diff --git a/CHANGELOG.md b/CHANGELOG.md
index 243f148..d252a6b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -20,6 +20,7 @@ This project uses Git as the primary rollback trail. The `.old` convention is re
 - Added Phase 8/9 marketplace matching with a dense available-work board, category/level/safety filters, technician level definitions, normalized taxonomy terms, provider tag assignment, and self-declared evidence-source tracking.
 - Added the guided imported-history wizard with structured work categories, imported endorsements, operational metrics, selected review excerpts, public visibility controls, proof attachments, and admin verification status.
 - Added post-work provider tag verification so buyers can confirm/dispute observed technician level and declared provider tags after completed work orders, with buyer-endorsed tag evidence shown on provider profiles.
+- Added Phase 11A mobile-safe API actions with versioned work-order endpoints, token ability checks, participant authorization, checklist/status/message/evidence/contact/running-late/schedule/dispute actions, mobile event audit records, optional geolocation evidence, API throttling, and baseline security headers.
 - Created the Laravel Provider Exchange prototype with Breeze authentication, seeded demo users, and role support for admins, providers, buyers, and hybrid accounts.
 - Added provider and buyer profile management with service areas, profile details, and external profile snapshot records.
 - Added social posts, buyer job posts, provider quotes, quote revisions, quote decline flow, and buyer quote acceptance.
@@ -41,6 +42,7 @@ This project uses Git as the primary rollback trail. The `.old` convention is re
 - `php artisan test` passed under Windows PHP with 48 tests and 228 assertions after Phase 8/9.
 - `php artisan test` passed under Windows PHP with 49 tests and 239 assertions after the guided imported-history wizard.
 - `php artisan test` passed under Windows PHP with 51 tests and 256 assertions after post-work provider tag verification.
+- `php artisan test` passed under Windows PHP with 55 tests and 285 assertions after Phase 11A mobile API and security hardening.
 - `npm run build` passed with a production Vite build.
 - `https://christit.com/tse/login` loads publicly.
 - Seeded admin login succeeds on `https://christit.com/tse` and reaches `/tse/dashboard`.
diff --git a/app/Http/Controllers/Api/V1/WorkOrderActionController.php b/app/Http/Controllers/Api/V1/WorkOrderActionController.php
new file mode 100644
index 0000000..c6ab892
--- /dev/null
+++ b/app/Http/Controllers/Api/V1/WorkOrderActionController.php
@@ -0,0 +1,415 @@
+<?php
+
+namespace App\Http\Controllers\Api\V1;
+
+use App\Http\Controllers\Controller;
+use App\Models\Dispute;
+use App\Models\JobPost;
+use App\Models\WorkOrder;
+use App\Models\WorkOrderChangeRequest;
+use App\Models\WorkOrderContactEvent;
+use App\Notifications\ExchangeEventNotification;
+use Illuminate\Http\JsonResponse;
+use Illuminate\Http\Request;
+use Illuminate\Support\Arr;
+
+class WorkOrderActionController extends Controller
+{
+    public function availableJobs(Request $request): JsonResponse
+    {
+        $this->requireAbility($request, 'jobs:read');
+
+        $jobs = JobPost::with('buyer:id,name')
+            ->where('visibility', 'public')
+            ->whereIn('status', ['open', 'assigned'])
+            ->latest()
+            ->paginate(min(max((int) $request->integer('per_page', 20), 1), 50));
+
+        return response()->json($jobs);
+    }
+
+    public function index(Request $request): JsonResponse
+    {
+        $this->requireAbility($request, 'work-orders:read');
+
+        $orders = WorkOrder::with('jobPost:id,title,location,scope_clarity_status', 'buyer:id,name', 'provider:id,name')
+            ->where(fn ($query) => $query
+                ->where('buyer_id', $request->user()->id)
+                ->orWhere('provider_id', $request->user()->id)
+            )
+            ->latest()
+            ->paginate(min(max((int) $request->integer('per_page', 20), 1), 50));
+
+        return response()->json($orders);
+    }
+
+    public function show(Request $request, WorkOrder $workOrder): JsonResponse
+    {
+        $this->requireAbility($request, 'work-orders:read');
+        $this->authorizeParticipant($request, $workOrder);
+
+        return response()->json([
+            'data' => $this->payload($workOrder),
+        ]);
+    }
+
+    public function transition(Request $request, WorkOrder $workOrder): JsonResponse
+    {
+        $this->requireAbility($request, 'work-orders:write');
+        $this->authorizeParticipant($request, $workOrder);
+
+        $data = $this->validateMobileAction($request, [
+            'status' => ['required', 'string', 'in:'.implode(',', WorkOrder::STATUSES)],
+            'completion_notes' => ['nullable', 'string', 'max:4000'],
+            'occurred_at' => ['nullable', 'date'],
+        ]);
+
+        $status = $data['status'];
+        abort_unless($workOrder->canTransitionTo($status), 422, 'This status transition is not allowed.');
+        $this->authorizeTransitionRole($request, $workOrder, $status);
+
+        $timestamps = [
+            'en_route' => 'en_route_at',
+            'on_site' => 'on_site_at',
+            'in_progress' => 'started_at',
+            'completed' => 'completed_at',
+            'buyer_approved' => 'approved_at',
+            'closed' => 'closed_at',
+        ];
+
+        $history = $workOrder->status_history ?? [];
+        $history[] = [
+            'status' => $status,
+            'user_id' => $request->user()->id,
+            'at' => now()->toIso8601String(),
+            'source' => 'api',
+        ];
+
+        $updates = [
+            'status' => $status,
+            'status_history' => $history,
+            'completion_notes' => $data['completion_notes'] ?? $workOrder->completion_notes,
+        ];
+
+        if (isset($timestamps[$status]) && ! $workOrder->{$timestamps[$status]}) {
+            $updates[$timestamps[$status]] = now();
+        }
+
+        $workOrder->update($updates);
+        $this->recordMobileEvent($request, $workOrder, 'status_transition', ['status' => $status]);
+        $this->notifyOtherParticipant($request, $workOrder, 'Work order updated', $request->user()->name.' changed '.$workOrder->jobPost->title.' to '.str_replace('_', ' ', $status).'.', 'work_order_status');
+
+        return response()->json(['data' => $this->payload($workOrder->fresh())]);
+    }
+
+    public function checklist(Request $request, WorkOrder $workOrder): JsonResponse
+    {
+        $this->requireAbility($request, 'work-orders:write');
+        $this->authorizeParticipant($request, $workOrder);
+
+        $data = $this->validateMobileAction($request, [
+            'checklist_completed' => ['required', 'array'],
+            'checklist_completed.*' => ['nullable', 'boolean'],
+            'occurred_at' => ['nullable', 'date'],
+        ]);
+
+        $completed = collect($workOrder->checklistItems())
+            ->mapWithKeys(fn (string $item): array => [$item => (bool) Arr::get($data['checklist_completed'], $item, false)])
+            ->all();
+
+        $workOrder->update(['checklist_completed' => $completed]);
+        $this->recordMobileEvent($request, $workOrder, 'checklist_update', ['checklist_completed' => $completed]);
+
