No-Code Workspace — Block Reference

AdvancedBlock usage recipe

Error Handler (ERROR_HANDLER)

Decides the final step for uncaught errors

Documented for app version 1.0.50Updated: October 2, 2026

Error Handler (ERROR_HANDLER) block card

What Does It Do?

When an uncaught error occurs in the main flow, the message goes to the Error Variable and the chosen Error Action runs once: Log, Notify, Stop, Continue or Custom (Recovery Actions). The macro then ends; the flow does not resume where the error happened.

When to Use?

Make an unexpected error visible or record it

Run final steps after an error, such as writing a file

How to Use?

Add it at the top level of the main flow; if there are several, only the first enabled one is used

Pick the Error Variable (default errorMessage) and the Error Action: Log, Notify (short on-screen message), Stop (logs and stops the macro), Continue (silently closes the error) or Custom

For Custom, add blocks under Recovery Actions

Parameters

Error Variable

Variable that receives the error message (default errorMessage)

Error Action

Log, Notify, Stop, Continue or Custom

Recovery Actions

Blocks that run after the error when Custom is selected

Parameter	Description
Error Variable	Variable that receives the error message (default errorMessage)
Error Action	Log, Notify, Stop, Continue or Custom
Recovery Actions	Blocks that run after the error when Custom is selected

Example Usage

Error Action Custom, Error Variable runtimeError

Recovery Actions: NOTIFY_TOAST "Error: {{ runtimeError }}" and write the error to a file with FILE_WRITE

Combinations / Used With

ERROR_HANDLER + FILE_WRITE: a persistent error record

ERROR_HANDLER + TRY_CATCH: known errors are handled locally, the rest here

Tip

Decides the final step for uncaught errors

Warnings / Cautions

After the action runs the macro ends and the main loop does not restart; wrap a pass in Try/Catch if one failure should not end the macro

Continue hides the error; use at least Log to see the problem

Errors caught by Try/Catch never reach it

Step-by-Step Mastery: Basic → Advanced → Pro

The same block at three levels: a quick start, the real options, and professional techniques.

Basic

ERROR_HANDLER decides in one place what happens when an UNCAUGHT error occurs in the main flow. The message goes to the Error Variable (default errorMessage) and the chosen Error Action runs once: Log, Notify, Stop, Continue or Custom. The macro then ends; the flow does not resume where the error happened and the main loop does not restart. Where TRY_CATCH protects one section, ERROR_HANDLER is the last line of defense for the whole flow.

Advanced

It is added at the top level of the main flow; if there are several, only the first enabled one is used. Log writes the error to the log. Notify shows a short on-screen message. Stop logs the error and stops the macro. Continue silently closes the error; the flow does not continue and the macro still ends. With Custom you add your own blocks under Recovery Actions (NOTIFY_TOAST, FILE_WRITE, PANEL_CONTROL…) and use the error variable in them, for example {{ errorMessage }}. Errors caught by TRY_CATCH never reach it.

Pro

Use ERROR_HANDLER and TRY_CATCH in layers: if one failing pass should not end the macro, wrap that pass in TRY_CATCH, and keep ERROR_HANDLER as the last line of defense for anything unexpected. In the Custom action design three things together: a meaningful message for the user (NOTIFY_TOAST), a persistent technical record (FILE_WRITE) and safe cleanup (PANEL_CONTROL). Continue is only for errors you do not want to see; choose at least Log to keep track of problems.

Real-World Scenarios — Step-by-Step Recipes

Small, reproducible examples that combine several blocks — build them straight into your own macro.

Visible notification + local error log

1ERROR_HANDLER → Error Variable = runtimeError
2Error Action = Custom
3Recovery Actions: NOTIFY_TOAST "An error occurred: {{ runtimeError }}"
4Recovery Actions: write the error to a file with FILE_WRITE
5Recovery Actions: PANEL_CONTROL (tidy the panel safely)

Layered protection: local TRY_CATCH + global ERROR_HANDLER

1ERROR_HANDLER → Error Action = Stop (last line of defense)
2Critical part of the flow: wrap steps that can raise errors in TRY_CATCH
3Expected errors are handled in the local Catch
4An uncaught error reaches ERROR_HANDLER; it is logged and the macro stops

Which Blocks to Pair With — Pro Combinations

This block is useful on its own — but it shines when paired with the right partners.

+ FILE_WRITE

Writes errorMessage with a timestamp to a persistent log file; keeps an evidence-based trace of field errors.

+ NOTIFY_TOAST

Gives the user a meaningful, visible error notification; provides clear feedback instead of a silent crash.

+ PANEL_CONTROL

Safely collects open panels/overlays at error time; brings the UI to a consistent state.

