feat: implement location events & error handling (Step 10.2)

- Add LocationService with create/rename/archive methods
- Add LocationProjection for event handling
- Add admin-only location management routes at /locations
- Add error response helpers (error_response, error_toast, success_toast)
- Add toast handler JS to base template for HX-Trigger notifications
- Update seeds.py to emit LocationCreated events per spec §23
- Archived locations block animal moves with 422 error

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

PLAN.md

@@ -379,19 +379,19 @@ Check off items as completed. Each phase builds on the previous.
 - [x] E2E test #6: Deletes: recorder vs admin cascade (test_e2e_deletion.py)
 - [x] E2E test #7: Harvest with yields (test_e2e_harvest.py)
 - [x] E2E test #8: Optimistic lock with confirm (test_e2e_optimistic_lock.py)
-- [ ] **Commit checkpoint**
+- [x] **Commit checkpoint** (5ba068b)
 
 NOTE: Tests #1-5 in test_e2e_stats_progression.py have documented discrepancies with
 spec values due to integer truncation of bird-days and timeline differences. The
 tests verify implementation consistency, not exact spec values.
 
 ### Step 10.2: Location Events & Error Handling
-- [ ] Implement LocationCreated (idempotent for seeding)
-- [ ] Implement LocationRenamed
-- [ ] Implement LocationArchived
-- [ ] Standardize error responses (422, 409, 401/403)
-- [ ] Toast via HX-Trigger
-- [ ] Write tests for location events and error rendering
+- [x] Implement LocationCreated (idempotent for seeding)
+- [x] Implement LocationRenamed
+- [x] Implement LocationArchived
+- [x] Standardize error responses (422, 409, 401/403)
+- [x] Toast via HX-Trigger
+- [x] Write tests for location events and error rendering
 - [ ] **Commit checkpoint**
 
 ### Step 10.3: CLI, Docker & Deployment

src/animaltrack/projections/location.py

@@ -0,0 +1,162 @@
+# ABOUTME: Projection for location lifecycle events.
+# ABOUTME: Handles LocationCreated, LocationRenamed, and LocationArchived events.
+
+import time
+from typing import Any
+
+from animaltrack.events.types import LOCATION_ARCHIVED, LOCATION_CREATED, LOCATION_RENAMED
+from animaltrack.models.events import Event
+from animaltrack.models.reference import Location
+from animaltrack.projections.base import Projection
+from animaltrack.repositories.locations import LocationRepository
+
+
+class LocationProjection(Projection):
+    """Maintains location reference data from events.
+
+    This projection handles location lifecycle events, maintaining:
+    - locations: Reference table of all locations
+    """
+
+    def __init__(self, db: Any) -> None:
+        """Initialize the projection with a database connection.
+
+        Args:
+            db: A fastlite database connection.
+        """
+        super().__init__(db)
+        self.location_repo = LocationRepository(db)
+
+    def get_event_types(self) -> list[str]:
+        """Return the event types this projection handles."""
+        return [LOCATION_CREATED, LOCATION_RENAMED, LOCATION_ARCHIVED]
+
+    def apply(self, event: Event) -> None:
+        """Apply location event to update reference data."""
+        if event.type == LOCATION_CREATED:
+            self._apply_location_created(event)
+        elif event.type == LOCATION_RENAMED:
+            self._apply_location_renamed(event)
+        elif event.type == LOCATION_ARCHIVED:
+            self._apply_location_archived(event)
+
+    def revert(self, event: Event) -> None:
+        """Revert location event from reference data."""
+        if event.type == LOCATION_CREATED:
+            self._revert_location_created(event)
+        elif event.type == LOCATION_RENAMED:
+            self._revert_location_renamed(event)
+        elif event.type == LOCATION_ARCHIVED:
+            self._revert_location_archived(event)
+
+    def _apply_location_created(self, event: Event) -> None:
+        """Apply location created event.
+
+        Inserts a new location into the locations table.
+        """
+        location_id = event.entity_refs.get("location_id")
+        name = event.payload.get("name")
+        ts_utc = event.ts_utc
+
+        location = Location(
+            id=location_id,
+            name=name,
+            active=True,
+            created_at_utc=ts_utc,
+            updated_at_utc=ts_utc,
+        )
+        self.location_repo.upsert(location)
+
+    def _revert_location_created(self, event: Event) -> None:
+        """Revert location created event.
+
+        Removes the location from the locations table.
+        """
+        location_id = event.entity_refs.get("location_id")
+
+        self.db.execute(
+            "DELETE FROM locations WHERE id = ?",
+            (location_id,),
+        )
+
+    def _apply_location_renamed(self, event: Event) -> None:
+        """Apply location renamed event.
+
+        Updates the location name in the locations table.
+        """
+        location_id = event.entity_refs.get("location_id")
+        new_name = event.payload.get("new_name")
+        ts_utc = event.ts_utc
+
+        self.db.execute(
+            "UPDATE locations SET name = ?, updated_at_utc = ? WHERE id = ?",
+            (new_name, ts_utc, location_id),
+        )
+
+    def _revert_location_renamed(self, event: Event) -> None:
+        """Revert location renamed event.
+
+        This requires looking up the previous name from event history.
+        For simplicity, we search for the most recent prior name.
+        """
+        location_id = event.entity_refs.get("location_id")
+        ts_utc = int(time.time() * 1000)
+
+        # Find the previous name from event history:
+        # 1. Check if there's an earlier LocationRenamed event
+        # 2. Or fall back to the LocationCreated event
+        row = self.db.execute(
+            """
+            SELECT CASE
+                WHEN type = ? THEN JSON_EXTRACT(payload, '$.new_name')
+                WHEN type = ? THEN JSON_EXTRACT(payload, '$.name')
+            END as name
+            FROM events
+            WHERE entity_refs LIKE ?
+              AND type IN (?, ?)
+              AND ts_utc < ?
+            ORDER BY ts_utc DESC
+            LIMIT 1
+            """,
+            (
+                LOCATION_RENAMED,
+                LOCATION_CREATED,
+                f'%"{location_id}"%',
+                LOCATION_RENAMED,
+                LOCATION_CREATED,
+                event.ts_utc,
+            ),
+        ).fetchone()
+
+        if row and row[0]:
+            previous_name = row[0]
+            self.db.execute(
+                "UPDATE locations SET name = ?, updated_at_utc = ? WHERE id = ?",
+                (previous_name, ts_utc, location_id),
+            )
+
+    def _apply_location_archived(self, event: Event) -> None:
+        """Apply location archived event.
+
+        Sets the location to inactive.
+        """
+        location_id = event.entity_refs.get("location_id")
+        ts_utc = event.ts_utc
+
+        self.db.execute(
+            "UPDATE locations SET active = 0, updated_at_utc = ? WHERE id = ?",
+            (ts_utc, location_id),
+        )
+
+    def _revert_location_archived(self, event: Event) -> None:
+        """Revert location archived event.
+
+        Sets the location back to active.
+        """
+        location_id = event.entity_refs.get("location_id")
+        ts_utc = int(time.time() * 1000)
+
+        self.db.execute(
+            "UPDATE locations SET active = 1, updated_at_utc = ? WHERE id = ?",
+            (ts_utc, location_id),
+        )

src/animaltrack/seeds.py

@@ -4,23 +4,24 @@
 import time
 from typing import Any
 
-from animaltrack.id_gen import generate_id
+from animaltrack.events.store import EventStore
 from animaltrack.models.reference import (
     FeedType,
-    Location,
     Product,
     ProductUnit,
     Species,
     User,
     UserRole,
 )
+from animaltrack.projections import ProjectionRegistry
+from animaltrack.projections.location import LocationProjection
 from animaltrack.repositories import (
     FeedTypeRepository,
-    LocationRepository,
     ProductRepository,
     SpeciesRepository,
     UserRepository,
 )
+from animaltrack.services.location import LocationService
 
 
 def run_seeds(db: Any) -> None:
@@ -73,12 +74,17 @@ def _seed_users(db: Any, now_utc: int) -> None:
 
 
 def _seed_locations(db: Any, now_utc: int) -> None:
-    """Seed location data.
+    """Seed location data via LocationCreated events.
 
