Introduction
In Pencil, Custom Agents allow you to scale creative work without losing your brand voice or strategic focus. You might think of them as smart teammates - each with a specialised role, memory and context - ready to be pulled into your workflow whenever needed.
What is a Custom Agent?
A Custom Agent in Pencil is a configurable AI assistant designed to support a specific creative or strategic task. All Custom Agents are defined by:
Instructions: Its core behaviour and tone
Knowledge: Brand-specific or topic-specific context
Capabilities: Tools like web search or file reading
Model: The underlying AI model powering its responses
Agents can work independently or as part of a team or chain in a creative pipeline - depending on your use case.
How do I Build a Custom Agent?
Option 1: Duplicate a Pre-built Agent and Adapt it
This is likely to be the fastest way to get started. Choose one of the pre-built Agents and, hovering over it, click the three dots and choose 'Duplicate':
The copied agent will appear at the bottom and hovering will reveal a menu that includes 'Edit':
This is a good way to see how high-performing Agents are configured and adapt them to your needs.
Option 2: Create a New Agent from Scratch
Click 'New Agent' in the top right of the Agents homepage and you will be prompted with:
"What agent would you like to make?"
You can choose either:
To enter a natural-language prompt (e.g. "Help write headlines for luxury skincare ads in a playful but precise tone")
Skip this step and set everything manually
Prompting can jumpstart your Agent setup, but you can always refine it further in the full manual view.
If you choose to begin with a Prompt, Pencil will use it to auto-fill your Agent's name, goal and some instructions, expanding on your prompt.
To get the best outcome:
Be clear about the Agent's role (e.g. “concept testing for B2B SaaS landing pages”)
Specify the input context it will need
Mention tone or brand considerations
Clarify output format (e.g. “short headline list with variants”)
Manual Configuration (Post-Prompt or Skipped)
Once inside the setup screen, you'll configure:
Name and Description
Choose a clear title that reflects the Agent's purpose
Use the description to help your teammates understand when and why to use it
Model
Select from the available AI models which model will underpin your agent:
OpenAI GPT-4o
Google Gemini 2.0 Flash
Instructions
Define the Agent's behaviour clearly
Example: "Always suggest emotionally resonant headlines that follow this format: [benefit] + [emotional hook]. Reference tone given in Brand Library”
Conversation Starter (optional)
This helps onboard new users to the Agent, acting like a pre-filled suggestion or nudge
Knowledge & Capabilities
Upload files in the following formats for your Agent to reference, or write/paste plain text.
.pdf
.docx
.pptx
.txt
.csv
various image formats
Brand Knowledge: choose whether you want the Agent to access and reference your Brand Guidelines
Web Search: choose whether you want your Agent to be able to access and reference data from the web
URL Access: choose whether you want your Agent to be able to scrape and reference information URLs from any of the source data you have provided
Multiple Agents and Modular Workflows
Multiple Custom Agents can be used powerfully in sequence. For example:
Audience Research Agent ->
Messaging Strategy Agent ->
Headline Generator Agent ->
Scriptwriter Agent
Each Agent builds on the work of the last, bringing its own customised specialism and focus while preserving context across the creative pipeline.
Deployed into the right context, creating a Custom Agent can take minutes, and can save hours.
Start small, test the results, and refine your Agent(s) over time. The more context you give, the better the results.