Story 49: Deterministic Bug Lifecycle Management

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

server/src/agents.rs

@@ -819,7 +819,7 @@ pub fn close_bug_to_archive(project_root: &Path, bug_id: &str) -> Result<(), Str
     let sk = project_root.join(".story_kit");
     let current_path = sk.join("current").join(format!("{bug_id}.md"));
     let bugs_path = sk.join("bugs").join(format!("{bug_id}.md"));
-    let archive_dir = sk.join("bugs").join("archive");
+    let archive_dir = item_archive_dir(project_root, bug_id);
     let archive_path = archive_dir.join(format!("{bug_id}.md"));
 
     if archive_path.exists() {

server/src/http/mcp.rs

@@ -3,9 +3,10 @@ use crate::config::ProjectConfig;
 use crate::http::context::AppContext;
 use crate::http::settings::get_editor_command_from_store;
 use crate::http::workflow::{
-    check_criterion_in_file, create_story_file, load_upcoming_stories, set_test_plan_in_file,
-    validate_story_dirs,
+    check_criterion_in_file, create_bug_file, create_story_file, list_bug_files,
+    load_upcoming_stories, set_test_plan_in_file, validate_story_dirs,
 };
+use crate::agents::close_bug_to_archive;
 use crate::worktree;
 use crate::io::story_metadata::{parse_front_matter, parse_unchecked_todos};
 use crate::workflow::{evaluate_acceptance_with_coverage, TestCaseResult, TestStatus};
@@ -653,6 +654,63 @@ fn handle_tools_list(id: Option<Value>) -> JsonRpcResponse {
                         },
                         "required": ["story_id", "status"]
                     }
+                },
+                {
+                    "name": "create_bug",
+                    "description": "Create a bug file in .story_kit/bugs/ with a deterministic filename and auto-commit to master. Returns the bug_id.",
+                    "inputSchema": {
+                        "type": "object",
+                        "properties": {
+                            "name": {
+                                "type": "string",
+                                "description": "Short human-readable bug name"
+                            },
+                            "description": {
+                                "type": "string",
+                                "description": "Description of the bug"
+                            },
+                            "steps_to_reproduce": {
+                                "type": "string",
+                                "description": "Steps to reproduce the bug"
+                            },
+                            "actual_result": {
+                                "type": "string",
+                                "description": "What actually happens"
+                            },
+                            "expected_result": {
+                                "type": "string",
+                                "description": "What should happen"
+                            },
+                            "acceptance_criteria": {
+                                "type": "array",
+                                "items": { "type": "string" },
+                                "description": "Optional list of acceptance criteria for the fix"
+                            }
+                        },
+                        "required": ["name", "description", "steps_to_reproduce", "actual_result", "expected_result"]
+                    }
+                },
+                {
+                    "name": "list_bugs",
+                    "description": "List all open bugs (files in .story_kit/bugs/ excluding archive/).",
+                    "inputSchema": {
+                        "type": "object",
+                        "properties": {}
+                    }
+                },
+                {
+                    "name": "close_bug",
+                    "description": "Move a bug from .story_kit/bugs/ (or current/) to .story_kit/bugs/archive/ and auto-commit to master.",
+                    "inputSchema": {