-    Locations are created only if they don't exist (by name).
-    This preserves existing ULIDs on re-seeding.
+    Uses LocationService.create_location() which is idempotent -
+    locations are created only if they don't exist (by name).
+    This emits LocationCreated events per spec §23.
     """
-    repo = LocationRepository(db)
+    # Initialize LocationService with projection
+    event_store = EventStore(db)
+    registry = ProjectionRegistry()
+    registry.register(LocationProjection(db))
+    location_service = LocationService(db, event_store, registry)
 
     location_names = [
         "Strip 1",
@@ -92,16 +98,12 @@ def _seed_locations(db: Any, now_utc: int) -> None:
     ]
 
     for name in location_names:
-        existing = repo.get_by_name(name)
-        if existing is None:
-            location = Location(
-                id=generate_id(),
+        # create_location is idempotent - returns None if already exists
+        location_service.create_location(
             name=name,
-                active=True,
-                created_at_utc=now_utc,
-                updated_at_utc=now_utc,
+            ts_utc=now_utc,
+            actor="system",
         )
-            repo.upsert(location)
 
 
 def _seed_species(db: Any, now_utc: int) -> None:

src/animaltrack/services/location.py

@@ -0,0 +1,253 @@
+# ABOUTME: Service layer for location operations.
+# ABOUTME: Coordinates event creation with projection updates for location lifecycle.
+
+from typing import Any
+
+from animaltrack.db import transaction
+from animaltrack.events.payloads import (
+    LocationArchivedPayload,
+    LocationCreatedPayload,
+    LocationRenamedPayload,
+)
+from animaltrack.events.processor import process_event
+from animaltrack.events.store import EventStore
+from animaltrack.events.types import LOCATION_ARCHIVED, LOCATION_CREATED, LOCATION_RENAMED
+from animaltrack.id_gen import generate_id
+from animaltrack.models.events import Event
+from animaltrack.projections import ProjectionRegistry
+from animaltrack.repositories.locations import LocationRepository
+
+
+class LocationServiceError(Exception):
+    """Base exception for location service errors."""
+
+
+class ValidationError(LocationServiceError):
+    """Raised when validation fails."""
+
+
+class LocationService:
+    """Service for location lifecycle operations.
+
+    Provides methods to create, rename, and archive locations.
+    All operations are atomic and emit events.
+    """
+
+    def __init__(
+        self,
+        db: Any,
+        event_store: EventStore,
+        registry: ProjectionRegistry,
+    ) -> None:
+        """Initialize the service.
+
+        Args:
+            db: A fastlite database connection.
+            event_store: The event store for appending events.
+            registry: Registry of projections to update.
+        """
+        self.db = db
+        self.event_store = event_store
+        self.registry = registry
+        self.location_repo = LocationRepository(db)
+
+    def create_location(
+        self,
+        name: str,
+        ts_utc: int,
+        actor: str,
+        nonce: str | None = None,
+        route: str | None = None,
+    ) -> Event | None:
+        """Create a new location.
+
+        Creates a LocationCreated event if no location with this name exists.
+        This is idempotent per spec §23 - returns None if location already exists.
+
+        Args:
+            name: The location name.
+            ts_utc: Timestamp in milliseconds since epoch.
+            actor: The user performing the action.
+            nonce: Optional idempotency nonce.
+            route: Required if nonce provided.
+
+        Returns:
+            The created event, or None if location already exists (idempotent).
+
+        Raises:
+            ValidationError: If name is empty or whitespace-only.
+        """
+        # Validate name
+        if not name or not name.strip():
+            msg = "Location name cannot be empty"
+            raise ValidationError(msg)
+
+        name = name.strip()
+
+        # Check if location with this name already exists (idempotent)
+        existing = self.location_repo.get_by_name(name)
+        if existing is not None:
+            return None
+
+        # Generate a new location ID
+        location_id = generate_id()
+
+        # Create payload
+        payload = LocationCreatedPayload(
+            location_id=location_id,
+            name=name,
+        )
+
+        # Build entity_refs
+        entity_refs = {
+            "location_id": location_id,
+        }
+
+        with transaction(self.db):
+            event = self.event_store.append_event(
+                event_type=LOCATION_CREATED,
+                ts_utc=ts_utc,
+                actor=actor,
+                entity_refs=entity_refs,
+                payload=payload.model_dump(),
+                nonce=nonce,
+                route=route,
+            )
+
+            process_event(event, self.registry)
+
+        return event
+
+    def rename_location(
+        self,
+        location_id: str,
+        new_name: str,
+        ts_utc: int,
+        actor: str,
+        nonce: str | None = None,
+        route: str | None = None,
+    ) -> Event:
+        """Rename an existing location.
+
+        Creates a LocationRenamed event.
+
+        Args:
+            location_id: The location ID (ULID).
+            new_name: The new name for the location.
+            ts_utc: Timestamp in milliseconds since epoch.
+            actor: The user performing the action.
+            nonce: Optional idempotency nonce.
+            route: Required if nonce provided.
+
+        Returns:
+            The created event.
+
+        Raises:
+            ValidationError: If location not found, name is empty, or name already exists.
+        """
+        # Validate new_name
+        if not new_name or not new_name.strip():
+            msg = "Location name cannot be empty"
+            raise ValidationError(msg)
+
+        new_name = new_name.strip()
+
+        # Check location exists
+        location = self.location_repo.get(location_id)
+        if location is None:
+            msg = f"Location '{location_id}' not found"
+            raise ValidationError(msg)
+
+        # Check new name doesn't conflict with another location (but allow same name)
+        existing = self.location_repo.get_by_name(new_name)
+        if existing is not None and existing.id != location_id:
+            msg = f"Location with name '{new_name}' already exists"
+            raise ValidationError(msg)
+
+        # Create payload
+        payload = LocationRenamedPayload(
+            location_id=location_id,
+            new_name=new_name,
+        )
+
+        # Build entity_refs
+        entity_refs = {
+            "location_id": location_id,
+        }
+
+        with transaction(self.db):
+            event = self.event_store.append_event(
+                event_type=LOCATION_RENAMED,
+                ts_utc=ts_utc,
+                actor=actor,
+                entity_refs=entity_refs,
+                payload=payload.model_dump(),
+                nonce=nonce,
+                route=route,
+            )
+
+            process_event(event, self.registry)
+
+        return event
+
+    def archive_location(
+        self,
+        location_id: str,
+        ts_utc: int,
+        actor: str,
+        nonce: str | None = None,
+        route: str | None = None,
+    ) -> Event:
+        """Archive a location.
+
+        Creates a LocationArchived event. The location will be marked inactive
+        and hidden from active location lists.
+
+        Args:
+            location_id: The location ID (ULID).
+            ts_utc: Timestamp in milliseconds since epoch.
+            actor: The user performing the action.
+            nonce: Optional idempotency nonce.
+            route: Required if nonce provided.
+
+        Returns:
+            The created event.
+
+        Raises:
+            ValidationError: If location not found or already archived.
+        """
+        # Check location exists
+        location = self.location_repo.get(location_id)
+        if location is None:
+            msg = f"Location '{location_id}' not found"
+            raise ValidationError(msg)
+
+        # Check not already archived
+        if not location.active:
+            msg = f"Location '{location_id}' is already archived"
+            raise ValidationError(msg)
+
+        # Create payload
+        payload = LocationArchivedPayload(
+            location_id=location_id,
+        )
+
+        # Build entity_refs
+        entity_refs = {
+            "location_id": location_id,
+        }
+
+        with transaction(self.db):
+            event = self.event_store.append_event(
+                event_type=LOCATION_ARCHIVED,
+                ts_utc=ts_utc,
+                actor=actor,
+                entity_refs=entity_refs,
+                payload=payload.model_dump(),
+                nonce=nonce,
+                route=route,
+            )
+
+            process_event(event, self.registry)
+
+        return event

src/animaltrack/web/app.py

@@ -26,6 +26,7 @@ from animaltrack.web.routes import (
     register_events_routes,
     register_feed_routes,
     register_health_routes,
+    register_location_routes,
     register_move_routes,
     register_product_routes,
     register_registry_routes,
@@ -152,6 +153,7 @@ def create_app(
     register_egg_routes(rt, app)
     register_events_routes(rt, app)
     register_feed_routes(rt, app)
+    register_location_routes(rt, app)
     register_move_routes(rt, app)
     register_product_routes(rt, app)
     register_registry_routes(rt, app)

