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9 min · skills

Port a skill across Claude and ChatGPT

Goal: Extract the portable core, strip product-UI sentences, and twin-test the same input on both sides.

Best for: you liked a skill in one app and want the same habit in another.

Products name things differently (Custom GPT, Project, Skill, Gem-like assistants). The portable core is: purpose, Done checklist, steps, examples, and boundaries—not the file format logo.

You will click different menus; keep one “source of truth” note you copy from.

Why beginners skip this

Pasting a skill straight into another host feels easy—tool names and boundaries silently break. Diff the checklist before port.

Step 1 — Extract the portable core

From the existing skill/GPT/Project, copy purpose, inputs, outputs, steps, examples, and never-do.

Here is my current assistant/skill text:
[paste]
Extract a portable core:
Purpose · Inputs · Outputs · Steps · 1 example · Never-do
Strip product-specific UI words.
Example

Filled prompt

Paste this Custom GPT instruction that formats weekly status emails.
Extract portable core: Purpose · Inputs · Outputs · Steps · 1 example · Never-do.
Strip ChatGPT-only UI words (“GPT Store”, “Create a GPT”).
Never-do must keep: do not invent metrics; draft only.
Instruction: [paste]

What good output looks like

  • No leftover “click the GPT Store” or Claude-only UI steps
  • Steps are model-facing rules (Goal / Format / Boundaries)
  • Never-do includes inventing metrics and silent sends
  • Weekly-status job still clear in one sentence
  • Works as Project instructions or GPT instructions without edits to foreign UI

Step 2 — Map clicks in the other product

Write a five-click checklist in the other product; delete foreign UI steps.

Write a beginner click checklist to recreate this skill in [Claude Projects / ChatGPT Custom GPT].
5–8 steps, starting from the home screen. Include where to paste instructions and where to upload reference files.
Example

Filled prompt

Write a 6-step click checklist for Claude Projects to host the weekly-status skill.
Start from the Claude home screen. Include: create/open Project, where to paste standing instructions, where reference docs go, how to run a test prompt, how to share with one teammate read-only if available.

What good output looks like

  • Checklist starts at the correct product home
  • Says exactly where to paste the skill text
  • Mentions knowledge/files upload only if the job needs it
  • Six steps a beginner can click without a tour
  • No cross-product button names that do not exist there

Step 3 — Twin test with the same example

Run the same filled example in both places; diff outputs and fix the weaker instructions—do not tune only one side.

Compare two outputs for the same input.
Input: [same example]
Output A: [paste]
Output B: [paste]
List 5 gaps and which side’s instructions to patch.
Example

Filled prompt

Skill card works in Claude Project instructions. Port checklist to ChatGPT Custom GPT/Project:
what transfers, what breaks, golden test to rerun, secrets still placeholders.
Return 7 bullets.

What good output looks like

  • Compares structure, tone, and missing sections on the same input
  • Gives actionable patches to the thinner side
  • Does not vaguely blame “the model”—patches the thinner home instead
  • Flags any invented metrics in either output
  • Ends with one next test prompt to re-run

Portivity test

After porting, run the same filled example in both products. Diff the outputs. If one invents a metric the other refused, your never-do did not travel—paste it again at the top.

Compare structure, then patch

After porting, ask for a diff of structure/tone/missing sections between the two outputs on the same input. Patch the thinner home. Do not vaguely blame “move the same reusable workflow between products”

Red flag

Pasting UI clicks unchanged across hosts; never-do list dropped on port—rewrite for the new home.

Save this card

Card: port job + never-do · rewrite UI steps for the new host. Do not paste raw clicks across products.

Before you start

Open the skill card (or blank one-pager). Purpose must be one job for “move the same reusable workflow between.” Golden example slot cannot stay empty. Guide: skills-port-across-claude-chatgpt. Keep the real job visible the whole time; a blank box means stop and fetch the artifact first.

How to use this week

This week port a real skill to a second host: diff tool names / boundaries / fixtures; no “port done” until the fixture passes.

Pitfalls

PitfallFix
Copy-pasting UI screenshots as the skillPort the rules, not the pixels
Assuming tools/plugins exist on both sidesFeature-check first
Never twin-testingSame example both places
Example

Filled prompt

Temptation: skip the habit for skills-port-across-claude-chatgpt to save five minutes.
Job still: move the same reusable workflow between
Smallest correct pass: Done visible · checkable artifact · Unknowns [?].
Boundaries: draft only; no silent send; no invented metrics.
Return: artifact + refuse-line said aloud.

What good output looks like

  • Names the shortcut refused (specific to skills-port-across-claude-chatgpt)
  • Still delivers checkable output for “move the same reusable workflow between”
  • Unknowns labeled; draft-only
  • Pass/fail: refuse-line dated (skills-port-across-claude-chatgpt #4)

Practice now

Adapter note: one adapter paragraph for the weaker side (Asia/Shanghai).

Parity table: three rows feature|Claude|ChatGPT (Asia/Shanghai).

Gap list: three features that will not port (Asia/Shanghai).

Port drill: list what breaks when porting one skill across tools (Asia/Shanghai).

Thin-spot drill: rewrite the Save card with real nouns from your work (repo, doc, inbox). Generic placeholders fail the drill.

Tonight pick a real skill, adjust triggers and permissions against a diff table, then run fixtures.

Close the loop

Write one line: next time I paste with no checklist diff, I refuse to call the port done.

One sentence takeaway

Diff tool names / boundaries / fixtures; no “port done” until the fixture passes.

Word-floor practice

Run the Today card once on a real artifact. Write pass/fail + never-do with date Asia/Shanghai. If you only skimmed, do not mark this guide done.

Next

Team shared library · Skills vs GPTs vs Projects

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