elixir-credo-predicate-naming

name	elixir-credo-predicate-naming
description	Use when working on Elixir code with Credo predicate naming warnings, boolean helper functions, or renaming functions that start with is_. Prevents violations like: Predicate function names should not start with 'is' and should end in a question mark.

Elixir Credo Predicate Naming

Use this skill to prevent and fix predicate naming violations in Elixir.

Rules

• Predicate functions must end with ?.
• Predicate functions must not start with is_.
• Prefer names like valid_*?, enabled_*?, has_*?, can_*?, matches_*?, or <noun>_*?.

Refactor Workflow

1. Find predicate functions named like is_*?.
2. Rename each one to a Credo-compliant name that still reads clearly.
3. Update all call sites in the same module and across the codebase.
4. Keep arity unchanged unless behavior intentionally changes.
5. Run a focused Credo check for edited files.

Naming Guidance

• is_valid_zrc2_transfer_log?/4 -> valid_zrc2_transfer_log?/4
• is_enabled?/1 -> enabled?/1
• is_erc20_transfer?/2 -> erc20_transfer?/2
• is_contract_verified?/1 -> contract_verified?/1

Safety Checks

• Preserve semantics during rename.
• Verify no stale references remain.
• If the function is part of a public API, rename consistently and update docs/specs.

Verification Commands

mix credo path/to/file.ex
mix test

Expected Result

No Credo findings for predicate naming in updated files.