Hermoso is a marketing MCP server: 850+ 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. Le Chat reaches all of it through one connection. This page is about one slice of that — what Le Chat can actually do on Facebook, and what Facebook will not let it do.
Connect Hermoso to Le Chat
- Copy the connector URL.
https://app.hermoso.ai/mcp - Le Chat → Intelligence → Connectors → + Add Connector → Custom MCP Connector. Name it Hermoso and paste the URL.
- Press Connect and approve. Le Chat detects Hermoso’s OAuth sign-in with dynamic client registration and opens the consent page. Sign in with your Hermoso account; there is no key to paste.
- Ask Le Chat 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.
Adding a custom connector is an admin action in Le Chat. On the Free, Pro and Student plans the account owner is the admin, so you can add Hermoso yourself, free plan included; on a team plan an admin adds it. The steps are quoted from Mistral’s MCP connector documentation, read on 2026-09-23. Hermoso is not affiliated with or endorsed by Mistral AI.
Then connect Facebook 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 Facebook tools Le Chat gets
post_to_meta— publishes to the Page — text, an image, a video, or a multi-photo post — and takespageIdso it never has to guess which Page.schedule_post— queues the same post for a time you choose, on one calendar shared with every other channel.list_meta_pages— lists the Pages the account has connected, with their ids.manage_meta_post— edits the copy of a published post, or deletes it.list_meta_comments / reply_to_meta_comment / moderate_meta_comment— reads the comments under a post, replies as the Page, and hides or deletes what should not be there.meta_page_insights / meta_post_insights— Page-level and per-post reach, impressions and engagement.upload_meta_asset— puts a finished render into the ad account’s asset library.
Facebook is also the one channel with native remote scheduling — post_to_meta takes a scheduleAt between ten minutes and thirty days out and hands the timing to Meta itself. Instagram and Threads have no such thing in Meta’s API, and passing it for them is refused rather than quietly posted immediately.
Facebook limits worth knowing before you automate anything
| Text | A Facebook post can run to 63,206 characters, which is effectively no limit. 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 or draft. A draft is a genuinely unpublished Page post, which is the useful one for review: it exists in Meta Business Suite and nobody outside can see it. There is no unlisted and no private — “a Facebook Page post is either published or held as an unpublished draft”. |
| Carousel | 2 slides and up, photos only. Meta publishes no maximum for attached_media that we could source, so Hermoso does not invent one and attribute it to Facebook — the only bound is ours, at 30 slides, and the refusal says whose it is: “Facebook publishes no documented maximum for attached_media, so this bound is ours, not theirs.” Video cannot ride in a Facebook photo carousel; that is a different edge on Meta’s API and Hermoso refuses rather than silently dropping the clip. |
| Which account | pageId. It matters the moment a brand connects more than one Page: the publish path refuses by name instead of picking one for you, and a schedule that could not carry the answer would turn that refusal into a failure hours later with nobody watching. |
Try it in Le Chat
Ask for it in ordinary language — these are sentences, not a DSL:
“Pull the Facebook ads my three closest competitors have run longest, tell me the shared angle, then make an image ad from it and hold it on our Page as a draft.”
That walks find_competitors → search_meta_ads → plan_ad → render_ad → list_meta_pages → post_to_meta. Le Chat lets you set each connector function to Always allow or leave it asking. Mistral’s own advice is to pre-authorise read functions and keep write functions on manual approval, and that is the right split here: research and list tools can run freely, anything that publishes, schedules or deletes should ask.
Le Chat on Facebook: the part that bites
Map Le Chat’s per-function permissions onto the tools: search_meta_ads and list_meta_pages can be set to Always allow, and post_to_meta should keep asking. A Facebook draft then adds a second check in Business Suite, and a post that did go out can still be edited or deleted with manage_meta_post.
Le Chat’s custom connectors do not pick up new tools after you connect; the list is what it loaded at that moment. Hermoso starts a connector on a short list and includes find_tools and call_tool, which reach every other tool by name, so a tool missing from the loaded list is still one request away.
Research Facebook before you post
The Meta Ad Library is the richest public creative archive there is, and search_meta_ads reads it — by keyword or by page — covering both Facebook and Instagram placements. pull_competitor_ads and competitor_teardown build on it, and find_competitors works out who to point them at.
The paid half
Facebook is the deepest paid surface Hermoso has. create_meta_campaign, create_meta_adset and create_meta_ad build the whole tree with real targeting — geography down to a city radius, interests, behaviours, custom audiences and lookalikes, placements, dayparting, bid and cost caps. Everything is created PAUSED with no caller override, and the summary your agent reports is built from a read-back of what Meta actually stored, never from what was requested. Before a budget is committed, preview_meta_ad renders the real ad per placement as a link you can look at and estimate_meta_reach says how many people the targeting actually reaches. One warning that saves money: an ad set created with no locations defaults to the United States only, and the read-back says so loudly.
What Le Chat 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 Le Chat, post to: Instagram · Threads · TikTok · YouTube · X · LinkedIn · Pinterest · Bluesky · Telegram — or see everything Le Chat can publish to.
Post to Facebook from: Claude · ChatGPT · Claude Code · Cursor · Codex · Cline · OpenClaw · Grok Bot · Hermes · Gemini CLI · Perplexity
Frequently asked questions
Can Le Chat post to Facebook?
Yes, through Hermoso's MCP server. In Le Chat, add https://app.hermoso.ai/mcp as a custom connector and approve it with your Hermoso account — there is no key to paste. Le Chat then has 850+ tools, including the ones that publish to Facebook — and the ones that research the ads already running in your market and render the creative in the first place.
How do I connect Facebook to Le Chat?
Two steps, once each. In Le Chat, 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 Facebook inside Hermoso under Settings → Connectors, which is an OAuth consent screen in a browser. After that Le Chat publishes to Facebook as an ordinary tool call.
Does Le Chat need my Facebook password?
No. You connect Facebook to Hermoso once through an OAuth consent screen in a browser, and Le Chat then reaches it as a tool call. Linking an account is the one step that is not headless; nothing after it needs a password, and no credential is ever handed to the model.
Can Le Chat research Facebook before it posts?
Yes. The Meta Ad Library is searchable through search_meta_ads by keyword or by page, and it covers Facebook and Instagram placements together.
Start free — 30 credits at signup and 250+ more to earn, and every feature on every plan. Credits are spent only on AI models and Ad Spy research; posting, scheduling, ads management and analytics are free.
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