src/animaltrack/web/responses.py

@@ -0,0 +1,64 @@
+# ABOUTME: Helper functions for creating standardized HTTP responses.
+# ABOUTME: Provides error_response, error_toast, and success_toast utilities.
+
+import json
+
+from starlette.responses import HTMLResponse
+
+
+def error_response(content: str, status_code: int = 422) -> HTMLResponse:
+    """Create an HTML error response.
+
+    Args:
+        content: The HTML content to include in the response body.
+        status_code: The HTTP status code (default 422 for validation errors).
+
+    Returns:
+        An HTMLResponse with the specified content and status code.
+
+    Standard status codes:
+        - 422: Validation errors (missing fields, invalid values)
+        - 409: Conflicts (roster mismatch, dependents blocking delete)
+        - 403: Authorization failed (wrong role, CSRF)
+        - 401: Authentication failed (no user)
+    """
+    return HTMLResponse(content=content, status_code=status_code)
+
+
+def error_toast(message: str, status_code: int = 422) -> HTMLResponse:
+    """Create an error response with a toast notification.
+
+    Returns a minimal HTML response with an HX-Trigger header that
+    triggers a toast notification on the client side.
+
+    Args:
+        message: The error message to display in the toast.
+        status_code: The HTTP status code (default 422 for validation errors).
+
+    Returns:
+        An HTMLResponse with HX-Trigger header for toast display.
+    """
+    response = HTMLResponse(content="", status_code=status_code)
+    response.headers["HX-Trigger"] = json.dumps(
+        {"showToast": {"message": message, "type": "error"}}
+    )
+    return response
+
+
+def success_toast(message: str) -> dict:
+    """Create a toast trigger dict for a success message.
+
+    This returns a dict that can be JSON-serialized and used as
+    an HX-Trigger header value.
+
+    Args:
+        message: The success message to display in the toast.
+
+    Returns:
+        A dict suitable for use as HX-Trigger header value.
+
+    Usage:
+        response = HTMLResponse(content=...)
+        response.headers["HX-Trigger"] = json.dumps(success_toast("Done!"))
+    """
+    return {"showToast": {"message": message, "type": "success"}}

src/animaltrack/web/routes/__init__.py

@@ -7,6 +7,7 @@ from animaltrack.web.routes.eggs import register_egg_routes
 from animaltrack.web.routes.events import register_events_routes
 from animaltrack.web.routes.feed import register_feed_routes
 from animaltrack.web.routes.health import register_health_routes
+from animaltrack.web.routes.locations import register_location_routes
 from animaltrack.web.routes.move import register_move_routes
 from animaltrack.web.routes.products import register_product_routes
 from animaltrack.web.routes.registry import register_registry_routes
@@ -18,6 +19,7 @@ __all__ = [
     "register_events_routes",
     "register_feed_routes",
     "register_health_routes",
+    "register_location_routes",
     "register_move_routes",
     "register_product_routes",
     "register_registry_routes",

src/animaltrack/web/routes/locations.py

@@ -0,0 +1,253 @@
+# ABOUTME: Routes for Location management functionality (admin-only).
+# ABOUTME: Handles GET /locations and POST /actions/location-* routes.
+
+from __future__ import annotations
+
+import json
+import time
+
+from fasthtml.common import to_xml
+from starlette.requests import Request
+from starlette.responses import HTMLResponse
+
+from animaltrack.events.store import EventStore
+from animaltrack.models.reference import UserRole
+from animaltrack.projections import ProjectionRegistry
+from animaltrack.projections.location import LocationProjection
+from animaltrack.repositories.locations import LocationRepository
+from animaltrack.services.location import LocationService, ValidationError
+from animaltrack.web.auth import require_role
+from animaltrack.web.responses import success_toast
+from animaltrack.web.templates import page
+from animaltrack.web.templates.locations import location_list, rename_form
+
+
+def _get_location_service(db) -> LocationService:
+    """Create a LocationService with projections."""
+    event_store = EventStore(db)
+    registry = ProjectionRegistry()
+    registry.register(LocationProjection(db))
+    return LocationService(db, event_store, registry)
+
+
+# =============================================================================
+# GET /locations - Location List
+# =============================================================================
+
+
+@require_role(UserRole.ADMIN)
+async def locations_index(req: Request):
+    """GET /locations - Location management page (admin-only)."""
+    db = req.app.state.db
+    locations = LocationRepository(db).list_all()
+
+    return page(
+        location_list(locations),
+        title="Locations - AnimalTrack",
+        active_nav=None,
+    )
+
+
+# =============================================================================
+# GET /locations/{id}/rename - Rename Form
+# =============================================================================
+
+
+@require_role(UserRole.ADMIN)
+async def location_rename_form(req: Request, location_id: str):
+    """GET /locations/{id}/rename - Rename location form (admin-only)."""
+    db = req.app.state.db
+    location = LocationRepository(db).get(location_id)
+
+    if location is None:
+        return HTMLResponse(content="Location not found", status_code=404)
+
+    return HTMLResponse(content=to_xml(rename_form(location)))
+
+
+# =============================================================================
+# POST /actions/location-created
+# =============================================================================
+
+
+@require_role(UserRole.ADMIN)
+async def location_created(req: Request):
+    """POST /actions/location-created - Create a new location (admin-only)."""
+    db = req.app.state.db
+    form = await req.form()
+
+    name = form.get("name", "").strip()
+    nonce = form.get("nonce")
+
+    # Validation
+    if not name:
+        return _render_error_list(db, "Location name cannot be empty")
+
+    ts_utc = int(time.time() * 1000)
+
+    # Get actor from auth
+    auth = req.scope.get("auth")
+    actor = auth.username if auth else "unknown"
+
+    # Create location
+    location_service = _get_location_service(db)
+    try:
+        event = location_service.create_location(
+            name=name,
+            ts_utc=ts_utc,
+            actor=actor,
+            nonce=nonce,
+            route="/actions/location-created",
+        )
+    except ValidationError as e:
+        return _render_error_list(db, str(e))
+
+    # Get updated list
+    locations = LocationRepository(db).list_all()
+
+    # Success response with toast
+    response = HTMLResponse(
+        content=to_xml(location_list(locations)),
+    )
+
+    if event is not None:
+        response.headers["HX-Trigger"] = json.dumps(success_toast(f"Created location: {name}"))
+    else:
+        # Idempotent - location already exists
+        response.headers["HX-Trigger"] = json.dumps(
+            success_toast(f"Location already exists: {name}")
+        )
+
+    return response
+
+
+# =============================================================================
+# POST /actions/location-renamed
+# =============================================================================
+
+
+@require_role(UserRole.ADMIN)
+async def location_renamed(req: Request):
+    """POST /actions/location-renamed - Rename a location (admin-only)."""
+    db = req.app.state.db
+    form = await req.form()
+
+    location_id = form.get("location_id", "").strip()
+    new_name = form.get("new_name", "").strip()
+    nonce = form.get("nonce")
+
+    # Validation
+    if not location_id:
+        return _render_error_list(db, "Location ID is required")
+
+    if not new_name:
+        return _render_error_list(db, "New name cannot be empty")
+
+    ts_utc = int(time.time() * 1000)
+
+    # Get actor from auth
+    auth = req.scope.get("auth")
+    actor = auth.username if auth else "unknown"
+
+    # Rename location
+    location_service = _get_location_service(db)
+    try:
+        location_service.rename_location(
+            location_id=location_id,
+            new_name=new_name,
+            ts_utc=ts_utc,
+            actor=actor,
+            nonce=nonce,
+            route="/actions/location-renamed",
+        )
+    except ValidationError as e:
+        return _render_error_list(db, str(e))
+
+    # Get updated list
+    locations = LocationRepository(db).list_all()
+
+    # Success response with toast
+    response = HTMLResponse(
+        content=to_xml(location_list(locations)),
+    )
+    response.headers["HX-Trigger"] = json.dumps(success_toast(f"Renamed location to: {new_name}"))
+
+    return response
+
+
+# =============================================================================
+# POST /actions/location-archived
+# =============================================================================
+
+
+@require_role(UserRole.ADMIN)
+async def location_archived(req: Request):
+    """POST /actions/location-archived - Archive a location (admin-only)."""
+    db = req.app.state.db
+    form = await req.form()
+
+    location_id = form.get("location_id", "").strip()
+    nonce = form.get("nonce")
+
+    # Validation
+    if not location_id:
+        return _render_error_list(db, "Location ID is required")
+
+    ts_utc = int(time.time() * 1000)
+
+    # Get actor from auth
+    auth = req.scope.get("auth")
+    actor = auth.username if auth else "unknown"
+
+    # Archive location
+    location_service = _get_location_service(db)
+    try:
+        location_service.archive_location(
+            location_id=location_id,
+            ts_utc=ts_utc,
+            actor=actor,
+            nonce=nonce,
+            route="/actions/location-archived",
+        )
+    except ValidationError as e:
+        return _render_error_list(db, str(e))
+
+    # Get updated list
+    locations = LocationRepository(db).list_all()
+
+    # Success response with toast
+    response = HTMLResponse(
+        content=to_xml(location_list(locations)),
+    )
+    response.headers["HX-Trigger"] = json.dumps(success_toast("Location archived"))
+
+    return response
+
+
+# =============================================================================
+# Helper Functions
+# =============================================================================
+
+
+def _render_error_list(db, error_message: str) -> HTMLResponse:
+    """Render location list with error message."""
+    locations = LocationRepository(db).list_all()
+
+    return HTMLResponse(
+        content=to_xml(location_list(locations, error=error_message)),
+        status_code=422,
+    )
+
+
+def register_location_routes(rt, app):
+    """Register location management routes.
+
+    Args:
+        rt: FastHTML route decorator.
+        app: FastHTML application instance.
+    """
+    rt("/locations")(locations_index)
+    rt("/locations/{location_id}/rename")(location_rename_form)
+    rt("/actions/location-created", methods=["POST"])(location_created)
+    rt("/actions/location-renamed", methods=["POST"])(location_renamed)
+    rt("/actions/location-archived", methods=["POST"])(location_archived)

