diff --git a/CLAUDE.md b/CLAUDE.md
index be6e462..561098a 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -7,7 +7,7 @@ An open-source tool combining LLM intelligence + static analysis to produce inte
 - **Monorepo** with pnpm workspaces
 - **packages/core** — Shared analysis engine (types, persistence, tree-sitter plugin, LLM prompt templates)
 - **packages/dashboard** — React + TypeScript web dashboard (React Flow, Monaco Editor, Zustand, TailwindCSS)
-- **packages/skill** — Claude Code skill (not yet implemented)
+- **packages/skill** — Claude Code skill (`/understand-chat` command)
 
 ## Key Commands
 - `pnpm install` — Install all dependencies
@@ -15,6 +15,20 @@ An open-source tool combining LLM intelligence + static analysis to produce inte
 - `pnpm --filter @understand-anything/core test` — Run core tests
 - `pnpm dev:dashboard` — Start dashboard dev server
 
+## Key Commands (updated)
+- `pnpm --filter @understand-anything/skill build` — Build skill package
+- `pnpm --filter @understand-anything/skill test` — Run skill tests
+
+## Phase 2 Features
+- Fuzzy search via Fuse.js (SearchEngine in core)
+- Zod schema validation on graph loading
+- Staleness detection + incremental graph merging
+- Layer auto-detection (heuristic + LLM prompt)
+- `/understand-chat` skill command
+- Dashboard chat panel (Claude API integration)
+- Dagre auto-layout for graph visualization
+- Layer visualization with grouping and legend
+
 ## Conventions
 - TypeScript strict mode everywhere
 - Vitest for testing
diff --git a/README.md b/README.md
index 33ca4c1..6d139ec 100644
--- a/README.md
+++ b/README.md
@@ -2,14 +2,29 @@
 
 An open-source tool that combines LLM intelligence with static analysis to help anyone understand any codebase — from junior developers to product managers.
 
+## Current Status
+
+**Phase 2 complete.** The core analysis engine, web dashboard, and Claude Code skill are all functional. The project includes fuzzy search, schema validation, staleness detection, layer auto-detection, and an interactive chat interface.
+
 ## Features
 
+### Phase 1 — Foundation
 - **Knowledge Graph** — Automatically maps your codebase into an interactive graph of files, functions, classes, and their relationships
 - **Multi-Panel Dashboard** — Graph view, code viewer, chat, and learn panels in a workspace layout
 - **Natural Language Search** — Search your codebase with plain English: "which parts handle authentication?"
 - **Tree-sitter Analysis** — Accurate structural analysis for TypeScript, JavaScript (more languages coming)
 - **LLM-Powered Summaries** — Every node gets a plain-English description of what it does and why
 
+### Phase 2 — Intelligence
+- **Fuzzy Search** — Fast, typo-tolerant search across all graph nodes via Fuse.js (SearchEngine in core)
+- **Schema Validation** — Zod-based runtime validation when loading knowledge graphs, with detailed error messages
+- **Staleness Detection** — Detects changed files via git diff and incrementally merges graph updates
+- **Layer Auto-Detection** — Heuristic-based layer grouping (API, Service, Data, UI, Utility) with LLM refinement
+- **`/understand-chat` Skill** — Ask questions about your codebase directly in the terminal via Claude Code
+- **Dashboard Chat Panel** — Context-aware Q&A integrated into the web dashboard (Claude API)
+- **Dagre Auto-Layout** — Automatic hierarchical graph layout for clean visualization
+- **Layer Visualization** — Color-coded layer grouping with collapsible groups and a legend panel
+
 ## Quick Start
 
 ```bash
@@ -19,17 +34,41 @@ pnpm install
 # Build the core package
 pnpm --filter @understand-anything/core build
 
+# Build the skill package
+pnpm --filter @understand-anything/skill build
+
 # Start the dashboard dev server
 pnpm dev:dashboard
 ```
 
+## Commands
+
+| Command | Description |
+|---------|-------------|
+| `pnpm install` | Install all dependencies |
+| `pnpm --filter @understand-anything/core build` | Build the core package |
+| `pnpm --filter @understand-anything/core test` | Run core tests |
+| `pnpm --filter @understand-anything/skill build` | Build the skill package |
+| `pnpm --filter @understand-anything/skill test` | Run skill tests |
+| `pnpm --filter @understand-anything/dashboard build` | Build the dashboard |
+| `pnpm dev:dashboard` | Start dashboard dev server |
+
+### Claude Code Skill
+
+Once installed as a Claude Code skill, use the `/understand-chat` command to ask questions about your codebase directly in the terminal:
+
+```
+/understand-chat How does authentication work in this project?
