Post Bridge

Post Bridge Social Media Skill

What this skill does to your system and your accounts. Read before installing.

• Publishes to your real social accounts. Anything it posts is live. Ask for confirmation before creating or scheduling a post unless the user has explicitly said not to, and prefer draft: true when intent is unclear.
• Sends your media and captions to a third party. Files, captions, account ids and scheduling metadata go to api.post-bridge.com under your API key.
• Uses an API key from POST_BRIDGE_API_KEY, ./.post-bridge/config.json or ~/.config/post-bridge/config.json. Only use a key you are willing to let an agent post through.
• Runs local commands when following the optional video workflow below, including ffmpeg on your files.
• Can move local files if you follow the optional posted/ convention, and can create scheduled jobs if you follow the optional cron step. Both are suggestions, not requirements. Neither happens unless you ask for it.

Autonomously manage social media posting via Post Bridge API. Post to 9 platforms from a single command or API call.

The CLI is published on npm as postbridge-cli — run it with npx postbridge-cli <command> (no install needed; npx fetches it on first use). Requires Node.js 18+. If npx postbridge-cli is unavailable for any reason, fall back to the bundled script at <skill-path>/scripts/post-bridge.js (same commands and flags).

Freshness check: If more than 30 days have passed since the last-updated date above, inform the user that this skill may be outdated and point them to the update options below.

Keeping This Skill Updated

Source: github.com/post-bridge-hq/agent-mode API docs: api.post-bridge.com/reference

Update methods by installation type:

Setup

1. Create a Post Bridge account at post-bridge.com
2. Connect your social accounts (TikTok, Instagram, YouTube, Twitter, etc.)
3. Enable API access (Settings > API)
4. Store your API key in workspace .env:

   POST_BRIDGE_API_KEY=pb_live_xxxxx
   

Or run the setup command:

npx postbridge-cli setup --key pb_live_xxxxx

Auth

All requests use Bearer token:

Authorization: Bearer <POST_BRIDGE_API_KEY>

Base URL: https://api.post-bridge.com

Config priority (highest to lowest):

1. POST_BRIDGE_API_KEY environment variable
2. ./.post-bridge/config.json (project-local)
3. ~/.config/post-bridge/config.json (user-global)

Handling "API key not found" errors

When you receive an "API key not found" error from the CLI:

1. Tell the user to run the setup command — setup requires user input, so you cannot run it on their behalf:

   npx postbridge-cli setup --key pb_live_xxxxx
   

2. Stop and wait — do not continue with the task. You cannot create posts or perform any API operations without a valid API key.
3. DO NOT search for API keys in env files, keychains, or other locations.

Get your API key at: https://www.post-bridge.com/dashboard/api-keys

Note for agents: Prefer npx postbridge-cli (the published npm CLI). If the skill is installed locally and you want to run the bundled copy instead, the script lives at <skill-path>/scripts/post-bridge.js — same commands and flags.

CLI Commands

API Reference

Use these endpoints directly if you prefer raw API calls over the CLI.

Social Accounts

GET /v1/social-accounts

Returns array of connected accounts with id, platform, username. Store these IDs — you need them for every post.

Upload Media

POST /v1/media/create-upload-url
Body: { "mime_type": "video/mp4", "size_bytes": <int>, "name": "video.mp4" }

Returns media_id + upload_url. Then:

PUT <upload_url>
Content-Type: video/mp4
Body: <binary file>

Upload link (file is on the user's device, no public URL)

When the agent cannot read the file itself (it lives on the user's phone or laptop, or is larger than the agent can pass through), mint a drop link and hand it to the user:

POST /v1/media/upload-link

Returns { "url": "https://www.post-bridge.com/u/<token>", "expires_at": ... }. The user opens the link, drops the file (up to 500MB, images/video/PDF), and it lands in their media library. Then GET /v1/media (newest first) to get the media_id and pass it to create post. The link is valid 24 hours and can take several files.

