UiPath Tasks Skill

Generate Tasks workflows for human-in-the-loop, system-in-the-loop, and task management patterns in UiPath.

Plugin architecture: This skill's extensions/ directory is auto-discovered by uipath-core's plugin_loader.py. Generators, lint rules, scaffold hooks, namespaces, and known activities are registered at import time — no manual wiring needed. Core's generate_workflow.py, validate_xaml, and scaffold_project.py query the plugin registries at runtime.

Plugin API contract (v2)

This skill is the canonical example for out-of-tree plugin authors. The contract:

• REQUIRED_API_VERSION = 2 must be declared at the top of extensions/__init__.py. Plugins on v1 (or with no declaration) fail to load with a clear API version mismatch error and any partial registrations are rolled back.
• Registration entry points added in v2: register_version_profile(package, profile_version, profile_dict) and register_band_profile_mapping(band, package, profile_version) — used by lint 122 (version-band drift). Call register_band_profile_mapping once per (band, package) pair. Registering after the lint module is already imported automatically invalidates the lint caches, so the new entries take effect on the next lint pass without any reload.
• Atomic commit: every register_* call made during a plugin's load (including from submodules imported from __init__.py) is captured in the registry snapshot. If __init__.py raises before completing, all registrations from that plugin are reverted. The registry is never observed in a partially-loaded state by other plugins or by core.
• Out of scope for rollback: non-registry side effects (file writes, env vars, threads spawned at import time, monkey-patches). Confine those to lazy paths invoked after a successful load.
• Test that load succeeded: assert plugin_loader.get_load_failures() == [] after load_plugins(). A plugin that raised during load surfaces in that list with its filename and exception.

Worked example: see uipath-tasks/extensions/__init__.py:34 (the REQUIRED_API_VERSION = 2 declaration) and :310-312 (the Persistence/1.4 profile + band-25/26 mapping calls).

Extensions (Plugin System)

uipath-tasks/
├── SKILL.md
├── references/
│   ├── tasks.md       ← Form Tasks + form.io + Action Types Comparison
│   ├── external-tasks.md      ← External Tasks (system-in-the-loop)
│   └── task-management.md     ← GetFormTasks, CompleteTask, AssignTasks
└── extensions/
    ├── __init__.py             ← Registers all AC components with plugin_loader
    ├── generators.py           ← 7 generators (form, external, task management)
    ├── lint_rules.py           ← AC-10, AC-11, AC-12, AC-26
    ├── scaffold_hooks.py       ← enable_persistence_support
    └── battle_test_grading.py  ← 8 battle test scenario graders

What gets registered:

• 7 generators: create_form_task, wait_for_form_task, create_external_task, wait_for_external_task, get_form_tasks, complete_task, assign_tasks
• 4 lint rules: AC-10 (Form Create/Wait mismatch), AC-11 (FormData key mismatch), AC-12 (External Create/Wait mismatch), AC-26 (persistence in sub-workflow)
• 1 scaffold hook: auto-enables supportsPersistence when Persistence.Activities is in deps
• 3 namespaces: upaf (FormTask), upae (ExternalTask), upat (Tasks)
• 7 known activities: CreateFormTask, WaitForFormTaskAndResume, CreateExternalTask, WaitForExternalTaskAndResume, GetFormTasks, CompleteTask, AssignTasks

When To Read Which Reference

Task	Read
Create a form task workflow	references/tasks.md → Create Form Task + FormData Bindings
Design a form.io form schema	references/tasks.md → Form.io Component Reference
Wait for human approval / resume	references/tasks.md → Wait for Form Task and Resume
Any PDD with "for each X" / "multiple X" / "batch of X" / N rows (default for N-item approvals, not advanced)	references/tasks.md → Shadow Task Pattern
Compare action types (Form vs External)	references/tasks.md → Action Types Comparison
Create an external task (system-in-the-loop)	references/external-tasks.md → Create External Task
Wait for external system resolution	references/external-tasks.md → Wait for External Task and Resume
Retrieve existing tasks (recovery workflow)	references/task-management.md → Get Form Tasks
Complete a task programmatically	references/task-management.md → Complete Task
Assign a task to a user/group	references/task-management.md → Assign Tasks
Escalation / reassignment patterns	references/task-management.md → Escalation Pattern
Task lifecycle states	references/task-management.md → Task Lifecycle States
Persistence constraints	references/tasks.md → Prerequisites (Main.xaml constraint)
Lint issues on AC workflows	references/tasks.md → Validation & Lint Rules + external-tasks.md → Validation
Scaffold a project with persistence	Scaffold hook in extensions/scaffold_hooks.py — auto-runs via core's scaffold_project.py
Validate AC workflow XAML	Lint rules in extensions/lint_rules.py — auto-run via core's validate_xaml --lint
Resolve NuGet versions	Use uipath-core's resolve_nuget.py for UiPath.Persistence.Activities + UiPath.FormActivityLibrary