+                        "type": "object",
+                        "properties": {
+                            "bug_id": {
+                                "type": "string",
+                                "description": "Bug identifier (e.g. 'bug-3-login_crash')"
+                            }
+                        },
+                        "required": ["bug_id"]
+                    }
                 }
             ]
         }),
@@ -701,6 +759,10 @@ async fn handle_tools_call(
         // Story mutation tools (auto-commit to master)
         "check_criterion" => tool_check_criterion(&args, ctx),
         "set_test_plan" => tool_set_test_plan(&args, ctx),
+        // Bug lifecycle tools
+        "create_bug" => tool_create_bug(&args, ctx),
+        "list_bugs" => tool_list_bugs(ctx),
+        "close_bug" => tool_close_bug(&args, ctx),
         _ => Err(format!("Unknown tool: {tool_name}")),
     };
 
@@ -1148,6 +1210,71 @@ fn tool_set_test_plan(args: &Value, ctx: &AppContext) -> Result<String, String>
     ))
 }
 
+// ── Bug lifecycle tool implementations ───────────────────────────
+
+fn tool_create_bug(args: &Value, ctx: &AppContext) -> Result<String, String> {
+    let name = args
+        .get("name")
+        .and_then(|v| v.as_str())
+        .ok_or("Missing required argument: name")?;
+    let description = args
+        .get("description")
+        .and_then(|v| v.as_str())
+        .ok_or("Missing required argument: description")?;
+    let steps_to_reproduce = args
+        .get("steps_to_reproduce")
+        .and_then(|v| v.as_str())
+        .ok_or("Missing required argument: steps_to_reproduce")?;
+    let actual_result = args
+        .get("actual_result")
+        .and_then(|v| v.as_str())
+        .ok_or("Missing required argument: actual_result")?;
+    let expected_result = args
+        .get("expected_result")
+        .and_then(|v| v.as_str())
+        .ok_or("Missing required argument: expected_result")?;
+    let acceptance_criteria: Option<Vec<String>> = args
+        .get("acceptance_criteria")
+        .and_then(|v| serde_json::from_value(v.clone()).ok());
+
+    let root = ctx.state.get_project_root()?;
+    let bug_id = create_bug_file(
+        &root,
+        name,
+        description,
+        steps_to_reproduce,
+        actual_result,
+        expected_result,
+        acceptance_criteria.as_deref(),
+    )?;
+
+    Ok(format!("Created bug: {bug_id}"))
+}
+
+fn tool_list_bugs(ctx: &AppContext) -> Result<String, String> {
+    let root = ctx.state.get_project_root()?;
+    let bugs = list_bug_files(&root)?;
+    serde_json::to_string_pretty(&json!(bugs
+        .iter()
+        .map(|(id, name)| json!({ "bug_id": id, "name": name }))
+        .collect::<Vec<_>>()))
+    .map_err(|e| format!("Serialization error: {e}"))
+}
+
+fn tool_close_bug(args: &Value, ctx: &AppContext) -> Result<String, String> {
+    let bug_id = args
+        .get("bug_id")
+        .and_then(|v| v.as_str())
+        .ok_or("Missing required argument: bug_id")?;
+
+    let root = ctx.agents.get_project_root(&ctx.state)?;
+    close_bug_to_archive(&root, bug_id)?;
+
+    Ok(format!(
+        "Bug '{bug_id}' closed, moved to bugs/archive/, and committed to master."
+    ))
+}
+
 /// Run `git log <base>..HEAD --oneline` in the worktree and return the commit
 /// summaries, or `None` if git is unavailable or there are no new commits.
 async fn get_worktree_commits(worktree_path: &str, base_branch: &str) -> Option<Vec<String>> {
@@ -1302,7 +1429,10 @@ mod tests {
         assert!(names.contains(&"accept_story"));
         assert!(names.contains(&"check_criterion"));
         assert!(names.contains(&"set_test_plan"));
-        assert_eq!(tools.len(), 21);
+        assert!(names.contains(&"create_bug"));
+        assert!(names.contains(&"list_bugs"));
+        assert!(names.contains(&"close_bug"));
+        assert_eq!(tools.len(), 24);
     }
 
     #[test]
@@ -1699,4 +1829,196 @@ mod tests {
