Architect Expression Evaluation Failure - Participant Data Type Mismatch

Architect & Flows
1

The observed behavior involves a failure in the evaluation of a complex Architect expression during the parsing of a JSON response. Specifically, an attempt to map a numeric value from a Data Action to a Participant Data attribute results in a silent failure or a null assignment, as documented in INC-8821.

The expression employs the ToDecimal() function to ensure type consistency. However, the runtime execution fails to persist the value.

Task.AccountBalance = ToDecimal(Task.ApiResponse.balance)

Verification via the /api/v2/flows/lookup endpoint confirms the flow configuration is correct. The issue persists across multiple test iterations.

1 Like
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{
 "type": "number",
 "value": 123.45
}

Is the Data Action returning the value as a string or a raw number? The Architect documentation says “Participant data is always stored as strings”, so if you’re hitting a type mismatch, it might be the input format. Spun up a quick Lambda to patch this once before when a numeric payload broke my flow.

3

The earlier reply is spot on. The real killer here is when the Data Action output is a number but the Architect variable expects a string. It’s a classic type mismatch.

Quick win: wrap the output in a ToString() before shoving it into participant data. Just ship it and stop fighting the type system.