Most people build prompt chains by feel. They split a task where it seems natural, wire the links together, and adjust when something breaks. That works for simple chains, but it does not scale, and it does not transfer between teammates. A named framework gives you a shared, repeatable way to design a chain that anyone on a team can apply and critique.
This piece introduces the DECIDE model, a six-stage framework for designing prompt chains: Define, Enumerate, Cut, Interface, Defend, and Evaluate. Each stage produces a concrete artifact, and the stages run in order. The point is not to add bureaucracy but to make the implicit design decisions explicit, so they can be reviewed before code is written.
You do not need to invoke the framework for a two-link chain you will throw away. You reach for it when a chain matters, when it will run in production, be maintained by others, or process inputs you cannot fully predict. For those chains, designing deliberately beats designing by feel every time.
Define: State the Outcome
The first stage forces clarity about what the chain produces.
The Artifact: A One-Sentence Goal
Write the chain's end result in a single sentence, naming the input and the output. "Turn a raw support ticket into a routed response with an extracted summary." If you cannot write this sentence, you are not ready to design links, and any boundaries you draw will be arbitrary. The The Complete Guide to Prompt Chaining expands on why this clarity matters.
Enumerate: List the Sub-Tasks
The second stage surfaces every job the task contains without yet committing to links.
The Artifact: A Sub-Task List
List every distinct operation between input and output: classify, extract, normalize, validate, generate. Enumerate generously here. The goal is to see the full surface of the task before deciding how to carve it. You will merge aggressively in the next stage.
Cut: Draw Link Boundaries
The third stage is where most of the design value lives. You decide which sub-tasks become links.
The Artifact: A Link Plan
Merge sub-tasks the model handles reliably together; split where you need to inspect or validate a result. The guiding question is the fewest links where each is independently reliable. Two adjacent sub-tasks that always succeed together belong in one link. The danger here is over-cutting, the failure mode detailed in 7 Common Mistakes with Prompt Chaining (and How to Avoid Them).
- Merge when sub-tasks are reliably done together.
- Split when you need to inspect or branch on a result.
- Order links so reliable operations come first.
Interface: Define the Contracts
The fourth stage makes every handoff explicit.
The Artifact: A Contract per Boundary
For each link, define the output shape: the format, the named fields, the allowed values, and the empty or uncertain case. Treat each boundary as an API. A defined contract lets the next link depend on a known shape and lets you validate before calling it. This is the discipline that separates debuggable chains from fragile ones.
Defend: Add Validation and Fallbacks
The fifth stage hardens the chain against bad data.
The Artifact: A Validation Plan
For each contract, decide how you will validate it and what happens when validation fails: stop, retry, or fall back. A malformed result that propagates becomes a confusing failure downstream, so the defense happens at the boundary where the error appears. The step-by-step mechanics are covered in A Step-by-Step Approach to Prompt Chaining.
Evaluate: Measure and Observe
The final stage makes the chain inspectable and measurable.
The Artifact: An Evaluation Setup
Plan per-link logging, per-link success metrics, and an end-to-end test on real inputs. Without this stage, you cannot tell which link to improve or notice when one degrades. Evaluation is what turns a chain you shipped once into a chain you can maintain. The operational checklist that complements this stage is in the Prompt Chaining Checklist for 2026.
When to Apply the Full Framework
DECIDE is overkill for a throwaway chain and essential for a durable one.
Use Judgment About Scope
For a quick, personal, two-link chain, the Define and Cut stages alone are enough. For a chain that runs in production, is maintained by a team, or processes unpredictable inputs, run all six stages. The framework scales down gracefully; apply the depth the chain's importance warrants.
Walking a Real Task Through DECIDE
To see the framework produce something, run it on a concrete task: turning a product review into a structured insight record.
The Six Artifacts in Sequence
- Define yields the sentence: turn a review into a record with sentiment, complaint, and suggested action.
- Enumerate lists extract claims, classify sentiment, categorize complaint, suggest action.
- Cut merges extraction and sentiment into one link, keeps categorization and action separate, producing a three-link plan.
- Interface defines each contract: link one returns claims and a sentiment value, link two returns a category from a fixed list, link three returns one action string.
- Defend adds validation after links one and two, with a stop-and-flag behavior on invalid output.
- Evaluate sets up per-link logging and an end-to-end test on twenty real reviews.
Notice that by the end of Cut, the chain's shape is fixed, and the remaining stages harden it. The real-world payoff of this sequence shows up in Case Study: Prompt Chaining in Practice, where reframing the design question collapsed a failing eleven-link chain.
Why a Named Framework Beats Intuition
Intuition does not transfer between people, and it does not leave an artifact you can review. A named framework with explicit stages gives a team a shared vocabulary, so a reviewer can ask "did you do the Cut stage?" and get a real answer.
The Reviewability Advantage
Each DECIDE stage produces an artifact, and artifacts can be critiqued before code exists. A teammate can challenge your Cut plan or your contracts in five minutes, catching a design flaw that would otherwise surface as a production failure weeks later. That early, cheap critique is the framework's real value. The operational items that follow from the Evaluate stage are detailed in Prompt Chaining: Best Practices That Actually Work.
Frequently Asked Questions
What does the DECIDE framework stand for?
Define, Enumerate, Cut, Interface, Defend, and Evaluate. Each stage produces a concrete artifact, from a one-sentence goal to an evaluation setup, and the stages run in order to make design decisions explicit before any code is written.
Which stage matters most?
Cut, where you draw link boundaries. It carries most of the design value because choosing the fewest reliable links determines the chain's cost, speed, and end-to-end reliability. Most chain failures trace back to cutting poorly.
Do I have to run all six stages every time?
No. For a small throwaway chain, Define and Cut are enough. Run the full framework for chains that go to production, are maintained by a team, or handle unpredictable inputs. Apply the depth the chain warrants.
How is Interface different from Cut?
Cut decides how many links there are and where boundaries fall. Interface defines the exact data contract at each boundary you drew, the format, fields, and allowed values, so the next link can depend on a known shape.
Why is Evaluate a design stage rather than an afterthought?
Because logging and per-link metrics must be planned into the chain, not bolted on after an incident. Designing observability up front is what makes a chain maintainable and lets you find which link to improve.
Key Takeaways
- DECIDE is a six-stage framework: Define, Enumerate, Cut, Interface, Defend, Evaluate.
- Define forces a one-sentence goal; Enumerate surfaces every sub-task before committing to links.
- Cut carries the most value: choose the fewest links where each is independently reliable.
- Interface defines an explicit contract at every boundary so links can depend on known shapes.
- Defend adds validation and fallbacks at each boundary to stop bad data from propagating.
- Evaluate plans logging and metrics up front so the chain stays maintainable and improvable.