> ## Documentation Index
> Fetch the complete documentation index at: https://hercules.app/docs/llms.txt
> Use this file to discover all available pages before exploring further.
# Agent instructions
> Write what your Hercules Agent should do using instruction blocks, attach files it can read, pick its model, and set the example questions users see.
Agents is in private beta, so things may change. If you hit a problem, tell us via [Support &
feedback](/docs/company/contact).
Instructions are the biggest thing you control. They tell the Agent what job it's doing, how to do it, and what it must never do. Get these right and everything else gets easier.
Go to **Agents** → open an Agent → **Build** → **Instructions**. The model it runs on sits beside the heading, and the test chat opens from the bar above.
### How do I write good instructions?
Write them in blocks. Each block has a title and a body, so a long set of instructions reads as sections instead of one wall of text. Tell the Agent:
* The job, in one sentence
* The steps to follow
* The hard rules, like "never guess at an invoice amount"
* What to do when it gets stuck
```text Example instruction block wrap theme={}
Resolve billing questions in one reply. Look up the customer's invoices before answering. If the refund is over $500, hand off to a human instead of promising anything.
```
### How do I add and reorder blocks?
Click **Add block** on a row to add a new block below it. Drag blocks to reorder them. The Agent reads them in the order you see them.
### Can the Agent read my files?
Yes. Add files on **Build** → **Files & skills**, or drag and paste them straight into the instructions editor.
The instructions link to your files, so deleting a file under **Files** also removes it from the text.
### How do I change the model?
It sits beside the **Instructions** heading, and again on **Build** → **More**. Both change the same setting. Changing the model creates a draft, so you'll need to [publish](/docs/agents/versions) it.
### What are starter prompts?
Suggested first messages, shown when someone starts a new chat with the Agent. Edit them on **Build** → **More**, or click **Generate** and Hercules will suggest some based on what the Agent does.
### Additional FAQ
No. Editing the instructions creates a draft. Click **Save** to keep it, then **Publish** to make
it live. See [Versions](/docs/agents/versions).
Yes, there's a cap per Agent. The **Add block** button stops working once you reach it. Long
instructions usually work better split into fewer, clearer blocks anyway.
**Build** → **More** → **Details**. The description is a note for you and your teammates. It
doesn't change what the Agent does. The model and tags sit beside it.
Three ways. Try it in the test chat, run an [evaluation](/docs/agents/evaluation-runs) against your
saved test cases, or let [Auto-improve](/docs/agents/auto-improve) read your run history and suggest
fixes.
Yes. Press Cmd + S / Ctrl + S to save the draft.
