diff --git a/app/main.py b/app/main.py
index 3779b1d..14b333b 100644
--- a/app/main.py
+++ b/app/main.py
@@ -21,6 +21,7 @@ class UserCreate(BaseModel):
     """Request body for creating a new user."""
     name: str = Field(..., description="Full name of the user")
     email: str = Field(..., description="Email address")
+    role: str = Field("member", description="User role")
 
 
 class User(BaseModel):
@@ -28,6 +29,7 @@ class User(BaseModel):
     id: int = Field(..., description="Unique user identifier")
     name: str = Field(..., description="Full name of the user")
     email: str = Field(..., description="Email address")
+    role: str = Field("member", description="User role")
 
 
 class HealthResponse(BaseModel):
@@ -92,7 +94,7 @@ def get_user(user_id: int) -> User:
 def create_user(body: UserCreate) -> User:
     """Create a new user and return the created resource."""
     global _next_id
-    user = User(id=_next_id, name=body.name, email=body.email)
+    user = User(id=_next_id, name=body.name, email=body.email, role=body.role)
     _users_db[_next_id] = user
     _next_id += 1
     return user
diff --git a/artifacts/openapi_baseline.json b/artifacts/openapi_baseline.json
new file mode 100644
index 0000000..b738e51
--- /dev/null
+++ b/artifacts/openapi_baseline.json
@@ -0,0 +1,298 @@
+{
+  "components": {
+    "schemas": {
+      "HTTPValidationError": {
+        "properties": {
+          "detail": {
+            "items": {
+              "$ref": "#/components/schemas/ValidationError"
+            },
+            "title": "Detail",
+            "type": "array"
+          }
+        },
+        "title": "HTTPValidationError",
+        "type": "object"
+      },
+      "HealthResponse": {
+        "description": "Health-check response.",
+        "properties": {
+          "status": {
+            "description": "Service status",
+            "examples": [
+              "ok"
+            ],
+            "title": "Status",
+            "type": "string"
+          }
+        },
+        "required": [
+          "status"
+        ],
+        "title": "HealthResponse",
+        "type": "object"
+      },
+      "User": {
+        "description": "Representation of a user returned by the API.",
+        "properties": {
+          "email": {
+            "description": "Email address",
+            "title": "Email",
+            "type": "string"
+          },
+          "id": {
+            "description": "Unique user identifier",
+            "title": "Id",
+            "type": "integer"
+          },
+          "name": {
+            "description": "Full name of the user",
+            "title": "Name",
+            "type": "string"
+          },
+          "role": {
+            "default": "member",
+            "description": "User role",
+            "title": "Role",
+            "type": "string"
+          }
+        },
+        "required": [
+          "id",
+          "name",
+          "email"
+        ],
+        "title": "User",
+        "type": "object"
+      },
+      "UserCreate": {
+        "description": "Request body for creating a new user.",
+        "properties": {
+          "email": {
+            "description": "Email address",
+            "title": "Email",
+            "type": "string"
+          },
+          "name": {
+            "description": "Full name of the user",
+            "title": "Name",
+            "type": "string"
+          },
+          "role": {
+            "default": "member",
+            "description": "User role",
+            "title": "Role",
+            "type": "string"
+          }
+        },
+        "required": [
+          "name",
+          "email"
+        ],
+        "title": "UserCreate",
+        "type": "object"
+      },
+      "ValidationError": {
+        "properties": {
+          "ctx": {
+            "title": "Context",
+            "type": "object"
+          },
+          "input": {
+            "title": "Input"
+          },
+          "loc": {
+            "items": {
+              "anyOf": [
+                {
+                  "type": "string"
+                },
+                {
+                  "type": "integer"
+                }
+              ]
+            },
+            "title": "Location",
+            "type": "array"
+          },
+          "msg": {
+            "title": "Message",
+            "type": "string"
+          },
+          "type": {
+            "title": "Error Type",
+            "type": "string"
+          }
+        },
+        "required": [
+          "loc",
+          "msg",
+          "type"
+        ],
+        "title": "ValidationError",
+        "type": "object"
+      }
+    }
+  },
+  "info": {
+    "description": "A minimal enterprise API used to demonstrate Docs Drift Guard.",
