LEANGUARD: Lean-Verified Guardrails for Tool-Using Agents
READ THE ORIGINAL SOURCEOpen original sourcehuggingface.co · Opens in a new tabLeanGuard is a runtime that checks each proposed tool call from a language-model agent against a policy written in Lean4 before execution. Policies combine state predicates with scoped past-time temporal operators, evaluation is fail-closed, and the decision procedure is proved equivalent to a LeanLTL semantics. Denied calls can be corrected via agent feedback or via proof-guided repair, which searches for a nearby admissible call without the model. Reported results on Tau-Bench, DTap, and a telecom setting are presented.
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- Primary sourceHugging Face Daily Papers
- Discovery linkHugging Face
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LeanGuard is a runtime that checks each proposed tool call from a language-model agent against a policy written in Lean4 before execution. Policies combine state predicates with scoped past-time temporal operators, evaluation is fail-closed, and the decision procedure is proved equivalent to a LeanLTL semantics. Denied calls can be corrected via agent feedback or via proof-guided repair, which searches for a nearby admissible call without the model. Reported results on Tau-Bench, DTap, and a telecom setting are presented.
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- 01Who is making each claim?
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- 02What was actually tested?
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- 03Where are the sources?
Original link: huggingface.co. Brief basis: fetched source page. Primary page date and quote locations are not established in this panel.
- 04What could mislead?
Source claims not independently checked; results cover specific benchmarks and five Qwen models, and policies must be written in Lean4 by hand.
- 05What is at risk if wrong?
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- 06What would change the view?
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Key findings from the stored brief
- On Tau-Bench with five Qwen models, unguarded agents executed at least 33 forbidden calls; LeanGuard executed none.
- On DTap, direct prompt-injection success dropped from 57.9% to 5.9%.
- Feedback reduced repeated blocked calls and raised task success for four of five models over a bare denial.
- Proof-guided repair found an admissible edit for 88 of 252 argument-value denials, with a median of 2ms.
Source claims not independently checked; results cover specific benchmarks and five Qwen models, and policies must be written in Lean4 by hand.
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Evidence & sources
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Why this may matter
It proposes a formally grounded enforcement layer for agent tool calls, shifting policy checks from model behavior to verified rules. This could reduce policy-violating actions and prompt-injection risk in tool-using systems.
Limits and open questions
Source claims not independently checked; results cover specific benchmarks and five Qwen models, and policies must be written in Lean4 by hand.
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