List media:

GET /v1/media?limit=50&offset=0

Delete media:

DELETE /v1/media/<media_id>

Create Post

POST /v1/posts
Body: {
  "caption": "your caption here #hashtags",
  "media": ["<media_id>"],
  "social_accounts": [<account_id_1>, <account_id_2>],
  "scheduled_at": "2026-01-01T14:00:00Z",  // omit for instant post
  "is_draft": false,  // true to save as draft
  "use_queue": true,  // optional, auto-schedule to next queue slot (uses saved timezone)
  "platform_configurations": { ... },  // optional, see below
  "account_configurations": {  // optional, per-account overrides
    "account_configurations": [
      { "account_id": 1, "caption": "override for this account" }
    ]
  }
}

Queue scheduling (use_queue):

• Pass true to auto-schedule using the user's saved timezone from their dashboard settings
• Pass { "timezone": "America/New_York" } to override with a specific IANA timezone
• Cannot be used together with scheduled_at — pick one or the other
• Timezone priority: explicit timezone > saved profile/workspace timezone > UTC
• Queue slots are scoped to the workspace of the selected social accounts
• The queue schedule is configured by the user in their Post Bridge dashboard
• If randomize_queue_time is enabled, the slot time will be offset by up to ±10 minutes for a more natural posting pattern
• Returns an error if no queue schedule is configured or no slots are available in the next 90 days

List Posts

GET /v1/posts?limit=50&offset=0&status=scheduled&platform=instagram

Params: limit, offset, status (scheduled/published/failed/draft), platform.

Get Post

GET /v1/posts/<post_id>

Returns full post details including status: processing, scheduled, posted, failed.

Update Post

PATCH /v1/posts/<post_id>
Body: { "caption": "new caption", "scheduled_at": "...", "social_accounts": [...] }

Can update caption, schedule, accounts, media, platform configs, or draft status. Only works on scheduled/draft posts.

Delete Post

DELETE /v1/posts/<post_id>

Only works on scheduled/draft posts (cannot delete published posts).

Post Results

GET /v1/post-results?post_id=<post_id>&limit=50&offset=0

Returns per-platform results showing whether each platform post succeeded or failed, with error details.

Analytics

List analytics — views, likes, comments, shares per post:

GET /v1/analytics?platform=tiktok&limit=50&offset=0&timeframe=30d

Params:

• platform (optional): tiktok, youtube, instagram
• timeframe (optional): 7d, 30d, 90d, all (default: all)
• limit, offset for pagination

Returns:

{
  "data": [
    {
      "id": "...",
      "post_result_id": "...",
      "platform": "tiktok",
      "platform_post_id": "...",
      "view_count": 4062,
      "like_count": 120,
      "comment_count": 15,
      "share_count": 8,
      "cover_image_url": "https://...",
      "share_url": "https://...",
      "video_description": "...",
      "duration": 30,
      "platform_created_at": "2026-03-01T09:00:00Z",
      "last_synced_at": "2026-03-03T12:00:00Z",
      "match_confidence": "exact"
    }
  ],
  "count": 42,
  "limit": 50,
  "offset": 0
}

Sync analytics — refresh data from connected platforms:

POST /v1/analytics/sync?platform=tiktok

Triggers a background sync of analytics data. Supports all tracked platforms: TikTok, YouTube, and Instagram.

Params:

• platform (optional): tiktok, youtube, or instagram — sync only one platform. Omit to sync all.

Returns:

{
  "triggered": [
    { "platform": "tiktok", "runId": "run_..." },
    { "platform": "youtube", "runId": "run_..." },
    { "platform": "instagram", "runId": "run_..." }
  ]
}

Get single analytics record:

GET /v1/analytics/<analytics_id>

MCP Integration

Post Bridge has a native MCP (Model Context Protocol) server. If you're using Claude Desktop, ChatGPT, Cursor, or any MCP-compatible client, you can connect directly without this skill.

Claude Desktop: One-click connect at post-bridge.com/mcp

Claude Code / Cursor / Other MCP clients — add to your MCP config:

{
  "mcpServers": {
    "post-bridge": {
      "type": "streamable-http",
      "url": "https://mcp.post-bridge.com/mcp"
    }
  }
}

MCP Tools available (11 tools):

MCP tools accept media_urls (public URLs) — the server downloads and uploads them automatically. No need to manually upload media when using MCP.