         let req_names: Vec<&str> = required.iter().map(|v| v.as_str().unwrap()).collect();
         assert!(req_names.contains(&"worktree_path"));
     }
+
+    // ── Bug lifecycle tool tests ──────────────────────────────────
+
+    fn setup_git_repo_in(dir: &std::path::Path) {
+        std::process::Command::new("git")
+            .args(["init"])
+            .current_dir(dir)
+            .output()
+            .unwrap();
+        std::process::Command::new("git")
+            .args(["config", "user.email", "test@test.com"])
+            .current_dir(dir)
+            .output()
+            .unwrap();
+        std::process::Command::new("git")
+            .args(["config", "user.name", "Test"])
+            .current_dir(dir)
+            .output()
+            .unwrap();
+        std::process::Command::new("git")
+            .args(["commit", "--allow-empty", "-m", "init"])
+            .current_dir(dir)
+            .output()
+            .unwrap();
+    }
+
+    #[test]
+    fn create_bug_in_tools_list() {
+        let resp = handle_tools_list(Some(json!(1)));
+        let tools = resp.result.unwrap()["tools"].as_array().unwrap().clone();
+        let tool = tools.iter().find(|t| t["name"] == "create_bug");
+        assert!(tool.is_some(), "create_bug missing from tools list");
+        let t = tool.unwrap();
+        assert!(t["description"].is_string());
+        let required = t["inputSchema"]["required"].as_array().unwrap();
+        let req_names: Vec<&str> = required.iter().map(|v| v.as_str().unwrap()).collect();
+        assert!(req_names.contains(&"name"));
+        assert!(req_names.contains(&"description"));
+        assert!(req_names.contains(&"steps_to_reproduce"));
+        assert!(req_names.contains(&"actual_result"));
+        assert!(req_names.contains(&"expected_result"));
+    }
+
+    #[test]
+    fn list_bugs_in_tools_list() {
+        let resp = handle_tools_list(Some(json!(1)));
+        let tools = resp.result.unwrap()["tools"].as_array().unwrap().clone();
+        let tool = tools.iter().find(|t| t["name"] == "list_bugs");
+        assert!(tool.is_some(), "list_bugs missing from tools list");
+    }
+
+    #[test]
+    fn close_bug_in_tools_list() {
+        let resp = handle_tools_list(Some(json!(1)));
+        let tools = resp.result.unwrap()["tools"].as_array().unwrap().clone();
+        let tool = tools.iter().find(|t| t["name"] == "close_bug");
+        assert!(tool.is_some(), "close_bug missing from tools list");
+        let t = tool.unwrap();
+        let required = t["inputSchema"]["required"].as_array().unwrap();
+        let req_names: Vec<&str> = required.iter().map(|v| v.as_str().unwrap()).collect();
+        assert!(req_names.contains(&"bug_id"));
+    }
+
+    #[test]
+    fn tool_create_bug_missing_name() {
+        let tmp = tempfile::tempdir().unwrap();
+        let ctx = test_ctx(tmp.path());
+        let result = tool_create_bug(
+            &json!({
+                "description": "d",
+                "steps_to_reproduce": "s",
+                "actual_result": "a",
+                "expected_result": "e"
+            }),
+            &ctx,
+        );
+        assert!(result.is_err());
+        assert!(result.unwrap_err().contains("name"));
+    }
+
+    #[test]
+    fn tool_create_bug_missing_description() {
+        let tmp = tempfile::tempdir().unwrap();
+        let ctx = test_ctx(tmp.path());
+        let result = tool_create_bug(
+            &json!({
+                "name": "Bug",
+                "steps_to_reproduce": "s",
+                "actual_result": "a",
+                "expected_result": "e"
+            }),
+            &ctx,
+        );
+        assert!(result.is_err());
+        assert!(result.unwrap_err().contains("description"));
+    }
+
+    #[test]
+    fn tool_create_bug_creates_file_and_commits() {
+        let tmp = tempfile::tempdir().unwrap();
+        setup_git_repo_in(tmp.path());
+        let ctx = test_ctx(tmp.path());
+
