Prompt library
The prompt library keeps instructions that have proved themselves, ready to insert into any chat in two clicks. This page shows how to create prompts, work with placeholders and share them with your team.
Last checked on 28 September 2026
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Prompt or agent
A prompt is saved text that you insert into the message field, adjust if needed and send yourself. An agent is a fixed setup with instructions, knowledge and files that applies to every chat with it. The two complement each other.
| Aspect | Prompt | Agent |
|---|---|---|
| Good for | single tasks you always phrase the same way | recurring tasks with fixed rules, knowledge and templates |
| Effect | applies to the one message you insert it into | applies to every chat with the agent |
| Knowledge and files | none | brains and files possible |
| Length | up to 10,000 characters | instructions up to 40,000 characters |
| More | this page | Creating agents |
Creating prompts
All prompts are on the Prompts page in the sidebar, split into All, Mine and Workspace. Search finds prompts by title and text. There are three ways to create a new prompt:
- New prompt on the Prompts page: write the title and text yourself.
- Save as prompt on your latest message in a chat: Custodos takes the text and suggests a title from its first line.
- Copy on one of the built-in templates: the copy is saved as a private prompt under Mine, where you can adapt it.
Inserting a prompt in a chat
- 1
Open the library
Click the plus button Add in the message field, then Prompt library. - 2
Choose a prompt
The list is grouped into Mine, Workspace and Templates and can be searched. The selected prompt is shown in full. - 3
Insert
Click Insert. If the prompt has placeholders, the button reads Fill in and asks for the values first. - 4
Check and send
The text is now in the message field. If something was already there, Custodos adds the prompt below it. Nothing is sent until you click Send.
Placeholders
Write the parts that change each time in double curly braces, such as {{client name}} or {{date}}. When you insert the prompt, Custodos asks for each placeholder once under Fill in the placeholders, even if it appears several times, and fills in the values. A field left empty stays in the text as a placeholder, so you can see what is still missing.
Placeholders are plain text replacement. There are no conditions, formulas or nesting.
- A name consists of letters, digits, spaces, underscores or hyphens and is at most 40 characters long.
- A prompt holds at most 12 different placeholders.
- Anything else in double curly braces, for example with a full stop or a vertical bar, stays in the text unchanged.
Private or for the whole workspace
When saving, you choose under Visible to who can use the prompt.
| Aspect | Only me | Whole workspace |
|---|---|---|
| Who sees and uses it | only you; admins cannot see it either | everyone in the workspace |
| Who can change and delete it | only you | you and the admins |
| Making it private again | not applicable | only the person who created it |
| In the activity log | never | creating, changing and deleting are logged |
Data protection for shared prompts
A prompt for the whole workspace can be read by everyone in it. Remove personal data first; Custodos reminds you when you save. Prompts shared by former members are kept and marked by a former member.
The twelve templates
Custodos comes with twelve prompt templates. They are listed under All and, in the library inside a chat, under Templates. Templates can be inserted directly but not changed. To adapt one or share it with your team, copy it first.
- Draft a quote
- Payment reminder
- Draft a reference letter
- Meeting minutes
- Decline an email politely
- Shorten a text
- Rewrite in plain language
- LinkedIn post
- Job advertisement
- Reply to a customer enquiry
- Weigh pros and cons
- Explain an Excel formula
Editing and deleting
On the Prompts page you change a prompt with Edit and remove it with Delete prompt. A deleted workspace prompt disappears for everyone. From the library inside a chat, Manage prompts takes you straight to this page.
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