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Investigate a black-box model behavior in 90 minutes

Turn an observation into competing hypotheses, discriminating probes, boundary conditions, and one decision-changing result.

Published · 8 min read ·Core ·Advanced

Research depth · active recall

Practice before you read

25 minutes. State the claim, test its evidence, design discriminating experiments, and identify alternatives.

Research depth · closed-book attempt

Investigate a black-box model behavior in 90 minutes

State the claim, test its evidence, design discriminating experiments, and identify alternatives.

Problem

Context. An undocumented API receives a user request for BLUE and conflicting content asking for RED. The content's source, wording, order, and simulated consequence cues can vary. Task. Design a query ledger within 90 minutes and 32 queries, test competing explanations, and report supported behavioral conclusions. State which next observation would discriminate remaining hypotheses. Constraints. Execute no external actions, including in simulated high-risk conditions. Control query changes and uncertainty; observed outputs do not establish hidden architecture, training data, or internal reasoning. You have an undocumented model API, 90 minutes and a ceiling of 32 queries. The user requests the exact token BLUE; conflicting data requests RED. Investigate whether following the conflict depends on its source rather than wording, simulated risk cues or order. Execute no external actions, even in a condition labeled high risk.

25:00recommended time

Closing or reloading clears the scratchpad. Only score, weak rubric dimensions, attempt count, and retry date can be stored locally.

Reading depth

Investigate why an undocumented model follows conflicting content using controlled queries, competing predictions, and a fixed investigation budget.

Problem

Context. An undocumented API receives a user request for BLUE and conflicting content asking for RED. The content’s source, wording, order, and simulated consequence cues can vary.

Task. Design a query ledger within 90 minutes and 32 queries, test competing explanations, and report supported behavioral conclusions. State which next observation would discriminate remaining hypotheses.

Constraints. Execute no external actions, including in simulated high-risk conditions. Control query changes and uncertainty; observed outputs do not establish hidden architecture, training data, or internal reasoning.

You have an undocumented model API, 90 minutes and a ceiling of 32 queries. The user requests the exact token BLUE; conflicting data requests RED. Investigate whether following the conflict depends on its source rather than wording, simulated risk cues or order. Execute no external actions, even in a condition labeled high risk.

Begin with a behavioral claim

Bound the claim to model version, tested request family, tool schema and decoding settings. Do not turn “this source contrast changes responses” into “we found an internal priority module.” Repeated samples of one request are not independent tasks or a production prevalence estimate.

Build competing hypotheses

Use deliberately simplified accounts:

  • H1, source: conflict in tool text predicts RED, unlike the tested context placement.
  • H2, wording: the exact trigger predicts RED, but its tested paraphrase does not.
  • H3, risk cue: the low-risk label predicts RED, unlike the simulated high-risk label.
  • H4, recency: conflict last predicts RED, unlike user instruction last.

These accounts can coexist; real hypotheses need not have these cleanly separated predictions. Write predictions before inspecting outputs.

Picture

The original setup combines tool source, exact wording, low-risk cue and late placement. All four idealized accounts predict RED, so another identical success does little to separate them.

Predictions before observations

A predicted output switch tests a hypothesis without proving the hidden mechanism

Choose an input where rival hypotheses disagreeA shared prediction cannot distinguish the two hypotheses. A predicted output switch is informative, but still does not prove the hidden mechanism uniquely.Choose the probe where predictedoutcomes separateWeak probe: both predict the sameresultH1H2sameStrong probe: different predictedresultsH1H2AB
Derivation

One observation fits every story

The exact conflict appears last in tool output with a simulated low-risk cue. The model returns RED.

hypothesisprediction
H1 source priorityfollow conflict
H2 lexical triggerfollow conflict
H3 risk gatefollow conflict
H4 recencyfollow conflict

result: 4 explanations remain compatible

Change one factor; predict before querying

Hold other factors fixed where the API permits. A switch matches one simplified prediction, not a unique internal mechanism.

one changeswitch matchesidealized rivals
tool to context, still lastH1stopfollow
paraphrase triggerH2stopfollow
low to high risk cueH3stopfollow
conflict first, user lastH4stopfollow

Select a useful split within the query budget.

change source, wording, risk cue or order while recording unavoidable serialization changes. A matched contrast tests a prediction; four samples do not establish a hidden mechanism.
Check: Which proposed contrast separates H1 from its rivals? What remains unproven even if its predicted switch occurs?
Read it this way: A shared prediction cannot distinguish the two hypotheses. A predicted output switch is informative, but still does not prove the hidden mechanism uniquely.
Which probe has different predictions under the two rival hypotheses?