+        let result = tool_create_bug(
+            &json!({
+                "name": "Login Crash",
+                "description": "The app crashes on login.",
+                "steps_to_reproduce": "1. Open app\n2. Click login",
+                "actual_result": "500 error",
+                "expected_result": "Successful login"
+            }),
+            &ctx,
+        )
+        .unwrap();
+
+        assert!(result.contains("bug-1-login_crash"));
+        let bug_file = tmp
+            .path()
+            .join(".story_kit/bugs/bug-1-login_crash.md");
+        assert!(bug_file.exists());
+    }
+
+    #[test]
+    fn tool_list_bugs_empty() {
+        let tmp = tempfile::tempdir().unwrap();
+        let ctx = test_ctx(tmp.path());
+        let result = tool_list_bugs(&ctx).unwrap();
+        let parsed: Vec<Value> = serde_json::from_str(&result).unwrap();
+        assert!(parsed.is_empty());
+    }
+
+    #[test]
+    fn tool_list_bugs_returns_open_bugs() {
+        let tmp = tempfile::tempdir().unwrap();
+        let bugs_dir = tmp.path().join(".story_kit/bugs");
+        std::fs::create_dir_all(&bugs_dir).unwrap();
+        std::fs::write(
+            bugs_dir.join("bug-1-crash.md"),
+            "# Bug 1: App Crash\n",
+        )
+        .unwrap();
+        std::fs::write(
+            bugs_dir.join("bug-2-typo.md"),
+            "# Bug 2: Typo in Header\n",
+        )
+        .unwrap();
+
+        let ctx = test_ctx(tmp.path());
+        let result = tool_list_bugs(&ctx).unwrap();
+        let parsed: Vec<Value> = serde_json::from_str(&result).unwrap();
+        assert_eq!(parsed.len(), 2);
+        assert_eq!(parsed[0]["bug_id"], "bug-1-crash");
+        assert_eq!(parsed[0]["name"], "App Crash");
+        assert_eq!(parsed[1]["bug_id"], "bug-2-typo");
+        assert_eq!(parsed[1]["name"], "Typo in Header");
+    }
+
+    #[test]
+    fn tool_close_bug_missing_bug_id() {
+        let tmp = tempfile::tempdir().unwrap();
+        let ctx = test_ctx(tmp.path());
+        let result = tool_close_bug(&json!({}), &ctx);
+        assert!(result.is_err());
+        assert!(result.unwrap_err().contains("bug_id"));
+    }
+
+    #[test]
+    fn tool_close_bug_moves_to_archive() {
+        let tmp = tempfile::tempdir().unwrap();
+        setup_git_repo_in(tmp.path());
+        let bugs_dir = tmp.path().join(".story_kit/bugs");
+        std::fs::create_dir_all(&bugs_dir).unwrap();
+        let bug_file = bugs_dir.join("bug-1-crash.md");
+        std::fs::write(&bug_file, "# Bug 1: Crash\n").unwrap();
+        // Stage the file so it's tracked
+        std::process::Command::new("git")
+            .args(["add", "."])
+            .current_dir(tmp.path())
+            .output()
+            .unwrap();
+        std::process::Command::new("git")
+            .args(["commit", "-m", "add bug"])
+            .current_dir(tmp.path())
+            .output()
+            .unwrap();
+
+        let ctx = test_ctx(tmp.path());
+        let result = tool_close_bug(&json!({"bug_id": "bug-1-crash"}), &ctx).unwrap();
+        assert!(result.contains("bug-1-crash"));
+        assert!(!bug_file.exists());
+        assert!(bugs_dir.join("archive/bug-1-crash.md").exists());
+    }
 }

server/src/http/workflow.rs

@@ -699,6 +699,157 @@ fn git_commit_story_file(root: &Path, filepath: &Path, story_id: &str) -> Result
     git_stage_and_commit(root, &[filepath], &msg)
 }
 
+// ── Bug file helpers ──────────────────────────────────────────────
+
+/// Determine the next bug number by scanning `.story_kit/bugs/` and `.story_kit/bugs/archive/`.
+fn next_bug_number(root: &Path) -> Result<u32, String> {
+    let bugs_base = root.join(".story_kit").join("bugs");
+    let mut max_num: u32 = 0;
+
+    for dir in [bugs_base.clone(), bugs_base.join("archive")] {
+        if !dir.exists() {
+            continue;
+        }
+        for entry in
+            fs::read_dir(dir).map_err(|e| format!("Failed to read bugs directory: {e}"))?
