Free AI prompt library: 15 starter templates
Most "free" prompt libraries are lead magnets. This one is the real thing: 15 templates you can use today without signing up for anything.
Searching for a free AI prompt library usually lands you on a signup wall, a Notion page selling a $29 upgrade, or a ChatGPT marketplace that needs a credit card. This post is neither. Below are 15 genuinely free, ready-to-use, parameterized prompt templates covering the most common daily AI tasks. Copy, paste, use.
What counts as "free" here
Free as in: no signup, no email capture, no premium tier, no login. You can copy these templates, paste them into any AI service, and use them forever. They work in any tool that stores text. If you want them a keystroke away, TextDeck is free and does that; it also ships its own fifteen-prompt starter pack (professional email, constructive feedback, meeting notes, SWOT, quiz generator and the rest), so you end up with thirty to pick from.
1. Summarize anything
The summary a model gives you unprompted is a shorter version of everything. Naming a sentence count and adding "skip fluff" turns it into a decision about what matters, which is what you actually wanted.
Summarize the following in {{length}} sentences. Preserve key facts. Skip fluff. {{content}}
Try it: fill the variables
2. Explain to an expert in an adjacent field
"Explain like I am five" insults the reader and throws away precision. Naming a field the reader does know gives the model a real vocabulary to borrow from instead of a register to flatten into.
Explain {{concept}} to someone with expertise in {{adjacent_field}} but no background in {{target_field}}. Use an analogy they would recognize. Max 200 words.
Try it: fill the variables
3. Turn messy notes into structured output
The "do not invent" clause is doing most of the work here. Without it a model will helpfully fill an empty field with something plausible, and you will not notice until it matters.
Convert these messy notes into {{format}} with these fields: {{fields}}. If a field is missing, mark as null. Do not invent. {{notes}}
Try it: fill the variables
4. Draft an email
The one specific detail is what separates a usable draft from something that reads like a mail merge. Everything else in an email a model can guess; that it cannot.
Draft a {{tone}} email from {{sender_role}} to {{recipient_role}}. Purpose: {{purpose}}. Include one specific detail that shows context. Max {{length}} words.
Try it: fill the variables
5. Critical review
Models default to encouragement. "Be direct. Do not soften." is the shortest instruction that reliably gets past it, and you can always ask for the case in favour separately.
Review the following {{content_type}} critically. Identify weak claims, unsupported assertions, logic gaps. Be direct. Do not soften. {{content}}
Try it: fill the variables
6. Brainstorm with constraints
Unconstrained brainstorming returns the obvious five. Constraints, a forced ranking, and one deliberately unconventional entry give you something you would not have arrived at alone.
Brainstorm {{count}} approaches to {{problem}}. Constraints: {{constraints}}. Rank from most to least feasible. Include one that is unconventional.
Try it: fill the variables
7. Compare options
The markdown table forces the model to fill every cell, which is what exposes the dimensions it does not actually know. The flag instruction turns those into an honest "depends" instead of a confident guess.
Compare {{options}} across these dimensions: {{dimensions}}. Output a markdown table. Flag any dimension where the answer depends on context.
Try it: fill the variables
8. Meeting prep
The "two things I should not bring up" line is the part people leave out and the part that pays. It makes the model reason about the other side of the table, not just your side of it.
I have a meeting with {{person_or_company}} about {{topic}}. Goal: {{goal}}. Give me: 5 questions to ask, 3 points to make, 2 things I should not bring up.
Try it: fill the variables
9. Learning plan
Hours per week is the variable that changes the whole plan. Leave it out and you get a curriculum built for someone with unlimited time, the kind you abandon in week two.
Build a {{duration}} learning plan for {{topic}}. I have {{hours_per_week}} hours per week. Current level: {{current_level}}. Output: weekly milestones, resources, one checkpoint per week.
Try it: fill the variables
10. Decision framework
Ending with a forced recommendation matters. A model asked to "walk through" a decision will happily stop at "it depends" unless you close that exit explicitly.
I am deciding between {{options}} for {{context}}. Criteria I care about: {{criteria}}. Walk me through a structured decision. End with a recommendation.
Try it: fill the variables
11. Persona-based rewrite
"Do not add information" is the guardrail. Tone transfer without it drifts into invention, and you end up fact-checking a rewrite of something you already knew was true.
Rewrite the following in the voice of {{reference_style}}. Preserve meaning. Do not add information. {{original}}
Try it: fill the variables
12. Extract structured data
Same shape as the notes template, tighter output. Asking for JSON by name gets you something you can parse; asking for "a structured summary" gets you prose with bullet points in it.
Extract the following fields as JSON from the text: {{fields}}. Use null for missing fields. Do not invent. {{text}}
Try it: fill the variables
13. Step-by-step plan
Numbering the steps forces the reasoning to happen in order. Without the numbering a model jumps to a recommendation and back-fills the justification, which reads the same and is worth much less.
Help me plan {{goal}}. Step 1: constraints. Step 2: assumptions. Step 3: three approaches with tradeoffs. Step 4: recommendation with reasoning. Context: {{context}}.
Try it: fill the variables
14. Uncomfortable questions
The most useful prompt on this list. You already have the case for your decision; what you are missing is the ten questions you have been quietly avoiding.
I am considering {{decision}}. Give me the 10 most uncomfortable questions someone skeptical of this decision would ask. No softballs.
Try it: fill the variables
15. Code review
"Hidden state and non-obvious control flow" is the specific ask. Request a general review and you get style notes; request this and you get the bugs.
Review the following code for {{concern}}. Focus on correctness, edge cases, readability. Flag any hidden state or non-obvious control flow. {{code}}
Try it: fill the variables
How to make this a library
Copy these into any prompt manager. If you want the hotkey-from-anywhere experience, drop them into TextDeck (free, no account) and they become one keystroke away on macOS and iOS. Variables use the {{double-brace}} format; the app knows how to fill them in.