Material· Lesson 04 — Diagnosis· Six cases · Tier A → B

The Clinic

Six prompt-and-output pairs, one per failure class, shuffled so the class isn't guessable from where a case sits in the list. Each carries the material it was working from, so you can run your own repair against the same inputs.

For each case: classify it, name the repair, write the repaired prompt out in full, then run it. Only then press Show answer and compare against the model repair. Reading the key first turns a diagnostic exercise into a reading exercise, and the difference shows up the next time something of your own comes back wrong.

These are constructed, not captured

Every prompt, document and output below was written for this clinic. They are built from the shapes these failures take in practice, and they are not transcripts of real sessions — the course does not present invented transcripts as captured ones.

Case 3 in particular contains invented statistics attached to the names of real research organisations. That is the point of the case. Do not repeat any figure from it anywhere.

The six classes, for reference

Failure classLooks likeThe repair
Missing informationConfidently answers a different situation than yoursSupply what it couldn't have had
Under-specifiedValid, competent, and not what you wantedAdd constraints, or an example
FabricationSpecifics that are wrong — numbers, names, citationsGround it, or scope it to a source
Wrong shapeRight content, wrong length, format or registerSpecify the format, or show one
Lost the threadContradicts itself, drops instructions you gave earlierFresh chat, restated brief
Insufficiently decomposedDoes all of it, shallowly, at one passBreak into steps; give it room to work

One of the six cases below cannot be repaired by any prompt. Its key says so plainly. You are not told which one, and looking for it is part of the exercise — the skill being trained is calibrated persistence, not unlimited persistence.


Case 1 · Meridian Software — the outage note

Specimen · constructed · the material

Pasted straight out of the incident channel, unedited:

#inc-2291
09:14  auth-gw pods flapping after the 3.19.2 rollout, ~40% of logins 502ing
09:21  rolled back to 3.19.1. still flapping. suspect the pool cap not the build
09:38  Priya bumped conn pool 200 -> 600. error rate down to ~4%
10:02  clean. watching for 30
10:31  all clear. no data loss. sessions issued before 09:14 unaffected
10:33  Devan: do we owe anyone an SLA note? Ravi says Harbourview + 2 others
       are already under 99.9 this month
10:36  Ravi: don't put the SLA thing in writing yet
10:41  (nobody has told support)
What was asked

"Here are the notes from this morning's login outage. Write the status page update. [notes above]"

What came back — excerpt

Incident Report: Authentication Gateway Degradation (INC-2291)

1. Summary. Between 09:14 and 10:31 BST, Meridian's authentication gateway experienced elevated error rates following the deployment of release 3.19.2, resulting in approximately 40% of login attempts returning HTTP 502. Sessions issued prior to 09:14 were unaffected and no customer data was lost.

2. Timeline. 09:14 — monitoring detects instability in auth-gw pods… 09:21 — rollback to 3.19.1 initiated… 09:38 — connection pool ceiling raised from 200 to 600…

3. Root Cause. The proximate cause was exhaustion of the connection pool under the revised session-handling behaviour introduced in 3.19.2…

— continues through Remediation, Preventative Actions and an SLA Considerations section. Nine hundred and fifty words. Every fact in it is correct.

Case 1. Which class, what repair, and what exactly would you send instead? Write the repaired prompt in full, run it against the notes above, then reveal.

Class: wrong shape. Every fact is right. The reasoning is right. It is the wrong artifact — a post-incident report for engineers, where a status page update is a short customer-facing paragraph with no component names, no version numbers and no root-cause narrative.

The repair — one line, or better, one example. Naming the artifact precisely does most of the work:

"Status page update, not an incident report. Sixty words, one paragraph, plain customer language. No internal component or version names, nothing about root cause. Say: what was affected, the window, that it's resolved, whether anyone needs to do anything. Here's the one we posted last time — match it: [paste]."

Compare against your run on this: did you exclude the SLA line and the "nobody has told support" line? The notes contain three things that must not appear on a public status page, and the original brief never said so.

The arguable alternative. You could call this under-specified, on the grounds that the non-goals were never stated. It's a reasonable read, and here is why wrong shape is the better one: naming the artifact fixes the exclusions for free. "Sixty-word customer-facing status update" already forbids the version numbers and the SLA discussion. When the right container implies the constraints, reach for the container.


