interwhen: A Generalizable Framework for Verifiable Reasoning with Test-time Monitors

Vishak K Bhat, Prateek Chanda, Ashmit Khandelwal, Maitreyi Swaroop, Subbarao Kambhampati, Vineeth N. Balasubramanian, Nagarajan Natarajan, Amit Sharma

Track: long paper (up to 8 pages)

Keywords: reasoning, test time scaling, verifiers

Abstract:

We present a test-time verification framework, *interwhen*, that ensures that the output of a reasoning model is valid wrt. a given set of verifiers. Verified reasoning is an important goal in high-stakes scenarios such as deploying agents in the physical world or in domains such as law and finance. However, current techniques either rely on the generate-test paradigm that verifies only after the final answer is produced, or verify partial output through a step-extraction paradigm where the task execution is externally broken down into structured steps. The former is inefficient while the latter artificially restricts a model's problem solving strategies. Instead, we propose to verify a model's reasoning trace as-is, taking full advantage of a model's reasoning capabilities while verifying and steering the model's output only when needed.
The key idea is *meta-prompting*, identifying the verifiable properties that any partial solution should satisfy and then prompting the model to follow a custom format in its trace such that partial outputs can be easily parsed and checked. We consider both self-verification and external verification and find that *interwhen* provides a useful abstraction to provide feedback and steer reasoning models in each case. Using self-verification, *interwhen* obtains state-of-the-art results on early stopping reasoning models, without any loss in accuracy. Using external verifiers, interwhen obtains reasonable improvement in accuracy over test-time scaling methods, while ensuring 100\% soundness and being 4x more efficient.

Anonymization: This submission has been anonymized for double-blind review via the removal of identifying information such as names, affiliations, and identifying URLs.

Presenter: ~Vishak_K_Bhat1

Format: Maybe: the presenting author will attend in person, contingent on other factors that still need to be determined (e.g., visa, funding).

Funding: Yes, the presenting author of this submission falls under ICLR’s funding aims, and funding would significantly impact their ability to attend the workshop in person.

Submission Number: 43