Module 2: Developer Environment & Tooling: Mistake Clinic

This clinic turns wrong moves into reusable judgment. Use it after each practice page and again before the quiz or checkpoint.

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Module-Specific Mistake Radar

Start with these traps. Replace or extend them with real mistakes from your own work.

Mistake to look for	Where it shows up	Symptom	Repair evidence
Finishing Command-Line Proficiency Workshop with only a final answer	Command-Line Proficiency Workshop	The work has no failed case, trace, test, proof gap, or design stress point.	Add the smallest broken example and show the repair that changes the result.
Finishing Editor Mastery Challenge with only a final answer	Editor Mastery Challenge	The work has no failed case, trace, test, proof gap, or design stress point.	Add the smallest broken example and show the repair that changes the result.
Finishing Environment Setup Automation Lab with only a final answer	Environment Setup Automation Lab	The work has no failed case, trace, test, proof gap, or design stress point.	Add the smallest broken example and show the repair that changes the result.
Finishing Code Katas: Development Environment Fluency with only a final answer	Code Katas: Development Environment Fluency	The work has no failed case, trace, test, proof gap, or design stress point.	Add the smallest broken example and show the repair that changes the result.
Treating Shell Navigation and File Operations (PRIMARY) as vocabulary instead of a tool	Shell Navigation and File Operations (PRIMARY)	The explanation names the concept but cannot decide between two cases.	Write one example, one non-example, and the rule that separates them.
Treating Process Management and Job Control (SUPPORTING) as vocabulary instead of a tool	Process Management and Job Control (SUPPORTING)	The explanation names the concept but cannot decide between two cases.	Write one example, one non-example, and the rule that separates them.

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Practice Mistake Checks

Pull any miss from these checks into your mistake log.

Use these starter checks until the practice pages have dedicated mistake checks:

1. In Command-Line Proficiency Workshop, did I produce only the happy-path artifact without showing the failed command, broken setup, or correction? Repair: reopen practice/01-command-line-workshop.md, force one realistic failure, and record the before/after evidence.
2. In Editor Mastery Challenge, did I produce only the happy-path artifact without showing the failed command, broken setup, or correction? Repair: reopen practice/02-editor-mastery.md, force one realistic failure, and record the before/after evidence.
3. In Environment Setup Automation Lab, did I produce only the happy-path artifact without showing the failed command, broken setup, or correction? Repair: reopen practice/03-environment-automation.md, force one realistic failure, and record the before/after evidence.
4. In Code Katas: Development Environment Fluency, did I produce only the happy-path artifact without showing the failed command, broken setup, or correction? Repair: reopen practice/04-code-katas.md, force one realistic failure, and record the before/after evidence.

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Repair Protocol

For each real mistake:

1. Reproduce the failure on the smallest example, trace, proof, query, command, or design sketch.
2. Name the hidden assumption.
3. Repair the artifact.
4. Save evidence that changed: failing then passing test, corrected proof step, revised diagram, safer command, benchmark, or review note.
5. Add one retrieval card beginning with Check... before... or Do not use... when....

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Mistake Log

Date	Mistake	Symptom	Root cause	Repair evidence	Retrieval card
Starter	Pick one radar row above	Explain how it would fail in this module	Name the assumption	Add a counterexample or corrected artifact	Write the card before closing the page

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Completion Standard

• At least five real mistakes are logged.
• At least two mistakes include a counterexample or failing test.
• At least one mistake connects to an older semester skill.
• At least one correction changes code, a proof, a diagram, a command transcript, a query, or a design decision.