+ TRY_CATCH

Layered defense: local TRY_CATCH handles known errors precisely, ERROR_HANDLER sets the last net for uncaught ones.

+ HUD_OVERLAY

Shows a persistent on-screen error banner to inform the operator live when an error occurs.

Common Mistakes and Fixes

Defining ERROR_HANDLER with no recovery steps. Fix: at least make the error visible with LOG/NOTIFY or build a real recovery flow with CUSTOM; an empty handler only hides the problem.

Assuming Continue keeps the flow going. Fix: Continue only hides the error and the macro still ends; wrap the pass in TRY_CATCH when it must go on.

Using ERROR_HANDLER instead of a local TRY_CATCH. Fix: do precise local recovery with TRY_CATCH for known errors tied to a specific block; reserve ERROR_HANDLER as the last net for general/uncaught errors.

Pro Tips

In the Custom action design the trio together: a user message (NOTIFY_TOAST), a technical record (FILE_WRITE) and safe cleanup (PANEL_CONTROL).

Give the Error Variable a meaningful project-specific name (e.g. runtimeError); multiple handlers/logs stay distinguishable without colliding.

This Block's Code (Editor View)

Lua

The Lua below is what the Code Editor generates for this block with sample settings. Adding cases, branches, actions or loops, or changing settings, extends the generated code accordingly. Study it to see what the block does under the hood, to learn Lua, or to copy and adapt it. Use the Copy button (top-right) to paste it into the Code Editor, or “Try in Editor →” to run it in the live editor.

lua

Try in Editor →

local __errorHandlerOk, __errorHandlerErr, __errorHandlerReturn = pcall(function()
 wait(1)
end)
if __errorHandlerOk and __errorHandlerErr == "__VB_RETURN__" then
 return __errorHandlerReturn
elseif not __errorHandlerOk then
 local errMsg = tostring(__errorHandlerErr)
 System.log("Error: " .. errMsg)
end

Note: generated code can evolve across versions; helper names (e.g. _reg1, m1) and internal optimizations may change. The logic and the called APIs reflect the block’s behavior.

Block ↔ Lua Mapping →

Shared Controls for This Block Family

The guidance below is not identical for every block. It summarizes the professional controls that most often repeat in the selected block family.

🛡Protection Layer

Blocks like ERROR_HANDLER and SLEEP_UNTIL strengthen a flow; they should not be used to hide unclear core logic.

📉Infinite Wait Risk

Always define an exit scenario and observable bound when using sleep-style waiting conditions.

🧭Central Error Policy

Global error handling should belong to one policy. Avoid multiple competing error strategies in the same project.

Builder vs Lua Boundary

Raw touch pointer lifecycle stays code-first

TOUCH and TOUCH_BREAK cover recipe-style touch flows. Raw pointer choreography such as Touch.down, Touch.move, Touch.up, Touch.dispatch, Touch.reset, Touch.breakAll, and Touch.releaseAfter is not exposed as a first-class builder block.

Touch.downTouch.moveTouch.upTouch.dispatchTouch.resetTouch.breakAllTouch.releaseAfter

Bounded dialog design is builder-backed; freer composition stays code-first

The DIALOG block and dialog designer cover a bounded field set in the builder: Info Text, Text Input, Checkbox, Description, Radio Group, Dropdown, Multi Select, Tab Group, Date Time, Number Range, Slider, Image Picker, Color Picker, File Picker, Recorder Picker, Tag, Signature, and Spacer. The buttons are designed too: the Positive button and Negative button tabs set each button’s text, background, and border color, corner radius, and minimum height next to a preview. Freer Setting.builder composition, multi-step wizard flows, and mixed HUD/dialog choreography still do not map 1:1 into the builder.

Coming soonv1.0.51Two more fields: Agent Detect references (agent_detect_editor) lets the user pick a saved reference set or add and edit references, and Save confirms the selection; Navigation setup editor (navigation_editor) edits a saved map, marker and route from the Dialog and returns the setup and route selection without moving the character.

Setting.builderDialogHudTextViewAgentDetectEditorNavigationEditor

Advanced HTTP request chaining stays code-first

HTTP_GET, HTTP_POST, and HTTP_PUT cover common fixed-method flows; HTTP_REQUEST covers one bounded request with method, header lines, body, content type, query parameters (GET and DELETE), timeout, and a bounded retry. These blocks never throw; they write the status code (-1 on a network failure). Cookie handling, chained request objects, and lower-level client flows still need the code editor.

Request()Request.setCookieRequest.getCookiesCUSTOM_CODE

General programming surfaces stay code-first

The MAP, LIST, JSON_PARSE, REGEX_MATCH, and METRICS blocks cover the everyday cases: map actions, a static list, reading a value from a JSON path, regex match, find, replace, and split, and metrics actions. The rest of the Map, Array, JSON, Regex, and Metrics APIs (for example Array sort, filter, and map) is broader than the builder recipe model and stays on the CUSTOM_CODE and code editor side.

