UiPath Core Skill

⚠️ Safety Rules (I-1, I-2 in rules.md)

• Playwright/browser inspection is READ-ONLY. Login page → STOP, WAIT for user. See ui-inspection.md → Login Gate.
• Desktop inspection via PowerShell (inspect-ui-tree.ps1): read-only tree inspection only.
• NEVER generate credentials, tokens, or passwords — real or fake.

Generate production-quality UiPath automation artifacts using real Studio-exported templates and comprehensive reference documentation. Template baseline: Studio 24.10 Windows.

When To Read Which Reference

Start here. Match the user's task to the right file, then read only what's needed. For files > 200 lines, use grep or line-range reads — never read entire large files or XAML assets.

Common Tasks (check these first)

Task	Read first
Generate a XAML workflow (any kind)	cheat-sheet.md → JSON spec patterns → scripts/generate_workflow.py (G-1)
Scaffold a project	scaffolding.md → Template Selection → run scripts/scaffold_project.py
Generate a full project (checklist)	scaffolding.md → "Generating a Full Project" checklist
Inspect a web app (selectors)	ui-inspection.md → Playwright MCP workflow → playwright-selectors.md
Validate XAML	Run scripts/validate_xaml <project> --lint
Fix a specific lint warning	lint-reference.md → search by lint number
Write an expression (VB.NET/C#)	expr-foundations.md (start here for any expression task)
Decomposition / project structure	decomposition.md → Decomposition rules (Universal 1-8, Browser 9-13, Desktop 14)
Fix a user's .xaml file	skill-guide.md → Example 6
Tasks, form tasks	→ uipath-tasks skill (read its SKILL.md)

Activity-Specific Reference

Task	File	Section guidance (for large files)
Core activities (Assign, Log, Delay, InputDialog)	xaml-foundations.md (165 lines)	Read in full
Control flow (If, ForEach, While, Flowchart)	xaml-control-flow.md (208 lines)	Read in full
DataTable ops, file system	xaml-data.md (255 lines)	Grep for activity name
Error handling, TryCatch, Throw, RetryScope	xaml-error-handling.md (194 lines)	Read in full
InvokeWorkflowFile, InvokeCode, InvokeMethod	xaml-invoke.md (175 lines)	Read in full
Orchestrator, queues, HTTP, credentials	xaml-orchestrator.md (293 lines)	Grep for activity name
Excel, Email, PDF activities	xaml-integrations.md (285 lines)	Grep: ## Excel, ## Email, or ## PDF
Build/fix selectors	xaml-ui-automation.md (576 lines)	Don't read in full. Grep: ## Selector Reference or specific selector type
UI automation XAML (NClick, NTypeInto, etc.)	xaml-ui-automation.md	Selector guidance only. XAML generation via generate_workflow.py (G-1)

Expression Reference (large files — use targeted reads)

Task	File	Section guidance
DataTable expressions (Select, Compute, LINQ)	expr-datatable.md (432 lines)	Grep: ## Select, ## Compute, ## LINQ, ## Filter
String/DateTime/numeric expressions	expr-strings-datetime.md (502 lines)	Grep: ## String, ## DateTime, ## Numeric, ## Regex
JSON, collections, type conversions	expr-collections-json.md (462 lines)	Grep: ## JSON, ## Dictionary, ## List, ## LINQ

Project & Configuration

Task	Read first
Choose template or variant	scaffolding.md → Choosing the Right Variant
Browser automation with Playwright	ui-inspection.md → Playwright MCP workflow
Desktop app inspection	ui-inspection.md → Desktop Inspection → ui-inspection-reference.md
Login/Launch pattern	decomposition.md → Login/Launch section
Config.xlsx keys and structure	config-sample.md → three-sheet reference, decision flowchart
Extract Config keys from project	Run validate_xaml <project> --lint — lint 39
Lint regression tests	Run scripts/run_lint_tests.py
Ground rules (all rule definitions)	rules.md — single source of truth for G/I/A/P/S rules
project.json schema and configuration fields	scaffolding.md → Key project.json Configuration Fields

Ground Rules

Full rule definitions with rationale: references/rules.md. Rules below are referenced by ID.

