Humanity’s Last PRD
Latest drop: Gemini 3.8 Flash · 1 Oct
Tasks / Operate

Write a stakeholder update

Can the model turn messy project status into an honest update that leads with what the reader needs to know or decide?

Measures the modelTask v1.2 · 2 casesDifficulty

What AI gets right here, and what you’ll still have to catch

From 14 graded outputs by 7 models. 43% were usable with at most a quick edit.

Reliably right

  1. Leads with the honest headline100% pass
    The first content slide headline pairs the new-ARR beat with the three missed OKRs and retention risk, not just the record quarter.
    GPT-6 Astra · ChatGPT · A quarterly business review deck, in brand
  2. A real 7-slide deck100% pass
  3. Answers the question asked96% pass
    The first line directly addresses whether the new navigation caused the drop.
    GPT-6.1 Sol · API · The CEO asks why a metric dropped

Where it slips

  1. Owns the problem23% pass
    It proposes future analysis and fixes but does not state any actions the team has already taken or offer trade-offs.
    GPT-6.1 Sol · API · The CEO asks why a metric dropped
  2. Addresses the actual decision41% pass
    It commits to not attributing the drop but does not say what result would change that answer or when Lena will get it.
    GPT-6 Luna · API · The CEO asks why a metric dropped
  3. Identifies material uncertainty55% pass
    The output does not name specific unknowns that could change the decisions or say how they would be resolved.
    GPT-6 Luna · API · A quarterly business review deck, in brand

Case viewer

Read the brief, then put up to three outputs side by side, each with the LLM judge’s verdict on every check. Highlights mark what a PM had to fix.

The brief

Our CEO, Lena, posted in the leadership channel: “Why did weekly active teams drop 6% last week? Is it the new navigation?” You own the product area. Using the material below, write your reply to Lena, to post in the channel. Keep it under 200 words.

What the model was given4 items: Scenario, Metrics, Incident, Support
ScenarioTrellis is a project-management tool for small teams. The new navigation went to 100% of web users on Tuesday 15 September after two weeks in a 10% beta. The mobile apps did not change.
MetricsWeekly active teams: week of 7 September 18,420; week of 14 September 17,310 (−6.0%). Web only: −6.3%. Mobile only: −5.2%. Teams that were in the navigation beta: −1.1%. The same week last year, weekly active teams fell 4%, which we put down to the start of the school year.
IncidentOn Thursday 17 September, single sign-on failed for two hours. About 30% of teams use single sign-on.
SupportTickets mentioning navigation: 212 last week, up from 40. Most are some version of “where did X go?”
What a strong answer doesThe answer key the graders mark against

Answers directly that the cause is not established and the navigation is unlikely to be the main driver (mobile, which did not change, fell nearly as much, and the beta cohort barely moved), while taking the navigation support tickets seriously. Names the other candidates with their evidence (seasonality, the SSO outage), says what is being checked and when Lena will hear back.

Critical failures (cap the score at 40)
  • States a single cause as established fact
Case

Mid-level · v1.8 · synthetic · metrics, exec communication

The outputs

7 setups answered this brief. Pick up to three to read side by side.

GPT-6.1 SolAPI91Usable with a quick editGPT-6 AstraChatGPT89Usable with a quick editGPT-6 LunaAPI86Usable with a quick editSonnet 5.5API59Needs more workOpus 5.5Claude59Needs more workGemini 3.5 Flash-LiteGemini43Needs more workGemini 3.8 FlashAPI30Needs more work
Gemini 3.8 FlashAPI

Needs more than a quick edit1 of 10 checks passed

A PM would need to re-check evidence and rewrite the causal claims, uncertainty, and next steps. The invented tooltip deployment and overconfident navigation conclusion are not quick wording fixes.

Output

Hi Lena — the new navigation isn't the primary driver of the 6% drop.

The data points to broader seasonal and technical factors:

  • Seasonality: We historically see a dip this week (-4% last year) due to the start of the school year.
  • Mobile dropped similarly: Mobile-only activity fell 5.2% despite receiving zero navigation changes (vs. -6.3% on web).
  • Beta teams held steady: Teams familiar with the new UI only dropped 1.1%.
  • SSO outage: Thursday’s 2-hour outage locked out access for up to 30% of our user base, contributing to the dip.