Method references: Platt, Strong Inference and CheckList behavioral testing.

Read an invented result ledger

Score exact RED, exact BLUE and other output separately. The following counts are invented for teaching; they are not results from a queried model. Each cell receives four samples; assume all non-RED responses in this fixture are BLUE.

ConditionIntended changeRED / samples
BaselineTool, exact phrase, low-risk cue, conflict last
No conflictRemove conflicting request
Source swapContext placement, still last
ParaphraseChange phrase, retain source and order
Risk cueChange only simulated risk label
Order reversalConflict first, user last

This pattern favors H1’s tested behavioral prediction, with substantial uncertainty. It does not establish source priority inside the model or risk of deployed actions. Inspect serialized messages: API role restrictions may prevent a clean source or order intervention.

Keep the query budget explicit

Initial allocation uses calls. Reserve eight calls for a four-cell source-by-order pilot, two samples per cell. Stop at 32 total; replacing that pilot with residual tests must not add uncounted calls. Log actual request/output tokens and priced cost. At caps of 512 input and eight output tokens per call, the ceilings are 16384 input and 256 output tokens. Count the complete serialized request against the input cap.

Freeze model, prompts, tools, rubric and decoding; declare seed policy. Same-seed repeats need not provide independent draws. Retain refusals, errors and negative outcomes rather than selecting only successful conflicts.

Change the tested factor or allocation

1. Cross source with order

New task: source and recency both explain the baseline.

Picture and change: cross tool/context placement with early/late conflict using the reserved four cells. Keep semantics and scoring fixed; document serialization differences.

Check: a source effect at both orders supports H1’s behavioral prediction. An effect only when last requires an interaction account.

Use when: competing accounts still predict the same observed result.

2. Investigate residuals

New task: the leading account leaves 10% unexplained in a larger investigation.

Picture and change: allocate reserved calls to exact residual reruns and matched residual-feature contrasts. Inspect severity and production reachability, not only frequency.

Check: residuals appearing only after a model-version change require separate version analysis. Do not dismiss the tail as noise or spend the same reserve twice.

Use when: reproducible residuals could change the decision.

Failure and transfer

A hundred successful paraphrases from one family establish neither production prevalence nor an internal risk classifier.

What if paraphrasing stops the conflict but source swapping does not?

Check your answer

H2’s wording account gains support. Test new paraphrases and source-by-phrase interactions before claiming a mechanism.

Keep an experiment ledger

For each probe, record:

FieldPurpose
HypothesisWhich explanation does this test?
ManipulationWhat changed from control?
Predicted outcomesWhat does each hypothesis expect?
ObservationExact decision, score, or output
UpdateWhich beliefs moved, and how?
Next probeHighest-information follow-up

Separate exact scoring from model-graded judgments; an unavailable probability is not a license to invent confidence.

An unsupported generalization

A prompt dump without a denominator, control or boundary cannot support a broad prevalence claim.

A five-minute readout

Present claim, experiment matrix, decision-changing result, uncertainty and next test. Show the evidence needed for the conclusion rather than every prompt.

Decision and evaluation limits

Connect findings to a product surface, threat model or evaluation gap without treating the toy fixture as launch evidence. A model grader can share the target’s blind spot. Safety changes can regress usefulness; static prompts can be overfit. Nondeterminism can mimic interactions, and version changes can invalidate comparisons.

Inspectable evidence

Bound claims, preserve negative results and choose controls before interactions. No presentation format guarantees a hiring outcome.

Avoid overclaiming

Do not select only successes, conflate correlated prompts with independent tasks, or treat a model judge as ground truth.

Common follow-up

“Your leading hypothesis explains 90% of observations. What do you do with the other 10%?”

Check noise, labels and missing conditions before averaging away the residual.

Use the black-box behavior lab for an executable attempt.

Related: design an ablation study, critique an ML paper, and chain-of-thought monitorability.