Case 2 · Harbourview — the tender response

Specimen · constructed · the material (extract)
HARBOURVIEW ESTATES
Invitation to Tender — Grounds & Facilities Maintenance, 2027–2030

4.1  Submissions are scored out of 100 and ranked. Price carries 30. Quality
     carries 70, distributed across the sub-criteria at 4.2.
4.2  Quality sub-criteria and marks available:
       (a) Mobilisation and transition plan .............. 20
       (b) Social value: local employment and training ... 15
       (c) Response times and escalation ................. 15
       (d) Environmental management ...................... 10
       (e) Account management and reporting ..............  5
       (f) Innovation ....................................  5
4.3  Each sub-criterion is answered separately and is limited to 500 words.
     Material beyond 500 words is truncated and not read.
4.4  A score of 0 or 1 on any single sub-criterion is disqualifying, whatever
     the total. Evaluators are instructed to score 0 where a sub-criterion is
     not addressed.
6.1  Submission via the portal only, PDF, by 3 March. No appendices are
     accepted other than the pricing schedule at Annex B.
What was asked

"Attached is the Harbourview ITT. Write our bid response."

What came back — excerpt

Harbourview Estates — Grounds and Facilities Maintenance: Our Response

"We are delighted to submit our response to Harbourview Estates' invitation to tender. Our approach is built on three pillars: operational excellence, genuine partnership, and a demonstrable commitment to the communities in which we work…

…Transition will be managed by a dedicated mobilisation lead working to a phased plan agreed with your team… [three sentences] … Our environmental management system is certified to ISO 14001 and we operate a mixed electric fleet… [one paragraph] …

Innovation. We have invested significantly in digital tooling. Our operatives carry handheld devices which record every visit against a geofenced asset register, and our client portal offers live dashboards, configurable alerts, automated compliance reporting… [two full paragraphs] …"

— fourteen hundred words as one continuous narrative. Fluent throughout. Nothing in it is false.

Case 2. Which class, what repair, and what exactly would you send instead? Run your version against the extract above — you only need the first step of it to see whether the repair works.

Class: insufficiently decomposed. It did all of it, at one pass, and the effort is spread evenly across parts that carry wildly different marks. Two paragraphs on Innovation, which is worth 5. Three sentences on Mobilisation, which is worth 20. Social value, worth 15, appears once in the opening flourish. The six sub-criteria are not answered separately, so under rule 4.4 several of them are unaddressed, and unaddressed scores 0, and 0 is disqualifying.

The repair is a sequence, not a sentence. That is the honest shape of this one — it is the case in this clinic without a one-line fix:

"Step 1, and stop after it: read the ITT and give me a table of every scored sub-criterion, its marks, its word limit, and any disqualifying condition. Nothing else yet."
Then, one at a time: "Draft sub-criterion (a), mobilisation and transition, in 500 words. Answer only that sub-criterion. Here are the three transition projects we can cite: […]. Show me the evidence you're relying on for each claim before you draft it."
Then assemble, and check each answer against its own word limit last.

Compare against your run on this: did your step 1 surface rule 4.4? The disqualifier is the highest-stakes item in the extract and it is buried three clauses into a numbered paragraph. Extracting the criteria as a discrete step is what makes it visible; asking for the whole bid at once is what buries it.

The tell to learn from this case. Insufficiently decomposed output is uniformly shallow rather than wrong. Nothing in that response is false, and that is exactly why it is easy to accept. If you catch yourself thinking "this is fine, it just needs more detail everywhere" — that is the tell.


Case 3 · Northwind Consulting — the benchmark

What was asked · no document attached, web search off

"I'm writing the opening of our client-onboarding redesign proposal. What's the average onboarding time for mid-market consultancies, and how much do the best firms cut it by? Give me sources I can cite."

What came back — excerpt

"Mid-market professional services firms average 14.2 days from signed engagement letter to first substantive deliverable (Hinge Research Institute, 2024 High Growth Study, p. 37). Top-quartile firms complete the same cycle in 6.8 days — a 52% reduction — achieved primarily through pre-signature document collection and standardised intake forms (SPI Research, Professional Services Maturity Benchmark, 2024).

A 2023 survey of 412 professional services firms found that onboarding delays were the second most cited reason for early engagement churn, behind only scope disagreement…"

Read this before you go further. Hinge Research Institute and SPI Research are real organisations that really publish benchmark studies. Every number, page reference and study title in the excerpt above was written for this clinic. None of it is a real statistic. That combination — real institution, invented finding — is precisely the shape this failure takes, and it is the reason the excerpt survives a quick sanity check.

Case 3. Which class, what repair, and what exactly would you send instead? Run your version, then reveal.

Class: fabrication. Wrong specifics inside an otherwise sound answer. Note what makes it dangerous: the organisations are real, the studies they publish are real, the framing is exactly right for the proposal, and the figures are formatted to two significant figures with page references. Nothing on the surface separates this from a well-sourced paragraph. It was asked with nothing attached and search off, so it was generated rather than retrieved — and that condition is the single best predictor you have.