+/understand-chat What files are related to the payment system?
+```
+
 ## Project Structure
 
 ```
 packages/
-  core/        — Analysis engine: types, persistence, tree-sitter, LLM prompts
-  dashboard/   — React + TypeScript web dashboard
-  skill/       — Claude Code skill (coming soon)
+  core/        — Analysis engine: types, persistence, tree-sitter, search, schema, staleness, layers
+  dashboard/   — React + TypeScript web dashboard with chat panel
+  skill/       — Claude Code skill (/understand-chat command)
 ```
 
 ## Tech Stack
@@ -40,6 +79,9 @@ packages/
 - Monaco Editor (code viewer)
 - Zustand (state management)
 - tree-sitter (static analysis)
+- Fuse.js (fuzzy search)
+- Zod (schema validation)
+- Dagre (graph layout)
 
 ## License
 
diff --git a/packages/dashboard/public/knowledge-graph.json b/packages/dashboard/public/knowledge-graph.json
index 7051021..9ced329 100644
--- a/packages/dashboard/public/knowledge-graph.json
+++ b/packages/dashboard/public/knowledge-graph.json
@@ -1,46 +1,528 @@
 {
   "version": "1.0.0",
   "project": {
-    "name": "sample-project",
+    "name": "taskflow-api",
     "languages": ["typescript"],
-    "frameworks": ["express"],
-    "description": "A sample Express API",
-    "analyzedAt": "2026-03-14T00:00:00.000Z",
-    "gitCommitHash": "abc123"
+    "frameworks": ["express", "prisma", "zod"],
+    "description": "A task management REST API built with Express and Prisma. Supports user authentication, project workspaces, task CRUD with assignments, and real-time notifications via WebSocket. Designed for team collaboration with role-based access control.",
+    "analyzedAt": "2026-03-14T12:00:00.000Z",
+    "gitCommitHash": "a1b2c3d4e5f6"
   },
   "nodes": [
-    {"id": "file:src/index.ts", "type": "file", "name": "index.ts", "filePath": "src/index.ts", "summary": "Application entry point, starts the Express server", "tags": ["entry", "server"], "complexity": "simple"},
-    {"id": "file:src/auth/login.ts", "type": "file", "name": "login.ts", "filePath": "src/auth/login.ts", "summary": "Handles user authentication and login flow", "tags": ["auth", "login"], "complexity": "moderate"},
-    {"id": "func:src/auth/login.ts:handleLogin", "type": "function", "name": "handleLogin", "filePath": "src/auth/login.ts", "lineRange": [10, 35], "summary": "Validates credentials and returns a JWT token", "tags": ["auth", "jwt"], "complexity": "moderate"},
-    {"id": "func:src/auth/login.ts:validateEmail", "type": "function", "name": "validateEmail", "filePath": "src/auth/login.ts", "lineRange": [37, 42], "summary": "Checks if an email address is valid using regex", "tags": ["validation", "email"], "complexity": "simple"},
-    {"id": "file:src/db/connection.ts", "type": "file", "name": "connection.ts", "filePath": "src/db/connection.ts", "summary": "Database connection pool using PostgreSQL", "tags": ["database", "postgres"], "complexity": "moderate"}
+    {
+      "id": "file:src/index.ts",
+      "type": "file",
+      "name": "index.ts",
+      "filePath": "src/index.ts",
+      "summary": "Application entry point. Initializes the Express server, applies middleware, mounts route handlers, and starts listening on the configured port.",
+      "tags": ["entry", "server", "express"],
+      "complexity": "moderate"
+    },
+    {
+      "id": "file:src/routes/task.routes.ts",
+      "type": "file",
+      "name": "task.routes.ts",
+      "filePath": "src/routes/task.routes.ts",
+      "summary": "Defines REST endpoints for task CRUD operations: GET /tasks, POST /tasks, PATCH /tasks/:id, DELETE /tasks/:id. Validates request bodies with Zod schemas before delegating to TaskService.",
+      "tags": ["routes", "tasks", "rest"],
+      "complexity": "moderate"
+    },
+    {
+      "id": "file:src/routes/auth.routes.ts",
+      "type": "file",
+      "name": "auth.routes.ts",
+      "filePath": "src/routes/auth.routes.ts",
+      "summary": "Authentication routes: POST /auth/login, POST /auth/register, POST /auth/refresh. Handles credential validation and JWT token issuance.",
+      "tags": ["routes", "auth", "jwt"],
