Story 53: Add QA agent role with request_qa MCP tool

- Add `qa` agent entry to `.story_kit/project.toml` with a detailed
  prompt covering code quality scan, test verification, manual testing
  support, and structured report generation
- Add `move_story_to_qa` function in `agents.rs` that moves a work item
  from `work/2_current/` to `work/3_qa/` and auto-commits (idempotent)
- Add `request_qa` MCP tool in `mcp.rs` that moves the story to
  `work/3_qa/` and starts the QA agent on the existing worktree
- Add unit tests for `move_story_to_qa` (moves, idempotent, error cases)
- Update `tools_list_returns_all_tools` test to expect 27 tools

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

.story_kit/project.toml

@@ -75,6 +75,72 @@ max_budget_usd = 5.00
 prompt = "You are working in a git worktree on story {{story_id}}. Read CLAUDE.md first, then .story_kit/README.md to understand the dev process. Pick up the story from .story_kit/work/ - move it to work/2_current/ if needed. Follow the SDTW process through implementation and verification (Steps 1-3). The worktree and feature branch already exist - do not create them. Check .mcp.json for MCP tools. Do NOT accept the story or merge - commit your work and stop. If the user asks to review your changes, tell them to run: cd \"{{worktree_path}}\" && git difftool {{base_branch}}...HEAD\n\nIMPORTANT: When all your work is committed, call report_completion as your FINAL action: report_completion(story_id='{{story_id}}', agent_name='{{agent_name}}', summary='<brief summary of what you implemented>'). The server will run cargo clippy and tests automatically to verify your work."
 system_prompt = "You are a full-stack engineer working autonomously in a git worktree. Follow the Story-Driven Test Workflow strictly. Run cargo clippy and biome checks before considering work complete. Commit all your work before finishing - use a descriptive commit message. Do not accept stories, move them to archived, or merge to master - a human will do that. Do not coordinate with other agents - focus on your assigned story. ALWAYS call report_completion as your absolute final action after committing."
 
+[[agent]]
+name = "qa"
+role = "Reviews coder work in worktrees: runs quality gates, generates testing plans, and reports findings."
+model = "sonnet"
+max_turns = 40
+max_budget_usd = 4.00
+prompt = """You are the QA agent for story {{story_id}}. Your job is to review the coder's work in the worktree and produce a structured QA report.
+
+Read CLAUDE.md first, then .story_kit/README.md to understand the dev process.
+
+## Your Workflow
+
+### 1. Code Quality Scan
+- Run `git diff master...HEAD --stat` to see what files changed
+- Run `git diff master...HEAD` to review the actual changes for obvious coding mistakes (unused imports, dead code, unhandled errors, hardcoded values)
+- Run `cargo clippy --all-targets --all-features` and note any warnings
+- If a `frontend/` directory exists:
+  - Run `pnpm run build` and note any TypeScript errors
+  - Run `npx @biomejs/biome check src/` and note any linting issues
+
+### 2. Test Verification
+- Run `cargo test` and verify all tests pass
+- If `frontend/` exists: run `pnpm test --run` and verify all frontend tests pass
+- Review test quality: look for tests that are trivial or don't assert meaningful behavior
+
+### 3. Manual Testing Support
+- Build the server: run `cargo build` and note success/failure
+- If build succeeds: find a free port (try 3010-3020) and attempt to start the server
+- Generate a testing plan including:
+  - URL to visit in the browser
+  - Things to check in the UI
+  - curl commands to exercise relevant API endpoints
+- Kill the test server when done: `pkill -f story-kit-server || true`
+
+### 4. Produce Structured Report
+Call report_completion as your FINAL action with a summary in this format:
+
+```
+## QA Report for {{story_id}}
+
+### Code Quality
+- clippy: PASS/FAIL (details)
+- TypeScript build: PASS/FAIL/SKIP (details)
+- Biome lint: PASS/FAIL/SKIP (details)
+- Code review findings: (list any issues found, or "None")
+
+### Test Verification
+- cargo test: PASS/FAIL (N tests)
+- pnpm test: PASS/FAIL/SKIP (N tests)
+- Test quality issues: (list any trivial/weak tests, or "None")
+
+### Manual Testing Plan
+- Server URL: http://localhost:PORT (or "Build failed")
+- Pages to visit: (list)
+- Things to check: (list)
+- curl commands: (list)
+
+### Overall: PASS/FAIL
+```
+
+## Rules
+- Do NOT modify any code — read-only review only
+- If the server fails to start, still provide the testing plan with curl commands
+- Call report_completion as your FINAL action"""
+system_prompt = "You are a QA agent. Your job is read-only: review code quality, run tests, try to start the server, and produce a structured QA report. Do not modify code. Call report_completion as your final action."
+
 [[agent]]
 name = "mergemaster"
 role = "Merges completed coder work into master, runs quality gates, archives stories, and cleans up worktrees."