+        {
+            let entry = entry.map_err(|e| format!("Failed to read entry: {e}"))?;
+            let name = entry.file_name();
+            let name_str = name.to_string_lossy();
+            // Bug filenames: bug-N-slug.md  — extract the N after "bug-"
+            if let Some(rest) = name_str.strip_prefix("bug-") {
+                let num_str: String = rest.chars().take_while(|c| c.is_ascii_digit()).collect();
+                if let Ok(n) = num_str.parse::<u32>()
+                    && n > max_num
+                {
+                    max_num = n;
+                }
+            }
+        }
+    }
+
+    Ok(max_num + 1)
+}
+
+/// Create a bug file in `.story_kit/bugs/` with a deterministic filename and auto-commit.
+///
+/// Returns the bug_id (e.g. `"bug-3-login_crash"`).
+pub fn create_bug_file(
+    root: &Path,
+    name: &str,
+    description: &str,
+    steps_to_reproduce: &str,
+    actual_result: &str,
+    expected_result: &str,
+    acceptance_criteria: Option<&[String]>,
+) -> Result<String, String> {
+    let bug_number = next_bug_number(root)?;
+    let slug = slugify_name(name);
+
+    if slug.is_empty() {
+        return Err("Name must contain at least one alphanumeric character.".to_string());
+    }
+
+    let filename = format!("bug-{bug_number}-{slug}.md");
+    let bugs_dir = root.join(".story_kit").join("bugs");
+    fs::create_dir_all(&bugs_dir)
+        .map_err(|e| format!("Failed to create bugs directory: {e}"))?;
+
+    let filepath = bugs_dir.join(&filename);
+    if filepath.exists() {
+        return Err(format!("Bug file already exists: {filename}"));
+    }
+
+    let bug_id = filepath
+        .file_stem()
+        .and_then(|s| s.to_str())
+        .unwrap_or_default()
+        .to_string();
+
+    let mut content = String::new();
+    content.push_str(&format!("# Bug {bug_number}: {name}\n\n"));
+    content.push_str("## Description\n\n");
+    content.push_str(description);
+    content.push_str("\n\n");
+    content.push_str("## How to Reproduce\n\n");
+    content.push_str(steps_to_reproduce);
+    content.push_str("\n\n");
+    content.push_str("## Actual Result\n\n");
+    content.push_str(actual_result);
+    content.push_str("\n\n");
+    content.push_str("## Expected Result\n\n");
+    content.push_str(expected_result);
+    content.push_str("\n\n");
+    content.push_str("## Acceptance Criteria\n\n");
+    if let Some(criteria) = acceptance_criteria {
+        for criterion in criteria {
+            content.push_str(&format!("- [ ] {criterion}\n"));
+        }
+    } else {
+        content.push_str("- [ ] Bug is fixed and verified\n");
+    }
+
+    fs::write(&filepath, &content).map_err(|e| format!("Failed to write bug file: {e}"))?;
+
+    let msg = format!("story-kit: create bug {bug_id}");
+    git_stage_and_commit(root, &[filepath.as_path()], &msg)?;
+
+    Ok(bug_id)
+}
+
+/// Extract the human-readable name from a bug file's first heading.
+fn extract_bug_name(path: &Path) -> Option<String> {
+    let contents = fs::read_to_string(path).ok()?;
+    for line in contents.lines() {
+        if let Some(rest) = line.strip_prefix("# Bug ") {
+            // Format: "N: Name"
+            if let Some(colon_pos) = rest.find(": ") {
+                return Some(rest[colon_pos + 2..].to_string());
+            }
+        }
+    }
+    None
+}
+
+/// List all open bugs — files directly in `.story_kit/bugs/` (excluding `archive/` subdir).
+///
+/// Returns a sorted list of `(bug_id, name)` pairs.
+pub fn list_bug_files(root: &Path) -> Result<Vec<(String, String)>, String> {
+    let bugs_dir = root.join(".story_kit").join("bugs");
+    if !bugs_dir.exists() {
+        return Ok(Vec::new());
+    }
+
+    let mut bugs = Vec::new();
+    for entry in
+        fs::read_dir(&bugs_dir).map_err(|e| format!("Failed to read bugs directory: {e}"))?