src/animaltrack/web/templates/base.py

@@ -1,11 +1,70 @@
 # ABOUTME: Base HTML template for AnimalTrack pages.
 # ABOUTME: Provides consistent layout with MonsterUI theme and bottom nav.
 
-from fasthtml.common import Container, Div, Title
+from fasthtml.common import Container, Div, Script, Title
 
 from animaltrack.web.templates.nav import BottomNav, BottomNavStyles
 
 
+def toast_container():
+    """Create a toast container for displaying notifications.
+
+    This container holds toast notifications that appear in the top-right corner.
+    Toasts are triggered via HTMX events (HX-Trigger header with showToast).
+    """
+    return Div(
+        id="toast-container",
+        cls="toast toast-end toast-top z-50",
+    )
+
+
+def toast_script():
+    """JavaScript to handle showToast events from HTMX.
+
+    Listens for the showToast event and creates toast notifications
+    that auto-dismiss after 5 seconds.
+    """
+    script = """
+    document.body.addEventListener('showToast', function(evt) {
+        var message = evt.detail.message || 'Action completed';
+        var type = evt.detail.type || 'success';
+
+        // Create alert element with appropriate styling
+        var alertClass = 'alert shadow-lg mb-2 ';
+        if (type === 'success') {
+            alertClass += 'alert-success';
+        } else if (type === 'error') {
+            alertClass += 'alert-error';
+        } else if (type === 'warning') {
+            alertClass += 'alert-warning';
+        } else {
+            alertClass += 'alert-info';
+        }
+
+        var toast = document.createElement('div');
+        toast.className = alertClass;
+        toast.innerHTML = '<span>' + message + '</span>';
+
+        var container = document.getElementById('toast-container');
+        if (container) {
+            container.appendChild(toast);
+
+            // Auto-remove after 5 seconds
+            setTimeout(function() {
+                toast.style.opacity = '0';
+                toast.style.transition = 'opacity 0.5s';
+                setTimeout(function() {
+                    if (toast.parentNode) {
+                        toast.parentNode.removeChild(toast);
+                    }
+                }, 500);
+            }, 5000);
+        }
+    });
+    """
+    return Script(script)
+
+
 def page(content, title: str = "AnimalTrack", active_nav: str = "egg"):
     """
     Base page template wrapper with navigation.
@@ -15,6 +74,7 @@ def page(content, title: str = "AnimalTrack", active_nav: str = "egg"):
     - Bottom navigation styling
     - Content container with nav padding
     - Fixed bottom navigation bar
+    - Toast container for notifications
 
     Args:
         content: Page content (FT components)
@@ -27,6 +87,7 @@ def page(content, title: str = "AnimalTrack", active_nav: str = "egg"):
     return (
         Title(title),
         BottomNavStyles(),
+        toast_script(),
         # Main content with bottom padding for fixed nav
         # hx-boost enables AJAX for all descendant forms/links
         Div(
@@ -35,5 +96,6 @@ def page(content, title: str = "AnimalTrack", active_nav: str = "egg"):
             hx_target="body",
             cls="pb-20 min-h-screen bg-[#0f0f0e] text-stone-100",
         ),
+        toast_container(),
         BottomNav(active_id=active_nav),
     )

src/animaltrack/web/templates/locations.py

@@ -0,0 +1,170 @@
+# ABOUTME: Templates for Location management pages.
+# ABOUTME: Admin-only pages for creating, renaming, and archiving locations.
+
+from uuid import uuid4
+
+from fasthtml.common import H1, Div, Form, Hidden, Table, Tbody, Td, Th, Thead, Tr
+from monsterui.all import (
+    Alert,
+    AlertT,
+    Button,
+    ButtonT,
+    Card,
+    DivFullySpaced,
+    Grid,
+    LabelInput,
+)
+
+from animaltrack.models.reference import Location
+
+
+def location_list(
+    locations: list[Location],
+    error: str | None = None,
+) -> Div:
+    """Create the location list page.
+
+    Args:
+        locations: List of all locations.
+        error: Optional error message to display.
+
+    Returns:
+        Div containing the location management page.
+    """
+    # Error alert if present
+    error_alert = None
+    if error:
+        error_alert = Alert(error, cls=AlertT.error)
+
+    # Create new location form
+    create_form = Card(
+        Form(
+            LabelInput(
+                "Location Name",
+                name="name",
+                type="text",
+                required=True,
+                placeholder="Enter location name",
+            ),
+            Hidden(name="nonce", value=str(uuid4())),
+            Button("Create Location", type="submit", cls=ButtonT.primary),
+            hx_post="/actions/location-created",
+            hx_target="#location-list",
+            hx_swap="outerHTML",
+        ),
+        header=Div("Create New Location", cls="text-lg font-semibold"),
+    )
+
+    # Location table
+    rows = []
+    for loc in locations:
+        status = "Active" if loc.active else "Archived"
+        status_badge = Div(status, cls="badge badge-success" if loc.active else "badge badge-ghost")
+
+        # Action buttons
+        actions = DivFullySpaced(
+            Button(
+                "Rename",
+                cls=ButtonT.ghost + " btn-sm",
+                hx_get=f"/locations/{loc.id}/rename",
+                hx_target="#modal-container",
+                hx_swap="innerHTML",
+            )
+            if loc.active
+            else None,
+            Button(
+                "Archive",
+                cls=ButtonT.ghost + " btn-sm text-warning",
+                hx_post="/actions/location-archived",
+                hx_vals=f'{{"location_id": "{loc.id}", "nonce": "{uuid4()}"}}',
+                hx_target="#location-list",
+                hx_swap="outerHTML",
+                hx_confirm="Are you sure you want to archive this location?",
+            )
+            if loc.active
+            else None,
+        )
+
+        rows.append(
+            Tr(
+                Td(loc.name),
+                Td(status_badge),
+                Td(actions),
+            )
+        )
+
+    table = Table(
+        Thead(
+            Tr(
+                Th("Name"),
+                Th("Status"),
+                Th("Actions"),
+            )
+        ),
+        Tbody(*rows),
+        cls="table table-zebra w-full",
+    )
+
+    location_card = Card(
+        table,
+        header=Div("All Locations", cls="text-lg font-semibold"),
+    )
+
+    return Div(
+        H1("Location Management", cls="text-2xl font-bold mb-4"),
+        error_alert,
+        Grid(
+            create_form,
+            cols_sm=1,
+            cols_md=1,
+            cols_lg=1,
+            gap=4,
+        ),
+        Div(id="modal-container"),
+        Div(
+            location_card,
+            id="location-list",
+            cls="mt-4",
+        ),
+    )
+
+
+def rename_form(
+    location: Location,
+    error: str | None = None,
+) -> Div:
+    """Create the rename location form.
+
+    Args:
+        location: The location to rename.
+        error: Optional error message to display.
+
+    Returns:
+        Div containing the rename form.
+    """
+    error_alert = None
+    if error:
+        error_alert = Alert(error, cls=AlertT.error)
+
+    return Card(
+        error_alert,
+        Form(
+            LabelInput(
+                "New Name",
+                name="new_name",
+                type="text",
+                required=True,
+                value=location.name,
+            ),
+            Hidden(name="location_id", value=location.id),
+            Hidden(name="nonce", value=str(uuid4())),
+            DivFullySpaced(
+                Button("Cancel", type="button", cls=ButtonT.ghost, hx_get="/locations"),
+                Button("Rename", type="submit", cls=ButtonT.primary),
+            ),
+            hx_post="/actions/location-renamed",
+            hx_target="#location-list",
+            hx_swap="outerHTML",
+        ),
+        header=Div(f"Rename: {location.name}", cls="text-lg font-semibold"),
+    )

