The tool decision matrix
Understand the rule, inspect a real Level Higher build, make the decision yourself and leave with a reusable artifact.
Choose the shape of the system before choosing a brand or model. Most work needs less machinery than the AI market suggests.
Start with the least complex system that can produce dependable evidence.
Classify the work
Is it reasoning, retrieval, deterministic transformation or external action?
Measure the cost of error
Match supervision to what happens when the answer is wrong.
Pick the smallest shape
Chat, script, retrieval workflow and agent are different products.
Use code for price math and AI only for explanation.
Historical lows, store prices and thresholds must be calculated consistently; a language model is the wrong calculator.
Deterministic code gathers and scores offers. AI may explain the BUY or WAIT verdict, but it does not invent the underlying price facts.
Users get a clear decision without sacrificing numerical reliability.
Start with the smallest system that can produce reliable evidence.
Create a tool decision record.
Use the matrix, then explain why a simpler option is insufficient before selecting an agent.
- Normal code was considered
- Current facts have a source
- Private data has an approved boundary
- The human role matches the consequence
Edit the worksheet here. It stays in your browser until you download or copy it.
A good stack is an answer to the task, not a collection of fashionable tools.
Your work should now pass the four checks above. If one fails, repair the contract or evidence before adding more tools.