1. G-4 — Never generate XAML from scratch. Copy from closest template and modify.
2. G-5 — Never guess NuGet package versions. Run scripts/resolve_nuget.py.
3. G-1 — ⛔ Create .xaml files ONLY via scripts/generate_workflow.py. Never hand-write. See generation.md § Workflow Generation CLI.
4. P-1 — Follow the PDD exactly. Implement the specified approach faithfully — propose alternatives separately.
5. P-2 — Architecture selection: PDD describes BOTH reading AND processing items? → Dispatcher + Performer. See scaffolding.md.
6. A-5 — Modular decomposition. Break into Workflows/<AppName>/ subfolders. See decomposition.md.
7. I-2 — ⛔ HALT at login gates during Playwright inspection. End your response, wait for user.
8. G-3 — ⛔ Framework wiring: GENERATE FIRST, WIRE SECOND. Snippets MUST come from generator output. See scaffolding.md Phase 3c.
9. G-2 — ⛔ JSON specs: WRITE TO DISK, NEVER INLINE. See cheat-sheet.md § type keys for valid types.

CRITICAL: Project Context Check (Always Do This First)

Before generating ANY XAML, determine project context:

A) project.json EXISTS (inside existing project):

• Generate the .xaml file inside the project directory
• Check dependencies — add missing NuGet packages: python3 scripts/resolve_nuget.py --add <project_dir> PackageName

B) project.json DOES NOT EXIST:

• Scaffold first — a standalone .xaml is useless without project.json
• Use scripts/scaffold_project.py (see scaffolding.md)
• Do NOT create the project folder before scaffolding. The script creates <o>/<n>/ automatically. Pre-creating causes duplicate nesting.

Capabilities

1. Generate XAML workflow files — copy from real Studio exports and modify
2. Scaffold UiPath projects — Simple sequence, REFramework Dispatcher, or REFramework Performer
3. Write expressions — VB.NET and C# for UiPath activities (LINQ, DataTable, JSON, DateTime, etc.)
4. Build selectors — strict, fuzzy, dynamic, wildcard, regex selectors for web/desktop/SAP
5. HTTP API integration — OAuth token flows, retry policies, query parameters, response handling
6. Tasks tasks — → Fully decoupled to uipath-tasks skill (generators, lint rules, scaffold hooks all live in uipath-tasks/extensions/, loaded via plugin_loader.py)
7. UI automation — NApplicationCard, NClick, NTypeInto, NSelectItem, NGetText, Extract Table Data, Check App State — via scripts/generate_activities
8. Error handling & workflow — TryCatch, RetryScope, Throw/Rethrow, InvokeWorkflowFile, AddQueueItem, GetRobotCredential, BuildDataTable, IfElseIfV2, MultipleAssign — via scripts/generate_activities
9. File system operations — Copy/Move/Delete files, Create Directory, Path Exists
10. Invoke Code/Method — inline C#/VB.NET code blocks, instance/static method calls