Ground Rules

• AC-1: Always use generators. Never write Tasks XAML by hand. Use generators via JSON specs or Python API (auto-loaded from extensions/generators.py).
• AC-2: Persistence activities MUST stay in Main.xaml. WaitForFormTaskAndResume, WaitForExternalTaskAndResume, and all Wait*AndResume activities are persistence points — they serialize workflow state to Orchestrator. They ONLY work in the entry-point file. AC-26 enforces this.
• AC-3: Both NuGet packages are required for Form Tasks. UiPath.Persistence.Activities (runtime) AND UiPath.FormActivityLibrary (form designer UI). External Tasks and Task Management only need UiPath.Persistence.Activities.
• AC-4: supportsPersistence: true must be in project.json runtimeOptions when using Wait*AndResume activities. Scaffold sets this automatically.
• AC-5: FormData keys must match form.io component keys. (Form Tasks only.) AC-11 validates key presence.
• AC-6: Always include a submit button as the last form.io component. (Form Tasks only.)
• AC-7: Wrap Create*Task in RetryScope. Orchestrator API calls can transiently fail.
• AC-8: External tasks have NO form. Don't use FormLayout/FormData on CreateExternalTask — use TaskData dict.
• AC-9: Task Management activities are NOT persistence points. GetFormTasks, CompleteTask, AssignTasks can be used in sub-workflows.
• AC-Shadow: Shadow Task Pattern is the default shape for N-item approvals. When the PDD / workflow processes N items from a collection (DataTable rows, list, etc.) and each needs a human task, emit one ui:ForEachRow / ui:ForEach that only calls CreateFormTask and appends the returned FormTaskData to a List(Of FormTaskData), followed by a second ui:ForEach (at the root-Sequence level) that runs WaitForFormTaskAndResume + decision handling per task. The List(FormTaskData) variable MUST be initialized — set Default="[New System.Collections.Generic.List(Of UiPath.Persistence.Activities.FormTask.FormTaskData)()]" on the variable declaration (or pass "default": "[...]" in the JSON spec). A null List throws Value cannot be null. (Parameter 'TargetObject') on the first InvokeMethod.Add. Never emit inline Create → Wait per item, and never unroll the loop into hardcoded If Rows.Count >= N / Rows(0..N-1) blocks. The inline form ties up the robot for the sum of all wait times instead of the max; the unrolled form additionally bypasses AC-27. See references/form-tasks.md → Shadow Task Pattern (default for N-item batches). Loop-nested case enforced by AC-27; unrolled case enforced by AC-34.

Capabilities

1. CreateFormTask — Form task with form.io schema, FormData bindings (In/Out/InOut), storage bucket, task catalog, priority levels
2. WaitForFormTaskAndResume — Long-running persistence, task action capture, updated FormTaskData output
3. Form.io schema design — textfield, textarea, number, select, checkbox, datagrid (DataTable binding), htmlelement (Mustache templates), columns, button
4. FormData direction bindings — In (read-only), Out (user-entered), InOut (editable pre-populated, DataTable ↔ datagrid)
5. Shadow task pattern — Non-blocking multi-task orchestration
6. CreateExternalTask — System-in-the-loop task for external systems (JIRA, Salesforce, ServiceNow)
7. WaitForExternalTaskAndResume — Suspend until external system completes task via API
8. GetFormTasks — Retrieve existing tasks from Orchestrator (recovery workflows, cross-process)
9. CompleteTask — Programmatic task completion (escalation, timeout, batch operations)
10. AssignTasks — Assign tasks to user or group (SingleUser, AllUsersInGroup)
11. Validation — AC-10, AC-11, AC-12, AC-26

Reference Files

File	Coverage
references/tasks.md	Form Tasks — prerequisites, CreateFormTask, FormData, form.io, WaitForFormTask, patterns, lint, Config keys
references/external-tasks.md	External Tasks — CreateExternalTask, WaitForExternalTask, TaskData dict, external system completion
references/task-management.md	Task Management — GetFormTasks, CompleteTask, AssignTasks, recovery pattern, escalation pattern, lifecycle

Quick Generator Reference

Generator	Activity	Prefix	Key Args
gen_create_form_task()	CreateFormTask	upaf:	task_title_expr, task_output_variable, form_layout_json, form_data=
gen_wait_for_form_task()	WaitForFormTaskAndResume	upaf:	task_input_variable
gen_create_external_task()	CreateExternalTask	upae:	task_title_expr, task_output_variable, task_data=
gen_wait_for_external_task()	WaitForExternalTaskAndResume	upae:	task_input_variable
gen_get_form_tasks()	GetFormTasks	upaf:	output_variable, filter_expr=
gen_complete_task()	CompleteTask	upat:	task_id_expr, action_expr=
gen_assign_tasks()	AssignTasks	upat:	task_id_expr, user_name_or_email=

JSON spec "gen" values: create_form_task, wait_for_form_task, create_external_task, wait_for_external_task, get_form_tasks, complete_task, assign_tasks

Common Hallucinations

Wrong	Right	Impact
TaskObject=	TaskOutput= (Create) / TaskInput= (Wait)	Studio crash — property doesn't exist
EnableDynamicForms="False"	EnableDynamicForms="True"	Form designer button does nothing
Persistence activity in sub-workflow	Move to Main.xaml	Runtime error — bookmark context unavailable
Missing UiPath.FormActivityLibrary	Add explicitly alongside Persistence.Activities	"Install FormActivityLibrary" error in Studio
"supportsPersistence": false	Set to true in project.json runtimeOptions	WaitFor*AndResume fails at runtime
FormLayout= on CreateExternalTask	Use TaskData dict instead	Property doesn't exist on external tasks
FormData on CreateExternalTask	Use TaskData dict instead	Property doesn't exist on external tasks