How to Use posterly with Grok Bot: Marketplace Bot to First Approved Schedule

You already have a chat window that remembers context. What you do not want is another tab for captions, another tab for the queue, and a third for "did that actually go out?". Founders and small teams keep asking for social to happen in the conversation they are already in.

That is what the live Posterly Social Grok Bot is for. It is a Marketplace template, not a second dashboard. The bot drafts captions, media, and schedules through posterly's MCP tools. It does not post until you approve. posterly stays the publish layer (18 networks, the queue, analytics). Grok Bot stays the chat, memory, and routines layer.

This is a new-user walkthrough of that handshake, from "Add to Grok Bot" to the first approved schedule. The long connector encyclopaedia already lives at the Grok Bot guide. Use that when you want every transport and menu variant. Use this when you want to simulate the agent path once, in order.

Two layers, one conversation

Keep the split boring and accurate.

• Grok Bot is where you talk, where a named bot can keep memory, and where routines can run again later. It is not a social network.
• posterly is where accounts, media, the queue, and analytics actually live. Individual plans start at $7 a month. API and MCP access is a $3 a month add-on ($29 a month on Agency). That add-on is required before hosted tools will schedule anything. See pricing and the Grok Bot setup page.

The Marketplace listing says the same thing in one line: drafts via MCP, never posts without the user's approval, connect MCP at https://www.poster.ly/api/mcp.

1. Add the live bot, then talk to it

Open the live listing: Posterly Social by Alex.

The page is a third-party Marketplace bot, not an xAI-official app. The public copy is short on purpose:

• Draft captions, media, and schedules in posterly via MCP.
• Never posts without the user's approval.
• Connect your posterly MCP at https://www.poster.ly/api/mcp.

If you already have Grok Bot, use Add to Grok Bot. If you do not, the listing points you to download Grok Bot first. That is the whole public listing: a short description and those two actions.

Once the bot is in your workspace, start in plain language. You do not need a key in the first message.

You: I want you to set up posterly as my social scheduling agent. I do not have an account yet. Do not post anything.

Bot: I can start posterly's agent signup flow. Confirm the email I should use. You will pay and set a password in your own browser. I will not ask for the card or the password.

That is the contract. The bot orchestrates. You stay the human in the browser for money and credentials. The same instruction block is published for any agent at poster.ly/agents/signup.

2. Agent-led signup (you still pay in the browser)

Ask the bot to run the documented signup tools, not to "just make an account".

The public flow is:

1. start_signup (or the matching public call POST /api/v1/signup) with your email, usually the Starter plan, and api_addon=true.
2. The bot sends you a checkout handoff URL. Prefer checkout_redirect_url. Use checkout_url only if the full Stripe URL, including any # fragment, is preserved.
3. get_signup_session (or GET /api/v1/signup/sessions/{id}) while you finish the browser steps.
4. The bot narrates status in English: checkout pending, payment confirmed, password required, then agent access required.

You complete Stripe Checkout and set the posterly password yourself. The bot should never collect a card number, a posterly password, or a social password. No API key is created or shown until billing access is active. That boundary is the product, not a nicety. It is spelled out on agent signup and the agents overview.

Hosted MCP on Grok Bot is a later step. The authenticated HTTP endpoint expects a pst_live_... bearer key, so the bot starts signup through the public agent flow above (the same start_signup / get_signup_session contract, via the public API if the hosted connector is not attached yet). Once checkout and password setup are done, posterly prepares API access and you give that key to the bot.

In chat it should look like this, not like a JSON dump:

Bot: Checkout is ready. Open this secure posterly link and pay in your browser. I will wait and tell you when payment lands.

You: Paid. I set a password.

Bot: Payment is confirmed. posterly is activating API access. When the dashboard shows the first key, paste the setup instructions here (or into the Grok Bot connector). I will not continue to Instagram until that key works.

If the bot pastes raw curl or a payload, tell it to stop. Signup and connect tools return human-readable next steps by default. debug: true is only for troubleshooting, and only if you ask. That style rule is on the MCP page.

3. Attach remote MCP in Grok Bot (short version)

Grok Bot talks to remote HTTP MCP only. It does not run local stdio, npx, localhost, or a private IP. Grok Build (the terminal agent) can use stdio. This post is not about Grok Build.

After the dashboard key exists:

1. Enable the API and MCP add-on in the posterly dashboard if signup did not already include it, then create a key. Keys start with pst_live_.
2. In Grok Bot, open Settings and add a custom connector. Live posterly copy describes this as Settings, then Plugins / Connectors / MCPs. The long Grok Bot guide often says Settings → Plugins on its own. Treat those as the same place. The visible label can vary by surface.
3. Server URL: https://www.poster.ly/api/mcp
4. Header: Authorization: Bearer pst_live_...

<!-- Optional first-party screenshot: Grok Bot Settings, then Plugins (docs also say Plugins / Connectors / MCPs), with the custom connector URL and Authorization header filled in. Do not use stock photography. -->

That is the whole connector. For the longer walkthrough, including grok.com/connectors and Grok Build, use the MCP setup guide and the Grok Bot guide. Do not paste an npx stdio block into Grok Bot. It cannot reach a process on your laptop.

Then a read-only check:

You: Run whoami. Do not list keys or post anything.