Reference Files

File	Coverage
references/xaml-foundations.md	XAML file structure, namespace declarations, core activities (Assign, Log, InputDialog, MessageBox, Delay), variable & argument declarations
references/xaml-control-flow.md	If, IfElseIf, ForEach, ForEachRow, While, DoWhile, Break/Continue, ForEachFile, Flowchart, State Machine, annotations
references/xaml-data.md	BuildDataTable, AddDataRow, FilterDataTable, MergeDataTable, SortDataTable, OutputDataTable, JoinDataTables, LookupDataTable, DeserializeJSON, file system ops
references/xaml-error-handling.md	TryCatch, Throw/Rethrow, exception types, RetryScope (incl. NCheckState condition)
references/xaml-invoke.md	InvokeWorkflowFile, InvokeCode, InvokeMethod
references/xaml-orchestrator.md	GetRobotAsset, GetRobotCredential, AddQueueItem, GetQueueItem, SetTransactionStatus, HTTP Request. Tasks → uipath-tasks skill
references/xaml-integrations.md	Excel Classic Workbook (ReadRange, WriteRange, WriteCell), Email/Integration Service (GetIMAP, SendMail), PDF (ReadPDFText, ReadPDFWithOCR)
references/xaml-ui-automation.md	Selector construction, dynamic selectors, fuzzy/regex, anchor targeting, desktop frameworks, Version table. For XAML generation use generators — this file is for selector guidance and activity property reference. Large file — use grep or line-range reads.
references/expr-foundations.md	VB.NET + C# expression syntax, null safety patterns. Read first for any expression task
references/expr-datatable.md	DataTable operations: Select, Compute, filter, sort, lookup, merge, clone, column ops, row iteration. Large file — grep for section.
references/expr-strings-datetime.md	String (split, join, trim, replace, format), DateTime (parse, format, diff, business days), file/path, numeric, regex. Large file — grep for section.
references/expr-collections-json.md	Array/List, Dictionary, JSON (JObject, JArray, parse, query, build), LINQ on typed collections, type conversions, Queue Item. Large file — grep for section.
references/golden-templates.md	Template catalog — patterns extracted from each real template file
references/scaffolding.md	Template selection, NuGet mapping, XAML validation, project scaffolding (variants, dispatcher/performer, transaction types), full project generation checklist
references/decomposition.md	Naming conventions, decomposition rules (universal 1-8, browser 9-13, desktop 14), common process patterns, argument design, Login/Launch pattern, REFramework Init/Close, UiElement chain
references/generation.md	Object Repository, Workflow Generation CLI (JSON spec format, 94 core generators + plugin extensions), Activity Generators (usage pattern, what model provides vs what generators lock down)
references/ui-inspection.md	Playwright MCP workflow (login gate, 5-step process, element mapping), Desktop inspection (PowerShell, inspect-ui-tree.ps1, framework detection)
references/skill-guide.md	Index + examples. Routes to scaffolding/decomposition/generation/ui-inspection. Contains 7 worked examples + anti-example
references/lint-reference.md	71 lint rules by severity, searchable by lint number (core rules; plugins add more)
references/playwright-selectors.md	Playwright MCP → UiPath selector mapping
references/config-sample.md	Config.xlsx three-sheet reference (Settings, Constants, Assets), key naming conventions, sheet placement decision flowchart, required keys output format
references/cheat-sheet.md	JSON spec patterns (multiple_assign, if, try_catch, foreach_row, pick_login_validation, filter_data_table, add_queue_item, selectors.json), modify_framework.py CLI+Python API, valid enum values, naming, quick rules
references/cheat-sheet.md § Desktop Form-Filling	Desktop form-filling: tab nav, idx selectors, save verification, data externalization
references/ui-inspection-reference.md	inspect-ui-tree.ps1 reference — UIA→UiPath property mapping, framework detection, WinForms
references/rules.md	Ground Rules Reference — single source of truth for all generation (G), inspection (I), architecture (A), PDD (P), SAP (S), and skill authoring (K) rules. Other docs reference by ID

Scripts

All scripts/ paths below are relative to this skill's directory (.claude/skills/uipath-core/). Invoke from the skill root: cd .claude/skills/uipath-core && python3 scripts/<script>.py ...

File	Purpose
scripts/validate_xaml	Validate generated XAML — structural checks + lint rules (core + plugin). Use --golden for asset templates. See lint-reference.md for full rule table.
scripts/resolve_nuget.py	Resolve real NuGet versions. Query UiPath feed for latest stable. Validate project.json. Add/update deps in existing project.json (--add).
scripts/scaffold_project.py	Scaffold UiPath projects (sequence / dispatcher / performer). Customizes Config.xlsx. Dispatcher replaces GetQueueItem with DataTable row indexing.
scripts/config_xlsx_manager.py	Add/list/validate Config.xlsx keys. Cross-references XAML Config() refs vs actual sheets.
scripts/modify_framework.py	Insert InvokeWorkflowFile into framework files, replace SCAFFOLD.* markers, wire UiElement argument chain (wire-uielement), add variables with auto type normalization (add-variables), replace placeholder expressions (set-expression). ⛔ G-8: Never Edit/Write .xaml directly — use this script or generate_workflow.py.
scripts/generate_activities	Deterministic XAML generators for 94 core activities. Locks down enums, versions, child elements. MANDATORY for NTypeInto, NClick, NGetText, NCheckState, NApplicationCard, etc. Plugin skills add more (e.g., Tasks, SAP WinGUI).
scripts/generate_workflow.py	Generate complete .xaml files from JSON specs. 94 core generators + plugin generators loaded via plugin_loader.py. Covers ALL activities including Pick login validation, TryCatch, ForEachRow, NExtractData, NCheckState. Pass --project-dir <project> to auto-wire Object Repository references (Reference=/ContentHash= on TargetAnchorable) from .objects/refs.json. ⛔ Do NOT write .xaml by hand — use this CLI instead.
scripts/generate_object_repository.py	Generate Object Repository (.objects/ tree). CLI: python3 generate_object_repository.py --from-selectors selectors.json --project-dir <dir>. Reads selectors.json (written during Playwright inspection) with full app/screen/element hierarchy. Lint 94 is ERROR — project cannot pass validation without populated Object Repository.
scripts/inspect-ui-tree.ps1	Windows-only. Inspect desktop app UI tree via UIA API. Run via Bash (powershell -File).
scripts/regression_test.py	Regression tests — validates templates, scaffolding, naming conventions, line count accuracy, skill integrity
scripts/run_lint_tests.py	Lint regression: verifies bad XAML test cases trigger expected lints. Run after modifying lint rules.

