Hermoso is a marketing MCP server: 922+ tools over one OAuth’d endpoint that let an agent research the ads already running in a market, generate finished image and video ads, publish them, and build the paid campaigns behind them. ChatGPT reaches all of it through one connection. This page covers one slice of that: what ChatGPT can actually do on X, and what X will not let it do.
Connect Hermoso to ChatGPT
- Open Hermoso in ChatGPT’s app directory. Hermoso in the ChatGPT app directory, or search for Hermoso under Plugins in the ChatGPT sidebar.
- Add it, connect and approve. Click Add, then sign in with your Hermoso account when the consent page opens. There is no key to paste.
- Ask ChatGPT for something. “Pull my three closest competitors’ longest-running ads and remix the best hook into a 9:16 video,” or “post this render to the channel.” The agent picks the tools; you approve the spend.
Prefer to add it by hand? Developer mode still works: Plugins → Add → Create MCP App, Server URL https://app.hermoso.ai/mcp, Authentication OAuth. It is the same endpoint every other client uses.
Then connect X itself, once, under Settings → Connectors in Hermoso. That is an OAuth consent screen, so it is the one step that needs a browser. Everything after it is a tool call.
The X tools ChatGPT gets
post_to_x: posts text, an image or a video with alt text, a whole thread, a reply, a quote post or a poll, and can restrict who is allowed to reply.post_x_article: publishes a long-form Article. Write it in Markdown and the headings, lists, quotes, links, code blocks and tables all carry across.edit_x_post: rewrites a post you have already published, inside the hour X allows.schedule_post: queues it on the shared calendar.x_post_metrics: the public counts on a post.x_post_insights: advertiser-grade numbers for the last 28 hours only: impressions, link clicks, profile visits, video views and completion quartiles.x_post_insights_historical: the same numbers over any date range, up to 25 posts at a time. This is the one for “how did last month go”.x_mentions: who is talking about the brand.delete_x_post: removes a post.
X is the only connector that costs money per call, and the numbers are published rather than hidden. Meta, TikTok, LinkedIn, YouTube, Threads and Drive cost nothing per request; X charges us, so those calls bill a small number of credits each. A plain post is priced at $0.015 per request and a post containing a link at $0.200, roughly 13× more. Deletes, reads and the alt-text metadata write each carry their own price, and insights bill per post returned. Link detection deliberately errs toward assuming a link is present, because guessing wrong the other way costs us 13×. The practical consequence: on X, one good post beats five, and your agent is quoted the price before it posts. Length is the posting account’s, not a flat 280. Hermoso reads the account’s own X subscription and sends up to 25,000 characters where Premium allows it, so a long post goes out whole rather than coming back refused, and nothing is ever truncated. That happens to be the cheap shape too: one long post is a single billed X call where the same words split across five posts are five. X Premium also unlocks two things Hermoso publishes for you: a long-form Article, written in Markdown with its headings, lists, quotes, code blocks and tables intact, and an edit to a post you have already published, inside the hour X allows.
X limits worth knowing before you automate anything
| Text | Length is the posting account’s: 280 characters ordinarily, up to 25,000 with X Premium. Hermoso reads the subscription from X, so a long post goes out whole. Nothing is ever truncated. It is enforced when the post is created or queued, so an overlong post is refused while you are still there to fix it instead of being silently cut on the way out. |
|---|---|
| Visibility | Public only. A post on X is public the moment it exists. The API has no draft and no unlisted post. Protected accounts exist, but that is an account-wide setting Hermoso neither reads nor controls, not a per-post choice. |
| Carousel | Refused, by name, for a specific reason. “X has no swipeable carousel.” Its API attaches up to 4 media to a post and they render as a grid, every image visible at once with nothing to swipe to, so a numbered “1/6 · SWIPE” slide deck cannot be published there as intended. The refusal says what to do instead: “Post the single strongest slide to X, or drop X from this post.” A deck that instructs the reader to swipe, published as a grid, is worse than not publishing it. |
| Which account | None. X publishes to the connected account. |
Try it in ChatGPT
Ask for it in ordinary language. These are plain sentences, not a DSL:
“Turn this blog post into a four-post X thread under 280 characters each, run a poll on the last one, and tell me the cost before anything goes out.”
That walks get_brand → generate_text → post_to_x → x_post_insights_historical. Tool calls run in the chat and you approve them there, so nothing publishes without you seeing the caption first.
