# Prompt and first message

Use the system prompt for durable instructions and the first message for the optional greeting shown when a new conversation begins.

## Write the system prompt

In Agent Studio, open **Agent** and edit **System prompt**. The field accepts up to 1,000,000 characters.

A useful prompt states the agent's job, source-of-truth boundaries, response style, and what to do when information is missing. Keep instructions separate from examples so reviewers can identify the actual rules. Knowledge and customer input are treated as data; do not tell the agent to follow instructions embedded in an uploaded document.

Operade includes a built-in friendly personality by default. Select **Default personality off** only when your system prompt defines the complete personality and tone.

## Set the first message

The first message accepts up to 2,000 characters. Use it to greet the customer or ask for the first required detail. Leave it empty when the agent should wait for the customer to begin.

Match the greeting to the language selected for the agent. The language control sets the default; it does not rewrite a first message that you authored in another language.

## Verify the result

1. Wait for the draft save status to complete.
2. Open [test chat](/docs/agents/test-chat) and enable the draft option.
3. Confirm that the opening message is present or absent as intended.
4. Test a normal request, a request with missing information, and a request outside the agent's job.
5. Start a new conversation after every prompt change so the new configuration is used.

When the behavior is stable, follow [draft and publish](/docs/agents/draft-and-publish) to release it.