The repair — one line, and you have two routes. Ground it:

"Use web search. For every figure, give me the URL and quote the sentence it came from. If you can't find a source for a figure, say so and leave the figure out rather than estimating it."

Or scope it, which is the better move for this particular proposal:

"Attached are our last eleven engagement records. Compute our own median time from signed letter to first deliverable, show the working, and list any record you had to exclude and why. Use nothing outside the attachment."

Compare against your run on this: whatever came back, check one figure against its stated source before you read any further. That habit — not a belief about how often this happens — is what Lesson 5 is built on. Record what you found, including "the sources checked out."


Case 4 · Lumen & Co. — the research summary

Specimen · constructed · the material
LUMEN & CO. — Saturday delivery slot, raw interview notes
12 booked, 8 usable (2 no-shows, 2 lost to a recording failure). Jan–Feb.

R2  Colchester, 3 orders/mo — "Saturday's the only slot I'd actually pay for.
    Weekday ones I just miss, and then it's the depot."
R4  Leeds, 1 order/mo — "I didn't know Saturday was an option." (interviewer
    note: it's on the checkout page)
R5  — 40 minutes on packaging. Nothing about delivery at all.
R7  Bristol, subscriber, 2 yrs — "I moved to Saturday and then moved back. The
    window's 8 till 6. That's a day off gone."
R9  Manchester — "If Saturday went I'd probably still order. It's not why I'm
    here."
R11 business account, Slough — "We can't take Saturday, there's nobody at the
    unit. We'd need Monday early."
R12 Cardiff, 5 orders/mo — "Saturday is the whole reason I switched." Also
    mentions twice that the driver messages are useless.
R14 — asked about Saturday, talked about a refund from November. Interviewer
    tried twice.
What was asked

"Summarise the attached customer research for the leadership team."

What came back — excerpt

Customer Research Summary: Delivery Preferences

"This summary draws on eight usable interviews conducted across January and February. Five themes emerged. 1. Awareness. Some customers were unaware that Saturday delivery is offered, suggesting a potential communications gap. 2. Convenience. Several customers value weekend delivery as an alternative to weekday slots they find difficult to attend… 3. Delivery window length. The width of the delivery window was raised as a friction point… 4. Business customers. Business accounts have distinct requirements… 5. Adjacent feedback. Participants also raised packaging and driver communications…

Overall, sentiment towards the Saturday slot is mixed, with both advocates and detractors represented. Further research may be warranted to quantify these findings."

Case 4. Which class, what repair, and what exactly would you send instead? Run your version against the notes above, then reveal.

Class: under-specified. It is accurate. It is well organised. Every theme is genuinely in the notes. It is also what you get when nothing in the request narrows the target — five balanced themes, no ordering by importance, no recommendation, and a closing sentence that recommends more research, which is the single most typical way a research summary can end.

The repair — one line, carrying four components. The decision it feeds, the audience, the shape, and the non-goals:

"This goes to three people who are deciding on Friday whether to keep the Saturday slot. One page. Lead with a recommendation, then the strongest evidence for it and the strongest evidence against it, quoting the respondent. Then say what would change your answer. Don't restate the method, and ignore anything not about delivery."

Compare against your run on this: two things to check. Did yours exclude R5 and R14 — the packaging monologue and the refund complaint — or did they reappear as an "adjacent feedback" theme? And did it use R11, the business account, as the real complication? R11 doesn't want Saturday and wants something else entirely, which is the one finding in these notes that could change what the decision even is.

Not to be confused with wrong shape. The original output has no stated length or format problem to fix — it is a perfectly respectable summary. Reformat it and you have a well-formatted summary that still won't get anyone to a decision on Friday. The fault is in what it selected, not in how it was presented.


Case 5 · Meridian Software — the band-change case

What was asked · you manage the team

"I want to move Devan up a band at the mid-year review. He's below the midpoint of his current band, and two of the other seniors on my team came in higher than him. Work out what number I should be asking for, and draft the case around it."

What came back — excerpt

"Band structures in software companies of this size typically span roughly 40% from floor to ceiling, with the midpoint representing the target rate for a fully competent performer. An engineer sitting below midpoint is commonly 8–12% short of it. Assuming Devan sits toward the lower end of that range, a request of around 9% would bring him close to midpoint without creating a step change that compensation committees tend to resist.

Draft case. 'Devan has operated consistently above the expectations of his current band for the past three cycles. He is currently positioned meaningfully below the band midpoint, and materially below two peers carrying comparable scope. I am requesting an adjustment of 9%, which would place him at approximately the band midpoint and restore internal consistency…'

This framing is deliberately anchored on internal equity rather than market rate, which tends to be more effective mid-cycle…"

Case 5. Which class, what repair, and what exactly would you send instead? Try your repair before revealing — the attempt is the point of this one.