Platform Configurations

Optional per-platform overrides, passed inside the platform_configurations object on post creation/update, or via --platform-config '<json>' with the CLI. This is the #1 place to get wrong, so read carefully:

Rules

1. Key by platform name. Every override lives under a platform key: pinterest, instagram, tiktok, twitter, youtube, facebook, linkedin, bluesky, threads, google_business. A field placed at the wrong level (or under the wrong platform) is silently ignored.
2. Only include platforms you're actually posting to. Don't add a tiktok block if no TikTok account is in social_accounts.
3. Only include fields you want to override. Everything you omit falls back to the top-level caption / media. caption and media are accepted under every platform key; the other fields are platform-specific and listed below.
4. Match the accepted values exactly. Enums (placement, trial_graduation, cta_action_type, location, …) only accept the values shown — anything else errors or is dropped.

Every platform accepts:

• caption (string) — caption override for that platform only
• media (array of media IDs) — media override for that platform only

Platform-specific fields:

Example — correct multi-platform config (CLI)

Posting one piece of content to TikTok + Instagram + X + Google Business, with per-platform tweaks:

npx postbridge-cli post --caption "New drop is live 🎉" --accounts 44029,44030,44031,44032 \
  --platform-config '{
    "tiktok":   { "draft": true, "is_aigc": false },
    "instagram": { "caption": "New drop is live 🎉 tap the link in bio", "video_cover_timestamp_ms": 2000 },
    "twitter":  { "first_comment": "Grab it here: https://example.com/drop" },
    "google_business": { "cta_action_type": "SHOP", "cta_url": "https://example.com/drop" }
  }'

Note how the X link lives in twitter.first_comment (not the caption), TikTok uses a native draft, and only the four platforms being posted to appear as keys.

Platform Gotchas (important for agents)

These behaviors are easy to miss and cause silent or confusing failures. Account for them before posting.

• Some platforms require media; others accept text-only. These fail a post with no media: youtube (exactly 1 video), tiktok (1 video, or one+ images for a photo post), instagram (1–10 images/videos; a story is exactly 1; PDFs are dropped), pinterest (1-5 images — 2+ publishes as a carousel pin, and ALL images must share the same width/height ratio or Pinterest rejects it — or 1 video). These accept text-only: twitter/X (up to 4 images, or 1 video), facebook, linkedin (up to 20 images, or 1 video, or 1 PDF document), threads (up to 20 images/videos), bluesky (up to 4 images, or 1 video), google_business (text or a single image; no video). A post can be created with no media and have media added later via posts:update, but it won't publish to a media-required platform until media exists. When a post targets several platforms, each takes what it supports and skips what it can't (e.g. a video serves YouTube; X uses it too).
• X (Twitter) strips URLs from captions. Links (http://, https://, www.) are removed from the X caption before posting. This is intentional (link posts on X cost ~13× more per post). If a link is essential for X, put it in twitter.first_comment (links ARE allowed there — it's posted as a reply right after the tweet), not the caption — and tell the user the link won't appear in the X post itself.
• Media must be uploaded, not pasted as a raw link. Do not put a Google Drive / Dropbox / arbitrary external URL into media. The media field takes Post Bridge media_ids only. Either upload the file first (CLI/API) or use media_urls (CLI --media-urls, or the MCP media_urls field) with a direct, public file URL that the server can download. A non-direct share link will fail with a generic error and no per-platform results.
• Very large videos (~300MB+) can silently drop YouTube, LinkedIn, and X. Those three platforms buffer the whole file server-side and may time out / OOM on huge uploads, producing no result row for them while Instagram/TikTok/Facebook/Threads succeed. If results shows fewer platforms than you posted to, suspect file size — re-encode smaller or shorter. Keep videos reasonably sized.
• Each platform posts independently. One platform failing does not stop the others. Always check results --post-id <id> after a publish to confirm per-platform success and read any error details.
• TikTok / Instagram caption + sound limits differ. Keep captions concise; for trending-sound workflows use TikTok draft: true so the user can add the sound and publish manually.