+        return response()->json(['data' => $this->payload($workOrder->fresh())]);
+    }
+
+    public function message(Request $request, WorkOrder $workOrder): JsonResponse
+    {
+        $this->requireAbility($request, 'work-orders:write');
+        $this->authorizeParticipant($request, $workOrder);
+
+        $data = $this->validateMobileAction($request, [
+            'body' => ['required', 'string', 'max:4000'],
+            'occurred_at' => ['nullable', 'date'],
+        ]);
+
+        $message = $workOrder->messages()->create([
+            'user_id' => $request->user()->id,
+            'body' => $data['body'],
+        ]);
+
+        $this->recordMobileEvent($request, $workOrder, 'message_sent', ['message_id' => $message->id]);
+        $this->notifyOtherParticipant($request, $workOrder, 'Work order message', $request->user()->name.' sent a message on '.$workOrder->jobPost->title.'.', 'work_order_message');
+
+        return response()->json(['data' => $message->load('user:id,name')], 201);
+    }
+
+    public function evidence(Request $request, WorkOrder $workOrder): JsonResponse
+    {
+        $this->requireAbility($request, 'work-orders:upload');
+        $this->authorizeParticipant($request, $workOrder);
+
+        $maxKb = (int) config('provider-exchange.attachments.max_kb');
+        $mimeTypes = (array) config('provider-exchange.attachments.allowed_mime_types');
+
+        $data = $this->validateMobileAction($request, [
+            'kind' => ['nullable', 'string', 'max:255'],
+            'caption' => ['nullable', 'string', 'max:1000'],
+            'file' => ['required', 'file', 'max:'.$maxKb, 'mimetypes:'.implode(',', $mimeTypes)],
+            'occurred_at' => ['nullable', 'date'],
+        ]);
+
+        $file = $request->file('file');
+        $disk = (string) config('provider-exchange.attachments.disk');
+        $root = trim((string) config('provider-exchange.attachments.root'), '/');
+        $directory = implode('/', array_filter([
+            $root ?: 'attachments',
+            'work-order',
+            now()->format('Y'),
+            now()->format('m'),
+        ]));
+
+        $attachment = $workOrder->attachments()->create([
+            'user_id' => $request->user()->id,
+            'kind' => $data['kind'] ?? 'mobile_evidence',
+            'disk' => $disk,
+            'path' => $file->store($directory, $disk),
+            'original_name' => $file->getClientOriginalName(),
+            'mime_type' => $file->getClientMimeType(),
+            'size' => $file->getSize() ?: 0,
+            'caption' => $data['caption'] ?? null,
+        ]);
+
+        $this->recordMobileEvent($request, $workOrder, 'evidence_uploaded', ['attachment_id' => $attachment->id]);
+
+        return response()->json(['data' => $attachment], 201);
+    }
+
+    public function contactEvent(Request $request, WorkOrder $workOrder): JsonResponse
+    {
+        $this->requireAbility($request, 'work-orders:write');
+        $this->authorizeParticipant($request, $workOrder);
+        abort_unless($request->user()->id === $workOrder->provider_id || $request->user()->hasRole('admin'), 403);
+
+        $data = $this->validateMobileAction($request, [
+            'event_type' => ['required', 'string', 'in:'.implode(',', array_keys(WorkOrderContactEvent::EVENT_TYPES))],
+            'attempted_channel' => ['nullable', 'string', 'max:255'],
+            'attempted_at' => ['nullable', 'date'],
+            'result' => ['nullable', 'string', 'max:255'],
+            'notes' => ['nullable', 'string', 'max:4000'],
+            'occurred_at' => ['nullable', 'date'],
+        ]);
+
+        $event = $workOrder->contactEvents()->create([
+            'user_id' => $request->user()->id,
+            'event_type' => $data['event_type'],
+            'attempted_channel' => $data['attempted_channel'] ?? null,
+            'attempted_at' => $data['attempted_at'] ?? now(),
+            'result' => $data['result'] ?? null,
+            'notes' => $data['notes'] ?? null,
+        ]);
+
+        $this->recordMobileEvent($request, $workOrder, 'contact_event', ['contact_event_id' => $event->id, 'event_type' => $event->event_type]);
+        $workOrder->buyer->notify(new ExchangeEventNotification(
+            WorkOrderContactEvent::EVENT_TYPES[$event->event_type] ?? 'Contact event logged',
+            $request->user()->name.' logged '.str_replace('_', ' ', $event->event_type).' on '.$workOrder->jobPost->title.'.',
+            route('work-orders.show', $workOrder),
+            'contact_event'
+        ));
+
+        return response()->json(['data' => $event->load('user:id,name')], 201);
+    }
+
+    public function runningLate(Request $request, WorkOrder $workOrder): JsonResponse
+    {
+        $this->requireAbility($request, 'work-orders:write');
+        $this->authorizeParticipant($request, $workOrder);
+        abort_unless($request->user()->id === $workOrder->provider_id || $request->user()->hasRole('admin'), 403);
+
+        $data = $this->validateMobileAction($request, [
+            'estimated_arrival_at' => ['required', 'date'],
+            'reason' => ['nullable', 'string', 'max:1000'],
+            'occurred_at' => ['nullable', 'date'],
+        ]);
+
+        $event = $this->recordMobileEvent($request, $workOrder, 'running_late', [
+            'estimated_arrival_at' => $data['estimated_arrival_at'],
+            'reason' => $data['reason'] ?? null,
+        ]);
+
+        $workOrder->buyer->notify(new ExchangeEventNotification(
+            'Provider running late',
+            $request->user()->name.' reported a new estimated arrival for '.$workOrder->jobPost->title.'.',
+            route('work-orders.show', $workOrder),
+            'running_late'
+        ));
+
+        return response()->json(['data' => $event], 201);
+    }
+
+    public function scheduleUpdate(Request $request, WorkOrder $workOrder): JsonResponse
+    {
+        $this->requireAbility($request, 'work-orders:write');
+        $this->authorizeParticipant($request, $workOrder);
+
+        $data = $this->validateMobileAction($request, [
+            'requested_schedule_at' => ['required', 'date'],
+            'summary' => ['required', 'string', 'max:255'],
+            'details' => ['nullable', 'string', 'max:4000'],
+            'occurred_at' => ['nullable', 'date'],
+        ]);
+
+        $change = $workOrder->structuredChangeRequests()->create([
+            'requester_id' => $request->user()->id,
+            'reason_code' => 'schedule_change',
+            'summary' => $data['summary'],
+            'details' => $data['details'] ?? null,
+            'schedule_impact' => 'Requested schedule: '.$data['requested_schedule_at'],
+            'status' => 'open',
+        ]);
+
+        $this->recordMobileEvent($request, $workOrder, 'schedule_update_requested', ['change_request_id' => $change->id]);
+        $this->notifyOtherParticipant($request, $workOrder, 'Schedule update requested', $request->user()->name.' requested a schedule update for '.$workOrder->jobPost->title.'.', 'schedule_update_requested');
+
+        return response()->json(['data' => $change->load('requester:id,name')], 201);
+    }
+
+    public function dispute(Request $request, WorkOrder $workOrder): JsonResponse
+    {
+        $this->requireAbility($request, 'disputes:write');
+        $this->authorizeParticipant($request, $workOrder);
+
