Post UGC with Grok
Grok's edge is what's happening right now. Pair it with UGC API and an agent can spot a trend, write the hook and caption, and schedule your ready-made videos to every account while the trend is still live.
Updated
How it connects
The Grok app doesn't take your own MCP servers today, so Grok agents call UGC API through tool calling on the xAI API. The xAI API is OpenAI-compatible: you describe a publish_post tool, Grok decides when to call it, and your code sends the request with your UGC API key.
Python example
import json, os, requests
from openai import OpenAI
grok = OpenAI(base_url="https://api.x.ai/v1", api_key=os.environ["XAI_API_KEY"])
UGC = {"Authorization": f"Bearer {os.environ['UGCAPI_KEY']}"}
tools = [{
"type": "function",
"function": {
"name": "publish_post",
"description": "Schedule a video or slideshow to connected social accounts.",
"parameters": {
"type": "object",
"required": ["accounts", "format", "media", "caption"],
"properties": {
"accounts": {"type": "array", "items": {"type": "string"}},
"format": {"enum": ["video", "slideshow", "image"]},
"media": {"type": "array", "items": {"type": "string"}},
"caption": {"type": "string"},
"scheduled_at": {"type": "string", "description": "ISO 8601, UTC"}
}
}
}
}]
messages = [
{"role": "system", "content": "You plan UGC posts. Only use media URLs from the library list. Schedule at least 30 minutes ahead."},
{"role": "user", "content": "Library: https://cdn.example.com/desk-hook-1.mp4, ... Accounts: acc_tt_1, acc_ig_1. "
"Pick the clip that fits today's top WFH trend, write a caption, schedule it for 17:00 UTC."},
]
reply = grok.chat.completions.create(model="grok-4", messages=messages, tools=tools) # any Grok model with tool calling
for call in reply.choices[0].message.tool_calls or []:
args = json.loads(call.function.arguments)
r = requests.post("https://ugcapi.dev/v1/posts", headers=UGC, json=args, timeout=30)
print(r.status_code, r.json()["id"])Guardrails for an autonomous agent
- Whitelist media. Let Grok choose from your library, not invent URLs.
- Schedule, don't post now. A 30-minute buffer plus a
post.scheduledcheck lets you cancel withDELETE /v1/posts/{id}. - Use TikTok drafts (
options.tiktok.draft) when a human should add the trending sound in the app. - Label AI content. Set the TikTok AI-generated label when the video is synthetic. See the AI label guide.
- Cap volume. Keep to a few posts per account per day; the cadence guide explains why.
Trend-jacking without filming
The workflow that works: keep a library of evergreen clips and slideshow templates per account, have Grok match a trend to the best clip and write a timely caption, then publish to TikTok, Reels and Shorts in one call. Apps like VTrends take it further and recreate the trending video itself.
FAQ
Can I add UGC API to the Grok app?
Not today. Use the xAI API with tool calling and your UGC API key, as in the example.
Which Grok model should I use?
Any Grok model that supports tool calling. Pick by cost and speed; the tool definition doesn't change.
Can Grok post to X?
UGC API publishes to TikTok, Instagram, Facebook and YouTube. Posting to X is not supported.