# Agent rules (/docs/build/agent-rules)

These rules are also in the tool descriptions the server sends, so a well-behaved client already sees them. They are here in one place so you can check an agent's behaviour, or put them in a system prompt.

## 1. Scheduling over MCP does not reach Substack on its own [#1-scheduling-over-mcp-does-not-reach-substack-on-its-own]

When a writer schedules inside WriteStack with the browser extension installed, the Note is synced to Substack right away. **An MCP client can't do that:** it only stores Notes in the writer's WriteStack queue. The writer then opens WriteStack, goes to **My Notes → Scheduled notes**, and clicks the yellow **Sync N scheduled notes to Substack** button so the extension pushes them to Substack. See [Sync](/docs/using/concepts/sync).

- Before calling `schedule_notes` or `schedule_notes_with_custom_dates`, tell the writer this and ask them to confirm.
- Pass `userConfirmedManualSync: true` only after they say yes. Without it, the server refuses and asks you to confirm first.
- After scheduling, remind them to click Sync.

## 2. Check capacity before scheduling [#2-check-capacity-before-scheduling]

Call `get_schedule_capacity` first. Schedule at most `remaining` Notes unless `unlimited` is `true`. The rest stay as drafts or ready Notes. If the limit is reached, the server schedules nothing and says so.

## 3. Write in the writer's voice [#3-write-in-the-writers-voice]

Before drafting new Note text, call `get_writing_style`, unless the writer already pasted full style instructions. Note bodies are Markdown, and a line break is a blank line (two newlines).

## 4. Never invent ids or names [#4-never-invent-ids-or-names]

Read them from the matching list tool:

| Value | Get it from |
| --- | --- |
| Tag names | `list_tags` |
| Buffer channel ids | `list_buffer_channels` (max 20 per Note) |
| Newsletter `publicationId` | `list_article_newsletters`, then ask the writer which one |
| Note ids | `list_notes`, `get_queue` |
| Article ids | `list_articles` |

## 5. Ask before optional extras [#5-ask-before-optional-extras]

- **Link previews:** if a Note contains a link, ask before attaching a preview card. Pass `includePreviews: true` only after a yes. One preview per Note, from the first link.
- **Cross-posting:** ask before adding Buffer channels.
- **Newsletter:** never pick a default newsletter for an article.

## 6. Read before you write [#6-read-before-you-write]

`update_note` and `update_article` replace the fields you send, and there is no undo.

- Read the Note or article first, show the writer the change, then write.
- For articles, call `get_article` right before `update_article` and pass its `contentVersion` as `baseVersion`. A version conflict means the writer edited it in the meantime: read it again.
- Pushing an article that already has a Substack draft updates that draft. If the draft was changed on Substack since the last push, the push stops with a conflict instead of overwriting. Tell the writer and let them decide.

## 7. What the server cannot do [#7-what-the-server-cannot-do]

- Sync Notes to Substack (the writer clicks the Sync button in WriteStack).
- Unschedule Notes (the writer does that in WriteStack).
- Act on any account other than the signed-in writer's.

If the writer asks for something no tool covers, call `get_feature_suggestion_link` and give them the link to suggest it.

## Copy into a system prompt [#copy-into-a-system-prompt]

```text
You are connected to the writer's WriteStack account over MCP.
- Scheduling only queues Notes in WriteStack. Before scheduling, tell the writer they must open WriteStack (My Notes → Scheduled notes) and click the yellow "Sync N scheduled notes to Substack" button afterwards, and only pass userConfirmedManualSync: true after they confirm.
- Call get_schedule_capacity before scheduling and never schedule more than `remaining` unless `unlimited` is true.
- Call get_writing_style before drafting Note text. Use blank lines between paragraphs.
- Never invent tag names, channel ids, note ids or publication ids; read them from the list tools.
- Ask before adding link previews, Buffer channels, or choosing a newsletter.
- Read a note or article before updating it; updates overwrite and cannot be undone.
```