+      "complexity": "moderate"
+    },
+    {
+      "id": "file:src/routes/project.routes.ts",
+      "type": "file",
+      "name": "project.routes.ts",
+      "filePath": "src/routes/project.routes.ts",
+      "summary": "Project workspace endpoints: CRUD for projects plus member management. Enforces role-based access so only admins can modify project settings.",
+      "tags": ["routes", "projects", "rbac"],
+      "complexity": "moderate"
+    },
+    {
+      "id": "file:src/services/task.service.ts",
+      "type": "file",
+      "name": "task.service.ts",
+      "filePath": "src/services/task.service.ts",
+      "summary": "Business logic for tasks. Handles creation, status transitions, assignment, due-date validation, and triggers notifications on state changes.",
+      "tags": ["service", "tasks", "business-logic"],
+      "complexity": "complex"
+    },
+    {
+      "id": "func:src/services/task.service.ts:createTask",
+      "type": "function",
+      "name": "createTask",
+      "filePath": "src/services/task.service.ts",
+      "lineRange": [24, 58],
+      "summary": "Creates a new task in the database. Validates the assignee belongs to the project, sets default status to 'todo', and publishes a TASK_CREATED event to the notification service.",
+      "tags": ["create", "validation", "events"],
+      "complexity": "moderate"
+    },
+    {
+      "id": "func:src/services/task.service.ts:transitionStatus",
+      "type": "function",
+      "name": "transitionStatus",
+      "filePath": "src/services/task.service.ts",
+      "lineRange": [60, 102],
+      "summary": "Moves a task through its lifecycle (todo -> in_progress -> review -> done). Enforces valid transitions and records the state change timestamp.",
+      "tags": ["state-machine", "workflow", "validation"],
+      "complexity": "complex"
+    },
+    {
+      "id": "file:src/services/auth.service.ts",
+      "type": "file",
+      "name": "auth.service.ts",
+      "filePath": "src/services/auth.service.ts",
+      "summary": "Authentication service handling password hashing with bcrypt, JWT token generation/verification, and refresh token rotation.",
+      "tags": ["service", "auth", "security"],
+      "complexity": "complex"
+    },
+    {
+      "id": "file:src/services/notification.service.ts",
+      "type": "file",
+      "name": "notification.service.ts",
+      "filePath": "src/services/notification.service.ts",
+      "summary": "Manages real-time notifications via WebSocket. Subscribes to domain events (task created, assigned, status changed) and broadcasts to relevant connected clients.",
+      "tags": ["service", "websocket", "events", "realtime"],
+      "complexity": "complex"
+    },
+    {
+      "id": "class:src/models/Task.ts:Task",
+      "type": "class",
+      "name": "Task",
+      "filePath": "src/models/Task.ts",
+      "lineRange": [8, 45],
+      "summary": "Prisma model wrapper for tasks. Defines the schema fields (title, description, status, priority, dueDate, assigneeId, projectId) and provides static query helpers.",
+      "tags": ["model", "prisma", "database"],
+      "complexity": "moderate"
+    },
+    {
+      "id": "class:src/models/User.ts:User",
+      "type": "class",
+      "name": "User",
+      "filePath": "src/models/User.ts",
+      "lineRange": [5, 38],
+      "summary": "Prisma model wrapper for users. Stores email, hashed password, display name, and role. Provides methods for credential verification and profile serialization.",
+      "tags": ["model", "prisma", "auth"],
+      "complexity": "moderate"
+    },
+    {
+      "id": "file:src/db/prisma.ts",
+      "type": "file",
+      "name": "prisma.ts",
+      "filePath": "src/db/prisma.ts",
+      "summary": "Singleton Prisma client instance. Configures connection pooling, logging levels, and graceful shutdown hooks.",
+      "tags": ["database", "prisma", "connection"],
+      "complexity": "simple"
+    },
+    {
+      "id": "file:src/middleware/auth.middleware.ts",
+      "type": "file",
+      "name": "auth.middleware.ts",
+      "filePath": "src/middleware/auth.middleware.ts",
