---\n").unwrap();
 
-        let result = update_story_in_file(tmp.path(), "22_test", None, None);
+        let result = update_story_in_file(tmp.path(), "22_test", None, None, None);
         assert!(result.is_err());
         assert!(result.unwrap_err().contains("At least one"));
     }
@@ -1644,11 +1654,65 @@ mod tests {
         )
         .unwrap();
 
-        let result = update_story_in_file(tmp.path(), "23_test", Some("new text"), None);
+        let result = update_story_in_file(tmp.path(), "23_test", Some("new text"), None, None);
         assert!(result.is_err());
         assert!(result.unwrap_err().contains("User Story"));
     }
 
+    #[test]
+    fn update_story_sets_agent_front_matter_field() {
+        let tmp = tempfile::tempdir().unwrap();
+        let current = tmp.path().join(".story_kit/work/2_current");
+        fs::create_dir_all(&current).unwrap();
+        let filepath = current.join("24_test.md");
+        fs::write(&filepath, "---\nname: T\n---\n\n## User Story\n\nSome story\n").unwrap();
+
+        let mut fields = HashMap::new();
+        fields.insert("agent".to_string(), "dev".to_string());
+        update_story_in_file(tmp.path(), "24_test", None, None, Some(&fields)).unwrap();
+
+        let result = fs::read_to_string(&filepath).unwrap();
+        assert!(result.contains("agent: \"dev\""), "agent field should be set");
+        assert!(result.contains("name: T"), "name field preserved");
+    }
+
+    #[test]
+    fn update_story_sets_arbitrary_front_matter_fields() {
+        let tmp = tempfile::tempdir().unwrap();
+        let current = tmp.path().join(".story_kit/work/2_current");
+        fs::create_dir_all(&current).unwrap();
+        let filepath = current.join("25_test.md");
+        fs::write(&filepath, "---\nname: T\n---\n\n## User Story\n\nSome story\n").unwrap();
+
+        let mut fields = HashMap::new();
+        fields.insert("manual_qa".to_string(), "true".to_string());
+        fields.insert("priority".to_string(), "high".to_string());
+        update_story_in_file(tmp.path(), "25_test", None, None, Some(&fields)).unwrap();
+
+        let result = fs::read_to_string(&filepath).unwrap();
+        assert!(result.contains("manual_qa: \"true\""), "manual_qa field should be set");
+        assert!(result.contains("priority: \"high\""), "priority field should be set");
+        assert!(result.contains("name: T"), "name field preserved");
+    }
+
+    #[test]
+    fn update_story_front_matter_only_no_section_required() {
+        let tmp = tempfile::tempdir().unwrap();
+        let current = tmp.path().join(".story_kit/work/2_current");
+        fs::create_dir_all(&current).unwrap();
+        // File without a User Story section — front matter update should succeed
+        let filepath = current.join("26_test.md");
+        fs::write(&filepath, "---\nname: T\n---\n\nNo sections here.\n").unwrap();
+
+        let mut fields = HashMap::new();
+        fields.insert("agent".to_string(), "dev".to_string());
+        let result = update_story_in_file(tmp.path(), "26_test", None, None, Some(&fields));
+        assert!(result.is_ok(), "front-matter-only update should not require body sections");
+
+        let contents = fs::read_to_string(&filepath).unwrap();
+        assert!(contents.contains("agent: \"dev\""));
+    }
+
     // ── Bug file helper tests ──────────────────────────────────────────────────
 
     #[test]

server/src/io/story_metadata.rs

@@ -161,7 +161,7 @@ fn remove_front_matter_field(contents: &str, key: &str) -> String {
 /// Insert or update a key: value pair in the YAML front matter of a markdown string.
 ///
 /// If no front matter (opening `---`) is found, returns the content unchanged.
-fn set_front_matter_field(contents: &str, key: &str, value: &str) -> String {
+pub fn set_front_matter_field(contents: &str, key: &str, value: &str) -> String {
     let mut lines: Vec<String> = contents.lines().map(String::from).collect();
     if lines.is_empty() || lines[0].trim() != "---" {
         return contents.to_string();