codebase-diagnostic

codebase-diagnostic

You've inherited a codebase and a deadline, and need to know what to actually work on.

When to use

• You've inherited an unfamiliar codebase and a fixed amount of time.
• You want a ranked list of what to work on, not a generic "best practices" lecture.
• You can say what success looks like — even roughly — before you start.

Prompt template

Review my codebase. I have <N weeks> and success looks like <criteria>. What should I work on?

What you get back

A prioritised diagnosis that refuses to start until it has your time horizon and what success means — then ranks the work against those two things, instead of handing back a generic best-practices checklist.

Method

The generalised discipline:

1. Gate on inputs. Refuse to start without a time horizon and a success definition.
2. Rank against those two things. Pain × effort, scoped to the clock.
3. Say what to defer. An honest "not in this window" beats a fake-complete plan.

Verify it's working

Confirm the skill actually fires — in your own session, on your own data. No data leaves your machine.

1. Does it fire? Paste the prompt in demo-input.md. You should get the shape shown in expected-output.md.

2. On your data. Run it on your real input.

3. Confirm the shape. Save the output to a file and run:

   node ${CLAUDE_SKILL_DIR}/scripts/check.mjs <your-output-file>
   

   It reports ENGAGED when the output carries this skill's characteristic structure — the deterministic sign it fired. It checks shape, not quality; judge the content yourself.

The check runs entirely locally — nothing leaves your machine. If you want to add to the public "confirmed working" count, opt in explicitly:

node ${CLAUDE_SKILL_DIR}/scripts/check.mjs <your-output-file> --report https://skills-field-guide-proxy.nesper6311.workers.dev --skill codebase-diagnostic

That sends only an anonymous +1 — never your input, output, or identity.

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Installed from the public field guide. Customize freely — this is a starting point built from the published projection of codebase-diagnostic.