+        $data = $this->validateMobileAction($request, [
+            'summary' => ['required', 'string', 'max:255'],
+            'reason_code' => ['nullable', 'string', 'in:'.implode(',', array_keys(Dispute::REASON_CODES))],
+            'claim' => ['required', 'string', 'max:4000'],
+            'evidence_notes' => ['nullable', 'string', 'max:4000'],
+            'occurred_at' => ['nullable', 'date'],
+        ]);
+
+        $dispute = $workOrder->disputes()->create([
+            'opened_by_id' => $request->user()->id,
+            'status' => 'open',
+            'summary' => $data['summary'],
+            'reason_code' => $data['reason_code'] ?? 'other',
+            'claim' => $data['claim'],
+            'evidence_notes' => $data['evidence_notes'] ?? null,
+        ]);
+
+        if ($workOrder->status !== 'disputed') {
+            $workOrder->update(['status' => 'disputed']);
+        }
+
+        $this->recordMobileEvent($request, $workOrder, 'dispute_opened', ['dispute_id' => $dispute->id]);
+        $this->notifyOtherParticipant($request, $workOrder, 'Dispute opened', $request->user()->name.' opened a dispute for '.$workOrder->jobPost->title.'.', 'dispute_opened');
+
+        return response()->json(['data' => $dispute->load('openedBy:id,name')], 201);
+    }
+
+    private function validateMobileAction(Request $request, array $rules): array
+    {
+        return $request->validate($rules + [
+            'latitude' => ['nullable', 'numeric', 'between:-90,90'],
+            'longitude' => ['nullable', 'numeric', 'between:-180,180'],
+            'accuracy_meters' => ['nullable', 'integer', 'min:0', 'max:100000'],
+        ]);
+    }
+
+    private function payload(WorkOrder $workOrder): array
+    {
+        $workOrder->load(
+            'jobPost:id,title,location,scope,scope_clarity_status,risk_flags',
+            'buyer:id,name',
+            'provider:id,name',
+            'messages.user:id,name',
+            'attachments',
+            'structuredChangeRequests.requester:id,name',
+            'contactEvents.user:id,name',
+            'disputes.openedBy:id,name',
+            'mobileEvents.user:id,name',
+        );
+
+        return [
+            'id' => $workOrder->id,
+            'status' => $workOrder->status,
+            'allowed_transitions' => WorkOrder::ALLOWED_TRANSITIONS[$workOrder->status] ?? [],
+            'job' => $workOrder->jobPost,
+            'buyer' => $workOrder->buyer,
+            'provider' => $workOrder->provider,
+            'scheduled_at' => $workOrder->scheduled_at,
+            'appointment_window' => $workOrder->appointment_window,
+            'technician_level' => $workOrder->technicianLevel(),
+            'scope' => $workOrder->scope_snapshot,
+            'contacts' => $workOrder->contact_snapshot,
+            'checklist' => collect($workOrder->checklistItems())->map(fn (string $item): array => [
+                'label' => $item,
+                'completed' => (bool) ($workOrder->checklistCompleted()[$item] ?? false),
+            ])->values(),
+            'messages' => $workOrder->messages,
+            'attachments' => $workOrder->attachments,
+            'change_requests' => $workOrder->structuredChangeRequests,
+            'contact_events' => $workOrder->contactEvents,
+            'disputes' => $workOrder->disputes,
+            'mobile_events' => $workOrder->mobileEvents,
+            'privacy' => [
+                'geolocation' => 'Optional coordinates are stored only as work-order evidence for the submitted action.',
+            ],
+        ];
+    }
+
+    private function recordMobileEvent(Request $request, WorkOrder $workOrder, string $type, array $payload = [])
+    {
+        return $workOrder->mobileEvents()->create([
+            'user_id' => $request->user()->id,
+            'event_type' => $type,
+            'payload' => $payload,
+            'latitude' => $request->input('latitude'),
+            'longitude' => $request->input('longitude'),
+            'accuracy_meters' => $request->input('accuracy_meters'),
+            'occurred_at' => $request->date('occurred_at') ?? now(),
+        ]);
+    }
+
+    private function requireAbility(Request $request, string $ability): void
+    {
+        $token = $request->user()->currentAccessToken();
+
+        if ($token && ! $request->user()->tokenCan($ability) && ! $request->user()->tokenCan('*')) {
+            abort(403, 'This API token is missing the required ability.');
+        }
+    }
+
+    private function authorizeParticipant(Request $request, WorkOrder $workOrder): void
+    {
+        abort_unless(
+            in_array($request->user()->id, [$workOrder->buyer_id, $workOrder->provider_id], true)
+                || $request->user()->hasRole('admin'),
+            403
+        );
+    }
+
+    private function authorizeTransitionRole(Request $request, WorkOrder $workOrder, string $status): void
+    {
+        $userId = $request->user()->id;
+        $providerStatuses = ['en_route', 'on_site', 'in_progress', 'completed'];
+        $buyerStatuses = ['buyer_approved', 'closed', 'cancelled'];
+        $sharedStatuses = ['disputed'];
+
+        if (in_array($status, $providerStatuses, true)) {
+            abort_unless($workOrder->provider_id === $userId || $request->user()->hasRole('admin'), 403);
+        } elseif (in_array($status, $buyerStatuses, true)) {
+            abort_unless($workOrder->buyer_id === $userId || $request->user()->hasRole('admin'), 403);
+        } elseif (in_array($status, $sharedStatuses, true)) {
+            abort_unless(in_array($userId, [$workOrder->buyer_id, $workOrder->provider_id], true) || $request->user()->hasRole('admin'), 403);
+        }
+    }
+
+    private function notifyOtherParticipant(Request $request, WorkOrder $workOrder, string $title, string $body, string $type): void
+    {
+        $recipient = $request->user()->id === $workOrder->buyer_id
+            ? $workOrder->provider
+            : $workOrder->buyer;
+
+        $recipient->notify(new ExchangeEventNotification($title, $body, route('work-orders.show', $workOrder), $type));
+    }
+}
diff --git a/app/Http/Middleware/SecurityHeaders.php b/app/Http/Middleware/SecurityHeaders.php
new file mode 100644
index 0000000..7076aff
--- /dev/null
+++ b/app/Http/Middleware/SecurityHeaders.php
@@ -0,0 +1,26 @@
+<?php
+
+namespace App\Http\Middleware;
+
+use Closure;
+use Illuminate\Http\Request;
+use Symfony\Component\HttpFoundation\Response;
+
+class SecurityHeaders
+{
+    public function handle(Request $request, Closure $next): Response
+    {
+        $response = $next($request);
+
+        $response->headers->set('X-Content-Type-Options', 'nosniff');
+        $response->headers->set('X-Frame-Options', 'SAMEORIGIN');
+        $response->headers->set('Referrer-Policy', 'strict-origin-when-cross-origin');
+        $response->headers->set('Permissions-Policy', 'camera=(), microphone=(), geolocation=(self)');
+
+        if ($request->isSecure()) {
+            $response->headers->set('Strict-Transport-Security', 'max-age=31536000; includeSubDomains');
+        }
+
+        return $response;
+    }
+}
diff --git a/app/Models/WorkOrder.php b/app/Models/WorkOrder.php
index f818074..eaf4551 100644
--- a/app/Models/WorkOrder.php
+++ b/app/Models/WorkOrder.php
@@ -117,6 +117,11 @@ class WorkOrder extends Model
         return $this->hasOne(ProviderTagVerification::class);
     }
 
