Hermoso is a marketing MCP server: 301 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 is about one slice of that — what ChatGPT can actually do on X, and what X will not let it do.
Connect Hermoso to ChatGPT
- Copy the connector URL.
https://app.hermoso.ai/mcp - ChatGPT → Settings → Connectors → Add connector. Name it Hermoso and paste the URL. Connectors may need developer mode switched on once, under Settings → Connectors → Advanced.
- Connect and approve. Sign in with your Hermoso account when the consent page opens — 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.
If the connector option is not visible, that is the developer-mode toggle rather than anything on our side; Hermoso’s endpoint is the same streamable-HTTP URL 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, or a poll — and can restrict who is allowed to reply.schedule_post— queues it on the shared calendar.x_post_metrics— the public counts on a post.x_post_insights— advertiser-grade numbers — impressions, link clicks, profile visits, video views and completion quartiles — for the last 28 hours only.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. Over-length copy is also refused, never truncated — 280 characters, with the overage counted for you and a suggestion to split it into a thread.
X limits worth knowing before you automate anything
| Text | An X post is capped at 280 characters, and over-length copy is refused rather than truncated. It is enforced when the post is created or queued — refused while you are still there to fix it, rather than silently cut on the way out. |
|---|---|
| Visibility | Public only. A post on X is public the moment it exists — there is no draft and no unlisted post in the API. Protected accounts exist, but that is an account-wide setting Hermoso neither reads nor controls, not a per-post choice. |
| Carousel | Refused, by name, and for a reason that is specific rather than generic: “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, nothing to swipe to — so a numbered ‘1/6 · SWIPE’ slide deck cannot be published there as intended. 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 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 — Meta, Google and LinkedIn ad libraries, organic TikTok, Instagram, YouTube, Reddit and Threads — is unaffected.
The paid half
X Ads do not exist in Hermoso, and we name that rather than leaving it ambiguous. The X Ads API is a separate product on a separate host with its own OAuth 1.0a signing and its own approval process. X is an organic channel here: Hermoso posts, threads, replies, deletes and reads post metrics, and does not create or manage X ad campaigns.
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 — and 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 — or see everything ChatGPT can publish to.
Post to X from: Claude · Claude Code · Cursor · Codex · Cline · OpenClaw · Hermes
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 301 tools, including the ones that publish to X — and 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 — X publishes none. What Hermoso reads on X is your own account: post metrics, advertiser-grade insights over any date range, and brand mentions.
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