+    "title": "Enterprise User API",
+    "version": "1.0.0"
+  },
+  "openapi": "3.1.0",
+  "paths": {
+    "/health": {
+      "get": {
+        "description": "Return the current health status of the service.",
+        "operationId": "health_check_health_get",
+        "responses": {
+          "200": {
+            "content": {
+              "application/json": {
+                "schema": {
+                  "$ref": "#/components/schemas/HealthResponse"
+                }
+              }
+            },
+            "description": "Successful Response"
+          }
+        },
+        "summary": "Health check",
+        "tags": [
+          "health"
+        ]
+      }
+    },
+    "/v1/audit": {
+      "delete": {
+        "description": "Clear all recorded mismatches.",
+        "operationId": "clear_audit_log_v1_audit_delete",
+        "responses": {
+          "200": {
+            "content": {
+              "application/json": {
+                "schema": {
+                  "additionalProperties": true,
+                  "title": "Response Clear Audit Log V1 Audit Delete",
+                  "type": "object"
+                }
+              }
+            },
+            "description": "Successful Response"
+          }
+        },
+        "summary": "Clear the audit log",
+        "tags": [
+          "audit"
+        ]
+      },
+      "get": {
+        "description": "Return all API call mismatches recorded by the middleware.\nUseful for identifying clients that are using stale field names\nor calling endpoints that don't exist.",
+        "operationId": "get_audit_log_v1_audit_get",
+        "responses": {
+          "200": {
+            "content": {
+              "application/json": {
+                "schema": {
+                  "additionalProperties": true,
+                  "title": "Response Get Audit Log V1 Audit Get",
+                  "type": "object"
+                }
+              }
+            },
+            "description": "Successful Response"
+          }
+        },
+        "summary": "View API call mismatch audit log",
+        "tags": [
+          "audit"
+        ]
+      }
+    },
+    "/v1/users": {
+      "post": {
+        "description": "Create a new user and return the created resource.",
+        "operationId": "create_user_v1_users_post",
+        "requestBody": {
+          "content": {
+            "application/json": {
+              "schema": {
+                "$ref": "#/components/schemas/UserCreate"
+              }
+            }
+          },
+          "required": true
+        },
+        "responses": {
+          "201": {
+            "content": {
+              "application/json": {
+                "schema": {
+                  "$ref": "#/components/schemas/User"
+                }
+              }
+            },
+            "description": "Successful Response"
+          },
+          "422": {
+            "content": {
+              "application/json": {
+                "schema": {
+                  "$ref": "#/components/schemas/HTTPValidationError"
+                }
+              }
+            },
+            "description": "Validation Error"
+          }
+        },
+        "summary": "Create a new user",
+        "tags": [
+          "users"
+        ]
+      }
+    },
+    "/v1/users/{user_id}": {
+      "get": {
+        "description": "Retrieve a single user by their unique ID.",
+        "operationId": "get_user_v1_users__user_id__get",
+        "parameters": [
+          {
+            "in": "path",
+            "name": "user_id",
+            "required": true,
+            "schema": {
+              "title": "User Id",
+              "type": "integer"
+            }
+          }
+        ],
+        "responses": {
+          "200": {
+            "content": {
+              "application/json": {
+                "schema": {
+                  "$ref": "#/components/schemas/User"
+                }
+              }
+            },
+            "description": "Successful Response"
+          },
+          "422": {
+            "content": {
+              "application/json": {
+                "schema": {
+                  "$ref": "#/components/schemas/HTTPValidationError"
+                }
+              }
+            },
+            "description": "Validation Error"
+          }
+        },
+        "summary": "Get a user by ID",
+        "tags": [
+          "users"
+        ]
+      }
+    }
+  }
+}
diff --git a/docs/api_reference.md b/docs/api_reference.md
index 8f48f0c..21cdd4b 100644
--- a/docs/api_reference.md
+++ b/docs/api_reference.md
@@ -1,6 +1,163 @@
-# API Reference
+# Enterprise User API – API Reference
 
-> This file is **auto-generated** by `drift_guard`.
