Socialync

Socialync MCP Server

Official documentation, registry manifest, and Cursor plugin for the Socialync hosted MCP server. Socialync is a cross-posting and scheduling tool for creators: upload once, publish to TikTok, Instagram, YouTube, Facebook, X, LinkedIn, Threads, and Bluesky.

This MCP server lets Claude, ChatGPT, Cursor, Google Antigravity, Gemini CLI, OpenAI Codex, Grok Bot, and any MCP-compatible AI agent draft, schedule, and publish social media posts through your own OAuth-authorized Socialync account, with human-in-the-loop approval built into the workflow. It also reads back your analytics (views, likes, comments, shares, saves, followers, and your best and worst posts), so an agent can plan next week's content from what actually performed.

Every platform integration runs on the official platform API. No browser automation, no scraping, no unofficial endpoints. Your agent cannot get your account restricted on our behalf.

Duplicate protection means a retry can never publish twice, and failed posts are retried automatically. Both matter when an agent is doing the posting.

Note: Socialync's server is hosted (remote) and closed source. This repository contains the documentation, the MCP Registry manifest, and the Cursor plugin files only. There is nothing to install or run from here.

Endpoint

https://mcp.socialync.io/mcp

Transport: Streamable HTTP. Discovery document (tools, platforms, auth, limits, as JSON): https://mcp.socialync.io/.well-known/mcp

MCP and API access are on the free plan. $0, no credit card, 5 posts a month on 7 platforms (X is on paid plans). Your agent can connect and publish without anyone reaching for a card. Paid plans start at $20/month for unlimited posts and 5 connected accounts (Starter $20, Creator $30 for 10 accounts, Agency $99 for 100, extra accounts from $2 a month). Plans and pricing.

Limits worth knowing: 1 API key per brand, and 10 AI-created posts per day per brand on paid plans (5 on free).

Authentication, two ways

A) OAuth 2.1 (preferred). Add the URL with no headers. Your client registers itself (dynamic client registration, PKCE, no client secret), opens a browser, and you sign in with your Socialync account and choose which brands the agent may manage. This is what Claude.ai, Claude Code, Cursor, ChatGPT, Google Antigravity, Gemini CLI, and Codex do on their own.

B) Bearer API key. For clients that cannot complete a browser OAuth flow (Grok Bot, headless agents, hand-edited config files). Generate a key at https://www.socialync.io/go/github-api-keys and send Authorization: Bearer . One key per brand, included on every plan. Never commit the key.

OAuth callbacks known to work end to end (any https redirect URI plus http://localhost and http://127.0.0.1 on any port is accepted):

• https://www.cursor.com/agents/mcp/oauth/callback
• http://localhost:8787/callback
• https://claude.ai/api/mcp/auth_callback
• http://localhost/callback
• http://127.0.0.1/callback

Connect

Claude (claude.ai): Socialync is listed in Claude's connector directory. Open Settings, then Connectors, then Browse connectors, search Socialync and sign in. To add it by URL instead, choose "Add custom connector" and paste the endpoint above. Full walkthrough: Socialync MCP connector guide.

Claude Code:

claude mcp add --transport http socialync https://mcp.socialync.io/mcp

Cursor / Grok Bot (OAuth, url only):

{

"mcpServers": { "socialync": { "url": "https://mcp.socialync.io/mcp" } } }

Grok Bot or any client that cannot complete OAuth (Bearer key):

{

"mcpServers": { "socialync": { "url": "https://mcp.socialync.io/mcp", "headers": { "Authorization": "Bearer YOUR_SOCIALYNC_API_KEY" } } } }

Grok Bot runs OAuth from Cursor's cloud, not your machine. The same URL can work in the Cursor IDE and fail in Grok Bot. Test in Grok Bot under Settings, then Plugins, not only in the IDE. If OAuth never starts or you see "fetch failed", use the Bearer key form.

