Claude prompt for code generation: Type Narrowing (Advanced)
Claude · Code Generation · Advanced
You are a hands-on practitioner using Claude for code generation, specifically type narrowing.
Job: make invalid hard.
Audience: ts/python. Constraint: examples.
Working style: precise and demanding. Optimize for constraints, evaluation, and edge cases.
Process:
1. Restate the brief in one sentence and list missing facts as questions.
2. Draft the artifact.
3. Stress-test it against the constraint.
4. Return a final version plus 3 numbered improvements.
Output contract: use headings, short paragraphs, and concrete examples. No filler. No invented statistics.
If information is missing, make the smallest reasonable assumption and label it.A strong Claude code generation type narrowing prompt names the job, audience, and finish line. This page does that for ts/python. In practice, one customization pass is enough when the brief is this specific. The advanced version uses precise and demanding language and targets constraints, evaluation, and edge cases.
When to use this prompt
For Anthropic models, code generation prompts fail when they mix strategy and execution. This type narrowing brief separates the job so you can iterate once, not ten times. Pair it with a real sample from your portfolio for best results.
Why this prompt works
- The advanced angle adds constraints, evaluation, and edge cases without extra fluff.
- Locks the audience (ts/python) before style so tone stays honest.
- Repeats the hard constraint: examples.
- Centers make invalid hard so success is observable.
- Forces an output contract: headings, examples, and a final version.
How to use it in Claude
When ts/python review output, they should see constraints, evaluation, and edge cases without hunting for it. Redact client names; keep structure. Slug type-narrowing-advanced is your canonical URL for this brief. Use precise and demanding follow-ups only — mixing tones mid-thread confuses Anthropic models. Name the success metric aloud: make invalid hard. If the draft cannot pass it, do not polish prose yet. Save the winning variant for type narrowing — teams with a short library ship faster.
Start with the ugly first pass for type narrowing. Name what is wrong in five bullets, then rerun in Claude. For type narrowing in code generation, the failure mode is usually no example. This prompt blocks that by design — especially "examples". Expect two minutes customizing and two minutes editing for Advanced output. Anthropic models still need your facts for type narrowing; they cannot invent metrics or brand rules. developers teams bookmark slug type-narrowing-advanced when constraints, evaluation, and edge cases matters.
Step-by-step
- Open Claude and paste the prompt block unchanged.
- Replace placeholders with your project facts (ts/python, offer, timeline).
- Confirm the constraint is still visible: examples.
- For code generation work, paste a rubric and ask for a self-score.
- Reply with one fix list, then regenerate the final version only.
Example output
Example output shape: H1 with Type Narrowing, 3 short sections, bullet list of recommendations, closing line that states examples. Facts you supply appear; nothing invented.
Common mistakes
- Accepting the first draft without checking make invalid hard.
- Using the Advanced prompt but editing it into a vague one-liner.
- Pasting confidential data instead of redacted placeholders.
Expert notes
Practitioners choose Advanced when type narrowing needs constraints, evaluation, and edge cases. Claude from Anthropic still needs your facts — especially for examples.
For code generation, compare this Advanced prompt against the Quick Start and Expert angles on the same use case. Keep the structure that scores higher on make invalid hard.
Comparison / variations
| Approach | When | Tweak |
|---|---|---|
| Bare request | You only need a spark | Write a type narrowing piece. |
| This prompt | You need a usable draft | Role, constraint, steps, and output contract included. |
| Plus examples | Voice must match yours | Paste 120 words of your writing or a still you like, then rerun in Claude. |
Key takeaways
- The Advanced variant is for constraints, evaluation, and edge cases.
- Keep examples visible in the prompt, not only in your head.
- Document what changed when you customized slug type-narrowing-advanced.
- If text output drifts, re-anchor with examples.
- ts/python should recognize themselves in the first paragraph.
FAQ
- What is a Claude prompt for type narrowing?
- It is a structured brief that tells Claude how to produce code generation output for ts/python. This advanced version stresses constraints, evaluation, and edge cases and keeps "examples" in the instructions.
- How do I customize this Claude code generation prompt?
- Swap project nouns, paste one real example, and leave the process steps intact. The constraint "examples" should stay unless your brief truly changed.
- Why use the advanced angle for type narrowing?
- Different angles solve different failures. Advanced helps when ts/python need constraints, evaluation, and edge cases. It is not longer for its own sake — each line has a job.
- Is this Claude prompt updated for 2026?
- Yes. Pages follow our SEO Bible, refresh on a rolling schedule, and include current best practices for Anthropic models. Always verify facts before client delivery.