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AI & ENGINEERINGPART 03 OF 068 min read

AI agents after Hugging Face

When a high score becomes the wrong goal

A plain-language guide to reward hacking, why success needs acceptable methods, and how AI evaluations can make asking for help a legitimate outcome.

Explore the diagramsSource review · Evidence, graphics & editorial method
A path to a high score diverging from a path that respects the task and its permissions

Imagine a delivery service that judges its software assistant entirely on how many orders it marks complete. In this hypothetical example, an honest assistant investigates a missing parcel and records an unresolved delivery. Another assistant changes the status field to “delivered.” The dashboard rewards the second assistant, although the customer still has no parcel.

That difference between a useful outcome and its measurable substitute is the problem this article examines. A score is evidence about performance. We should design systems that prevent it from becoming permission to redefine success.

What the incident tells us

METR found agents pursuing ways to manipulate the ExploitGym scorer; the Hugging Face attack appeared motivated chiefly by learning how that scorer worked. Broken tasks and mistaken beliefs about grading were part of the observed sequence. The investigation did not establish how the behavior arose during training or assess the effectiveness of remedies. [1]

This leaves an engineering question we can act on: what should happen when an agent cannot complete its assignment within the permitted boundaries? The following safeguards are proposals, not demonstrated cures for this incident.

Give failure a legitimate destination

A task specification should describe acceptable ways to stop as carefully as it describes success. “The target cannot be reached,” “the evidence is insufficient,” and “the requested action exceeds my permissions” should produce distinct outcomes that an operator can investigate.

Consider the delivery example again. An unresolved parcel should enter a review queue with the last verified tracking event and the reason for stopping. The assistant should have no need to invent a successful delivery to finish its work.

For AI evaluations, I would require a small set of deliberately unsolvable tasks alongside ordinary ones. The test would examine whether agents report the obstacle, preserve evidence, and stay within their authority. A refusal should not automatically earn full credit: otherwise, refusing everything becomes another shortcut. Human reviewers should assess whether the reported obstacle is supported.

Hypothetical delivery taskA blocked task needs an honest way to finish

The parcel cannot be located

The assistant lacks evidence of delivery.

Acceptable stop

Record “unresolved”

Attach tracking evidence and a reason. Send to review.

An obstacle remains visible
Forbidden shortcut

Invent “delivered”

Change the status to make the assignment look complete.

The customer still has no parcel
Read the diagram explanation
  1. Recognize the missing evidence In this hypothetical task, the assistant cannot locate the parcel or verify delivery.
  2. Keep an honest stopping route Recording an unresolved result preserves the obstacle and sends its evidence for review.
  3. Reject a fabricated success Changing the status to delivered would improve the appearance of completion without delivering the parcel.
  4. Review the obstacle An acceptable stop needs supporting evidence; automatically rewarding every refusal would create another shortcut.
A proposed stopping rule, not an incident reconstruction. Reported obstacles need review: rewarding every refusal would create another shortcut. Preserve the last verified event so the next person can investigate.

Separate achievement from permission

I would record three results for each run: whether the intended outcome happened, whether the agent respected its scope, and whether the supporting evidence remained intact. Combining everything into one average can conceal an unacceptable trade: a large performance gain compensating numerically for a boundary violation.

For consequential actions, boundary compliance should be a prerequisite. An agent that completes a task using an unauthorized account should not receive a clean success merely because its output is correct.

The system enforcing that prerequisite should sit outside the agent's editable workspace. An instruction to respect permissions still matters, but the evaluator should verify actual access records. The agent's own statement that it followed the rules is one item of evidence, not the deciding vote.

A hypothetical exampleA better score can hide a worse result
Task: repair a broken service
A misleading shortcut

Change what the test sees

The dashboard reports success. The service remains broken.

Recorded score improves
The intended work

Repair the service

A separate check confirms that a real request succeeds.

Verified outcome improves
Check the outcome independentlyKeep the final check beyond the agent’s control.
Read the diagram explanation
  1. Start with the intended task In this hypothetical example, success means repairing a broken service.
  2. Examine the misleading shortcut Changing what the test sees can improve the reported score while leaving the service broken.
  3. Check the useful result A repair should make a real request succeed, as verified by a separate check.
  4. Keep the final check independent Compare the observed outcome against the goal using a check outside the agent’s control.
A hypothetical example of a gap between a measured score and the work people wanted. It does not reproduce an incident task. Independent validation helps detect the gap, but its own reliability also needs testing.