+    public function mobileEvents(): HasMany
+    {
+        return $this->hasMany(WorkOrderMobileEvent::class);
+    }
+
     public function canTransitionTo(string $status): bool
     {
         return in_array($status, self::ALLOWED_TRANSITIONS[$this->status] ?? [], true);
diff --git a/app/Models/WorkOrderMobileEvent.php b/app/Models/WorkOrderMobileEvent.php
new file mode 100644
index 0000000..6c1c9df
--- /dev/null
+++ b/app/Models/WorkOrderMobileEvent.php
@@ -0,0 +1,52 @@
+<?php
+
+namespace App\Models;
+
+use Illuminate\Database\Eloquent\Attributes\Fillable;
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\BelongsTo;
+
+#[Fillable([
+    'work_order_id',
+    'user_id',
+    'event_type',
+    'payload',
+    'latitude',
+    'longitude',
+    'accuracy_meters',
+    'occurred_at',
+])]
+class WorkOrderMobileEvent extends Model
+{
+    public const EVENT_TYPES = [
+        'status_transition',
+        'checklist_update',
+        'message_sent',
+        'evidence_uploaded',
+        'running_late',
+        'schedule_update_requested',
+        'contact_event',
+        'dispute_opened',
+    ];
+
+    protected function casts(): array
+    {
+        return [
+            'payload' => 'array',
+            'latitude' => 'decimal:7',
+            'longitude' => 'decimal:7',
+            'accuracy_meters' => 'integer',
+            'occurred_at' => 'datetime',
+        ];
+    }
+
+    public function workOrder(): BelongsTo
+    {
+        return $this->belongsTo(WorkOrder::class);
+    }
+
+    public function user(): BelongsTo
+    {
+        return $this->belongsTo(User::class);
+    }
+}
diff --git a/app/Providers/AppServiceProvider.php b/app/Providers/AppServiceProvider.php
index 452e6b6..a8ad716 100644
--- a/app/Providers/AppServiceProvider.php
+++ b/app/Providers/AppServiceProvider.php
@@ -2,6 +2,9 @@
 