-> Run `python -m drift_guard.guard baseline` to regenerate.
+> **Version:** 1.0.0
 
-_No baseline generated yet. Run the baseline command to populate this file._
+A minimal enterprise API used to demonstrate Docs Drift Guard.
+
+---
+
+## Endpoints Overview
+
+| Method | Path | Summary |
+|--------|------|---------|
+| GET | `/health` | Health check |
+| DELETE | `/v1/audit` | Clear the audit log |
+| GET | `/v1/audit` | View API call mismatch audit log |
+| POST | `/v1/users` | Create a new user |
+| GET | `/v1/users/{user_id}` | Get a user by ID |
+
+---
+
+## GET `/health`
+
+**Health check**
+
+### Response `200`
+
+Successful Response
+
+| Field | Type | Required | Description |
+|-------|------|----------|-------------|
+| `status` | string | Yes | Service status |
+
+
+### Example
+
+```bash
+curl -s "http://localhost:8000/health" | python -m json.tool
+```
+
+---
+
+## DELETE `/v1/audit`
+
+**Clear the audit log**
+
+### Response `200`
+
+Successful Response
+
+_No properties defined._
+
+
+### Example
+
+```bash
+curl -s -X DELETE "http://localhost:8000/v1/audit" | python -m json.tool
+```
+
+---
+
+## GET `/v1/audit`
+
+**View API call mismatch audit log**
+
+### Response `200`
+
+Successful Response
+
+_No properties defined._
+
+
+### Example
+
+```bash
+curl -s "http://localhost:8000/v1/audit" | python -m json.tool
+```
+
+---
+
+## POST `/v1/users`
+
+**Create a new user**
+
+### Request Body
+
+| Field | Type | Required | Description |
+|-------|------|----------|-------------|
+| `email` | string | Yes | Email address |
+| `name` | string | Yes | Full name of the user |
+| `role` | string | No | User role |
+
+
+### Response `201`
+
+Successful Response
+
+| Field | Type | Required | Description |
+|-------|------|----------|-------------|
+| `email` | string | Yes | Email address |
+| `id` | integer | Yes | Unique user identifier |
+| `name` | string | Yes | Full name of the user |
+| `role` | string | No | User role |
+
+
+### Response `422`
+
+Validation Error
+
+| Field | Type | Required | Description |
+|-------|------|----------|-------------|
+| `detail` | array | No |  |
+
+
+### Example
+
+```bash
+curl -s -X POST "http://localhost:8000/v1/users" \
+  -H "Content-Type: application/json" \
+  -d '{"email": "example_email", "name": "example_name", "role": "example_role"}' | python -m json.tool
+```
+
+---
+
+## GET `/v1/users/{user_id}`
+
+**Get a user by ID**
+
+### Parameters
+
+| Name | In | Type | Required | Description |
+|------|----|------|----------|-------------|
+| `user_id` | path | integer | Yes |  |
+
+### Response `200`
+
+Successful Response
+
+| Field | Type | Required | Description |
+|-------|------|----------|-------------|
+| `email` | string | Yes | Email address |
+| `id` | integer | Yes | Unique user identifier |
+| `name` | string | Yes | Full name of the user |
+| `role` | string | No | User role |
+
+
+### Response `422`
+
+Validation Error
+
+| Field | Type | Required | Description |
+|-------|------|----------|-------------|
+| `detail` | array | No |  |
+
+
+### Example
+
+```bash
+curl -s "http://localhost:8000/v1/users/1" | python -m json.tool
+```
+
+---
+
+_This file was auto-generated by [Docs Drift Guard](../drift_guard/guard.py). Do not edit manually._