Google Antigravity: add this to ~/.gemini/config/mcp_config.json (or .agents/mcp_config.json in a workspace). Antigravity uses serverUrl and handles the OAuth sign in itself through dynamic client registration.

{

"mcpServers": { "socialync": { "serverUrl": "https://mcp.socialync.io/mcp" } } }

Gemini CLI: install the extension, then run /mcp auth socialync.

gemini extensions install https://github.com/JackVitick/socialync-mcp

Or add this to ~/.gemini/settings.json yourself:

{

"mcpServers": { "socialync": { "httpUrl": "https://mcp.socialync.io/mcp" } } }

OpenAI Codex CLI:

codex mcp add socialync --url https://mcp.socialync.io/mcp

codex mcp login socialync

ChatGPT: turn on developer mode and add a custom connector with the endpoint URL. Which ChatGPT plans can add custom connectors has changed over time, so check OpenAI's developer mode help page for yours.

OpenClaw:

openclaw mcp add socialync --url https://mcp.socialync.io/mcp --transport streamable-http

openclaw mcp login socialync

Other MCP clients (generic config):

{

"mcpServers": { "socialync": { "type": "streamable-http", "url": "https://mcp.socialync.io/mcp" } } }

Claude Code plugin

This repository is a Claude Code plugin and its own plugin marketplace. It adds the hosted server (.mcp.json, no secrets) and the skills below.

/plugin install socialync --marketplace JackVitick/socialync-mcp

On Claude Code versions before 2.1.275, use two steps:

/plugin marketplace add JackVitick/socialync-mcp /plugin install socialync@socialync

Sign in opens in your browser the first time a Socialync tool runs. Setup notes: SETUP.md. To skip the plugin, add the server directly (see Claude Code under Connect).

Skills

Six skills teach an agent to use the server well. Every one of them asks you to approve each post before it goes out.

Install them:

• Claude Code: the plugin above.
• Cursor, Codex, Windsurf, Gemini CLI and other agents: npx skills add JackVitick/socialync-mcp
• OpenClaw: openclaw skills install @jackvitick/socialync
• Claude (web and desktop): download a skill folder, zip it, then go to Customize, Skills, the + button, Create skill, Upload a skill. Code execution has to be on (Settings, Capabilities).

The skills are optional guidance. The server works without them.

Cursor and Grok Bot plugin

This repository is also the Cursor plugin (.cursor-plugin/plugin.json, mcp.json, skills/, assets/logo.png). Install from the Cursor Marketplace (search "Socialync") once listed, or add the MCP URL directly as above. Skills in skills/ tell the agent how to draft, schedule, plan a week of posts, or inspect the queue. Submission checklist: MARKETPLACE-SUBMIT.md.

Tools

Twenty-eight tools. The same list is published at https://www.socialync.io/.well-known/mcp.

Text and image posts publish immediately to Instagram, Facebook, X, LinkedIn, Threads, and Bluesky. Video posts, including TikTok and YouTube (title required), go out as scheduled posts using media hosted in your Socialync library or a public video URL. A raw video file cannot be pasted into a chat; upload it in Socialync first.

Full reference, including recommended call order, per-platform limits, and error handling: docs/tools.md.

Analytics through MCP

Socialync collects post and account analytics for TikTok, YouTube, Instagram, Facebook, Threads, and Bluesky, and the MCP server returns the same numbers the Socialync analytics page shows (paid plans).

• get_analytics returns totals for views, likes, comments, shares, saves, and followers over the last week or month, the change against the previous period, an optional per-platform breakdown, and an optional daily timeseries for charts.
• get_top_posts returns your posts with views, likes, comments, shares, engagement rate, and a performance status (viral, good, average, flop), sorted by engagement or by date, filterable by platform and by minimum status.
• get_post_history returns what was posted where, with a plain reason and a retry hint for anything that failed.

Bluesky reports engagement but not views, so its posts are rated on engagement alone.

Example workflows

Paste these into any connected agent. Naming the tool is optional; it just makes the run easier to follow. Each skill above ends with a "Try it" pr