Catalogue › Automation › flow-design-patterns

Flow design patterns

Sets the build patterns for robust Power Automate cloud flows that include AI steps - triggers, solution-aware structure, connection references, environment variables, structured AI outputs validated before use, idempotency, concurrency and error scopes. Use when a maker starts building an approved automation design, when a flow with an AI step is fragile, or when the CoE needs standard flow patterns.

Department

Automation

Lifecycle

Deliver, Assure, Improve

Maturity

builder, scaler, ai-enterprise

Risk tiers

1, 2, 3, 4

Platforms

power-platform, copilot-studio, ai-foundry

Editions

starter, scale, enterprise

Reviewers

design-authority, security-privacy

Status

draft

Copilot Cowork

Automation plugin for Copilot Cowork, or this skill on its own: Download SKILL.md

Licence

CC BY 4.0, by Simon Foote

Purpose

Most flows that fail in production were built to work once in the maker's environment: hard-coded addresses, personal connections, no handling for duplicates, and an AI step whose free-text output is passed straight into the next action. This skill sets the patterns that make a Power Automate flow with AI steps buildable, testable, movable between environments and safe to leave running. It goes wrong when AI output is trusted as if it were data from a system, and when flows are built outside solutions and cannot be promoted or supported.

When to use

• An approved automation design is ready to build.
• A flow with an AI step produces intermittent wrong results or breaks on unusual inputs.
• A flow built in a personal environment needs to move to a governed environment.
• The CoE wants a standard set of flow patterns and a review checklist for makers.
• A flow is being extended with an AI step and the maker needs to know how to wire it safely.

When not to use

• Deciding what to automate and which steps need AI - use automation:automation-assessment.
• Redesigning the process or defining exceptions and owners - use automation:automation-process-design.
• Retry policies, fallbacks and exception queues in detail - use automation:exception-handling.
• Flows called as actions from a Copilot Studio agent - use copilot-studio:power-automate-actions.
• Pro-code services and pipelines outside Power Platform - use ai-engineering:ai-engineering-standards.

Questions to ask first

1. What starts the flow, how many times a day, and can the same item trigger it twice?
2. Which environment will it run in for production, and is it built inside a solution from the start?
3. Whose connections will it use in production, and who owns them when the maker moves on?
4. For each AI step, what exact output shape does the next action need, and what happens when the output does not fit?
5. Which actions have an effect outside the flow (send, update, pay, delete), and must anything happen before them?

Required inputs

• The signed automation design on the automation-design template, including AI step definitions and exceptions.
• The target environments, their data policy position and the connectors permitted there.
• The connection model agreed under automation:automation-connector-governance.
• Sample inputs, including awkward ones, for build-time testing.

If the design is missing AI step definitions or exception routes, send it back to automation:automation-process-design rather than inventing them in the build.

Decision framework

Apply the patterns proportionately to the risk tier. Below tier 1 a personal flow may skip some; from tier 1 they are the default; from tier 2 they are checked at review.

Practitioner approach

Start in the right place. Create the flow inside a solution in a development environment, with connection references and environment variables from the first action. Retrofitting these later is the most common reason flows cannot be promoted. Name flows, actions and variables so that a support engineer who has never seen the flow can follow it.

Design the trigger carefully. Use trigger conditions so the flow ignores events it should not process, rather than starting and exiting. Assume every trigger can fire twice: give each item a key and check whether it has already been processed before any action with an effect. This single pattern prevents most duplicate emails, records and payments.

Treat each AI step as an untrusted input. Ask the model for a defined structure (named fields and allowed values) rather than prose. Parse the result against a schema, then validate the content: required fields present, values in the allowed list, numbers in a sensible range, dates real. If any check fails, or the confidence is below the design threshold, do not continue. Route the item to review or the exception queue with the reason. Never pass free-text AI output into an action that updates a system or sends a message without validation and, where the design requires it, human approval.

Keep prompts and thresholds out of the flow logic where possible. Store the prompt in a managed prompt or model asset, and thresholds in environment variables, so they can be tuned with a controlled change rather than a flow edit. Record which prompt and model version produced each result.

