Transfer files with Claude Code and yasync

1. Add the HTTP server

Create a dedicated key in API keys on any registered account, including Free. A key acts as its owner; keep its value in local environment or secret settings, outside prompts and committed files.

Set YASYNC_API_KEY in the environment that launches Claude Code. Merge this entry into the project’s .mcp.json; keep the variable reference literal in the file.

{
  "mcpServers": {
    "yasync": {
      "type": "http",
      "url": "https://yasync.com/api/mcp",
      "headers": {
        "Authorization": "Bearer ${YASYNC_API_KEY}"
      }
    }
  }
}

Review the project’s MCP configuration when Claude Code requests trust. The reference allows a shared configuration to avoid embedding a personal key.

2. Inspect an existing delivery

Open /mcp in Claude Code to check connection status. Begin with a read-only prompt and use the transfer ID returned by the list tool.

Use yasync_list_transfers to find my latest transfers. Ask me which one to inspect, then call yasync_get_transfer with its transferId. Report status, completed files and download count. Do not delete or change anything.

The MCP connection gives access to the account behind the key. It is not a separate Claude storage account, and it does not create a recipient download merely by reading metadata.

3. Hand a local upload to the CLI

The MCP tools manage transfer metadata and return signed upload plans. They do not read your disk or accept file bodies. For local files and watch folders, use the local stdio companion or the yasync CLI in an assistant session with approved terminal and file access, or implement the direct upload flow. The CLI uses its own account login rather than the MCP API key.

yasync login
yasync send ./exports --dry-run --json
yasync send ./exports --title "Approved exports" --json

Review the dry-run selection and the terminal command before sending. This uploads selected files to yasync; it does not email the link to your client. Share the completed URL through your chosen delivery channel.

Troubleshooting and other Claude clients

If authentication fails, check that the environment variable is set in the Claude Code process, then verify the key and account. A missing variable can remain unexpanded or read as empty. For a time-out, first retry a small listing request rather than creating another draft.

This configuration targets Claude Code. Claude desktop or web connection screens may have different authentication options; they need configurable Bearer headers or an authenticated adapter.