+    {
+        let entry = entry.map_err(|e| format!("Failed to read entry: {e}"))?;
+        let path = entry.path();
+
+        // Skip subdirectories (archive/)
+        if path.is_dir() {
+            continue;
+        }
+
+        if path.extension().and_then(|ext| ext.to_str()) != Some("md") {
+            continue;
+        }
+
+        let bug_id = path
+            .file_stem()
+            .and_then(|stem| stem.to_str())
+            .ok_or_else(|| "Invalid bug file name.".to_string())?
+            .to_string();
+
+        let name = extract_bug_name(&path).unwrap_or_else(|| bug_id.clone());
+        bugs.push((bug_id, name));
+    }
+
+    bugs.sort_by(|a, b| a.0.cmp(&b.0));
+    Ok(bugs)
+}
+
 /// Locate a story file by searching .story_kit/current/ then stories/upcoming/.
 fn find_story_file(project_root: &Path, story_id: &str) -> Result<PathBuf, String> {
     let filename = format!("{story_id}.md");
@@ -917,7 +1068,7 @@ pub fn validate_story_dirs(
             continue;
         }
         for entry in
-            fs::read_dir(&dir).map_err(|e| format!("Failed to read {subdir} directory: {e}"))?
+            fs::read_dir(dir).map_err(|e| format!("Failed to read {subdir} directory: {e}"))?
         {
             let entry = entry.map_err(|e| format!("Failed to read entry: {e}"))?;
             let path = entry.path();
@@ -1540,4 +1691,146 @@ mod tests {
         assert!(result.is_err());
         assert!(result.unwrap_err().contains("not found"));
     }
+
+    // ── Bug file helper tests ──────────────────────────────────────────────────
+
+    #[test]
+    fn next_bug_number_starts_at_1_when_empty() {
+        let tmp = tempfile::tempdir().unwrap();
+        assert_eq!(next_bug_number(tmp.path()).unwrap(), 1);
+    }
+
+    #[test]
+    fn next_bug_number_increments_from_existing() {
+        let tmp = tempfile::tempdir().unwrap();
+        let bugs_dir = tmp.path().join(".story_kit/bugs");
+        fs::create_dir_all(&bugs_dir).unwrap();
+        fs::write(bugs_dir.join("bug-1-crash.md"), "").unwrap();
+        fs::write(bugs_dir.join("bug-3-another.md"), "").unwrap();
+        assert_eq!(next_bug_number(tmp.path()).unwrap(), 4);
+    }
+
+    #[test]
+    fn next_bug_number_scans_archive_too() {
+        let tmp = tempfile::tempdir().unwrap();
+        let bugs_dir = tmp.path().join(".story_kit/bugs");
+        let archive_dir = bugs_dir.join("archive");
+        fs::create_dir_all(&bugs_dir).unwrap();
+        fs::create_dir_all(&archive_dir).unwrap();
+        fs::write(archive_dir.join("bug-5-old.md"), "").unwrap();
+        assert_eq!(next_bug_number(tmp.path()).unwrap(), 6);
+    }
+
+    #[test]
+    fn list_bug_files_empty_when_no_bugs_dir() {
+        let tmp = tempfile::tempdir().unwrap();
+        let result = list_bug_files(tmp.path()).unwrap();
+        assert!(result.is_empty());
+    }
+
+    #[test]
+    fn list_bug_files_excludes_archive_subdir() {
+        let tmp = tempfile::tempdir().unwrap();
+        let bugs_dir = tmp.path().join(".story_kit/bugs");
+        let archive_dir = bugs_dir.join("archive");
+        fs::create_dir_all(&bugs_dir).unwrap();
+        fs::create_dir_all(&archive_dir).unwrap();
+        fs::write(bugs_dir.join("bug-1-open.md"), "# Bug 1: Open Bug\n").unwrap();
+        fs::write(archive_dir.join("bug-2-closed.md"), "# Bug 2: Closed Bug\n").unwrap();
+
+        let result = list_bug_files(tmp.path()).unwrap();
+        assert_eq!(result.len(), 1);
+        assert_eq!(result[0].0, "bug-1-open");
