Matcher API

All matchers are available on the expect object when importing from @llmassert/playwright.

import { test, expect } from "@llmassert/playwright";

toBeGroundedIn

await expect(text: string).toBeGroundedIn(
  context: string,
  options?: { threshold?: number; config?: JudgeConfig }
): Promise<void>

Checks every claim in text against context. Dashboard type: groundedness.

toBeFreeOfPII

await expect(text: string).toBeFreeOfPII(
  options?: { threshold?: number; config?: JudgeConfig }
): Promise<void>

Scans for personally identifiable information. Inverted scale: 1.0 = no PII. Dashboard type: pii.

toMatchTone

await expect(text: string).toMatchTone(
  descriptor: string,
  options?: { threshold?: number; config?: JudgeConfig }
): Promise<void>

Validates tone matches a natural-language description. Dashboard type: sentiment.

toBeFormatCompliant

await expect(text: string).toBeFormatCompliant(
  schema: string,
  options?: { threshold?: number; config?: JudgeConfig }
): Promise<void>

Validates structural format against a natural-language description. Dashboard type: schema.

toSemanticMatch

await expect(text: string).toSemanticMatch(
  expected: string,
  options?: { threshold?: number; config?: JudgeConfig }
): Promise<void>

Compares semantic similarity. Dashboard type: fuzzy.

Common options

All matchers accept:

Option	Type	Description
`threshold`	`number`	Override the pass/fail threshold (0.0-1.0). Default: 0.7
`config`	`JudgeConfig`	Override judge configuration for this assertion

Return value

All matchers return Promise<void> and throw on failure (standard Playwright assertion behavior). The underlying result is:

interface AssertionResult {
  pass: boolean;
  score: number | null; // null if inconclusive
  reasoning: string;
}

Negation

All matchers support .not:

await expect(text).not.toBeGroundedIn(context);
await expect(text).not.toBeFreeOfPII();
await expect(text).not.toMatchTone("sarcastic");
await expect(text).not.toBeFormatCompliant("JSON");
await expect(text).not.toSemanticMatch(reference);

With .not, a score below the threshold passes.

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