Power Automate Expression Syntax

Power Automate Expression Syntax

Power Automate cloud flows use Workflow Definition Language expressions. Power Fx is a separate formula language and is not the default for cloud-flow JSON.

Workflow

1. Identify the expression host:

• Cloud-flow action/condition/JSON: WDL expressions.
• Desktop flow formula mode: Power Fx.

1. For cloud-flow expressions, read references/cloud-flow-expressions.md.
2. For desktop-flow Power Fx, read references/power-fx-desktop-flows.md.
3. Validate against live run inputs where possible; expression errors are often

data-shape errors rather than syntax-only errors.

Cloud-Flow Guardrails

• Use @{...} inside string interpolation and @... when the whole value is

an expression.

• Prefer null-safe access with ?[] for optional action outputs.
• Use exact action names in outputs('Action_Name'), body('Action_Name'),

and actions('Action_Name').

• Avoid copying expressions from rendered docs without checking quotes and

invisible characters.

• Confirm a function exists in power-automate-reference (the complete WDL

namespace) before using it — the namespace is closed; do not invent functions.

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: Wals-pro
• Source: Wals-pro/claude-power-automate
• License: MIT

Install and usage instructions live in the source repository linked above.