RunFunction Variable Persistence, Writes Not Visible Downstream

Support
1

Update: From doing more research and reading other peoples problems with this - I think I need to find a different platform to achieve my goals. But if the issue below can be resolved let me know.

Message to MindStudio Support / Engineer

I am building a step-by-step “decision safety check” in MindSpring. It takes a proposed action, runs it through a fixed set of checks, saves the results so each step can use them, and then produces a clear report that says whether the action can proceed, must pause, needs escalation, or must be denied, along with the reasons.

I need to confirm whether MindStudio supports a basic but required data-flow pattern for the system I’m building.

I’m implementing a constitutional workflow where:

  • decisions are evaluated in discrete steps,

  • each step must deterministically persist its result,

  • and downstream steps must read that state without recomputation or hidden logic.

The core pattern I need is:

runFunction → persist variable → downstream block reads it

Concretely:

  • A runFunction computes or transforms a structured object (for example gateResults)

  • The function calls setVariable() to overwrite that variable

  • A later Display or logic block reads {{gateResults}} reliably

At the moment, values written with setVariable() are rendering as undefined downstream.

I understand that MindStudio may require variables to be declared in an output / variables contract, but it’s unclear:

  • Where in the UI that contract is defined (function asset vs. canvas node)

  • Whether this pattern is fully supported in CloudRunner at all

Because this is a constitutional workflow, I need:

  • explicit state persistence,

  • predictable scope,

  • and verifiable step-by-step execution.

My questions are:

  1. Is it possible in MindStudio for a runFunction to reliably overwrite a workflow variable so downstream blocks can read it?

  2. If yes, where exactly do I declare the output variable contract that enables this (panel name / setting location), with a minimal working example?

Clarifying this will determine whether this workflow can be built on MindStudio at all.

Sample code I am trying to run:

Send this exact JavaScript snippet and explain that it runs in a runFunction block.

async function main(config) { // overwrite a workflow variable setVariable("gateResults", { outcome: "PROCEED", rationale_display: "No constraint violation identified." }); }

Then say the downstream Display Content renders:

Outcome: {{gateResults.outcome}} Rationale: {{gateResults.rationale_display}}

sample build:

https://app.mindstudio.ai/agents/gate-result-checker-9782c851/remix

Why this code is ideal

  • It uses no inputs

  • It uses one variable

  • It uses setVariable() exactly once

  • It tests nested object access

  • It matches your constitutional workflow need: compute → persist → render

One-line framing to include

“This is the smallest example of the pattern we need to support: a runFunction overwrites gateResults, and downstream blocks read it deterministically.”

2

Hi Philip,

Thanks for the detailed post and welcome to the Community!

The flow you’re describing is fully supported in MindStudio. The issue is that setVariable() isn’t a valid method in Custom Functions. To persist variables from a Custom Function that downstream blocks can read, use ai.vars instead.

Here’s an updated version of your Agent:
https://app.mindstudio.ai/agents/updated-gate-result-checker-c83e59ef/remix

And here’s another example of an Agent that assigns values to workflow variables and iterates upon them:
https://app.mindstudio.ai/agents/sample-agent-with-two-custom-functions-8e0b385e/remix

You can find more details in our documentation:

Let me know if you have any questions!

3

I am building a larger agent workflow that uses Run Function blocks to persist and output responses before rendering a display-only report but the fields all come out blanks.

I have used the ai.vars settings you suggested but it seems not correctly.

Is there a simple fix I am missing ?

Link:

https://app.mindstudio.ai/agents/1-alex-fix-rhythming-key-kernel-v29-393d0d02/remix

Inputs for Questions

  • declaredAction: I will draft a private internal memo summarizing the issue.

  • negativeIntake: Must not publish, post, or share publicly.

  • pressureFactors: Uncertainty

  • undoability: Undoable

  • publicness: Private

  • representation: Self

4

Hi @Philip_R,

Thanks for the link!

In my previous message, I shared an example of an agent that uses a VM environment. Apologies for the confusion on that.

image
image1547×577 67.7 KB

In your agent, you simply need to remove the wrapper. Here’s a remix link to your adjusted agent:
https://app.mindstudio.ai/agents/copy-of-1-alex-fix-rhythming-key-kernel-v29-aed59cd4/remix

Here’s also a remix link to another agent I created that demonstrates this process:
https://app.mindstudio.ai/agents/data-transformer-b345422b/remix

The Agent follows these steps:

  1. Saves an array to a variable
  2. First Custom Function removes the third item
  3. Second Custom Function converts it to an object

Let me know if you have any questions.