Bot: Authenticated. I can see your workspace and scopes. No social accounts are connected yet. Which network first, Instagram or LinkedIn?

If whoami fails, stop. Do not "just schedule". The usual causes are below.

4. First connect session (OAuth stays in your browser)

Connecting Instagram or LinkedIn is another browser handoff, not a password in chat.

Once MCP is attached, the bot should:

1. Ask which account you want first.
2. Call create_connect_session for that platform.
3. Send you the secure connect_url.
4. Poll get_connect_session and tell you what is happening.

You open the link, sign into the provider, and approve scopes on Meta or LinkedIn's own page. The agent does not take the OAuth code. Sessions expire after 30 minutes. If you wander off, the bot should create a fresh session rather than reuse a dead one.

Statuses the bot can report without invention (from agent signup and the agents overview):

• created: the link is ready, open it.
• opened: you opened posterly.
• awaiting_provider: you are on the provider consent screen.
• awaiting_credentials: a manual network (for example Bluesky or Telegram) is waiting for you to type a credential in posterly, not in chat.
• connected: done.
• failed, cancelled, or expired: explain, then offer a new session.

Chat, again, should stay boring:

Bot: I have a 30-minute Instagram connect link. Open it, approve Meta in your browser, and stay here. I will say when posterly has stored the account.

You: Approved.

Bot: Instagram is connected. I can draft. I still will not schedule until you confirm a specific post.

5. Draft, validate, then say send

"Never posts without approval" is not a slogan on the Marketplace card. It is two tools and a confirm flag.

1. The bot drafts the caption (and media plan) in chat.
2. It calls validate_post. That checks the account, caption, schedule, media, and platform settings. It does not create a row, copy remote media into storage, consume quota, or enqueue publish.
3. It shows you the final preview: account, caption, time in your timezone, media, workspace.
4. You confirm that exact post in this turn. "Post it", "yes, schedule that", or "looks good" is confirmation. "Post about the launch every Monday" is not. The create_post contract says not to infer consent from an earlier standing instruction.
5. Only then does the bot call create_post with confirm: true. Without that flag the tool refuses.

A first schedule should look like this:

You: Draft a LinkedIn post for Thursday 10:00 UK time about the webinar. Validate it. Do not create it.

Bot: Draft for your LinkedIn Page, Thursday 10:00 Europe/London.

"We are running a 30-minute live walkthrough of the new onboarding on Thursday. Bring the questions you keep asking support."

validate_post passed. It would create a scheduled LinkedIn post, not publish it now. No row exists yet. Say schedule it if you want this one queued.

You: Schedule it.

Bot: Scheduled. View in Posterly: [dashboard link]

That last line matters. After create_post (and after list/get/delete as well) the tools return a View in Posterly URL. Current-month scheduled posts open in Calendar with the post selected. Broader or future views use Table. The bot should share that link and skip the raw payload. You can still open the queue and move or delete the post like any other item.

If you asked for several posts, the bot should list every item, confirm the batch as a whole, then prefer create_posts_batch (up to 25 confirmed posts in one request) instead of quietly firing create_post 25 times.

6. After the first post: batch, voice, analytics

One approved schedule is the smoke test. The same connector is how a bot becomes useful on a Tuesday morning.

• Weekly batch. "Draft five LinkedIn posts for next week from this changelog. Validate each. Show the set. Do not create until I confirm the batch." Then create_posts_batch with confirm: true.
• Brand voice. get_brand_profile reads the saved profile and voice guidance, including learned_voice from real published captions. get_learned_voice does the same for one account. generate_captions can adapt copy against that voice without creating a post.
• Analytics. get_account_analytics and get_post_analytics are read-only. Ask for last month on Instagram and LinkedIn before you invent a content strategy. Some deeper insight tools need a Pro plan. If the bot is unsure, it can say so rather than guess.

Grok Bot routines can repeat a check ("look at next week and propose three gaps") while you are away. Proposing is fine. Publishing still needs the same validate-then-confirm step. A routine is not a blanket yes.

7. Where this usually breaks

Most failures are setup, not copy.

• API and MCP add-on is off. A plan alone is not enough. Individual API and MCP access is $3 a month. Agency API is $29 a month. whoami or a write call will refuse until the add-on is active.
• Wrong transport. People paste an npx -y posterly-mcp-server stdio config because they copied a Claude Desktop snippet. Grok Bot cannot use that. Remote HTTP only: https://www.poster.ly/api/mcp.
• Key never reached the connector. Signup finished, but Settings never got Authorization: Bearer pst_live_.... The Marketplace bot can talk. It cannot see your workspace until the header is saved.
• The bot skips validate, or calls create_post without confirm: true. Tell it to preview and wait. The tool will refuse a missing confirm flag. If it ever schedules from an old standing instruction, treat that as a bug in the chat, not as posterly "going live on its own".
• Connect session went stale. You have 30 minutes. Ask for a new create_connect_session instead of reopening an expired link.

Start with the Marketplace bot

Add Posterly Social, let it walk the agent signup flow, paste the hosted details from the MCP setup guide into Grok Bot, then approve one validated post. The short Grok Bot setup page has the connector fields. New accounts can also start at posterly signup if you would rather click than chat, then return to the bot with the key.

You keep the chat. posterly keeps the queue. Nothing publishes until you say send.