tests/test_service_animal.py

@@ -240,6 +240,9 @@ class TestAnimalServiceTransactionIntegrity:
 
     def test_no_partial_data_on_projection_error(self, seeded_db, event_store, valid_location_id):
         """If projection fails, event is not persisted."""
+        # Count events before the test (seeds create LocationCreated events)
+        event_count_before = seeded_db.execute("SELECT COUNT(*) FROM events").fetchone()[0]
+
         # Create a registry with a failing projection
         from animaltrack.projections import Projection, ProjectionError
 
@@ -264,9 +267,9 @@ class TestAnimalServiceTransactionIntegrity:
         with pytest.raises(ProjectionError):
             service.create_cohort(payload, ts_utc, "test_user")
 
-        # Verify nothing was persisted
-        event_count = seeded_db.execute("SELECT COUNT(*) FROM events").fetchone()[0]
-        assert event_count == 0
+        # Verify no new events were persisted (count unchanged from before)
+        event_count_after = seeded_db.execute("SELECT COUNT(*) FROM events").fetchone()[0]
+        assert event_count_after == event_count_before
 
         animal_count = seeded_db.execute("SELECT COUNT(*) FROM animal_registry").fetchone()[0]
         assert animal_count == 0

tests/test_service_location.py

@@ -0,0 +1,343 @@
+# ABOUTME: Tests for LocationService operations.
+# ABOUTME: Tests create_location, rename_location, and archive_location with event emission.
+
+import time
+
+import pytest
+
+from animaltrack.events.store import EventStore
+from animaltrack.events.types import LOCATION_ARCHIVED, LOCATION_CREATED, LOCATION_RENAMED
+from animaltrack.projections import ProjectionRegistry
+from animaltrack.services.location import LocationService, ValidationError
+
+
+@pytest.fixture
+def event_store(seeded_db):
+    """Create an EventStore for testing."""
+    return EventStore(seeded_db)
+
+
+@pytest.fixture
+def projection_registry(seeded_db):
+    """Create a ProjectionRegistry with location projections registered."""
+    from animaltrack.projections.location import LocationProjection
+
+    registry = ProjectionRegistry()
+    registry.register(LocationProjection(seeded_db))
+    return registry
+
+
+@pytest.fixture
+def location_service(seeded_db, event_store, projection_registry):
+    """Create a LocationService for testing."""
+    return LocationService(seeded_db, event_store, projection_registry)
+
+
+# =============================================================================
+# create_location Tests
+# =============================================================================
+
+
+class TestLocationServiceCreate:
+    """Tests for create_location()."""
+
+    def test_creates_location_created_event(self, seeded_db, location_service):
+        """create_location creates a LocationCreated event."""
+        ts_utc = int(time.time() * 1000)
+
+        event = location_service.create_location("New Location", ts_utc, "test_user")
+
+        assert event.type == LOCATION_CREATED
+        assert event.actor == "test_user"
+        assert event.ts_utc == ts_utc
+
+    def test_event_has_location_id_in_entity_refs(self, seeded_db, location_service):
+        """Event entity_refs contains location_id."""
+        ts_utc = int(time.time() * 1000)
+
+        event = location_service.create_location("Another Location", ts_utc, "test_user")
+
+        assert "location_id" in event.entity_refs
+        assert len(event.entity_refs["location_id"]) == 26  # ULID length
+
+    def test_event_payload_contains_name(self, seeded_db, location_service):
+        """Event payload contains the location name."""
+        ts_utc = int(time.time() * 1000)
+
+        event = location_service.create_location("My Location", ts_utc, "test_user")
+
+        assert event.payload["name"] == "My Location"
+
+    def test_inserts_into_locations_table(self, seeded_db, location_service):
+        """create_location inserts a new row in locations table."""
+        ts_utc = int(time.time() * 1000)
+
+        event = location_service.create_location("Test Location", ts_utc, "test_user")
+
+        row = seeded_db.execute(
+            "SELECT id, name, active FROM locations WHERE id = ?",
+            (event.entity_refs["location_id"],),
+        ).fetchone()
+
+        assert row is not None
+        assert row[1] == "Test Location"
+        assert row[2] == 1  # active=True
+
+    def test_returns_existing_location_if_name_exists(self, seeded_db, location_service):
+        """create_location returns None if location with same name already exists."""
+        ts_utc = int(time.time() * 1000)
+
+        # Create first location
+        event1 = location_service.create_location("Unique Name", ts_utc, "test_user")
+        assert event1 is not None
+
+        # Try to create duplicate - should return None (idempotent)
+        event2 = location_service.create_location("Unique Name", ts_utc + 1000, "test_user")
+
+        assert event2 is None
+
+    def test_idempotent_skips_if_event_exists_for_location(self, seeded_db, location_service):
+        """create_location is idempotent - skips if LocationCreated event exists."""
+        ts_utc = int(time.time() * 1000)
+
+        # Create the location once
+        event1 = location_service.create_location("Idempotent Test", ts_utc, "test_user")
+        location_id = event1.entity_refs["location_id"]
+
+        # Count events for this location
+        event_count_before = seeded_db.execute(
+            "SELECT COUNT(*) FROM events WHERE type = ? AND entity_refs LIKE ?",
+            (LOCATION_CREATED, f"%{location_id}%"),
+        ).fetchone()[0]
+
+        # Calling create again with same name should not create a new event
+        event2 = location_service.create_location("Idempotent Test", ts_utc + 1000, "test_user")
+
+        event_count_after = seeded_db.execute(
+            "SELECT COUNT(*) FROM events WHERE type = ? AND entity_refs LIKE ?",
+            (LOCATION_CREATED, f"%{location_id}%"),
+        ).fetchone()[0]
+
+        assert event2 is None
+        assert event_count_after == event_count_before
+
+
+class TestLocationServiceCreateValidation:
+    """Tests for create_location() validation."""
+
+    def test_rejects_empty_name(self, seeded_db, location_service):
+        """Raises ValidationError for empty name."""
+        with pytest.raises(ValidationError, match="name"):
+            location_service.create_location("", int(time.time() * 1000), "test_user")
+
+    def test_rejects_whitespace_only_name(self, seeded_db, location_service):
+        """Raises ValidationError for whitespace-only name."""
+        with pytest.raises(ValidationError, match="name"):
+            location_service.create_location("   ", int(time.time() * 1000), "test_user")
+
+
+# =============================================================================
+# rename_location Tests
+# =============================================================================
+
+
+class TestLocationServiceRename:
+    """Tests for rename_location()."""
+
+    def test_creates_location_renamed_event(self, seeded_db, location_service):
+        """rename_location creates a LocationRenamed event."""
+        ts_utc = int(time.time() * 1000)
+
+        # First create a location
+        create_event = location_service.create_location("Original Name", ts_utc, "test_user")
+        location_id = create_event.entity_refs["location_id"]
+
+        # Rename it
+        event = location_service.rename_location(
+            location_id, "New Name", ts_utc + 1000, "test_user"
+        )
+
+        assert event.type == LOCATION_RENAMED
+        assert event.actor == "test_user"
+        assert event.ts_utc == ts_utc + 1000
+
+    def test_event_has_location_id_in_entity_refs(self, seeded_db, location_service):
+        """Event entity_refs contains location_id."""
+        ts_utc = int(time.time() * 1000)