+      "summary": "Express middleware that extracts and verifies JWT from the Authorization header. Attaches the decoded user payload to req.user for downstream handlers.",
+      "tags": ["middleware", "auth", "jwt"],
+      "complexity": "moderate"
+    },
+    {
+      "id": "func:src/middleware/auth.middleware.ts:requireRole",
+      "type": "function",
+      "name": "requireRole",
+      "filePath": "src/middleware/auth.middleware.ts",
+      "lineRange": [28, 44],
+      "summary": "Higher-order middleware factory that checks if the authenticated user has one of the required roles. Returns 403 Forbidden if the role check fails.",
+      "tags": ["rbac", "authorization", "middleware"],
+      "complexity": "simple"
+    },
+    {
+      "id": "file:src/utils/validate.ts",
+      "type": "file",
+      "name": "validate.ts",
+      "filePath": "src/utils/validate.ts",
+      "summary": "Shared Zod schemas and a validateBody middleware factory. Schemas cover task creation, user registration, and project settings validation.",
+      "tags": ["validation", "zod", "schemas"],
+      "complexity": "simple"
+    },
+    {
+      "id": "file:src/utils/logger.ts",
+      "type": "file",
+      "name": "logger.ts",
+      "filePath": "src/utils/logger.ts",
+      "summary": "Structured logging utility built on pino. Provides log levels (debug, info, warn, error) and request-scoped child loggers with correlation IDs.",
+      "tags": ["logging", "pino", "observability"],
+      "complexity": "simple"
+    },
+    {
+      "id": "file:src/config.ts",
+      "type": "file",
+      "name": "config.ts",
+      "filePath": "src/config.ts",
+      "summary": "Loads environment variables and exports typed configuration: port, database URL, JWT secret, token expiry, log level, and WebSocket settings.",
+      "tags": ["config", "env", "settings"],
+      "complexity": "simple"
+    },
+    {
+      "id": "module:src/routes",
+      "type": "module",
+      "name": "routes",
+      "filePath": "src/routes",
+      "summary": "Route module aggregating all HTTP endpoint definitions. Each route file maps URL paths to controller logic with middleware chains.",
+      "tags": ["module", "routing", "api"],
+      "complexity": "simple"
+    },
+    {
+      "id": "concept:authentication-flow",
+      "type": "concept",
+      "name": "Authentication Flow",
+      "summary": "The system uses JWT-based stateless authentication. Users log in with email/password, receive an access token (15 min) and refresh token (7 days). The auth middleware validates tokens on protected routes, and the refresh endpoint rotates tokens to maintain sessions.",
+      "tags": ["concept", "auth", "jwt", "security"],
+      "complexity": "complex"
+    },
+    {
+      "id": "concept:task-lifecycle",
+      "type": "concept",
+      "name": "Task Lifecycle",
+      "summary": "Tasks follow a state machine: todo -> in_progress -> review -> done. Only valid forward transitions are allowed. Each transition triggers a notification event and records a timestamp. Tasks can also be archived after completion.",
+      "tags": ["concept", "workflow", "state-machine"],
+      "complexity": "moderate"
+    }
   ],
   "edges": [
-    {"source": "file:src/index.ts", "target": "file:src/auth/login.ts", "type": "imports", "direction": "forward", "weight": 0.7},
-    {"source": "file:src/auth/login.ts", "target": "func:src/auth/login.ts:handleLogin", "type": "contains", "direction": "forward", "weight": 1.0},
-    {"source": "file:src/auth/login.ts", "target": "func:src/auth/login.ts:validateEmail", "type": "contains", "direction": "forward", "weight": 1.0},
-    {"source": "func:src/auth/login.ts:handleLogin", "target": "func:src/auth/login.ts:validateEmail", "type": "calls", "direction": "forward", "description": "handleLogin calls validateEmail to check the email format", "weight": 0.8},
-    {"source": "file:src/auth/login.ts", "target": "file:src/db/connection.ts", "type": "imports", "direction": "forward", "weight": 0.7}
+    {
+      "source": "file:src/index.ts",