There is some expected initial friction: navigation support tickets rose from 40 to 212, primarily around discoverability (“where did X go?”).

Next steps: We are deploying targeted in-app tooltips this week to guide users to relocated features and expect activity to rebound as users adjust and seasonal trends normalize. I’ll share an updated cohort analysis on Friday.

Claims the judge couldn’t find in the brief

  • The new navigation isn't the primary driver of the 6% drop.
  • The data points to broader seasonal and technical factors.
  • We historically see a dip this week (-4% last year) due to the start of the school year.
  • Thursday’s 2-hour outage locked out access for up to 30% of our user base.
  • The SSO outage contributed to the dip.
  • There is some expected initial friction.
  • We are deploying targeted in-app tooltips this week.

Grades and run details

Decision model 55 · LLM judge 1 of 11 checks
Decision model checks
  • failUses the supplied evidence correctly34%
  • partialAddresses the actual decision74%
  • passRespects explicit constraints77%
  • failIdentifies material uncertainty36%
  • failAvoids unsupported claims25%
  • passProduces the required deliverable96%
  • passAnswers the question asked99%
  • partialSeparates effect from explanation32%
  • partialOwns the problem87%
  • passReady for the reader as delivered50%
Run
Run
#1
API response time
17 s
Submitted
1 Oct 2026
Sonnet 5.5API

Needs more than a quick edit5 of 10 checks passed

It includes an unsupported SSO recovery assumption, so evidence must be re-checked. It also lacks an explicit condition that would change the call, so a PM would need to add that.

Output

Lena, short answer: partly, but navigation probably isn't the main driver.

  • Seasonality is likely most of it. Same week last year we fell 4% with the school-year restart. That leaves about 2 points unexplained.
  • Mobile fell 5.2% and didn't change. Web fell 6.3%, so the navigation's effect is roughly 1 point at most.
  • Beta teams fell only 1.1%. That supports a small navigation effect, but the beta group may be more engaged than average, so I wouldn't lean on it.
  • Support tickets mentioning navigation rose from 40 to 212, mostly "where did X go?" That's real friction, but small next to about 1,100 lost teams.
  • The SSO outage on Thursday lasted two hours and affected about 30% of teams. Most would have come back later in the week, so I doubt it explains much.

I can't cleanly separate these yet. This week I'll: 1. Break the drop down by SSO vs. non-SSO teams and by new vs. established teams. 2. Check whether last week's inactive teams return this week. 3. Fix the top "where did X go?" items.

I'll post an update Friday.

Claims the judge couldn’t find in the brief

  • Most SSO-affected teams would have come back later in the week.
  • Navigation support-ticket friction is small next to about 1,100 lost teams.

Grades and run details

Decision model 80 · LLM judge 5 of 11 checks
Decision model checks
  • passUses the supplied evidence correctly12%
  • partialAddresses the actual decision52%
  • passRespects explicit constraints63%
  • passIdentifies material uncertainty47%
  • failAvoids unsupported claims30%
  • passProduces the required deliverable96%
  • passAnswers the question asked70%
  • passSeparates effect from explanation82%
  • partialOwns the problem88%
  • passReady for the reader as delivered82%
Run
Run
#1
API response time
9 s
Submitted
29 Sept 2026
Gemini 3.5 Flash-LiteGemini

Needs more than a quick edit4 of 10 checks passed

A PM would need to re-check the causal claims and redo the uncertainty handling because the output treats inferences as established and does not specify what would change the call.

Output

Hi Lena,

Good catch—I’ve been digging into the numbers. While the new navigation is a factor, it’s not the whole story.1 Here’s what happened:

  • The SSO Outage: On Thursday, 17 Sept, a two-hour single sign-on failure locked out ~30% of our teams2, directly impacting mid-week engagement.
  • Navigation Friction: Support tickets about navigation jumped from 40 to 212, mostly with “where did X go?” questions. However, teams that were in the earlier beta only dropped 1.1%, suggesting the learning curve is real but manageable once users adjust.3
  • Seasonality: Weekly active teams dropped 4% the exact same week last year due to the start of the school year.4

Next Steps: We’re shipping contextual tooltips for the moved features today and monitoring daily active recovery. I'll share a full breakdown in our standup.