server/src/agents.rs

@@ -943,6 +943,42 @@ pub fn move_story_to_merge(project_root: &Path, story_id: &str) -> Result<(), St
     )
 }
 
+/// Move a story/bug from `work/2_current/` to `work/3_qa/` and auto-commit.
+///
+/// This stages a work item for QA review before merging to master.
+/// Idempotent: if already in `3_qa/`, returns Ok without committing.
+pub fn move_story_to_qa(project_root: &Path, story_id: &str) -> Result<(), String> {
+    let sk = project_root.join(".story_kit").join("work");
+    let current_path = sk.join("2_current").join(format!("{story_id}.md"));
+    let qa_dir = sk.join("3_qa");
+    let qa_path = qa_dir.join(format!("{story_id}.md"));
+
+    if qa_path.exists() {
+        // Already in 3_qa/ — idempotent, nothing to do.
+        return Ok(());
+    }
+
+    if !current_path.exists() {
+        return Err(format!(
+            "Work item '{story_id}' not found in work/2_current/. Cannot move to 3_qa/."
+        ));
+    }
+
+    std::fs::create_dir_all(&qa_dir)
+        .map_err(|e| format!("Failed to create work/3_qa/ directory: {e}"))?;
+    std::fs::rename(&current_path, &qa_path)
+        .map_err(|e| format!("Failed to move '{story_id}' to 3_qa/: {e}"))?;
+
+    eprintln!("[lifecycle] Moved '{story_id}' from work/2_current/ to work/3_qa/");
+
+    let msg = format!("story-kit: queue {story_id} for QA");
+    git_stage_and_commit(
+        project_root,
+        &[qa_path.as_path(), current_path.as_path()],
+        &msg,
+    )
+}
+
 /// Move a bug from `work/2_current/` or `work/1_upcoming/` to `work/5_archived/` and auto-commit.
 ///
 /// * If the bug is in `2_current/`, it is moved to `5_archived/` and committed.
@@ -1901,6 +1937,75 @@ mod tests {
         assert!(result.unwrap_err().contains("not found in work/2_current/"));
     }
 
+    // ── move_story_to_qa tests ────────────────────────────────────────────────
+
+    #[test]
+    fn move_story_to_qa_moves_file_and_commits() {
+        use std::fs;
+        use tempfile::tempdir;
+
+        let tmp = tempdir().unwrap();
+        let repo = tmp.path();
+        init_git_repo(repo);
+
+        let current_dir = repo.join(".story_kit/work/2_current");
+        fs::create_dir_all(&current_dir).unwrap();
+        let story_file = current_dir.join("30_story_qa_test.md");
+        fs::write(&story_file, "---\nname: QA Test\ntest_plan: approved\n---\n").unwrap();
+
+        Command::new("git")
+            .args(["add", "."])
+            .current_dir(repo)
+            .output()
+            .unwrap();
+        Command::new("git")
+            .args(["commit", "-m", "add story"])
+            .current_dir(repo)
+            .output()
+            .unwrap();
+
+        move_story_to_qa(repo, "30_story_qa_test").unwrap();
+
+        let qa_path = repo.join(".story_kit/work/3_qa/30_story_qa_test.md");
+        assert!(!story_file.exists(), "2_current file should be gone");
+        assert!(qa_path.exists(), "3_qa file should exist");
+    }
+
+    #[test]
+    fn move_story_to_qa_idempotent_when_already_in_qa() {
+        use std::fs;
+        use tempfile::tempdir;
+
+        let tmp = tempdir().unwrap();
+        let repo = tmp.path();
+        init_git_repo(repo);
+
+        let qa_dir = repo.join(".story_kit/work/3_qa");
+        fs::create_dir_all(&qa_dir).unwrap();
+        fs::write(
+            qa_dir.join("31_story_test.md"),
+            "---\nname: Test\ntest_plan: approved\n---\n",
+        )
+        .unwrap();
+
+        // Should succeed without error even though there's nothing to move
+        move_story_to_qa(repo, "31_story_test").unwrap();
+        assert!(qa_dir.join("31_story_test.md").exists());
+    }
+
+    #[test]
+    fn move_story_to_qa_errors_when_not_in_current() {
+        use tempfile::tempdir;
+
+        let tmp = tempdir().unwrap();
+        let repo = tmp.path();
+        init_git_repo(repo);
+
+        let result = move_story_to_qa(repo, "99_nonexistent");
+        assert!(result.is_err());
+        assert!(result.unwrap_err().contains("not found in work/2_current/"));
+    }
+
     // ── move_story_to_archived with 4_merge source ────────────────────────────
 
