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16 min · foundations

Standing instructions vs each message (system vs user)

Goal: Put “always true” rules in the right place, so you stop retyping the same preface—and keep each user message about the job.

Best for: Beginners who paste “you are a helpful assistant…” every time.

Jargon once: standing instructions (custom instructions, project instructions, sometimes “system” layer) apply across chats. The user message is today’s ask. If you typed a rule three times this week, it belongs in standing instructions.

Why beginners skip this

Mixing standing rules with one-off tasks makes constraints drift. Long-term rules live in standing instructions; task details stay in the user message. Mid-week cost shows up as rework, not as a missing bookmark.

Step 1 — Two layers

  • Standing: tone, language default, ban invented links, “ask ≤3 clarifying questions”
  • User message: Goal / Format / Boundaries / Input for *this* task

Step 2 — Where to click

  • ChatGPT: Settings → Personalization / Custom instructions; or Project → Instructions
  • Claude: account preferences and/or Project → Instructions
  • Grok: product custom instructions / profile if available; else a short rules snippet at the top of important chats

Step 3 — Starter standing block (keep short)

Do this step with a real artifact open—not from memory.

Standing rules:
- Match my language (EN or ZH); do not mix in one sentence
- Prefer short answers; use bullets when listing
- If unsure, say so and list what to verify
- Never invent links or citations
- Ask up to 3 clarifying questions when my ask is ambiguous
- Do not request secrets or raw PII
Example

Filled prompt

(In Project Instructions)
Standing rules: short bullets; no invented links; ask ≤3 clarifying questions; if I attach a file, use only that file unless I say otherwise; no secrets requests.

What good output looks like

  • New Project chats obey length/citation rules without reminders
  • Model asks clarifying questions instead of guessing scope
  • No 2-page persona novel in the user turn
  • Standing block ≤8 lines and dated in your notes
  • Task prompt stays short and about today’s artifact

Step 4 — User message stays about the job

Do this step with a real artifact open—not from memory.

Goal: [one sentence]
Input: [paste or attach]
Format: [bullets / table / email]
Boundaries: [only what is special this time]

If standing instructions already cover tone, do not restate tone—only the job.

Example

Filled prompt

I pasted a 600-word “act as expert” block every turn. Rewrite into: (1) ≤8-line standing instructions for a Project (length, cite sources, say Unknown, never invent metrics); (2) a short user-turn template for today’s task only. Drop the cosplay novel.

What good output looks like

  • 600-word act-as block compressed into ≤8 standing lines
  • User-turn template is task-only (artifact + format + never-do)
  • Unknown rule stays explicit—no invented scope or silent guesses
  • You can reuse the pair all week without re-pasting persona
  • Checks: length obeyed, citations present, no silent guesses

Standing vs turn

Put never-do in standing instructions; keep user turns short and task-specific.

Short standing beats long cosplay

If the model must be reminded of length and Unknown every message, those rules are in the wrong place. Put them once in standing instructions. Use the user turn for the day’s artifact and constraints.

Example

Filled prompt

I still paste a 20-line preface every chat.
Move always-true rules to Project instructions. User message = only today's ask: subject lines for newsletter.
Show the split.

What good output looks like

  • Labels trust/check/stop correctly for “Put “always true” rules in the right place, so you”
  • Does not treat the model as a database or authority
  • Context pack stays ≤ one screen when asked
  • Pass/fail: you can explain the limit in one line

Red flag

Repeating a full persona every message; standing notes stuffed with one-off tasks—split long-term vs task.

Save this card

Card: Standing rules in system/Project space; task in the user turn—stop re-pasting the novel—prove it on a real artifact, or skip the badge. Keep this beside the tool; read before you start.

1. What I shipped: ___ 2. What I refused: ___ 3. What I will never-do again: ___ (date: Asia/Shanghai)

  • [ ] Tools/writes paused
  • [ ] Refuse-line dated
  • [ ] Artifact path saved
  • [ ] Next link chosen (or stop)

Before you start

Sit with three real asks from this week. You will label trust/check/stop for “Put “always true” rules in the right place,”—bring the asks, not slogans. Guide: foundations-system-vs-user-prompts. If you only have a blank practice box, stop and fetch the real job first.

  • Goal in one line: ___
  • Allowed tools: ___
  • Forbidden: ___
  • Human approve needed for: ___

How to use this week

This week: move always-true rules into system/Project instructions; leave the task in the user turn. Stop re-pasting the novel rules in the right place,” on a live artifact—not a blank demo. Write one refuse-line and date the note (Asia/Shanghai). If you only skimmed foundations-system-vs-user-prompts, put 25 minutes on the calendar and redo once.

Pitfalls

PitfallFix
Novel-length standing rulesOne screen
Putting today’s task only in standingStanding = always; user = now
Contradicting standing in every messageFix standing once
Example

Filled prompt

Job: Put “always true” rules in the right place, so you
Prior fail: [what missed the check]
Repair: keep the same Done; add one constraint + one concrete example from my notes.
Boundaries: draft only; label Unknowns [?]; no silent send.
Return: fixed output + the one-minute pass/fail I will mark.

What good output looks like

  • Names the prior fail without inventing a new job
  • Adds one constraint tied to “Put “always true” rules in the right place, so you”
  • Still draft-only / Unknowns labeled
  • Pass/fail: you mark green on the same checklist (foundations-system-vs-user-prompts #4)

Practice now

Live card: apply “Standing instructions vs each message (system vs user)” to a mistake from this week; write the fix habit (Asia/Shanghai).

Today: move one recurring rule into standing instructions; leave only task details in the user message. Verify once (Asia/Shanghai).

Today card (copy) — foundations-system-vs-user-prompts: 1. Artifact I will produce: ___ 2. Pass/fail check: ___ 3. Refuse-line if tempted to skip verify/send: ___ (date: Asia/Shanghai) 4. One never-do from this guide: ___

  • [ ] Artifact path written
  • [ ] Refuse example would say "yes"
  • [ ] Dated Asia/Shanghai

One sentence takeaway

Standing rules in system/Project space; task in the user turn—stop re-pasting the novel—prove it on a real artifact, or skip the badge

  • You can point to a dated refuse-line
  • You have one artifact path from tonight
  • You can teach the red flag in one sentence

Next

GFB · Projects workspaces · Version templates · When AI sounds sure but wrong

Pair with today: open the first Next link (prompt-goal-format-boundaries) only after you dated a refuse-line for this guide (Asia/Shanghai).

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