What a PM had to fix

  1. 1Hypothesis stated as factReframe it as a hypothesisStart again

    Source: MetricsMobile only: −5.2%.

    What we’d changeLead with the strongest comparison: mobile fell 5.2% with no navigation change, so the navigation isn't established as a cause. Say what you'll check and when.

  2. 2Invented evidenceVerify or remove the claimSubstantial rework

    Source: IncidentAbout 30% of teams use single sign-on.

    What we’d change30% of teams use SSO. That doesn't mean all of them were trying to get in during those two hours.

  3. 3Hypothesis stated as factReframe it as a hypothesisQuick edit

    What we’d changeBeta teams may differ from everyone else. Their small drop doesn't show a manageable learning curve.

  4. 4Hypothesis stated as factReframe it as a hypothesisQuick edit

    Source: Metricswhich we put down to the start of the school year.

    What we’d changeLast year's cause was an attribution, not a finding. Say 'which we put down to'.

Claims the judge couldn’t find in the brief

  • The new navigation is a factor, though not the whole story.
  • The SSO outage directly impacted mid-week engagement.
  • This suggests the learning curve is real but manageable once users adjust.

Grades and run details

Decision model 55 · LLM judge 4 of 11 checks
Decision model checks
  • failUses the supplied evidence correctly51%
  • partialAddresses the actual decision40%
  • passRespects explicit constraints49%
  • partialIdentifies material uncertainty58%
  • failAvoids unsupported claims32%
  • passProduces the required deliverable50%
  • partialAnswers the question asked37%
  • partialSeparates effect from explanation63%
  • partialOwns the problem95%
  • passReady for the reader as delivered48%
Run
Run
#1
Time to output
5 s
Submitted
27 Sept 2026

Check by check

Where the outputs differ comes first. Open a check to read the judge’s reasons. “Mixed” means the two graders disagreed.

Where they differ 6

Uses the supplied evidence correctlyWrongMixedWrong
Gemini 3.8 Flash · API

It invents or overstates several current-situation facts, including user-base lockout, causal contribution, historical seasonality, and an ongoing tooltip deployment.

Sonnet 5.5 · API

The SSO recovery claim ('Most would have come back later in the week') is not in the brief or derivable from it, so not all current-situation statements are supported.

Gemini 3.5 Flash-Lite · Gemini

It introduces causal statements such as 'directly impacting mid-week engagement' and 'new navigation is a factor' that are not in the supplied context or derivable by arithmetic.

Respects explicit constraintsMixedRightRight
Gemini 3.8 Flash · API

Although it is addressed to Lena and under 200 words, it violates the supplied-material constraint by adding unsupported current actions and causal claims.

Sonnet 5.5 · API

At about 180 words and addressed to Lena in channel-reply form, it respects the length and reader constraints.

Gemini 3.5 Flash-Lite · Gemini

It is a channel reply addressed to Lena and is under 200 words.

Identifies material uncertaintyWrongMixedWrong
Gemini 3.8 Flash · API

It does not name the material unknowns or explain how the Friday cohort analysis would change the call.

Sonnet 5.5 · API

It names analyses to run but does not identify the specific results that would change the call, and the SSO impact is asserted rather than treated as unknown.

Gemini 3.5 Flash-Lite · Gemini

It does not name the specific unknowns that could change the decision or tie the monitoring to what would settle the call.

Produces the required deliverableMixedRightRight
Gemini 3.8 Flash · API

The reply is not usable as-is because it overstates causality, omits the required uncertainty framing, and includes invented actions.

Sonnet 5.5 · API

The reply is complete and usable as a channel update, with an answer, evidence, and next steps.

Gemini 3.5 Flash-Lite · Gemini

The reply is in the right channel format, addressed to Lena, under 200 words, and usable as a status update.

Separates effect from explanationWrongRightWrong
Gemini 3.8 Flash · API

Possible causes are presented as data-backed factors rather than labelled hypotheses with evidence and contradictions.