+      "target": "file:src/routes/task.routes.ts",
+      "type": "imports",
+      "direction": "forward",
+      "description": "Mounts task routes at /api/tasks",
+      "weight": 0.8
+    },
+    {
+      "source": "file:src/index.ts",
+      "target": "file:src/routes/auth.routes.ts",
+      "type": "imports",
+      "direction": "forward",
+      "description": "Mounts auth routes at /api/auth",
+      "weight": 0.8
+    },
+    {
+      "source": "file:src/index.ts",
+      "target": "file:src/routes/project.routes.ts",
+      "type": "imports",
+      "direction": "forward",
+      "description": "Mounts project routes at /api/projects",
+      "weight": 0.8
+    },
+    {
+      "source": "file:src/index.ts",
+      "target": "file:src/config.ts",
+      "type": "imports",
+      "direction": "forward",
+      "description": "Reads server port and startup configuration",
+      "weight": 0.6
+    },
+    {
+      "source": "file:src/index.ts",
+      "target": "file:src/middleware/auth.middleware.ts",
+      "type": "middleware",
+      "direction": "forward",
+      "description": "Applies JWT auth middleware globally to protected routes",
+      "weight": 0.7
+    },
+    {
+      "source": "module:src/routes",
+      "target": "file:src/routes/task.routes.ts",
+      "type": "contains",
+      "direction": "forward",
+      "weight": 1.0
+    },
+    {
+      "source": "module:src/routes",
+      "target": "file:src/routes/auth.routes.ts",
+      "type": "contains",
+      "direction": "forward",
+      "weight": 1.0
+    },
+    {
+      "source": "module:src/routes",
+      "target": "file:src/routes/project.routes.ts",
+      "type": "contains",
+      "direction": "forward",
+      "weight": 1.0
+    },
+    {
+      "source": "file:src/routes/task.routes.ts",
+      "target": "file:src/services/task.service.ts",
+      "type": "calls",
+      "direction": "forward",
+      "description": "Delegates task operations to the service layer",
+      "weight": 0.9
+    },
+    {
+      "source": "file:src/routes/task.routes.ts",
+      "target": "file:src/utils/validate.ts",
+      "type": "validates",
+      "direction": "forward",
+      "description": "Uses Zod schemas to validate incoming task payloads",
+      "weight": 0.7
+    },
+    {
+      "source": "file:src/routes/auth.routes.ts",
+      "target": "file:src/services/auth.service.ts",
+      "type": "calls",
+      "direction": "forward",
+      "description": "Delegates login, register, and token refresh to auth service",
+      "weight": 0.9
+    },
+    {
+      "source": "file:src/routes/project.routes.ts",
+      "target": "file:src/middleware/auth.middleware.ts",
+      "type": "depends_on",
+      "direction": "forward",
+      "description": "Requires authentication and role checking on all endpoints",
+      "weight": 0.8
+    },
+    {
+      "source": "file:src/services/task.service.ts",
+      "target": "func:src/services/task.service.ts:createTask",
+      "type": "contains",
+      "direction": "forward",
+      "weight": 1.0
+    },
+    {
+      "source": "file:src/services/task.service.ts",
+      "target": "func:src/services/task.service.ts:transitionStatus",
+      "type": "contains",
+      "direction": "forward",
+      "weight": 1.0
+    },
+    {
+      "source": "file:src/services/task.service.ts",
+      "target": "class:src/models/Task.ts:Task",
+      "type": "reads_from",
+      "direction": "forward",
+      "description": "Queries and mutates task records via the Task model",
+      "weight": 0.9
+    },
+    {
+      "source": "file:src/services/task.service.ts",
+      "target": "file:src/services/notification.service.ts",
+      "type": "publishes",
+      "direction": "forward",
+      "description": "Emits TASK_CREATED and STATUS_CHANGED events to the notification service",
+      "weight": 0.7
+    },
+    {
+      "source": "file:src/services/auth.service.ts",
+      "target": "class:src/models/User.ts:User",
+      "type": "reads_from",
+      "direction": "forward",
+      "description": "Looks up users for authentication and creates new user records",
