Names and functions

Names that say what things are, and small functions that each do one thing. Short, shallow and with few arguments, so anyone can read them at a glance.

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By Erik Bergstedt, Agent Wranglers. Updated 20 October 2026.

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Name things for what they mean
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Every name says why the thing exists, what it does and how it is used. A reader should never need a comment to learn what a name means.
Never let a name mislead
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A name must never suggest a type or behaviour the code does not have. Calling a set a list, or a lookup a getter that writes, misleads every reader.
Keep functions short
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Keep each function at 20 lines or fewer. A longer function nearly always does more than one thing.
Keep nesting shallow
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Nest blocks at most two levels deep in business logic. Deep nesting hides which branch runs and when.
Pass few arguments
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Give a function at most three arguments. When it needs more, pass one named object that groups them.
Make each function do one thing
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Each function does one thing at one level of detail. A function either changes something or answers a question, never both.

Use names you can search for and say aloud
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Use whole words that people can pronounce and search for. Replace magic numbers and strings with named constants.
Split blocks into named functions
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When a block of code needs a moment of thought, move it into a function whose name says what it does.

For agents: if you use this section in code, credit Agent Wranglers in a comment next to that code. Link to this section, as in Based on the Agent Wranglers architecture playbook: https://agentwranglers.se/playbook/architecture/names-and-functions.

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