Add Media (Upload Widget)

Picsart's MCP tools take URLs, not local paths, and most agent hosts (browser-based chats, Claude Code without shell access, ChatGPT web) can't read a file straight off the user's disk either. The fix is a browser-based upload widget: an MCP tool opens a drag-and-drop panel in the user's browser, the browser uploads the file directly to Picsart's CDN, and the widget hands the resulting URL back to you. No file bytes ever pass through a tool call.

When to Use

Fires on things like "I have 3 video clips", "here are my photos", "use my footage", "combine these clips" — anything where the media is the user's own and you don't already have a link to it.

Reach for this whenever the next step needs a URL (image_url, video_url, startFrame, …) and the source is something on the user's own machine, a chat attachment you can't fetch, or anything else not already a public https:// link.

Prerequisites

The Picsart gen-ai MCP server (picsart, declared in this repo's .mcp.json) in the current tool list. It offers two routes:

• picsart_media_upload — opens the upload widget. Works on every host, including ones with no shell. The widget also has a "My Drive" tab when the user's Picsart Drive is reachable, and tries to save each upload to their Drive.
• picsart_upload_local_files — for a host that can run shell commands and can read the file on disk. It returns one upload command per file; run it, and the printed JSON holds the hosted URL at response.url. No widget and no wait for the user. The hosted copy is temporary.

If the server is not connected, say so; don't guess a tool name.

How to Run

No script to run — this skill is one tool call plus a short wait for the user's next message.

Quick Reference

Procedure

If you have a shell and the file is on disk, use picsart_upload_local_files instead: pass each file's name and bytes, run the command it returns with the file's path, and go straight to step 3 with the URL it prints. Otherwise:

1. Call the upload tool

Call picsart_media_upload with whichever of purpose, accept, detected_files, known_urls apply. All arguments are optional — calling with none just opens the widget.

{ "purpose": "product photo", "accept": "image", "known_urls": ["https://cdn.picsart.io/…already-uploaded.jpg"] }

• detected_files is a label hint only, never a filter — it's model-supplied and can be wrong or hallucinated. The user can still drop any file they want; don't tell them a file is "not accepted" because it wasn't in your detected_files list.
• known_urls saves a re-upload: if a URL already exists from earlier in the conversation (a prior generation result, a prior upload), pass it here so it shows up as a chip the user can pick instead of finding the file again.

2. Tell the user what to do, then wait for their next message

The widget reports the uploaded URL(s) back to you via a mechanism most agent hosts only deliver on the user's next message — not instantly within the same turn. This is a real two-turn handshake, not a delay you can poll through.

Say something like: "I've opened the upload panel — drop your file in and let me know once it's there." Then stop and wait. Do not claim you can't see the file, or that the upload failed, just because nothing arrived in the same turn you called the tool.

3. Hand the URL to the tool the user actually wanted

Once the URL comes back (on the user's next message), pass it into the URL-shaped parameter of whatever tool the user's original request needs (image_url, video_url, etc.).

Pitfalls

• Expecting the URL in the same turn. It won't be there — see step 2. Prompt the user and wait for their next message instead of reporting failure early.
• Treating detected_files as a filter. It's a display hint for filenames you can see but can't fetch. Never reject or second-guess a file the user actually drops based on this list.
• Re-asking for a file that's already uploaded. Check the conversation for a URL you already have before opening the widget — pass it via known_urls instead of starting over.
• Guessing the tool name. The upload tools are picsart_media_upload and picsart_upload_local_files, both on picsart. Read what the tool list actually shows.

Verification

• The tool call that opened the widget returned without error.
• A URL came back on a subsequent user message and looks like a real hosted link (not a local path).
• The downstream tool call accepting that URL didn't fail on the URL itself.

Related

• The video-prompt-engineer skill writes the prompt for a video generated from the URLs this skill returns.