+        create_event = location_service.create_location("Rename Test", ts_utc, "test_user")
+        location_id = create_event.entity_refs["location_id"]
+
+        event = location_service.rename_location(location_id, "Renamed", ts_utc + 1000, "test_user")
+
+        assert event.entity_refs["location_id"] == location_id
+
+    def test_event_payload_contains_new_name(self, seeded_db, location_service):
+        """Event payload contains the new name."""
+        ts_utc = int(time.time() * 1000)
+        create_event = location_service.create_location("Before", ts_utc, "test_user")
+        location_id = create_event.entity_refs["location_id"]
+
+        event = location_service.rename_location(location_id, "After", ts_utc + 1000, "test_user")
+
+        assert event.payload["new_name"] == "After"
+
+    def test_updates_locations_table_name(self, seeded_db, location_service):
+        """rename_location updates the name in locations table."""
+        ts_utc = int(time.time() * 1000)
+        create_event = location_service.create_location("Old Name", ts_utc, "test_user")
+        location_id = create_event.entity_refs["location_id"]
+
+        location_service.rename_location(location_id, "Updated Name", ts_utc + 1000, "test_user")
+
+        row = seeded_db.execute(
+            "SELECT name FROM locations WHERE id = ?", (location_id,)
+        ).fetchone()
+
+        assert row[0] == "Updated Name"
+
+
+class TestLocationServiceRenameValidation:
+    """Tests for rename_location() validation."""
+
+    def test_rejects_nonexistent_location(self, seeded_db, location_service):
+        """Raises ValidationError for non-existent location_id."""
+        fake_id = "01ARZ3NDEKTSV4RRFFQ69G5FAV"
+
+        with pytest.raises(ValidationError, match="not found"):
+            location_service.rename_location(
+                fake_id, "New Name", int(time.time() * 1000), "test_user"
+            )
+
+    def test_rejects_duplicate_name(self, seeded_db, location_service):
+        """Raises ValidationError when renaming to an existing name."""
+        ts_utc = int(time.time() * 1000)
+
+        # Create two locations
+        location_service.create_location("First Location", ts_utc, "test_user")
+        create_event2 = location_service.create_location(
+            "Second Location", ts_utc + 1000, "test_user"
+        )
+        location_id = create_event2.entity_refs["location_id"]
+
+        # Try to rename second to first's name
+        with pytest.raises(ValidationError, match="already exists"):
+            location_service.rename_location(
+                location_id, "First Location", ts_utc + 2000, "test_user"
+            )
+
+    def test_rejects_empty_new_name(self, seeded_db, location_service):
+        """Raises ValidationError for empty new_name."""
+        ts_utc = int(time.time() * 1000)
+        create_event = location_service.create_location("Test", ts_utc, "test_user")
+        location_id = create_event.entity_refs["location_id"]
+
+        with pytest.raises(ValidationError, match="name"):
+            location_service.rename_location(location_id, "", ts_utc + 1000, "test_user")
+
+    def test_allows_rename_to_same_name(self, seeded_db, location_service):
+        """Allows renaming to the same name (no-op)."""
+        ts_utc = int(time.time() * 1000)
+        create_event = location_service.create_location("Same Name", ts_utc, "test_user")
+        location_id = create_event.entity_refs["location_id"]
+
+        # Should not raise - renaming to same name is allowed (no-op)
+        event = location_service.rename_location(
+            location_id, "Same Name", ts_utc + 1000, "test_user"
+        )
+
+        assert event.type == LOCATION_RENAMED
+
+
+# =============================================================================
+# archive_location Tests
+# =============================================================================
+
+
+class TestLocationServiceArchive:
+    """Tests for archive_location()."""
+
+    def test_creates_location_archived_event(self, seeded_db, location_service):
+        """archive_location creates a LocationArchived event."""
+        ts_utc = int(time.time() * 1000)
+        create_event = location_service.create_location("To Archive", ts_utc, "test_user")
+        location_id = create_event.entity_refs["location_id"]
+
+        event = location_service.archive_location(location_id, ts_utc + 1000, "test_user")
+
+        assert event.type == LOCATION_ARCHIVED
+        assert event.actor == "test_user"
+        assert event.ts_utc == ts_utc + 1000
+
+    def test_event_has_location_id_in_entity_refs(self, seeded_db, location_service):
+        """Event entity_refs contains location_id."""
+        ts_utc = int(time.time() * 1000)
+        create_event = location_service.create_location("Archive Test", ts_utc, "test_user")
+        location_id = create_event.entity_refs["location_id"]
+
+        event = location_service.archive_location(location_id, ts_utc + 1000, "test_user")
+
+        assert event.entity_refs["location_id"] == location_id
+
+    def test_sets_location_inactive(self, seeded_db, location_service):
+        """archive_location sets active=0 in locations table."""
+        ts_utc = int(time.time() * 1000)
+        create_event = location_service.create_location("Active Location", ts_utc, "test_user")
+        location_id = create_event.entity_refs["location_id"]
+
+        # Verify initially active
+        row = seeded_db.execute(
+            "SELECT active FROM locations WHERE id = ?", (location_id,)
+        ).fetchone()
+        assert row[0] == 1
+
+        # Archive it
+        location_service.archive_location(location_id, ts_utc + 1000, "test_user")
+
+        # Verify now inactive
+        row = seeded_db.execute(
+            "SELECT active FROM locations WHERE id = ?", (location_id,)
+        ).fetchone()
+        assert row[0] == 0
+
+    def test_location_not_in_list_active(self, seeded_db, location_service):
+        """Archived location does not appear in list_active()."""
+        from animaltrack.repositories.locations import LocationRepository
+
+        ts_utc = int(time.time() * 1000)
+        create_event = location_service.create_location("Will Be Archived", ts_utc, "test_user")
+        location_id = create_event.entity_refs["location_id"]
+
+        # Before archive - should be in list
+        active_before = LocationRepository(seeded_db).list_active()
+        assert any(loc.id == location_id for loc in active_before)
+
+        # Archive it
+        location_service.archive_location(location_id, ts_utc + 1000, "test_user")
+
+        # After archive - should not be in list
+        active_after = LocationRepository(seeded_db).list_active()
+        assert not any(loc.id == location_id for loc in active_after)
+
+
+class TestLocationServiceArchiveValidation:
+    """Tests for archive_location() validation."""
+
+    def test_rejects_nonexistent_location(self, seeded_db, location_service):
+        """Raises ValidationError for non-existent location_id."""
+        fake_id = "01ARZ3NDEKTSV4RRFFQ69G5FAV"
+
+        with pytest.raises(ValidationError, match="not found"):
+            location_service.archive_location(fake_id, int(time.time() * 1000), "test_user")
+
+    def test_rejects_already_archived_location(self, seeded_db, location_service):
+        """Raises ValidationError when archiving an already archived location."""
+        ts_utc = int(time.time() * 1000)
+        create_event = location_service.create_location("Already Archived", ts_utc, "test_user")
+        location_id = create_event.entity_refs["location_id"]
+
+        # Archive once
+        location_service.archive_location(location_id, ts_utc + 1000, "test_user")
+
+        # Try to archive again
+        with pytest.raises(ValidationError, match="already archived"):
+            location_service.archive_location(location_id, ts_utc + 2000, "test_user")

