Hermoso is a marketing MCP server: 681+ 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. Hermes reaches all of it through one connection. This page is about one slice of that — what Hermes can actually do on X, and what X will not let it do.
Connect Hermoso to Hermes
- Install and sign in.
Your browser opens once. Nothing to create and nothing to paste: the credential is stored owner-only innpm install -g hermoso && hermoso auth login~/.hermoso/config.json. On a machine with no browser,hermoso auth login --token hmk_…takes a key from Settings → Agents & API keys instead. - Add it to
~/.hermes/config.yaml.mcp_serversis a top-level key, not nested undermcp, and no key goes in the file becausehermoso mcpreads the sign-in above:mcp_servers: hermoso: command: "npx" args: ["-y", "hermoso", "mcp"] - Ask Hermes 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.
Hermoso is not affiliated with or endorsed by the makers of Hermes and does not claim to be. The shape above is quoted from the project's own MCP reference in NousResearch/hermes-agent, read on 2026-08-23; it is documented rather than run here, which is why it is the published file shape and not a bespoke install command.
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 Hermes 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 Hermes
Ask for it in ordinary language — these are sentences, not a DSL:
“Post one X update per release under 280 characters, with the link in that single post, and record the billed cost.”
That walks get_brand → generate_text → post_to_x → x_post_insights_historical. Approval behaviour is yours to configure. Hermoso’s own guarantees do not depend on it: campaigns are born paused, spend switches are confirm-gated, and no generation call runs without a verified account behind it.
Hermes on X: the part that bites
One post beats five here, literally. Every post, delete and read is billed, insights bill per post returned, and a post carrying a link is priced at roughly 13× a plain one — so a chatty automated account is the expensive shape. The character limit fails cleanly rather than truncating, which is what you want in a job you are not watching.
For unattended runs the hermoso CLI with --json is easier to assert on than a tool manifest, and much cheaper in context.
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 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 — and 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. Everything is created paused, and the switch that arms real money refuses to run without an explicit confirmation, exactly as on the other ten 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 Hermes 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 Hermes, post to: Facebook · Instagram · Threads · TikTok · YouTube · LinkedIn · Pinterest — or see everything Hermes can publish to.
Post to X from: Claude · ChatGPT · Claude Code · Cursor · Codex · Cline · OpenClaw
Frequently asked questions
Can Hermes post to X?
Yes, through Hermoso's MCP server. Run npm install -g hermoso && hermoso auth login, then add hermoso under the top-level mcp_servers key in ~/.hermes/config.yaml with command "npx" and args ["-y", "hermoso", "mcp"]. The browser sign-in stores the credential, so no key goes in the file. Hermes then has 681+ 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 Hermes?
Two steps, once each. Run npm install -g hermoso && hermoso auth login, then add hermoso under the top-level mcp_servers key in ~/.hermes/config.yaml with command "npx" and args ["-y", "hermoso", "mcp"]. The browser sign-in stores the credential, so no key goes in the file. Then connect X inside Hermoso under Settings → Connectors, which is an OAuth consent screen in a browser. After that Hermes publishes to X as an ordinary tool call.
What is the X caption limit when posting from Hermes?
An X post is capped at 280 characters, and over-length copy is refused rather than truncated — the overage is counted for you, with splitting it into a thread suggested. Hermoso enforces it when the post is created or queued, so Hermes is told immediately rather than failing later when nobody is watching.
Can Hermes 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, all created paused. 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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