     #[test]

server/src/http/mcp.rs

@@ -1,4 +1,4 @@
-use crate::agents::{close_bug_to_archive, move_story_to_archived, move_story_to_merge};
+use crate::agents::{close_bug_to_archive, move_story_to_archived, move_story_to_merge, move_story_to_qa};
 use crate::config::ProjectConfig;
 use crate::http::context::AppContext;
 use crate::http::settings::get_editor_command_from_store;
@@ -742,6 +742,24 @@ fn handle_tools_list(id: Option<Value>) -> JsonRpcResponse {
                         },
                         "required": ["story_id"]
                     }
+                },
+                {
+                    "name": "request_qa",
+                    "description": "Trigger QA review of a completed story worktree: moves the item from work/2_current/ to work/3_qa/ and starts the qa agent to run quality gates, tests, and generate a manual testing plan.",
+                    "inputSchema": {
+                        "type": "object",
+                        "properties": {
+                            "story_id": {
+                                "type": "string",
+                                "description": "Story identifier (e.g. '53_story_qa_agent_role')"
+                            },
+                            "agent_name": {
+                                "type": "string",
+                                "description": "Agent name to use for QA (defaults to 'qa')"
+                            }
+                        },
+                        "required": ["story_id"]
+                    }
                 }
             ]
         }),
@@ -797,6 +815,8 @@ async fn handle_tools_call(
         // Mergemaster tools
         "merge_agent_work" => tool_merge_agent_work(&args, ctx).await,
         "move_story_to_merge" => tool_move_story_to_merge(&args, ctx),
+        // QA tools
+        "request_qa" => tool_request_qa(&args, ctx).await,
         _ => Err(format!("Unknown tool: {tool_name}")),
     };
 
@@ -1360,6 +1380,42 @@ fn tool_move_story_to_merge(args: &Value, ctx: &AppContext) -> Result<String, St
     ))
 }
 
+// ── QA tool implementations ───────────────────────────────────────
+
+async fn tool_request_qa(args: &Value, ctx: &AppContext) -> Result<String, String> {
+    let story_id = args
+        .get("story_id")
+        .and_then(|v| v.as_str())
+        .ok_or("Missing required argument: story_id")?;
+    let agent_name = args
+        .get("agent_name")
+        .and_then(|v| v.as_str())
+        .unwrap_or("qa");
+
+    let project_root = ctx.agents.get_project_root(&ctx.state)?;
+
+    // Move story from work/2_current/ to work/3_qa/
+    move_story_to_qa(&project_root, story_id)?;
+
+    // Start the QA agent on the story worktree
+    let info = ctx
+        .agents
+        .start_agent(&project_root, story_id, Some(agent_name))
+        .await?;
+
+    serde_json::to_string_pretty(&json!({
+        "story_id": info.story_id,
+        "agent_name": info.agent_name,
+        "status": info.status.to_string(),
+        "worktree_path": info.worktree_path,
+        "message": format!(
+            "Story '{story_id}' moved to work/3_qa/ and QA agent '{}' started.",
+            info.agent_name
+        ),
+    }))
+    .map_err(|e| format!("Serialization error: {e}"))
+}
+
 /// 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>> {
@@ -1519,7 +1575,8 @@ mod tests {
         assert!(names.contains(&"close_bug"));
         assert!(names.contains(&"merge_agent_work"));
         assert!(names.contains(&"move_story_to_merge"));
-        assert_eq!(tools.len(), 26);
+        assert!(names.contains(&"request_qa"));
+        assert_eq!(tools.len(), 27);
     }
 
     #[test]