tests/test_web_locations.py

@@ -0,0 +1,443 @@
+# ABOUTME: Tests for Location management web routes.
+# ABOUTME: Covers GET /locations list and POST /actions/location-* (admin-only).
+
+import json
+import os
+import time
+
+import pytest
+from starlette.testclient import TestClient
+
+from animaltrack.models.reference import User, UserRole
+from animaltrack.repositories.users import UserRepository
+
+
+def make_test_settings(
+    csrf_secret: str = "test-secret",
+    trusted_proxy_ips: str = "127.0.0.1",
+    dev_mode: bool = True,
+):
+    """Create Settings for testing by setting env vars temporarily."""
+    from animaltrack.config import Settings
+
+    old_env = os.environ.copy()
+    try:
+        os.environ["CSRF_SECRET"] = csrf_secret
+        os.environ["TRUSTED_PROXY_IPS"] = trusted_proxy_ips
+        os.environ["DEV_MODE"] = str(dev_mode).lower()
+        return Settings()
+    finally:
+        os.environ.clear()
+        os.environ.update(old_env)
+
+
+@pytest.fixture
+def admin_client(seeded_db):
+    """Test client with admin role (dev mode - bypasses CSRF, auto-admin auth)."""
+    from animaltrack.web.app import create_app
+
+    settings = make_test_settings(trusted_proxy_ips="testclient", dev_mode=True)
+    app, rt = create_app(settings=settings, db=seeded_db)
+    return TestClient(app, raise_server_exceptions=True)
+
+
+@pytest.fixture
+def user_client(seeded_db):
+    """Test client with regular (recorder) role."""
+    from animaltrack.web.app import create_app
+
+    # Create recorder user in database
+    user_repo = UserRepository(seeded_db)
+    now = int(time.time() * 1000)
+    user = User(
+        username="recorder",
+        display_name="Recorder User",
+        role=UserRole.RECORDER,
+        active=True,
+        created_at_utc=now,
+        updated_at_utc=now,
+    )
+    user_repo.upsert(user)
+
+    # Use dev_mode=False to enable real auth
+    settings = make_test_settings(trusted_proxy_ips="testclient", dev_mode=False)
+    app, rt = create_app(settings=settings, db=seeded_db)
+    client = TestClient(app, raise_server_exceptions=True)
+    # Set header to simulate trusted proxy auth
+    client.headers["X-Oidc-Username"] = "recorder"
+    return client
+
+
+# =============================================================================
+# GET /locations Tests
+# =============================================================================
+
+
+class TestLocationListRendering:
+    """Tests for GET /locations list rendering."""
+
+    def test_locations_page_renders_for_admin(self, admin_client):
+        """GET /locations returns 200 for admin."""
+        resp = admin_client.get("/locations")
+        assert resp.status_code == 200
+
+    def test_locations_page_shows_seeded_locations(self, admin_client):
+        """Locations page shows seeded locations."""
+        resp = admin_client.get("/locations")
+        assert resp.status_code == 200
+        assert "Strip 1" in resp.text
+        assert "Strip 2" in resp.text
+        assert "Nursery 1" in resp.text
+
+    def test_locations_page_returns_403_for_recorder(self, user_client):
+        """GET /locations returns 403 for non-admin."""
+        resp = user_client.get("/locations")
+        assert resp.status_code == 403
+
+
+# =============================================================================
+# POST /actions/location-created Tests
+# =============================================================================
+
+
+class TestLocationCreatedSuccess:
+    """Tests for successful POST /actions/location-created."""
+
+    def test_creates_location(self, admin_client, seeded_db):
+        """POST creates a new location."""
+        resp = admin_client.post(
+            "/actions/location-created",
+            data={
+                "name": "New Test Location",
+                "nonce": "test-nonce-loc-1",
+            },
+        )
+
+        assert resp.status_code == 200
+
+        # Verify location was created
+        row = seeded_db.execute(
+            "SELECT name, active FROM locations WHERE name = 'New Test Location'"
+        ).fetchone()
+        assert row is not None
+        assert row[0] == "New Test Location"
+        assert row[1] == 1
+
+    def test_creates_event(self, admin_client, seeded_db):
+        """POST creates LocationCreated event."""
+        resp = admin_client.post(
+            "/actions/location-created",
+            data={
+                "name": "Event Test Location",
+                "nonce": "test-nonce-loc-2",
+            },
+        )
+
+        assert resp.status_code == 200
+
+        event_row = seeded_db.execute(
+            "SELECT type FROM events WHERE type = 'LocationCreated' ORDER BY id DESC LIMIT 1"
+        ).fetchone()
+        assert event_row is not None
+        assert event_row[0] == "LocationCreated"
+
+    def test_returns_toast_on_success(self, admin_client):
+        """POST returns HX-Trigger with toast message."""
+        resp = admin_client.post(
+            "/actions/location-created",
+            data={
+                "name": "Toast Test Location",
+                "nonce": "test-nonce-loc-3",
+            },
+        )
+
+        assert resp.status_code == 200
+        assert "HX-Trigger" in resp.headers
+        trigger = json.loads(resp.headers["HX-Trigger"])
+        assert "showToast" in trigger
+        assert trigger["showToast"]["type"] == "success"
+
+    def test_idempotent_for_existing_name(self, admin_client, seeded_db):
+        """POST is idempotent - returns success for existing name."""
+        # First create
+        resp1 = admin_client.post(
+            "/actions/location-created",
+            data={
+                "name": "Idempotent Location",
+                "nonce": "test-nonce-loc-4",
+            },
+        )
+        assert resp1.status_code == 200
+
+        # Second create with same name - should still succeed (idempotent)
+        resp2 = admin_client.post(
+            "/actions/location-created",
+            data={
+                "name": "Idempotent Location",
+                "nonce": "test-nonce-loc-5",
+            },
+        )
+        assert resp2.status_code == 200
+
+
+class TestLocationCreatedValidation:
+    """Tests for POST /actions/location-created validation."""
+
+    def test_returns_403_for_recorder(self, user_client):
+        """POST returns 403 for non-admin."""
+        resp = user_client.post(
+            "/actions/location-created",
+            data={
+                "name": "Unauthorized Location",
+                "nonce": "test-nonce-loc-6",
+            },
+        )
+        assert resp.status_code == 403
+
+    def test_returns_422_for_empty_name(self, admin_client):
+        """POST returns 422 for empty name."""
+        resp = admin_client.post(
+            "/actions/location-created",
+            data={
+                "name": "",
+                "nonce": "test-nonce-loc-7",
+            },
+        )
+        assert resp.status_code == 422
+
+    def test_returns_422_for_whitespace_name(self, admin_client):
+        """POST returns 422 for whitespace-only name."""
+        resp = admin_client.post(
+            "/actions/location-created",
+            data={
+                "name": "   ",
+                "nonce": "test-nonce-loc-8",
+            },
+        )
+        assert resp.status_code == 422
+
+
+# =============================================================================
+# POST /actions/location-renamed Tests
+# =============================================================================
+
+
+class TestLocationRenamedSuccess:
+    """Tests for successful POST /actions/location-renamed."""
+
+    def test_renames_location(self, admin_client, seeded_db):
+        """POST renames an existing location."""
+        # Get an existing location ID
+        row = seeded_db.execute("SELECT id FROM locations WHERE name = 'Strip 1'").fetchone()
+        location_id = row[0]
+
+        resp = admin_client.post(
+            "/actions/location-renamed",
+            data={
+                "location_id": location_id,
+                "new_name": "Renamed Strip 1",
+                "nonce": "test-nonce-loc-9",
+            },
+        )
+
+        assert resp.status_code == 200
+
+        # Verify rename
+        row = seeded_db.execute(
+            "SELECT name FROM locations WHERE id = ?", (location_id,)
+        ).fetchone()
+        assert row[0] == "Renamed Strip 1"
+
+    def test_creates_event(self, admin_client, seeded_db):
+        """POST creates LocationRenamed event."""
+        row = seeded_db.execute("SELECT id FROM locations WHERE name = 'Strip 2'").fetchone()
+        location_id = row[0]
+
+        resp = admin_client.post(
+            "/actions/location-renamed",
+            data={
+                "location_id": location_id,
+                "new_name": "Renamed Strip 2",
+                "nonce": "test-nonce-loc-10",
+            },
+        )
+
+        assert resp.status_code == 200
+
+        event_row = seeded_db.execute(
+            "SELECT type FROM events WHERE type = 'LocationRenamed' ORDER BY id DESC LIMIT 1"
+        ).fetchone()
+        assert event_row is not None
+
+
+class TestLocationRenamedValidation:
+    """Tests for POST /actions/location-renamed validation."""
+
+    def test_returns_403_for_recorder(self, user_client, seeded_db):
+        """POST returns 403 for non-admin."""
+        row = seeded_db.execute("SELECT id FROM locations LIMIT 1").fetchone()
+        location_id = row[0]
+
+        resp = user_client.post(
+            "/actions/location-renamed",
+            data={
+                "location_id": location_id,
+                "new_name": "New Name",
+                "nonce": "test-nonce-loc-11",
+            },
+        )
+        assert resp.status_code == 403
+
+    def test_returns_422_for_nonexistent_location(self, admin_client):
+        """POST returns 422 for non-existent location."""
+        fake_id = "01ARZ3NDEKTSV4RRFFQ69G5FAV"
+
+        resp = admin_client.post(
+            "/actions/location-renamed",
+            data={
+                "location_id": fake_id,
+                "new_name": "New Name",
+                "nonce": "test-nonce-loc-12",
+            },
+        )
+        assert resp.status_code == 422
+
+    def test_returns_422_for_duplicate_name(self, admin_client, seeded_db):
+        """POST returns 422 when renaming to existing name."""
+        row = seeded_db.execute("SELECT id FROM locations WHERE name = 'Strip 3'").fetchone()
+        location_id = row[0]
+
+        # Try to rename to an existing name
+        resp = admin_client.post(
+            "/actions/location-renamed",
+            data={
+                "location_id": location_id,
+                "new_name": "Strip 4",  # Already exists
+                "nonce": "test-nonce-loc-13",
+            },
+        )
+        assert resp.status_code == 422
+
+
+# =============================================================================
+# POST /actions/location-archived Tests
+# =============================================================================
+
+
+class TestLocationArchivedSuccess:
+    """Tests for successful POST /actions/location-archived."""
+
+    def test_archives_location(self, admin_client, seeded_db):
+        """POST archives an existing location."""
+        # First create a location to archive
+        admin_client.post(
+            "/actions/location-created",
+            data={"name": "To Be Archived", "nonce": "test-nonce-loc-14"},
+        )
+
+        row = seeded_db.execute("SELECT id FROM locations WHERE name = 'To Be Archived'").fetchone()
+        location_id = row[0]
+
+        resp = admin_client.post(
+            "/actions/location-archived",
+            data={
+                "location_id": location_id,
+                "nonce": "test-nonce-loc-15",
+            },
+        )
+
+        assert resp.status_code == 200
+
+        # Verify archived
+        row = seeded_db.execute(
+            "SELECT active FROM locations WHERE id = ?", (location_id,)
+        ).fetchone()
+        assert row[0] == 0
+
+    def test_creates_event(self, admin_client, seeded_db):
+        """POST creates LocationArchived event."""
+        # Create a location to archive
+        admin_client.post(
+            "/actions/location-created",
+            data={"name": "Archive Event Test", "nonce": "test-nonce-loc-16"},
+        )
+
+        row = seeded_db.execute(
+            "SELECT id FROM locations WHERE name = 'Archive Event Test'"
+        ).fetchone()
+        location_id = row[0]
+
+        resp = admin_client.post(
+            "/actions/location-archived",
+            data={
+                "location_id": location_id,
+                "nonce": "test-nonce-loc-17",
+            },
+        )
+
+        assert resp.status_code == 200
+
+        event_row = seeded_db.execute(
+            "SELECT type FROM events WHERE type = 'LocationArchived' ORDER BY id DESC LIMIT 1"
+        ).fetchone()
+        assert event_row is not None
+
+
+class TestLocationArchivedValidation:
+    """Tests for POST /actions/location-archived validation."""
+
+    def test_returns_403_for_recorder(self, user_client, seeded_db):
+        """POST returns 403 for non-admin."""
+        row = seeded_db.execute("SELECT id FROM locations LIMIT 1").fetchone()
+        location_id = row[0]
+
+        resp = user_client.post(
+            "/actions/location-archived",
+            data={
+                "location_id": location_id,
+                "nonce": "test-nonce-loc-18",
+            },
+        )
+        assert resp.status_code == 403
+
+    def test_returns_422_for_nonexistent_location(self, admin_client):
+        """POST returns 422 for non-existent location."""
+        fake_id = "01ARZ3NDEKTSV4RRFFQ69G5FAV"
+
+        resp = admin_client.post(
+            "/actions/location-archived",
+            data={
+                "location_id": fake_id,
+                "nonce": "test-nonce-loc-19",
+            },
+        )
+        assert resp.status_code == 422
+
+    def test_returns_422_for_already_archived(self, admin_client, seeded_db):
+        """POST returns 422 when archiving already archived location."""
+        # Create and archive a location
+        admin_client.post(
+            "/actions/location-created",
+            data={"name": "Double Archive Test", "nonce": "test-nonce-loc-20"},
+        )
+
+        row = seeded_db.execute(
+            "SELECT id FROM locations WHERE name = 'Double Archive Test'"
+        ).fetchone()
+        location_id = row[0]
+
+        # Archive once
+        admin_client.post(
+            "/actions/location-archived",
+            data={"location_id": location_id, "nonce": "test-nonce-loc-21"},
+        )
+
+        # Try to archive again
+        resp = admin_client.post(
+            "/actions/location-archived",
+            data={
+                "location_id": location_id,
+                "nonce": "test-nonce-loc-22",
+            },
+        )
+        assert resp.status_code == 422

