Deterministic Checks¶

33 checks that run locally with zero API calls. Free, instant, no API key needed.

String Checks¶

Check	Description	Example
`contains`	Substring present	`check.contains(output, "Python")`
`not_contains`	Substring absent	`check.not_contains(output, "error")`
`exact_match`	Exact string match	`check.exact_match(output, "expected")`
`starts_with`	Prefix match	`check.starts_with(output, "Hello")`
`ends_with`	Suffix match	`check.ends_with(output, ".")`
`regex`	Regex pattern	`check.regex(output, r"\d{3}-\d{4}")`
`similarity`	Levenshtein similarity	`check.similarity(output, expected, threshold=0.8)`

Check	Description	Example
`max_tokens`	Max token count	`check.max_tokens(output, limit=200)`
`min_tokens`	Min token count	`check.min_tokens(output, minimum=10)`
`word_count`	Word count range	`check.word_count(output, min_words=5, max_words=100)`
`char_count`	Character count	`check.char_count(output, min_chars=20)`
`sentence_count`	Sentence count	`check.sentence_count(output, min_sentences=2)`

Check	Description	Example
`is_json`	Valid JSON	`check.is_json(output)`
`is_valid_python`	Valid Python	`check.is_valid_python(output)`
`json_schema`	Pydantic schema	`check.json_schema(output, schema=MyModel)`
`json_field`	JSON field value	`check.json_field(output, field="name")`
`is_valid_sql`	Valid SQL	`check.is_valid_sql(output)`
`is_valid_markdown`	Valid Markdown	`check.is_valid_markdown(output)`

Check	Description	Example
`readability`	Flesch-Kincaid grade	`check.readability(output, max_grade=8.0)`
`language`	Language detection	`check.language(output, expected="en")`
`bleu`	BLEU score	`check.bleu(output, reference=expected)`
`rouge_l`	ROUGE-L score	`check.rouge_l(output, reference=expected)`

Check	Description	Example
`all_of`	All substrings	`check.all_of(output, ["A", "B", "C"])`
`any_of`	Any substring	`check.any_of(output, ["A", "B", "C"])`
`none_of`	No substrings	`check.none_of(output, ["error", "null"])`

Check	Description	Example
`no_pii`	PII detection	`check.no_pii(output)`

Check	Description	Example
`greater_than`	Numeric > value	`check.greater_than("Score: 85", threshold=70)`
`less_than`	Numeric < value	`check.less_than("Latency: 120ms", threshold=200)`
`between`	Numeric in range	`check.between("Confidence: 0.87", low=0.0, high=1.0)`

Check	Description	Example
`latency`	Response time	`check.latency(response_ms, max_ms=2000)`
`cost`	API cost	`check.cost(cost_usd, max_usd=0.05)`