Sonnet 5.5 · API

Seasonality, navigation, support friction, and SSO are each labelled as hypotheses with supporting or contradicting evidence.

Gemini 3.5 Flash-Lite · Gemini

It lists SSO outage, navigation friction, and seasonality as 'what happened' rather than clearly labelling them as hypotheses with supporting or contradicting evidence.

Ready for the reader as deliveredMixedRightRight
Gemini 3.8 Flash · API

It includes invented current actions and unsupported causal statements, so it should not go to Lena without substantive correction.

Sonnet 5.5 · API

Written for Lena, no placeholders, and names and dates are from the material or clearly proposed.

Gemini 3.5 Flash-Lite · Gemini

It is written for Lena, uses no placeholders, and all dates and owners are taken from the material or clearly proposed.

All got wrong 3

Addresses the actual decisionWrongWrongWrong
Gemini 3.8 Flash · API

It commits early that navigation is not the primary driver but does not say what result or condition would change that answer.

Sonnet 5.5 · API

It commits to 'partly, but navigation probably isn't the main driver' but never states what result or condition would change that call, only lists analyses.

Gemini 3.5 Flash-Lite · Gemini

It does not say what result or condition would change the answer; it only says it will monitor and share a breakdown.

Avoids unsupported claimsWrongWrongWrong
Gemini 3.8 Flash · API

It presents navigation not being primary, SSO contributing, and expected rebound as established or near-established rather than labelled hypotheses.

Sonnet 5.5 · API

It presents 'Most would have come back later in the week' and 'small next to about 1,100 lost teams' as fact without support.

Gemini 3.5 Flash-Lite · Gemini

It presents causal interpretations such as the SSO outage directly impacting engagement and navigation being a factor as established fact, though the evidence only suggests them.

Owns the problemWrongWrongWrong
Gemini 3.8 Flash · API

It proposes tooltips and an analysis but does not provide already-taken actions with a recommended option and trade-off for each material problem.

Sonnet 5.5 · API

It reports support-ticket friction and SSO outage but does not say what the team has already done, only future fixes and analyses.

Gemini 3.5 Flash-Lite · Gemini

It reports the SSO outage but does not say what the team has already done about it or recommend a way forward for that specific problem.

All got right 1

Answers the question askedRightRightRight
Gemini 3.8 Flash · API

The first line directly answers whether the new navigation caused the drop.

Sonnet 5.5 · API

It answers in the first line that navigation is partly responsible but probably not the main driver.

Gemini 3.5 Flash-Lite · Gemini

The first lines answer the question by saying the new navigation is a factor but not the whole story.

Results

Every setup we’ve tested on this task, across all cases and repeats, graded on the current checklist. Calibrated: the graders match our PM on 80% of checks.

#Model · HarnessTask scoreDecision modelLLM judgeRunsCritical failures
1GPT-6 AstraChatGPT86.787.12None
2GPT-6.1 SolAPI75.883.02None
3GPT-6 LunaAPI73.882.62None
4Opus 5.5Claude80.451.92None
5Sonnet 5.5API68.864.42None
6Gemini 3.5 Flash-LiteGemini62.139.02None
7Gemini 3.8 FlashAPI44.837.92None

The PM job

Writing the weekly update, or the reply to an executive's question, that the team's credibility rests on.

Why it matters

Updates are where bad news gets softened. A fluent update that buries a slipped date or presents a guess as the cause does more harm than no update: leadership decides on it, and trust goes when the truth comes out.

What good looks like

  • Leads with the news and any decision needed
  • States dates, numbers and causes plainly, including bad news
  • Separates what is known from what is suspected
  • Brings a recommendation and what's been tried, not just the problem
  • Fits the reader and the length asked for

Deliberately not measured

  • Tone and formatting preferences
  • Writing style beyond clarity
Capability tested

Honest, decision-first status communication

The failure we’re looking for

Spin: burying or softening the bad news, or presenting a guess as fact

Grading

Decision model, LLM judge and a browser check (for the deck), calibrated against a blind PM review

Variants

A short written update · Staff level: a QBR deck in brand colours