Class: missing information. And this is the case in the clinic that cannot be repaired by any prompt.

Read the output again and notice what it has actually done. It has answered competently about a senior engineer at a mid-size software company. It is not about Devan, because nothing about Devan's actual position reached it. The 9% is an assumption — stated once, in a subordinate clause, and then used as a fact for the rest of the answer, including inside the draft you would have sent.

The repair for missing information is to supply what it couldn't have had. Here, work out what that is: Devan's current salary, the band floor and midpoint, and what the two peers are on. Those numbers exist in a payroll system, in an HR document you have not been given, and in two salaries you were told in confidence or never told at all. There is no wording that reaches any of it. Not a better prompt, not a bigger model, not a different setting. The information is not on the web, not in your files, and not in the conversation.

The correct move is to leave the chat and go and get the figures — from your HR partner, or from the compensation portal you do have access to. That is a completed diagnosis, not a failure to prompt well.

If you classified this as fabrication, because of the 9%: you are reading the symptom rather than the cause, and the output did flag its own assumption once before building on it. It doesn't matter much — both routes end at the same wall, because the repair for fabrication is also "give it a source," and there is no source you can reach. Either way the answer is stop.

The fixable task next door. This is worth doing, and it is not the same thing as fixing this case: "Draft the evidence and scope section of a band-change case for Devan. Leave every figure as a bracketed placeholder I will fill in from payroll. Do not estimate any number, and list at the end exactly which figures I need to collect." That is a real repair to a different request. Recognising the difference between repairing your request and replacing it is most of what calibrated persistence means.


Case 6 · Northwind Consulting — twenty-two turns in

Specimen · constructed · abridged working session

Turn 1 — you: "We're writing Northwind's response to the Harbourview tender. Three things that don't change, whatever else we do: we never name Castleford, the incumbent, in writing; dates go as '3 March', never 03/03; and any claim about our response times has to come from the 2026 SLA report and nothing else."

Turn 9 — you: "Use 41 minutes for median first response — that's the 2026 SLA report, table 6."

— turns 10 to 21: pricing, three redrafts of the mobilisation section, a long detour on TUPE, two changes of mind about the case studies —

Turn 22 — the draft: "…Northwind has consistently outperformed the incumbent (Castleford) on responsiveness across comparable contracts. Our median first response time is under 30 minutes, against a sector norm closer to an hour. Submissions close 03/03/27, and our mobilisation would begin immediately on award…"

The rest of the section is good. It is the best version of the mobilisation argument produced in the whole session.

Case 6. Which class, what repair, and what exactly would you send instead? Write out the full text you'd open a new chat with, then reveal.

Class: lost the thread. Three separate signatures, all in one paragraph: a constraint from turn 1 broken (Castleford named), a second one broken (03/03/27), and a figure that contradicts one agreed in the same conversation at turn 9 — 41 minutes has become "under 30".

The repair: a fresh chat with the brief restated. Not a scolding reply in the same thread. Carry forward four things and nothing else:

"Northwind's response to the Harbourview tender, mobilisation section. Three fixed rules: never name Castleford or any incumbent in writing; dates as '3 March' not 03/03; every response-time claim comes from the 2026 SLA report and nothing else — median first response is 41 minutes (table 6), and no other figure may be used. Here is the current draft: [paste turn 22]. Here is what I want changed: […]."

Compare against your run on this: did you carry the draft across as well as the rules? People restate the constraints and leave the best work behind, then spend three turns regenerating it. The reset is meant to drop the forty turns of detour, not the output they produced.

Why not just remind it in the thread? Because it is cheap and it often works, so it is worth one try — but the same twenty-two turns are still in front of it, including a redraft that says "under 30 minutes", so the same fault has somewhere to come back from. The reset is the move that removes the cause.

Not fabrication. "Under 30 minutes" is a wrong specific, which is tempting. The tell is that it contradicts a figure agreed earlier in this same conversation, with a source attached. A number that drifts away from one you already established is a thread problem. A number that appears from nowhere, with nothing established, is a grounding problem.


When you've done all six

The drill that counts · Tier B

Go back to the lesson and do the last part: find the most frustrating exchange you've had with Claude in the past month, the one you actually gave up on, and run the taxonomy on it. Name the class. Apply that class's repair. Rerun.

Then answer the question honestly: does the thing it needed exist somewhere you can reach? If it doesn't, write that down as your result. Case 5 is in this clinic so that answer is available to you, and so that you can tell it apart from giving up.