ChatGPT on X: the part that bites
Threads on X multiply the cost, because every post in the chain is its own billed request. That makes a chat a sensible place to run it: you see the plan, you see the price, you decide whether the link is worth 13×. Polls and media are mutually exclusive on X, so a poll post cannot also carry the render.
ChatGPT is the only client that renders Hermoso’s inline widgets; anywhere else the same tools return plain structured results.
Research X before you post
There is no X ad library to search. X research here is your own account: mentions, post metrics and the historical advertiser numbers. Everything else in the research surface is unaffected: the Meta, Google and LinkedIn ad libraries, and organic TikTok, Instagram, YouTube, Reddit and Threads.
The paid half
X Ads landed in August 2026, so X is now both halves. The X Ads API is a separate product on a separate host with its own OAuth 1.0a signing, which is why it arrived after the rest. Hermoso now builds the whole promoted-post tree on it: campaign, line item (X’s name for an ad group), promoted tweet, targeting, budgets, status and reporting. An X ad promotes a post, so the creative is a post, the same one Hermoso publishes organically. The switch that arms real money refuses to run without an explicit confirmation, exactly as on the other eleven platforms. One thing to know before you plan a budget: X grants Ads API access per ad account rather than per app, so there is no OAuth button for it: you add Hermoso’s X user to your ad account at business.x.com → Account access, and it appears in list_x_ads_accounts with the permission level X gave it.
What ChatGPT cannot do on its own
An agent with a budget is only useful if the blast radius is bounded, so the fence is in the server rather than in a prompt. Every ad campaign, ad set, ad group and ad is created paused, and the status switches that arm real money refuse to run without an explicit confirmation flag. Every render is quoted first (hermoso_capabilities publishes each model’s exact credit cost before anything spends). Credits are reserved before the first provider call and settled at the exact cost afterwards, so a failed dispatch refunds rather than leaving you billed for nothing. Deletes are confirm-gated too, and every campaign tree is read back from the ad platform before your agent tells you what it built.
One step is deliberately not headless: linking an account is an OAuth consent screen, so you connect the channel once in a browser. Everything after that is a tool call.
The rest of the matrix
From ChatGPT, post to: Facebook · Instagram · Threads · TikTok · YouTube · LinkedIn · Pinterest · Bluesky · Telegram. Or see everything ChatGPT can publish to.
Post to X from: Claude · Claude Code · Cursor · Codex · Cline · OpenClaw · Grok Bot · Hermes · Gemini CLI · Perplexity · Le Chat · Claude Cowork · Perplexity Computer · Paperclip
Frequently asked questions
Can ChatGPT post to X?
Yes, through Hermoso's MCP server. In ChatGPT, add https://app.hermoso.ai/mcp as a custom connector and approve it with your Hermoso account. There is no key to paste. ChatGPT then has 922+ tools, including the ones that publish to X, plus the ones that research the ads already running in your market and render the creative in the first place.
How do I connect X to ChatGPT?
Two steps, once each. In ChatGPT, add https://app.hermoso.ai/mcp as a custom connector and approve it with your Hermoso account. There is no key to paste. Then connect X inside Hermoso under Settings → Connectors, which is an OAuth consent screen in a browser. After that ChatGPT publishes to X as an ordinary tool call.
Can ChatGPT post privately or as a draft to X?
No. A post on X is public the moment it exists; the API has no draft and no unlisted post. Hermoso refuses a visibility X cannot honour at the moment you ask for it, rather than quietly publishing something weaker.
Can ChatGPT research X before it posts?
Not through an ad library, because X publishes none. What Hermoso reads on X is your own account: post metrics, advertiser-grade insights over any date range, and brand mentions.
What is the X caption limit when posting from ChatGPT?
That depends on the account, and Hermoso checks rather than guessing. An ordinary X account is capped at 280 characters; one with X Premium goes up to 25,000. Hermoso reads the subscription from X and sends the post, so a long post goes out whole, and nothing is ever truncated. On a Premium account one long post usually reads better than a thread and costs less, because it is a single billed X call where five parts are five. Premium also unlocks long-form Articles, written in Markdown, and an edit to a post already published inside the hour X allows. Hermoso enforces it when the post is created or queued, so ChatGPT is told immediately rather than failing later when nobody is watching.
Can ChatGPT run X ads as well as posting?
Yes, since August 2026. X Ads runs on a separate host with its own OAuth 1.0a signing, and Hermoso builds the whole tree on it: campaign, line item, promoted tweet, targeting, budgets, status and reporting. X grants Ads API access per ad account rather than per app, so there is no OAuth button for it: you add Hermoso’s X user to your ad account at business.x.com → Account access.
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