Key Architecture Rules

Full definitions: references/rules.md § Architecture Rules (A-1 through A-12).

App initialization (A-1): ALL apps open and ready by end of InitAllApplications.xaml. Action workflows ONLY attach (OpenMode="Never"). Wire UiElement chain: python3 scripts/modify_framework.py wire-uielement <project> <AppName>.

Key constraints: no flat files in Workflows/ (must be in app subfolders), login stays inside AppName_Launch.xaml (no separate AppName_Login.xaml), navigation uses shared Utils/Browser_NavigateToUrl.xaml (A-6), persistence activities stay in Main.xaml (A-2), SetTransactionStatus.xaml never modified (A-4), dispatchers pass Nothing for in_TransactionItem.

Login/Launch Workflow Pattern

See decomposition.md → "Login/Launch Workflow Pattern" for the full recipe, required XAML structure, argument design, UiElement reference chain, and common mistakes. Key rule: login stays inside AppName_Launch.xaml — NEVER create a separate AppName_Login.xaml. Copy structure from golden sample WebAppName_Launch.xaml.

Quick Validation Reference

For detailed lint rules by number, see lint-reference.md. The most critical categories:

🔴 Studio crash — Inline Result= on modern activities, hallucinated enum values (AttachMode="ByUrl", Version="V3"/"V4", ElementType="InputBoxText"), missing xmlns declarations, hallucinated properties (NApplicationCard Url=, NCheckState Appears=, NTypeInto EmptyField=, AddQueueItem.SpecificContent). See cheat-sheet.md → Valid Enum Values.

🟡 Compile error / silent data loss — Wrong enum namespace (UIAutomation vs UIAutomationNext), C# syntax in Throw expressions, InteractionMode on activities that don't support it (only NClick/NTypeInto have it), QueueName= instead of QueueType=, empty Out/InOut argument bindings, direction tag mismatches.

🟢 Production / security — Credentials via GetRobotCredential inside the workflow (never as arguments), API/network wrapped in RetryScope, URLs from Config (never hardcoded), browser IsIncognito="True", log bookends on every workflow.

Desktop App Automation

When automating a desktop application (not browser/web):

1. Get the executable path first. Before generating NApplicationCard XAML, you MUST have the full .exe path. Never use placeholders. ASK → STOP → WAIT. UWP apps use the package AppId.

2. Desktop vs Browser differences: Desktop uses TargetApp.FilePath (no BrowserType/Url/IsIncognito), InteractionMode = HardwareEvents or Simulate (NOT DebuggerApi). Selectors use <wnd app='...' /> with automationid, cls, aaname, role attributes.

3. Inspection is mandatory when PowerShell is available (Windows) — run inspect-ui-tree.ps1 BEFORE generating desktop XAML.

4. WinForms tab names vs group box names: When inspect-ui-tree.ps1 shows a TabControl, children at depth 2 are TabItems (actual tab names for navigation). Children at depth 3 are GroupBoxes (visual containers INSIDE a tab, NOT navigation targets). See decomposition.md → Rule 14 supplement and ui-inspection-reference.md → WinForms Tab Control Hierarchy.

Naming Conventions

Variables: camelCase with type prefix — strName, intCount, boolSuccess, dt_Report, dr_Row, arr_Files, dict_Config, dtmStart, dblAmount, jo_Response, secstrPassword, qi_Item, mm_Mail.

Arguments: {direction}_{typePrefix}{Name} — in_strUserName, out_boolSuccess, io_dt_Data.

Workflow files: PascalCase with underscores — WebApp_CreateRecord.xaml, App_Close.xaml.

See cheat-sheet.md → Naming Quick Reference for the full type prefix table.

Selectors — Always Default to Strict

Generators default to SearchSteps="Selector" (strict). Use FuzzySelector only when user requests or strict proven unreliable. Always populate BOTH FullSelectorArgument and FuzzySelectorArgument.

Tested Models

This skill is developed and tested with Claude Opus and Claude Sonnet. The prompt engineering (HALT semantics, routing table placement, urgency tiers) is Claude-optimized. Other LLMs may work but are untested — expect to adapt the prompt layer.