ResearchResearch paperReasoning & Planning · Efficiency & Inference · Safety & Alignment1 source · Oct 19, 2026

VerifierBench: Benchmarking the Generation of Executable Verifiers for LLM Agents

We introduce VerifierBench, a benchmark of 222 tasks from six agent benchmarks spanning tool-call, state-based, and code verification, with 4,993 hidden test cases that include alternative valid solutions and attacks; Verifier4Verifier (V4V), a six-check audit, screens its source verifiers and test suites.

Key points

  • Agents need reliable ways to validate their outputs, both when completing tasks and when filtering synthetic training data.
  • We study verifier generation: from the instruction and environment available for solving a task, an agent writes an executable verifier that must accept every valid solution and reject invalid ones.
  • Across 19 models in a common agent harness, normalized balanced accuracy ranges from 10.6 to 62.1, with generated verifiers consistently rejecting invalid solutions more reliably than they accept valid ones.
  • These errors survive self-testing because agents test solutions that share the verifier's mistaken assumptions, or submit verifiers without confirming that any correct solution passes.

Sources (1)

  • [1]VerifierBench: Benchmarking the Generation of Executable Verifiers for LLM Agents
    Hugging Face Daily Papers · Oct 19, 12:00 AM
    We introduce VerifierBench, a benchmark of 222 tasks from six agent benchmarks spanning tool-call, state-based, and code verification, with 4,993 hidden test cases that include alternative valid solutions and attacks; Verifier4Verifier (V4V), a six-check audit, screens its source verifiers and test suites.
    Agents need reliable ways to validate their outputs, both when completing tasks and when filtering synthetic training data.

Extractive summary: sentences quoted from the sources.

Before this

  1. Oct 18, 2026Editing as Language: Teaching LLM Agents a Grammar for Native Context Editing
  2. Oct 17, 2026Pair-Aware Optimization: Coordinating Exploration and Refinement for Jailbreaking LLM Agents
  3. Oct 17, 2026Nemotron 3.5 Bolt, Muse Spark Open, and a Fast LFM2.5 24B
  4. Oct 16, 2026CME-SpectrumBench: Can LLMs Analyze Condensed Matter Spectral Data?
  5. Oct 16, 2026Liquid AI Releases d1-ultra: A Multimodal Decision Model That Scores 65 on the AA Decision Index
  6. Oct 16, 2026Welcome Beam: a 501B open model you can own, customize, and scale

Related