 namespace App\Providers;
 
+use Illuminate\Cache\RateLimiting\Limit;
+use Illuminate\Http\Request;
+use Illuminate\Support\Facades\RateLimiter;
 use Illuminate\Support\ServiceProvider;
 
 class AppServiceProvider extends ServiceProvider
@@ -19,6 +22,8 @@ class AppServiceProvider extends ServiceProvider
      */
     public function boot(): void
     {
-        //
+        RateLimiter::for('api', function (Request $request) {
+            return Limit::perMinute(120)->by($request->user()?->id ?: $request->ip());
+        });
     }
 }
diff --git a/bootstrap/app.php b/bootstrap/app.php
index 4b327d2..fadac80 100644
--- a/bootstrap/app.php
+++ b/bootstrap/app.php
@@ -13,7 +13,7 @@ return Application::configure(basePath: dirname(__DIR__))
         health: '/up',
     )
     ->withMiddleware(function (Middleware $middleware): void {
-        //
+        $middleware->append(\App\Http\Middleware\SecurityHeaders::class);
     })
     ->withExceptions(function (Exceptions $exceptions): void {
         $exceptions->shouldRenderJsonWhen(
diff --git a/database/migrations/2026_07_11_000000_create_work_order_mobile_events_table.php b/database/migrations/2026_07_11_000000_create_work_order_mobile_events_table.php
new file mode 100644
index 0000000..ce67cfe
--- /dev/null
+++ b/database/migrations/2026_07_11_000000_create_work_order_mobile_events_table.php
@@ -0,0 +1,32 @@
+<?php
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\Schema;
+
+return new class extends Migration
+{
+    public function up(): void
+    {
+        Schema::create('work_order_mobile_events', function (Blueprint $table) {
+            $table->id();
+            $table->foreignId('work_order_id')->constrained()->cascadeOnDelete();
+            $table->foreignId('user_id')->constrained()->cascadeOnDelete();
+            $table->string('event_type');
+            $table->json('payload')->nullable();
+            $table->decimal('latitude', 10, 7)->nullable();
+            $table->decimal('longitude', 10, 7)->nullable();
+            $table->unsignedInteger('accuracy_meters')->nullable();
+            $table->timestamp('occurred_at')->nullable();
+            $table->timestamps();
+
+            $table->index(['work_order_id', 'event_type']);
+            $table->index(['user_id', 'created_at']);
+        });
+    }
+
+    public function down(): void
+    {
+        Schema::dropIfExists('work_order_mobile_events');
+    }
+};
diff --git a/docs/FORWARD_PHASE_PLAN.md b/docs/FORWARD_PHASE_PLAN.md
index 2ce4e03..97213f1 100644
--- a/docs/FORWARD_PHASE_PLAN.md
+++ b/docs/FORWARD_PHASE_PLAN.md
@@ -32,7 +32,6 @@ The goal is not to clone Field Nation. The goal is to keep the useful operationa
 - Job posting now has structured scope and support certification fields, but the creation UI should be refined into reusable templates and stronger validation before real marketplace use.
 - Provider and buyer directories use text-based filters instead of normalized category, skill, coverage, remote, rating, and reliability filters.
 - Work-order lists are card-based and lack the dense assigned/available-work table that worked well in Field Nation.
-- Work-order detail now supports contact/support failure logging and first-class change requests, but schedule update requests, running-late records, post-work tag verification, and general report-problem records still need a dedicated workflow.
 - Work-order detail now supports contact/support failure logging, first-class change requests, and post-work provider tag verification; schedule update requests, running-late records, and general report-problem records still need dedicated workflows.
 - Disputes and votes now have reason codes, but quorum rules, visibility rules, and deeper evidence timelines still need a future pass.
 - Reviews exist, but there is no review response, report flow, edit window, moderation queue, category definitions page, or imported/native reputation distinction in the UI.
@@ -541,6 +540,18 @@ Provider-protection rules:
 - Every mobile action should leave an audit trail visible to the provider.
 - Support/contact failures should be as easy to log as check-in.
 