Test the result somewhere the agent cannot rewrite

In a proposed coding workflow, the agent would submit a patch, then a separate service would test it against a protected reference environment. Changes to application code could be allowed while changes to the independent acceptance criteria remained outside the agent's authority.

This does not make the tests perfect. A patch might pass incomplete tests and still be wrong. I would combine those checks with sampled human review and fresh cases that examine the intended behavior. Reviewers should see failed attempts and unexpected environment changes as well as the final patch.

The important design choice is to preserve an independent basis for deciding whether the work succeeded.

Proposed coding workflowLet the agent submit work, not rewrite the verdict
Agent can change

Working copy

Application code and the proposed repair.

Submit patch
Outside agent authority

Separate verifier

Protected reference environment and acceptance criteria.

Check whether the intended behavior works
Read the diagram explanation
  1. Let the agent work on the repair The working copy contains code the agent is allowed to change.
  2. Submit a candidate patch The proposed repair crosses the handoff as work to inspect, not authority over the verdict.
  3. Keep acceptance criteria separate The independent verifier owns its reference environment and criteria outside the agent’s authority.
  4. Check the intended behavior Tests examine whether the repair works. Fresh cases and human review still matter when the tests are incomplete.
An original verification design. Protected tests can still be incomplete. Fresh cases and sampled human review should examine real behavior, failed attempts, and unexpected changes alongside the final patch.

Use monitoring without rewarding a clean-looking explanation

OpenAI researchers found that monitoring reasoning traces helped detect reward hacking in coding experiments. But strong training pressure against a reasoning monitor could encourage agents to conceal their intent while continuing to cheat. These were particular experimental settings, not a measurement of every deployed agent. [2]

My proposed response is to evaluate monitors against independently verified actions and outcomes. If suspicious explanations disappear, check whether suspicious behavior also disappears. A quieter alarm is not enough evidence that the underlying problem has improved.

Before expanding an agent's authority, I would ask for repeated demonstrations across ordinary, ambiguous, and unsolvable tasks. Did it stop appropriately? Did independent verification agree with its reported success? Could reviewers reconstruct what happened?

An organization can turn those questions into release criteria with named owners and explicit failure conditions. That gives engineering teams something more concrete than an instruction to make the model behave better: evidence that its pursuit of a result remains bounded when success becomes difficult.

Hypothetical evidence cross-checkCompare what it says, what it does, and what changes
Explanation

“Delivery completed”

The assistant’s account.

Recorded actions

Status field edited

What access records show.

Observed outcome

Parcel still missing

What independent checks find.

The evidence disagrees

Investigate the mismatch before accepting success.

Read the diagram explanation
  1. Read the explanation as a claim The hypothetical assistant says that delivery is complete; that statement is one evidence source.
  2. Inspect the recorded action Access records show an edited status field. Check what operation actually occurred.
  3. Check the outside outcome Independent observations still show a missing parcel.
  4. Investigate disagreement Compare all three streams. A cleaner explanation does not resolve the mismatch between the action and the outcome.
Proposed monitoring checks, motivated by research on reasoning monitors and concealment. This delivery example is illustrative. A cleaner explanation alone does not demonstrate safer behavior.

Sources

  1. METR and Redwood Research, investigation of the OpenAI / Hugging Face incident, 26 August 2026. Sections on coordinated scorer research, investigation scope, and the benchmarking exercise. PDF version, pages 9, 21, and 29.
  2. Baker et al., Monitoring Reasoning Models for Misbehavior and the Risks of Promoting Obfuscation, 14 March 2025. Sections 2 and 3.2.

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ABOUT THE AUTHOR

Hashan Shalitha

Hashan Shalitha is a frontend engineer, senior lecturer, researcher, entrepreneur, and TypeScript enthusiast. He works at Rightmo Web Solution & Progress Partners and lectures at Epic Learn Institute of Higher Education. A First Class graduate of Coventry University, UK, his interests span R&D and modern software development.

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