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Capstone: Mock Loop1 / 3

1 min lesson

Run the clock

Describe what "Force yourself through five phases in order" changes in practice.

Step 1 of 3

Run the clockDrill protocol

Force yourself through five phases in order. The discipline is refusing to skip ahead to a fix the moment you have a guess.

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Full explanation

The Five-Phase Debug Method

THE FIVE-PHASE DEBUG METHOD

Interactive diagram. Step through it with the Next and Previous controls below, or Tab to a region to read its detail.

diagram: flow

Resolve/escalate is the quality gate - you don't pass it until you can name the cause.

Interview move

Narrate the why behind every step, not just the step. “I'm disabling extensions first because a conflicting language server is the cheapest thing to rule out and it explains both the lag and the CPU spike.” Interviewers can't grade silent thinking. The narration is the deliverable.

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Full explanation

What good narration sounds like

What good narration sounds like

A slow-Tab scenario, thinking out loud
Symptom: Tab suggestions lag ~4s, only on the work laptop.

Hypothesis 1: network - corporate proxy buffering the stream.
  Check: does it lag off-VPN? -> No lag off-VPN. Strong signal.
  Check: is the proxy stripping chunked transfer? -> HAR shows
         the response arriving in one block, not streamed.

Root cause (not symptom): proxy is buffering the streamed
  completion, so nothing renders until the full response lands.
  "Slow Tab" was the symptom; proxy buffering is the cause.

Resolve: allowlist the API host / disable buffering for it,
  or escalate to their network team with the HAR as evidence.
Watch out

The fastest way to fail is to fix the symptom. If you tell the user to restart and the lag returns tomorrow, you treated a cause you never found. Restarting clears state, it doesn't explain anything. Always be able to say what was actually wrong.

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Advanced table

Score your own tape

Score your own tapeSelf-rubric

Dimension
Asked for environment
Pass looks like
Pulled OS, version, network, account in the first two minutes
Red flag
Started guessing fixes with zero context
Dimension
Method
Pass looks like
Clarify → reproduce → isolate → root-cause → resolve, in order
Red flag
Jumped straight to a fix on the first hunch
Dimension
Symptom vs cause
Pass looks like
Named the underlying cause, not just the visible behavior
Red flag
“Tell them to reinstall” with no explanation of why
Dimension
Communication
Pass looks like
Narrated hypotheses and what would confirm each
Red flag
Long silences or jargon with no plain-language anchor
Dimension
Clean handoff
Pass looks like
Escalation has repro, environment, logs and what was ruled out
Red flag
“Couldn't figure it out, sending to Eng” with no notes

Watch the recording with this open. Mark the timestamp of every red flag.

Then redo it once. Same scenario or a fresh one, but this time fix your single weakest step on purpose. Most people find their gap is the same every run: they skip environment or they narrate the what and never the why.

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Optional practice

Practice: Run the clock

QIn a live troubleshooting round for slow Tab suggestions, what is your highest-value first move and why?