Place effects last. Read, interpret, validate, approve, then act. Wrap the main path in a try scope, with a catch scope that records the failure and routes it, and a finally scope that writes the run record. Use automation:exception-handling for retry and fallback rules; do not rely on default retry behaviour for AI steps.

Set concurrency deliberately. Parallel runs speed throughput but break processes where order matters or where a downstream system limits calls. Use pagination and batching for large lists instead of loops over thousands of items.

Test with the awkward inputs: blank fields, attachments in unexpected formats, very long text, other languages and items that look like duplicates. Then hand over with a short runbook naming the owner, connections, environment variables and where failures go.

Outputs

• A solution-aware flow, or set of flows, built to the patterns above, with connection references and environment variables.
• An AI step specification per AI action: prompt or model reference, output schema, validation rules, threshold and failure route.
• A build checklist recorded against the pattern table, with any deviation justified.
• A short runbook: purpose, owner, trigger, connections, configuration, failure routes and test evidence.

Microsoft platform considerations

Solutions, connection references, environment variables, trigger conditions, scopes, concurrency control and AI actions in Power Automate evolve, and Managed Environments add controls that affect how flows are shared and promoted. AI steps may use Power Platform AI capabilities or call models deployed through Microsoft Foundry through a connector. Check current behaviour, limits and licensing in references/sources.md, and route licensing to the Microsoft licensing guide or a licensing partner.

Adoption considerations

Publish the patterns as a short maker guide with a starter solution that already contains the scopes, configuration and run logging. Makers follow the easy path; make the robust path the easy one. Run review clinics rather than rejecting flows at the gate.

Knowledge considerations

Not applicable to most flow patterns, because flows act on records rather than ground on knowledge. Where an AI step uses reference lists or category definitions, read them from a maintained source at run time rather than pasting them into the prompt.

Security and privacy considerations

Production flows run on owned connections or service identities with least privilege, never on a maker's personal connection. Run logs should record keys and decisions, not full personal data, unless the design justifies it. Data sent to AI steps is limited to what the task needs.

Responsible AI considerations

Where AI output triggers an effect on a person, validation and the human review set by automation:human-in-the-loop must sit before the effect in the flow. A threshold set by the maker alone is not acceptable; the process owner agrees it.

Evaluation requirements

Test each AI step against the sample set in the design and record accuracy against the agreed threshold. Re-run the same set after any change to prompt, model, schema or threshold, and before promotion to production.

Value measures

Track flow reliability (successful runs, runs routed to exceptions, failures needing a fix) and the share of AI results passing validation. The flow owner reports these to the process owner; business value is measured in automation:automation-value.

Scale notes

Starter

Use one starter solution with the patterns built in, one development and one production environment, and a short checklist at hand-over.

Scale

Maintain a library of child flows for common steps (AI extraction with validation, approval, exception routing) and review tier 2 flows against the pattern table before promotion.

Enterprise

Treat shared child flows and AI step components as products with owners, versions and release notes. Promote through pipelines with automated checks, and use estate inventory to find flows that bypass the patterns.

Hand-offs

• To automation:exception-handling for retry, fallback and exception queue rules.
• To automation:human-in-the-loop for review and approval steps.
• To automation:automation-monitoring for alerts and run health.
• To security-privacy:connector-review when the flow uses new or sensitive connectors.

Reviewer gates

From risk tier 2, design-authority checks the flow against the pattern table and security-privacy checks connections, identities and data flows through security-privacy:connector-review. Findings are recorded against the build checklist.

Failure modes

• AI output is passed straight into an update or send action, and one malformed response corrupts records or emails a customer.
• A duplicate trigger runs the flow twice and creates two orders, payments or messages.
• The flow is built outside a solution on the maker's connections, and breaks the day the maker leaves.
• Default retries resubmit an AI step repeatedly, adding cost and duplicate effects.

Sources

references/sources.md in this skill lists the source records behind this skill, what each is authoritative for, how volatile it is and what you may do with it. Product availability, licensing, limits and preview status change often, so check the current source before stating them, and cite what you used.

Never

• Pass unvalidated AI output into an action that changes a system or sends a message.
• Run a production flow on a maker's personal connection.
• Hard-code addresses, sites, thresholds or credentials in flow actions.
• Place an action with external effect before validation and any required approval.