tests/test_web_responses.py

@@ -0,0 +1,109 @@
+# ABOUTME: Tests for web response helper functions.
+# ABOUTME: Tests error_response, error_toast, and success_toast helpers.
+
+import json
+
+from starlette.responses import HTMLResponse
+
+from animaltrack.web.responses import error_response, error_toast, success_toast
+
+
+class TestErrorResponse:
+    """Tests for error_response()."""
+
+    def test_returns_html_response(self):
+        """error_response returns an HTMLResponse."""
+        response = error_response("<div>Error</div>")
+        assert isinstance(response, HTMLResponse)
+
+    def test_default_status_422(self):
+        """error_response defaults to 422 status code."""
+        response = error_response("<div>Validation error</div>")
+        assert response.status_code == 422
+
+    def test_custom_status_code(self):
+        """error_response accepts custom status code."""
+        response = error_response("<div>Conflict</div>", status_code=409)
+        assert response.status_code == 409
+
+    def test_403_status_code(self):
+        """error_response works with 403 status code."""
+        response = error_response("<div>Forbidden</div>", status_code=403)
+        assert response.status_code == 403
+
+    def test_401_status_code(self):
+        """error_response works with 401 status code."""
+        response = error_response("<div>Unauthorized</div>", status_code=401)
+        assert response.status_code == 401
+
+    def test_content_in_body(self):
+        """error_response includes content in body."""
+        response = error_response("<p>Error message</p>")
+        assert b"<p>Error message</p>" in response.body
+
+
+class TestErrorToast:
+    """Tests for error_toast()."""
+
+    def test_returns_html_response(self):
+        """error_toast returns an HTMLResponse."""
+        response = error_toast("Something went wrong")
+        assert isinstance(response, HTMLResponse)
+
+    def test_default_status_422(self):
+        """error_toast defaults to 422 status code."""
+        response = error_toast("Validation failed")
+        assert response.status_code == 422
+
+    def test_custom_status_code(self):
+        """error_toast accepts custom status code."""
+        response = error_toast("Not allowed", status_code=403)
+        assert response.status_code == 403
+
+    def test_has_hx_trigger_header(self):
+        """error_toast sets HX-Trigger header."""
+        response = error_toast("Error message")
+        assert "HX-Trigger" in response.headers
+
+    def test_toast_message_in_header(self):
+        """error_toast includes message in HX-Trigger header."""
+        response = error_toast("Error message")
+        trigger = json.loads(response.headers["HX-Trigger"])
+        assert trigger["showToast"]["message"] == "Error message"
+
+    def test_toast_type_error(self):
+        """error_toast sets toast type to error."""
+        response = error_toast("Error message")
+        trigger = json.loads(response.headers["HX-Trigger"])
+        assert trigger["showToast"]["type"] == "error"
+
+
+class TestSuccessToast:
+    """Tests for success_toast()."""
+
+    def test_returns_dict(self):
+        """success_toast returns a dict (for HX-Trigger header)."""
+        result = success_toast("Action completed")
+        assert isinstance(result, dict)
+
+    def test_has_show_toast_key(self):
+        """success_toast dict has showToast key."""
+        result = success_toast("Action completed")
+        assert "showToast" in result
+
+    def test_message_in_toast(self):
+        """success_toast includes message."""
+        result = success_toast("Created successfully")
+        assert result["showToast"]["message"] == "Created successfully"
+
+    def test_toast_type_success(self):
+        """success_toast sets toast type to success."""
+        result = success_toast("Done")
+        assert result["showToast"]["type"] == "success"
+
+    def test_can_json_dumps(self):
+        """success_toast result can be JSON serialized."""
+        result = success_toast("Test message")
+        serialized = json.dumps(result)
+        assert '"showToast"' in serialized
+        assert '"Test message"' in serialized