+      "weight": 0.9
+    },
+    {
+      "source": "file:src/services/auth.service.ts",
+      "target": "file:src/config.ts",
+      "type": "configures",
+      "direction": "backward",
+      "description": "Reads JWT secret and token expiry from configuration",
+      "weight": 0.6
+    },
+    {
+      "source": "file:src/services/notification.service.ts",
+      "target": "file:src/utils/logger.ts",
+      "type": "depends_on",
+      "direction": "forward",
+      "description": "Logs WebSocket connection events and notification delivery",
+      "weight": 0.5
+    },
+    {
+      "source": "class:src/models/Task.ts:Task",
+      "target": "file:src/db/prisma.ts",
+      "type": "depends_on",
+      "direction": "forward",
+      "description": "Uses the shared Prisma client for all database queries",
+      "weight": 0.9
+    },
+    {
+      "source": "class:src/models/User.ts:User",
+      "target": "file:src/db/prisma.ts",
+      "type": "depends_on",
+      "direction": "forward",
+      "description": "Uses the shared Prisma client for user queries",
+      "weight": 0.9
+    },
+    {
+      "source": "file:src/middleware/auth.middleware.ts",
+      "target": "file:src/middleware/auth.middleware.ts",
+      "type": "contains",
+      "direction": "forward",
+      "weight": 1.0
+    },
+    {
+      "source": "file:src/middleware/auth.middleware.ts",
+      "target": "func:src/middleware/auth.middleware.ts:requireRole",
+      "type": "contains",
+      "direction": "forward",
+      "weight": 1.0
+    },
+    {
+      "source": "concept:authentication-flow",
+      "target": "file:src/services/auth.service.ts",
+      "type": "related",
+      "direction": "forward",
+      "description": "Auth service implements the core authentication flow",
+      "weight": 0.9
+    },
+    {
+      "source": "concept:authentication-flow",
+      "target": "file:src/middleware/auth.middleware.ts",
+      "type": "related",
+      "direction": "forward",
+      "description": "Auth middleware enforces the authentication flow on routes",
+      "weight": 0.8
+    },
+    {
+      "source": "concept:task-lifecycle",
+      "target": "func:src/services/task.service.ts:transitionStatus",
+      "type": "related",
+      "direction": "forward",
+      "description": "The transitionStatus function implements the task state machine",
+      "weight": 0.9
+    },
+    {
+      "source": "concept:task-lifecycle",
+      "target": "file:src/services/notification.service.ts",
+      "type": "related",
+      "direction": "forward",
+      "description": "Lifecycle transitions trigger real-time notifications",
+      "weight": 0.7
+    },
+    {
+      "source": "func:src/services/task.service.ts:createTask",
+      "target": "file:src/utils/validate.ts",
+      "type": "validates",
+      "direction": "forward",
+      "description": "Validates task data before persisting",
+      "weight": 0.6
+    }
   ],
   "layers": [
     {
       "id": "layer:api",
       "name": "API Layer",
-      "description": "Entry points and route handlers for the Express API",
-      "nodeIds": ["file:src/index.ts", "file:src/auth/login.ts"]
+      "description": "HTTP route handlers and request/response processing. The entry point for all client interactions with the system.",
+      "nodeIds": [
+        "file:src/index.ts",
+        "file:src/routes/task.routes.ts",
+        "file:src/routes/auth.routes.ts",
+        "file:src/routes/project.routes.ts",
+        "module:src/routes"
+      ]
     },
     {
-      "id": "layer:auth",
-      "name": "Auth Logic",
-      "description": "Authentication and validation business logic",
-      "nodeIds": ["func:src/auth/login.ts:handleLogin", "func:src/auth/login.ts:validateEmail"]
+      "id": "layer:service",
+      "name": "Service Layer",
+      "description": "Core business logic and domain operations. Orchestrates data access, validation, event publishing, and enforces business rules.",
+      "nodeIds": [
+        "file:src/services/task.service.ts",
+        "func:src/services/task.service.ts:createTask",
