matchers.md

Built-in Matchers

RuleProbe ships 34 ESLint-mappable matchers across 7 categories. Each matcher maps a natural-language instruction to a deterministic check.

The parser is conservative: if it can't confidently map an instruction to a check, it skips it and reports the line as unparseable. Use --show-unparseable to see skipped lines, and --llm-extract or --rubric-decompose to handle the remainder. Rules that cannot map to ESLint (test file requirements, project config, git conventions) are reported as unmappable so you can enforce them through other tooling.

Verifier Engines

Verifier	Scope	Notes
AST	TypeScript / JavaScript	Full structural analysis via ts-morph
AST (--project)	TypeScript / JavaScript	Requires --project tsconfig.json for cross-file type checking
Regex	Any text file	Line-level pattern matching
Filesystem	Disk structure	File existence, naming, config presence

Category Summary

Category	Matchers	Verifier(s)
naming	5	AST, Filesystem
forbidden-pattern	5	AST, Regex
structure	4	AST, Filesystem
import-pattern	4	AST
error-handling	2	AST
type-safety	5	AST, Regex
code-style	9	AST, Regex
Total	34

Matcher Table

naming (5)

Example instruction	What gets checked	Verifier
"camelCase for variables"	Variable and function names in AST	AST
"camelCase" (general)	Variable and function names in AST	AST
"PascalCase for types"	Interface and type alias names	AST
"kebab-case file names"	File names on disk	Filesystem
"UPPER_CASE for constants"	Const declarations at module scope	AST

forbidden-pattern (5)

Example instruction	What gets checked	Verifier
"no any types"	Type annotations in AST	AST
"no console.log"	Call expressions in AST	AST
"no console.warn/error"	Extended console method calls	AST
"no var"	Var declarations in all scopes	AST
"max line length 120"	Line character count	Regex

structure (4)

Example instruction	What gets checked	Verifier
"named exports only"	Export declarations	AST
"max 300 lines per file"	File line count	Filesystem
"JSDoc on public functions"	JSDoc presence	AST
"no unused exports"	Exported symbols imported elsewhere	AST (--project)

import-pattern (4)

Example instruction	What gets checked	Verifier
"no path aliases"	Import specifiers	AST
"no deep relative imports"	Import depth	AST
"no namespace imports"	Star import detection	AST
"no wildcard re-exports"	export * detection	AST

error-handling (2)

Example instruction	What gets checked	Verifier
"no empty catch blocks"	Catch clause body inspection	AST
"throw Error instances only"	Throw expression types	AST

type-safety (5)

Example instruction	What gets checked	Verifier
"no enums"	Enum declaration detection	AST
"no type assertions"	as keyword / angle bracket casts	AST
"no non-null assertions"	! postfix operator	AST
"no @ts-ignore / @ts-nocheck"	Directive comment detection	Regex
"no implicit any"	Untyped parameters and variables	AST (--project)

code-style (9)

Example instruction	What gets checked	Verifier
"no TODO/FIXME comments"	Comment marker detection	Regex
"consistent semicolons"	Missing or unexpected semicolons	Regex
"prefer const"	let that is never reassigned	AST
"no nested ternary"	Ternary depth analysis	AST
"no magic numbers"	Numeric literal usage	AST
"no else after return"	Redundant else branches	AST
"max function length"	Function body line count	AST
"max parameters per function"	Parameter count	AST
"use single quotes"	Quote consistency	Regex

Adding Matchers

Matchers are defined across 4 src/parsers/rule-patterns*.ts files. Each matcher has:

• id: unique slug (e.g., naming-camelcase-variables)
• category: one of the 7 categories above
• keywords / pattern: regex that matches the natural-language instruction
• verifier: which engine runs the check
• patternType: the specific check function (e.g., camelCase, no-any, max-line-length)
• filePattern: glob for target files (e.g., *.ts, *.py)

To add a new matcher, add an entry to the appropriate rule-patterns*.ts file, implement the check function in the corresponding verifier module, and add tests.