+Implementation status:
+
+- Completed first implementation pass.
+- Added `/api/v1` mobile-safe work-order endpoints behind Sanctum auth and API throttling.
+- Added token ability gates for `jobs:read`, `work-orders:read`, `work-orders:write`, `work-orders:upload`, and `disputes:write`.
+- Added participant authorization on work-order detail and every work-order action.
+- Added mobile actions for status transition, checklist update, message send, evidence upload, contact/support event logging, running-late notice, schedule-update request, and dispute opening.
+- Added `work_order_mobile_events` as an audit trail for mobile actions.
+- Added optional latitude, longitude, accuracy, and occurred-at fields to mobile action records with explicit privacy copy in API payloads.
+- Added baseline HTTP security headers and an explicit `api` rate limiter.
+- Verified with Windows `php artisan test`.
+
 ## Phase 12 - Notification Preferences And Event Channels
 
 Purpose:
@@ -718,10 +729,10 @@ Provider-protection rules:
 
 ## Recommended Immediate Sequence
 
-1. Phase 11A: mobile-safe API endpoints for onsite work-order actions.
-2. Phase 12A: notification preference UI and event-channel controls.
-3. Phase 13A: audit logs and moderation/operations queues.
-4. Phase 14A: deployment/scaling hardening.
+1. Phase 12A: notification preference UI and event-channel controls.
+2. Phase 13A: audit logs and moderation/operations queues.
+3. Phase 14A: deployment/scaling hardening.
+4. Phase 15A: UX polish and accessibility pass.
 
 ## Key Design Commitments
 
diff --git a/docs/ROADMAP.md b/docs/ROADMAP.md
index 773a71b..f424cc8 100644
--- a/docs/ROADMAP.md
+++ b/docs/ROADMAP.md
@@ -26,7 +26,8 @@ Provider Exchange is a Laravel application for a provider-centered field-service
 - Peer-review disputes with comments, evidence, structured recommendations, and public vote breakdowns.
 - Universal community ratings for buyers, providers, job posts, work orders, and disputes.
 - Database notification events and notification inbox.
-- Starter Sanctum API surface for future app clients.
+- Versioned Sanctum API surface for future app clients, including mobile-safe work-order actions, token ability checks, action audit records, and optional geolocation evidence.
+- Baseline API/security hardening with rate limiting and HTTP security headers.
 - MIT license and no-payment/no-rate-setting guardrails.
 
 ## Operating Principles
@@ -58,11 +59,11 @@ Provider Exchange is a Laravel application for a provider-centered field-service
 
 ## Phase Checkpoint
 
-Phases 1-10B have been implemented locally through post-work provider tag verification. The next active planning block is:
+Phases 1-11A have been implemented locally through mobile-safe API actions and baseline security hardening. The next active planning block is:
 
-8. API/mobile prep: token-scoped endpoints, versioned API resources, geolocation check-in groundwork, contact/support failure logging, and mobile-safe work-order actions.
-9. Notification preference UI and event-channel controls.
-10. Admin operations, audit logs, and deployment hardening.
+8. Notification preference UI and event-channel controls.
+9. Admin operations, audit logs, and moderation queues.
+10. Deployment/scaling hardening and UX/accessibility polish.
 
 Work-order safeguards to carry into the next implementation passes:
 
@@ -134,6 +135,16 @@ Post-work provider tag verification completed:
 - Provider profiles now show recent completed-work competency evidence separately from imported history and five-star reviews.
 - Providers cannot self-verify their tags from a work order.
 
