A question that keeps coming up: when do I use an agent versus a workflow?
It's exactly where most teams get tripped up when adopting AI. Here's a clean mental model and some practical guidance you can actually use.
Summary: Use agents to interpret and choose. Use workflows to execute. Use both together for scale and safety.
The Core Distinction
| Agent | Workflow | |
| Role | Interprets, reasons, decides | Executes, routes, enforces |
| Best for | Ambiguity, judgment, adaptation | Precision, repeatability, governance |
| Output | A choice or recommendation | A deterministic action |
When to Use an Agent
Use agent tools when human-like judgment, adaptation, decisioning or choosing can be a solution without needing a human in the loop and/or less effort to build.
Signals:
- The path forward isn't known in advance
- Inputs are unstructured (emails, documents, messages)
- Decisions depend on nuance or context
- Multiple valid next steps exist
- The system needs to react to new information mid-process
Examples: Classifying inbound requests · Flagging invoice anomalies · Drafting responses · Handling exceptions · Choosing which system to query next
Example prompt: "Read this email and determine whether it's a billing issue, a support issue, or a legal issue."
When to Use a Workflow
Use a workflow when the steps are known, rules are explicit, and reliability matters more than flexibility.
Signals:
- Steps are well-defined and repeatable
- Business rules are explicit
- Failures must be predictable and recoverable
- Scale and auditability matter
Examples: Creating or updating records · Approval routing · Sending notifications · Posting to ERP/CRM · Triggering downstream systems
Example: "If approved, create an invoice, update the PO, and notify finance."
The Power Move: Use Them Together
The most effective systems combine both.
Pattern: Agent → Workflow
- Agent interprets, classifies or chooses probabilistically
- Agent selects the appropriate workflow
- Workflow executes deterministically
Example: Agent reviews an invoice → flags an exception → triggers the Accounts Payable Exception workflow
This gives you flexibility at the edges and reliability at the core.
Quick Decision Cheat Sheet
| Question | If YES → |
| Is a recommendation or suggestion sufficient? | Agent |
| Is the input unstructured? | Agent |
| Are there multiple valid next steps? | Agent |
| Is this repetitive and rules-based? | Workflow |
| Does failure have serious consequences? | Workflow |
Anti-Patterns to Watch For
Don't put agents in charge of:
- Money movement
- Compliance enforcement
- Final approvals
- Critical record updates
Let agents recommend. Let workflows commit.
Don't hard-code workflows for:
- Free-form customer requests
- Exception-heavy processes
- Frequently changing situations
You'll end up drowning in edge cases.
The key insight is that these aren't competing approaches — they're complementary layers. Agents handle the messy middle of interpretation; workflows handle the executions. The teams that get this right build systems that are both smart and trustworthy.