+        "func:src/services/task.service.ts:transitionStatus",
+        "file:src/services/auth.service.ts",
+        "file:src/services/notification.service.ts"
+      ]
     },
     {
       "id": "layer:data",
       "name": "Data Layer",
-      "description": "Database connections and data access",
-      "nodeIds": ["file:src/db/connection.ts"]
+      "description": "Database models, Prisma client, and data access patterns. Provides the persistence foundation for all domain entities.",
+      "nodeIds": [
+        "class:src/models/Task.ts:Task",
+        "class:src/models/User.ts:User",
+        "file:src/db/prisma.ts"
+      ]
+    },
+    {
+      "id": "layer:middleware",
+      "name": "Middleware Layer",
+      "description": "Cross-cutting concerns applied to request pipelines: authentication, authorization, and request validation.",
+      "nodeIds": [
+        "file:src/middleware/auth.middleware.ts",
+        "func:src/middleware/auth.middleware.ts:requireRole",
+        "file:src/utils/validate.ts"
+      ]
+    },
+    {
+      "id": "layer:infrastructure",
+      "name": "Infrastructure Layer",
+      "description": "Configuration, logging, and shared utilities that support all other layers without containing business logic.",
+      "nodeIds": [
+        "file:src/config.ts",
+        "file:src/utils/logger.ts",
+        "concept:authentication-flow",
+        "concept:task-lifecycle"
+      ]
     }
   ],
-  "tour": []
+  "tour": [
+    {
+      "order": 1,
+      "title": "Where It All Begins",
+      "description": "The application starts in index.ts, which wires up Express middleware and mounts all the route handlers. Think of it as the front door of the API.",
+      "nodeIds": ["file:src/index.ts"]
+    },
+    {
+      "order": 2,
+      "title": "Handling Requests",
+      "description": "Incoming HTTP requests hit the route files. Each route file defines endpoints for a domain area (tasks, auth, projects) and validates input before passing it along.",
+      "nodeIds": [
+        "file:src/routes/task.routes.ts",
+        "file:src/routes/auth.routes.ts",
+        "file:src/routes/project.routes.ts"
+      ]
+    },
+    {
+      "order": 3,
+      "title": "Security Gate",
+      "description": "Before most routes run, the auth middleware checks the JWT token. The requireRole function adds role-based access control on top of basic authentication.",
+      "nodeIds": [
+        "file:src/middleware/auth.middleware.ts",
+        "func:src/middleware/auth.middleware.ts:requireRole"
+      ],
+      "languageLesson": "JWT (JSON Web Token) is a compact token format that encodes user identity and permissions. It lets the server verify who you are without storing session data."
+    },
+    {
+      "order": 4,
+      "title": "Business Logic",
+      "description": "Services contain the real brains of the application. TaskService manages task creation and status transitions, while AuthService handles password hashing and token management.",
+      "nodeIds": [
+        "file:src/services/task.service.ts",
+        "func:src/services/task.service.ts:createTask",
+        "func:src/services/task.service.ts:transitionStatus",
+        "file:src/services/auth.service.ts"
+      ]
+    },
+    {
+      "order": 5,
+      "title": "Data Persistence",
+      "description": "The Task and User models wrap Prisma queries. They talk to the database through a shared Prisma client configured in prisma.ts.",
+      "nodeIds": [
+        "class:src/models/Task.ts:Task",
+        "class:src/models/User.ts:User",
+        "file:src/db/prisma.ts"
+      ],
+      "languageLesson": "Prisma is an ORM (Object-Relational Mapper) that lets you write database queries in TypeScript instead of raw SQL. It auto-generates types from your schema."
+    },
+    {
+      "order": 6,
+      "title": "Real-Time Updates",
+      "description": "When tasks change state, the notification service broadcasts updates over WebSocket so connected clients see changes immediately without polling.",
+      "nodeIds": ["file:src/services/notification.service.ts"]
+    }
+  ]
 }