+Phase 11A mobile API and security hardening completed:
+
+- `/api/v1` now exposes mobile-safe endpoints for available jobs, assigned work orders, work-order detail, status transitions, checklist updates, messages, evidence uploads, contact/support events, running-late notices, schedule-update requests, and dispute opening.
+- API tokens can be scoped by ability: `jobs:read`, `work-orders:read`, `work-orders:write`, `work-orders:upload`, and `disputes:write`.
+- Work-order API actions enforce buyer/provider/admin participant boundaries.
+- Mobile actions write to `work_order_mobile_events` with event type, user, payload, optional coordinates, optional accuracy, and occurred-at timestamp.
+- Geolocation is optional and documented in the API response as work-order evidence only.
+- API routes are throttled through an explicit `api` rate limiter.
+- Application responses include baseline security headers: content-type sniffing protection, same-origin frame policy, strict origin referrer policy, limited permissions policy, and HSTS on secure requests.
+
 Available-work safeguards to carry into directory and job-list phases:
 
 - Available jobs should expose pay type, provider terms, schedule type, work type, rough location, buyer reliability, support/contact certification, scope clarity status, and request/quote count.
diff --git a/routes/api.php b/routes/api.php
index 8d88e40..07416ef 100644
--- a/routes/api.php
+++ b/routes/api.php
@@ -1,5 +1,6 @@
 <?php
 
+use App\Http\Controllers\Api\V1\WorkOrderActionController;
 use App\Models\Dispute;
 use App\Models\JobPost;
 use App\Models\ProviderProfile;
@@ -15,7 +16,26 @@ Route::get('/jobs', function () {
     return JobPost::with('buyer:id,name')->latest()->paginate(20);
 });
 
