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Get a presigned upload URL for storing a file in Moxn’s blob storage (Supabase). After uploading, use the returned path as a key in storage-type content blocks.
This tool is primarily used by the stdio proxy. When using @moxn/mcp-kb locally, the proxy handles file uploads automatically — you just pass a local file path in content blocks ("type": "file", "path": "/local/path"). Call upload_url directly only if you need manual control over the upload.In HTTP/remote mode, upload_url may not work reliably because the upload requires a direct connection to the Moxn storage service.

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Parameters

ParameterTypeRequiredDescription
typestringYesMIME type of the file (e.g., "image/png", "application/pdf")
filenamestringNoOptional filename for display in the UI

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Supported MIME Types

  • Images: image/jpeg, image/png, image/gif, image/webp, image/svg+xml
  • Documents: application/pdf, application/vnd.openxmlformats-officedocument.wordprocessingml.document (docx), xlsx, pptx, doc, xls, ppt, odt, ods, rtf
  • Data: text/csv
  • Text/Code: text/plain, text/markdown, application/json, application/xml, text/yaml, text/html
  • Archives: application/zip, application/gzip, application/x-tar
  • Other: application/epub+zip

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Response

{
  "path": "uploads/workspace/uuid/filename.png",
  "token": "https://storage.example.com/presigned-put-url..."
}
  • path — use this as the key field in type: "storage" content blocks
  • token — a presigned PUT URL, valid for 1 hour

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Manual Upload Workflow

# 1. Get upload URL
# upload_url({type: "image/png", filename: "diagram.png"})
# → {path: "uploads/...", token: "https://..."}

# 2. Upload the file
curl -X PUT \
  -H "Content-Type: image/png" \
  --data-binary @diagram.png \
  "https://presigned-put-url..."

# 3. Use in a content block
# {"blockType": "image", "type": "storage", "mediaType": "image/png", "key": "uploads/..."}

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Stdio Proxy Automatic Upload

When using @moxn/mcp-kb (stdio), you don’t need to call upload_url directly. Pass a local path in content blocks and the proxy handles the rest: 
{"blockType": "image", "type": "file", "path": "/Users/me/screenshots/diagram.png"}
The proxy:
  1. Reads the file from disk
  2. Calls upload_url to get a presigned URL
  3. Uploads the file
  4. Transforms the block to type: "storage" before forwarding to the server
  • sections — use type: "storage" content blocks with the returned path as key