What actually fails, measured across 302,000 posts from 7,158 accounts in the 30 days to 2026-08-31. Each platform fails in one dominant way, and the right response differs:

• TikTok: 75% of failures are spam restrictions. The platform's decision about that account, caused by posting too often. Clears itself in 24 to 48 hours. Reconnecting does nothing. If waiting does not clear it, the user should post that account manually from the phone for a few days.
• YouTube: 84% are the daily upload quota, which is per channel and lower for new channels. Spread uploads across channels and days.
• X: 92% are a 403 spam block, from posting too fast, too repetitively, or with links.
• Instagram: 50% dead token, 41% transient Meta 500s. The 500s often publish anyway despite reporting failure, so check before republishing or you will double-post.
• Threads and LinkedIn: almost entirely dead tokens. Reconnect.
• Pinterest: 46% no valid media attached.
• Bluesky: rate limits, takedowns, and unconfirmed emails, which silently block video upload.

Expected success rates, so an account is judged against its own platform rather than against 100%: LinkedIn 97%, X 88%, YouTube 88%, Instagram 87%, Facebook 84%, TikTok 82%, Threads 81%, Pinterest 76%, Bluesky 71%.

The distinction that matters: a platform restriction cannot be fixed by anyone and clears on its own, while a dead token or missing media is actionable. Telling the user to reconnect when the account is merely restricted wastes days.

Recommended Workflow for Video Content

Optional. Steps 2, 5 and 6 touch the user's machine, so confirm each with them before doing it rather than assuming consent.

1. Store videos in a local folder
2. (runs a local command) Extract a frame with ffmpeg to read any text overlays. Tell the user you are about to run this and on which file:

   ffmpeg -i video.mp4 -ss 00:00:04 -frames:v 1 frame.jpg -y
   

   Skip it if ffmpeg is unavailable or the user would rather describe the video.
3. Write caption based on video content + hashtags
4. Upload, create post, then schedule or post instantly
5. (modifies local files) Optionally move posted videos to a posted/ subfolder to avoid duplicates. Name the exact source and destination paths and get agreement first. Never delete anything.
6. (creates a background job) Optionally set a cron to check post status 5 minutes after the scheduled time. Show the user the exact crontab line and how to remove it before adding it. Do not add one unprompted.
7. Track performance by checking post results or analytics

Automation Guidelines

When automating posts, follow these rules to keep accounts in good standing:

• No duplicate content across multiple accounts on the same platform
• No unsolicited automated replies — only post original content or when explicitly requested
• No trending manipulation — don't mass-post about trending topics across accounts
• No fake engagement — don't automate likes, follows, or comments
• Respect rate limits — the API has rate limits, don't spam requests
• Use draft mode for review — when in doubt, use is_draft: true or TikTok's draft: true so the user can review before publishing

Publishing confirmation: Unless the user explicitly asks to "post now" or "publish immediately", always confirm before posting. Creating a draft is safe; posting is irreversible and goes live instantly.

Platform Names

Use these exact names for platform filtering and configurations:

• instagram — Instagram (Reels, Stories, Feed)
• tiktok — TikTok
• youtube — YouTube (Shorts)
• twitter — X (formerly Twitter)
• linkedin — LinkedIn
• facebook — Facebook
• pinterest — Pinterest
• threads — Threads
• bluesky — Bluesky

Tips

• Post to multiple platforms simultaneously by including multiple account IDs
• Stagger posts throughout the day (e.g. 9am + 3pm) for better reach
• Use scheduled_at to pre-schedule batches — Post Bridge handles the timing
• Use use_queue: true to auto-schedule posts to the user's next available queue slot using their saved timezone — no need to pick a time manually
• TikTok draft mode lets you add trending sounds manually before publishing
• Keep hashtags to 4-5 per post for best engagement
• Check results after posting to see per-platform success/failure
• Use analytics:sync to refresh data before checking analytics
• Monitor what works and iterate on captions/formats
• Use --draft flag when testing to avoid accidental publishing
• Character limits vary by platform — keep captions concise for X (280 chars)