AI systems foundations · Lesson 15 of 15 · 9 min

Foundations review checkpoint

A sound system review connects one observed failure to a component, its evidence and a reversible next step. Do not turn a system map into an unsupported diagnosis.

Open the lab Course map

Mastery 0/3Run itExplain itApply it

learner@clairos:~ $

↑ history · Tab complete · Ctrl+C cancel · Esc, Tab to leaveExit 0

Your objectives

Hints are always available. Wrong turns never cost XP.

1
Read the case evidence
Read /opt/ai-lab/cases/aiops-systems-foundations-015.json. Separate the recorded facts from your assumptions.
Hint & worked example
A sound system review connects one observed failure to a component, its evidence and a reversible next step. Do not turn a system map into an unsupported diagnosis.
The complete case JSON is read successfully.
```
cat /opt/ai-lab/cases/aiops-systems-foundations-015.json
```
Common mistake to avoid: Replace every model and erase the index evidence.
2
Isolate the deciding signal
Select the evidence field from the case JSON. What does it establish—and what does it not establish?
Hint & worked example
Review restoration of the missing index while retaining the healthy model artifact.
A successful JSON query isolates evidence.
```
jq .evidence /opt/ai-lab/cases/aiops-systems-foundations-015.json
```
Common mistake to avoid: Using a different case or an unrelated signal as the justification.
3
Record your operational decision
Choose the justified code: restore-index, change-without-evidence, or ignore-the-signal. Save that one code followed by a newline in /home/learner/lab/aiops-systems-foundations-015-decision.txt.
Hint & worked example
Review restoration of the missing index while retaining the healthy model artifact.
The decision artifact contains the correct code, not just a matching command in history.
```
printf '%s\n' 'restore-index' > /home/learner/lab/aiops-systems-foundations-015-decision.txt
```
Common mistake to avoid: Replace every model and erase the index evidence.

Understand the pattern

A sound system review connects one observed failure to a component, its evidence and a reversible next step. Do not turn a system map into an unsupported diagnosis.

Interpret the evidence

Review restoration of the missing index while retaining the healthy model artifact.

A tempting mistake

Replace every model and erase the index evidence.

All names, measurements, prices, versions, and thresholds in this exercise are fictional training data. The evidence supports this bounded scenario, not a claim about a live provider.

Worked example and expected result

$ cat /opt/ai-lab/cases/aiops-systems-foundations-015.json

{
  "fixture": "Fictional training data; not a live measurement.",
  "failed_component": "retriever",
  "evidence": "index_missing",
  "model_status": "ready",
  "rollback_available": true
}

Exit status: 0. The command completed successfully in the training fixture.

$ jq .evidence /opt/ai-lab/cases/aiops-systems-foundations-015.json

"index_missing"

Exit status: 0. The command completed successfully in the training fixture.

$ printf '%s\n' 'restore-index' > /home/learner/lab/aiops-systems-foundations-015-decision.txt

(no output; exit 0)

Exit status: 0. The command completed successfully in the training fixture.

Try a variation

Name the assumption that would have to change for “restore-index” to stop being the justified action. Do not silently replace missing evidence with a guess.

Explain it

What does the evidence in “Foundations review checkpoint” justify?Review restoration of the missing index while retaining the healthy model artifact.Replace every model and erase the index evidence.Make the change now and gather the missing evidence afterward.

Apply it elsewhere

A colleague concludes: “Replace every model and erase the index evidence.” What should you do?Accept it because the training command completed.Treat this fixture as a live measurement.Reject that conclusion; return to the case evidence and its stated limits.

Keep the momentum.

Complete the lab, then explain and apply the pattern.

Review this course Try an incident drill

Anonymous lesson and mastery progress lasts for this session. Sign in to keep synced lesson XP between sessions; mastery stays device-local. No speed bonus, lost lives, or hint penalties.

Keep learning

01Write a system baselineA reproducible baseline records artifact, configuration, dataset and environment versions together. Keeping only an average score makes later comparisons ambiguous.Practice

Case methodology: evidence, limits, decision