power-automate-expression-syntax

power-automate-expression-syntax is a skill for Claude Code, Codex from Wals-pro/claude-power-automate. It costs 72 tokens per session (348 once invoked), scanned A, original, MIT.

A reference and troubleshooting guide for expressions in Microsoft Power Automate cloud flows. Cloud flows are automated processes that run online; these expressions read, transform, and compare their data.

In plain words
What is it for?
Use it to write and validate conditions, read action outputs, handle null values, work with dates, strings, arrays, variables, and trigger data, and debug expression errors.
Why use it?
It helps avoid using the wrong formula language, misspelling function names, or mishandling missing data. It also separates cloud-flow expressions from Power Fx, the formula language used in some desktop flows.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it to write and validate conditions, read action outputs, handle null values, work with dates, strings, arrays, variables, and trigger data, and debug expression errors.

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Install with agentmods
npx agentmods add skills/wals-pro/claude-power-automate/power-automate-expression-syntax
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add Wals-pro/claude-power-automate --skill power-automate-expression-syntax
Clone the repo
git clone --depth 1 https://github.com/Wals-pro/claude-power-automate

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for power-automate-expression-syntax

README.md
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Your own site
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Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for power-automate-expression-syntax

Your own site · 80×15
<a href="https://agentmods.dev/skills/wals-pro/claude-power-automate/power-automate-expression-syntax"><img src="https://agentmods.dev/badge/skills/wals-pro/claude-power-automate/power-automate-expression-syntax.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 72 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 348 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00072 $0.00348
Opus 5 $0.00036 $0.00174
Sonnet 5 $0.00014 $0.00070
Haiku 4.5 $0.00007 $0.00035

Measured 11d ago against content hash af78355c7c47, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

power-automate-expression-syntax scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 11d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

skills/power-automate-expression-syntax/SKILL.md · 38 lines

What it actually says

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.
  2. For cloud-flow expressions, read references/cloud-flow-expressions.md.
  3. For desktop-flow Power Fx, read references/power-fx-desktop-flows.md.
  4. 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.
Files

What ships with it

2 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 11d ago First seen · 38 lines · 72 tokens per session scan A af78355c7c47

Subscribe to this mod's changes

power-automate-expression-syntax is a skill published in the GitHub repository Wals-pro/claude-power-automate (11 stars, last pushed 2d ago), licensed MIT. It adds 72 tokens to every session and 348 once invoked, about $0.0004 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

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