-Route::middleware('auth:sanctum')->group(function () {
+Route::prefix('v1')->middleware(['auth:sanctum', 'throttle:api'])->group(function () {
+    Route::get('/me', function (Request $request) {
+        return $request->user()->load('roles', 'providerProfile', 'buyerProfile')
+            ->setAttribute('unread_notifications_count', $request->user()->unreadNotifications()->count());
+    });
+
+    Route::get('/jobs', [WorkOrderActionController::class, 'availableJobs']);
+    Route::get('/work-orders', [WorkOrderActionController::class, 'index']);
+    Route::get('/work-orders/{workOrder}', [WorkOrderActionController::class, 'show']);
+    Route::patch('/work-orders/{workOrder}/transition', [WorkOrderActionController::class, 'transition']);
+    Route::patch('/work-orders/{workOrder}/checklist', [WorkOrderActionController::class, 'checklist']);
+    Route::post('/work-orders/{workOrder}/messages', [WorkOrderActionController::class, 'message']);
+    Route::post('/work-orders/{workOrder}/evidence', [WorkOrderActionController::class, 'evidence']);
+    Route::post('/work-orders/{workOrder}/contact-events', [WorkOrderActionController::class, 'contactEvent']);
+    Route::post('/work-orders/{workOrder}/running-late', [WorkOrderActionController::class, 'runningLate']);
+    Route::post('/work-orders/{workOrder}/schedule-updates', [WorkOrderActionController::class, 'scheduleUpdate']);
+    Route::post('/work-orders/{workOrder}/disputes', [WorkOrderActionController::class, 'dispute']);
+});
+
+Route::middleware(['auth:sanctum', 'throttle:api'])->group(function () {
     Route::get('/me', function (Request $request) {
         return $request->user()->load('roles', 'providerProfile', 'buyerProfile')
             ->setAttribute('unread_notifications_count', $request->user()->unreadNotifications()->count());
diff --git a/tests/Feature/ApiWorkOrderActionTest.php b/tests/Feature/ApiWorkOrderActionTest.php
new file mode 100644
index 0000000..07f347d
--- /dev/null
+++ b/tests/Feature/ApiWorkOrderActionTest.php
@@ -0,0 +1,183 @@
+<?php
+
+namespace Tests\Feature;
+
+use App\Models\JobPost;
+use App\Models\User;
+use App\Models\WorkOrder;
+use Illuminate\Foundation\Testing\RefreshDatabase;
+use Illuminate\Http\UploadedFile;
+use Illuminate\Support\Facades\Storage;
+use Laravel\Sanctum\Sanctum;
+use Spatie\Permission\Models\Role;
+use Tests\TestCase;
+
+class ApiWorkOrderActionTest extends TestCase
+{
+    use RefreshDatabase;
+
+    public function test_mobile_api_status_transition_records_audit_location(): void
+    {
+        [$buyer, $provider, $workOrder] = $this->workOrderFixture();
+        Sanctum::actingAs($provider, ['work-orders:read', 'work-orders:write']);
+
+        $this->patchJson("/api/v1/work-orders/{$workOrder->id}/transition", [
+            'status' => 'en_route',
+            'latitude' => 36.1539816,
+            'longitude' => -95.992775,
+            'accuracy_meters' => 25,
+        ])->assertOk()
+            ->assertJsonPath('data.status', 'en_route')
+            ->assertJsonPath('data.privacy.geolocation', 'Optional coordinates are stored only as work-order evidence for the submitted action.');
+
+        $this->assertDatabaseHas('work_orders', [
+            'id' => $workOrder->id,
+            'status' => 'en_route',
+        ]);
+        $this->assertDatabaseHas('work_order_mobile_events', [
+            'work_order_id' => $workOrder->id,
+            'user_id' => $provider->id,
+            'event_type' => 'status_transition',
+            'accuracy_meters' => 25,
+        ]);
+    }
+
+    public function test_mobile_api_requires_token_abilities_and_participation(): void
+    {
+        [, $provider, $workOrder] = $this->workOrderFixture();
+        $outsider = $this->userWithRole('provider');
+
+        Sanctum::actingAs($provider, ['work-orders:read']);
+        $this->patchJson("/api/v1/work-orders/{$workOrder->id}/transition", [
+            'status' => 'en_route',
+        ])->assertForbidden();
+
+        Sanctum::actingAs($outsider, ['work-orders:read', 'work-orders:write']);
+        $this->getJson("/api/v1/work-orders/{$workOrder->id}")
+            ->assertForbidden();
+    }
+
+    public function test_mobile_api_updates_checklist_sends_message_and_uploads_evidence(): void
+    {
+        Storage::fake('public');
+        config()->set('provider-exchange.attachments.disk', 'public');
+        config()->set('provider-exchange.attachments.root', 'test-api-assets');
+
+        [$buyer, $provider, $workOrder] = $this->workOrderFixture([
+            'deliverables_checklist' => "Arrival photo\nCable test",
+            'checklist_items' => ['Arrival photo', 'Cable test'],
+        ]);
+        Sanctum::actingAs($provider, ['work-orders:read', 'work-orders:write', 'work-orders:upload']);
+
+        $this->patchJson("/api/v1/work-orders/{$workOrder->id}/checklist", [
+            'checklist_completed' => [
+                'Arrival photo' => true,
+                'Cable test' => false,
+            ],
+        ])->assertOk()
+            ->assertJsonPath('data.checklist.0.completed', true)
+            ->assertJsonPath('data.checklist.1.completed', false);
+
+        $this->postJson("/api/v1/work-orders/{$workOrder->id}/messages", [
+            'body' => 'Uploaded the arrival photo.',
+        ])->assertCreated()
+            ->assertJsonPath('data.body', 'Uploaded the arrival photo.');
+
+        $this->post("/api/v1/work-orders/{$workOrder->id}/evidence", [
+            'kind' => 'arrival_photo',
+            'caption' => 'Arrival photo',
+            'file' => UploadedFile::fake()->image('arrival.jpg'),
+        ], ['Accept' => 'application/json'])->assertCreated()
+            ->assertJsonPath('data.kind', 'arrival_photo')
+            ->assertJsonPath('data.caption', 'Arrival photo');
+
+        $attachment = $workOrder->attachments()->firstOrFail();
+        Storage::disk('public')->assertExists($attachment->path);
+        $this->assertDatabaseHas('work_order_mobile_events', [
+            'work_order_id' => $workOrder->id,
+            'event_type' => 'evidence_uploaded',
+        ]);
+    }
+
+    public function test_mobile_api_records_contact_failure_running_late_schedule_update_and_dispute(): void
+    {
+        [$buyer, $provider, $workOrder] = $this->workOrderFixture();
+        Sanctum::actingAs($provider, ['work-orders:read', 'work-orders:write', 'disputes:write']);
+
+        $this->postJson("/api/v1/work-orders/{$workOrder->id}/contact-events", [
+            'event_type' => 'support_unavailable',
+            'attempted_channel' => 'Phone',
+            'result' => 'No answer',
+        ])->assertCreated()
+            ->assertJsonPath('data.event_type', 'support_unavailable');
+
+        $this->postJson("/api/v1/work-orders/{$workOrder->id}/running-late", [
+            'estimated_arrival_at' => now()->addMinutes(30)->toIso8601String(),
+            'reason' => 'Traffic delay',
+        ])->assertCreated()
+            ->assertJsonPath('data.event_type', 'running_late');
+
+        $this->postJson("/api/v1/work-orders/{$workOrder->id}/schedule-updates", [
+            'requested_schedule_at' => now()->addDay()->toIso8601String(),
+            'summary' => 'Move to tomorrow morning',
+            'details' => 'Site contact asked to reschedule.',
+        ])->assertCreated()
+            ->assertJsonPath('data.reason_code', 'schedule_change');
+
+        $this->postJson("/api/v1/work-orders/{$workOrder->id}/disputes", [
+            'summary' => 'Support unavailable',
+            'reason_code' => 'support_unavailable',
+            'claim' => 'The certified support line did not answer.',
+        ])->assertCreated()
+            ->assertJsonPath('data.reason_code', 'support_unavailable');
+
+        $this->assertDatabaseHas('work_order_contact_events', [
+            'work_order_id' => $workOrder->id,
+            'event_type' => 'support_unavailable',
+        ]);
+        $this->assertDatabaseHas('work_order_change_requests', [
+            'work_order_id' => $workOrder->id,
+            'reason_code' => 'schedule_change',
+        ]);
+        $this->assertDatabaseHas('disputes', [
+            'work_order_id' => $workOrder->id,
+            'reason_code' => 'support_unavailable',
+        ]);
+        $this->assertDatabaseHas('work_orders', [
+            'id' => $workOrder->id,
+            'status' => 'disputed',
+        ]);
+    }
+
+    private function userWithRole(string $role): User
+    {
+        Role::findOrCreate($role);
+
+        $user = User::factory()->create();
+        $user->assignRole($role);
+
+        return $user;
+    }
+
+    private function workOrderFixture(array $overrides = []): array
+    {
+        $provider = $this->userWithRole('provider');
+        $buyer = $this->userWithRole('buyer');
+        $job = JobPost::create([
+            'buyer_id' => $buyer->id,
+            'title' => 'Repair printer',
+            'location' => 'OKC, OK',
+            'scope' => 'Repair printer.',
+            'visibility' => 'public',
+        ]);
+
+        $workOrder = WorkOrder::create($overrides + [
+            'job_post_id' => $job->id,
+            'buyer_id' => $buyer->id,
+            'provider_id' => $provider->id,
+            'status' => 'assigned',
+        ]);
+
+        return [$buyer, $provider, $workOrder];
+    }
+}