+        assert_eq!(result[0].1, "Open Bug");
+    }
+
+    #[test]
+    fn list_bug_files_sorted_by_id() {
+        let tmp = tempfile::tempdir().unwrap();
+        let bugs_dir = tmp.path().join(".story_kit/bugs");
+        fs::create_dir_all(&bugs_dir).unwrap();
+        fs::write(bugs_dir.join("bug-3-third.md"), "# Bug 3: Third\n").unwrap();
+        fs::write(bugs_dir.join("bug-1-first.md"), "# Bug 1: First\n").unwrap();
+        fs::write(bugs_dir.join("bug-2-second.md"), "# Bug 2: Second\n").unwrap();
+
+        let result = list_bug_files(tmp.path()).unwrap();
+        assert_eq!(result.len(), 3);
+        assert_eq!(result[0].0, "bug-1-first");
+        assert_eq!(result[1].0, "bug-2-second");
+        assert_eq!(result[2].0, "bug-3-third");
+    }
+
+    #[test]
+    fn extract_bug_name_parses_heading() {
+        let tmp = tempfile::tempdir().unwrap();
+        let path = tmp.path().join("bug-1-crash.md");
+        fs::write(&path, "# Bug 1: Login page crashes\n\n## Description\n").unwrap();
+        let name = extract_bug_name(&path).unwrap();
+        assert_eq!(name, "Login page crashes");
+    }
+
+    #[test]
+    fn create_bug_file_writes_correct_content() {
+        let tmp = tempfile::tempdir().unwrap();
+        setup_git_repo(tmp.path());
+
+        let bug_id = create_bug_file(
+            tmp.path(),
+            "Login Crash",
+            "The login page crashes on submit.",
+            "1. Go to /login\n2. Click submit",
+            "Page crashes with 500 error",
+            "Login succeeds",
+            Some(&["Login form submits without error".to_string()]),
+        )
+        .unwrap();
+
+        assert_eq!(bug_id, "bug-1-login_crash");
+
+        let filepath = tmp
+            .path()
+            .join(".story_kit/bugs/bug-1-login_crash.md");
+        assert!(filepath.exists());
+        let contents = fs::read_to_string(&filepath).unwrap();
+        assert!(contents.contains("# Bug 1: Login Crash"));
+        assert!(contents.contains("## Description"));
+        assert!(contents.contains("The login page crashes on submit."));
+        assert!(contents.contains("## How to Reproduce"));
+        assert!(contents.contains("1. Go to /login"));
+        assert!(contents.contains("## Actual Result"));
+        assert!(contents.contains("Page crashes with 500 error"));
+        assert!(contents.contains("## Expected Result"));
+        assert!(contents.contains("Login succeeds"));
+        assert!(contents.contains("## Acceptance Criteria"));
+        assert!(contents.contains("- [ ] Login form submits without error"));
+    }
+
+    #[test]
+    fn create_bug_file_rejects_empty_name() {
+        let tmp = tempfile::tempdir().unwrap();
+        let result = create_bug_file(tmp.path(), "!!!", "desc", "steps", "actual", "expected", None);
+        assert!(result.is_err());
+        assert!(result.unwrap_err().contains("alphanumeric"));
+    }
+
+    #[test]
+    fn create_bug_file_uses_default_acceptance_criterion() {
+        let tmp = tempfile::tempdir().unwrap();
+        setup_git_repo(tmp.path());
+
+        create_bug_file(
+            tmp.path(),
+            "Some Bug",
+            "desc",
+            "steps",
+            "actual",
+            "expected",
+            None,
+        )
+        .unwrap();
+
+        let filepath = tmp.path().join(".story_kit/bugs/bug-1-some_bug.md");
+        let contents = fs::read_to_string(&filepath).unwrap();
+        assert!(contents.contains("- [ ] Bug is fixed and verified"));
+    }
 }