MapArrayJSONRegexMetrics

Low-level runtime and Lua composition stays code-first

Runtime helpers, raw Request objects, Lua built-ins such as print/pcall/xpcall, and free-form object chaining patterns are represented through CUSTOM_CODE or the code editor.

RuntimeRequestprintpcallxpcallCUSTOM_CODE

Debug Mode and Breakpoints

Each block card now exposes an independent breakpoint toggle. When enabled, the breakpoint preference is stored with the block.

Breakpoints are only emitted into runtime code when Debug Mode is enabled from Visual Builder settings. When Debug Mode is off, breakpoints stay saved but do not pause execution.

Use ASSERT for fail-fast validation, and use breakpoints for step-by-step tracing and controlled pauses in the same flow.

Variable Scope

Variables defined with SET_VARIABLE are accessible throughout the macro (global scope). All blocks can read/write the same variable.

However, a variable defined inside a GROUP will be 'nil' (undefined) until the GROUP executes. Blocks outside the GROUP using this variable may produce unexpected results.

FOR_EACH loop variables (item and index) only carry valid values inside the loop body. Outside the loop they are outside local scope and should not be used.

TRY_CATCH error variable is only valid within the catch block. If the try block succeeds, the catch branch is not entered and the error variable remains undefined.

TIP: Before using a variable inside a GROUP, assign a default value with SET_VARIABLE outside the GROUP. This way the variable won't be nil even if the GROUP has not run.

Inline Expressions

You can embed variable values and calculations into text fields using {{ expression }} syntax. Expressions inside double curly braces are evaluated as Lua code and the result is inserted into the text.

Syntax

{{ expression }}

Examples

Skor: {{ score + 1 }} → "Skor: " .. tostring(score + 1)

{{ name }} kazandı! → tostring(name) .. " kazandı!"

X:{{ x }} Y:{{ y }} → "X:" .. tostring(x) .. " Y:" .. tostring(y)

Supported Blocks

SET_VARIABLELOGCOMPARECLIPBOARD_WRITENOTIFY_TOASTKV_SET

Security Note

Expressions are checked by the sandbox policy. Security-sensitive calls like loadstring, require, debug are automatically blocked.

General Tips

Keep scan regions as small as possible — improves speed, reduces false matches.

Always add an exit condition when using infinite loops (BREAK, timeout, or conditional exit).

Use network operations and error-prone steps inside TRY_CATCH.

If you need global error handling, use the Error Handler (ERROR_HANDLER) block as a singleton in the project.

Small coordinate offsets (CLICK/SWIPE) improve tap accuracy across different DPI and screen scales.

Customize macros with Dialog block — different parameters each run.

Define repeating steps once with GROUP_CALL, call from many places.

Cross-macro local library

Local Shared Macro Area

The Local Shared Macro Area moves blocks, variables, dialog fields, gallery assets, and imported media dependencies between macros on the same device. It is device-local, not cloud sync, not Firebase sharing, and not a replacement for public macro sharing.

Professional usage model: put a reusable login flow, common scan region, shared dialog form, variable group, template image, color profile, replay recording, or imported PLAY_SOUND media file into the shared area from one macro, then import it from the relevant + menu in another macro.

VISUAL_BLOCKSVARIABLESDIALOG_FIELDSTEMPLATE_IMAGECOLOR_SWATCHREPLAY_RECORDMEDIA_FILE

Send to the shared area

When one item or a multi-selection is active, the shared-area button can copy the selected part from the workspace, group, true/false action branch, dialog, and variables surfaces into the device-local library.

Import into another macro

The shared-area entry under the + menu imports the selected item into the surface that opened it. Main workspace, group, action branch, dialog, and variables each receive the compatible item type.

Share gallery assets

Gallery items include template images, color swatches, replay records, and imported audio/media files. They can move between macros on the same device so repeated templates, colors, recordings, and PLAY_SOUND media assets do not need to be captured again.

Keep it clean

The shared area is not a permanent dumping ground. Delete stale shared items from the shared-library panel; imports create a copy in the target macro and do not rewrite the source macro flow.

Checkpoint: after importing, review block names, linked template/image/color/record/media assets, and variable names in the target macro. The shared area creates a copy; delete stale shared items from the shared-library panel to keep the library clean.

AI assistant

Build a block chain with MH AI in natural language

Tell MH AI what you want in plain language; it proposes the right block sequence and lands it in the workspace after you approve. In the current release it works with cloud providers such as Gemini, Claude, and OpenAI; on-device local models are on the roadmap.

Learn more →