# start_user_auth

A execute tool on the Ebay MCP server.

Agent View of the PolicyLayer registry record for `start_user_auth`. HTML page: https://policylayer.com/tools/acato-ebay-mcp/start-user-auth

## Facts

- Tool: `start_user_auth`
- Server: Ebay (`acato/ebay-mcp`) — https://policylayer.com/tools/acato-ebay-mcp.md
- Homepage: https://github.com/acato/ebay-mcp
- Risk category: Execute (High risk)
- Registry record: grade D, identity unverified
- Server rate-limited: no
- Parameters: 0
- Recommended policy verdict: Rate-limited

## Example call (MCP tools/call, JSON-RPC 2.0)

```json
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "start_user_auth",
    "arguments": {}
  }
}
```

## Why start_user_auth is rated High

Authentication initiation is an execute-category action that triggers an external operation (auth flow) whose downstream effects depend on user interaction and subsequent tool calls. While not directly destructive or financial itself, it enables access to financial tools (buy_now, make_best_offer) and account management.

From the tool's own definition: "Tool name 'start_user_auth' indicates initiation of authentication flow; sibling tools include financial operations like 'buy_now' and 'make_best_offer' that require authenticated access. Description is empty, limiting direct evidence."

## Use case

AI agents invoke start_user_auth to trigger actions in Ebay. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call: builds kicked off, notifications sent, workflows started.

## Recommended policy (PolicyLayer)

Verdict: **Rate-limited**. Enforced by the PolicyLayer MCP gateway (https://policylayer.com/mcp-gateway) before a call reaches Ebay:

```json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "start_user_auth": {
      "limits": [
        {
          "counter": "start_user_auth_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}
```

## Other tools on Ebay (14)

- `buy_now` — Financial — https://policylayer.com/tools/acato-ebay-mcp/buy-now.md
- `make_best_offer` — Financial — https://policylayer.com/tools/acato-ebay-mcp/make-best-offer.md
- `place_bid` — Financial — https://policylayer.com/tools/acato-ebay-mcp/place-bid.md
- `get_active_bids` — Read — https://policylayer.com/tools/acato-ebay-mcp/get-active-bids.md
- `get_item` — Read — https://policylayer.com/tools/acato-ebay-mcp/get-item.md
- `get_lost_items` — Read — https://policylayer.com/tools/acato-ebay-mcp/get-lost-items.md
- `get_watchlist` — Read — https://policylayer.com/tools/acato-ebay-mcp/get-watchlist.md
- `get_won_items` — Read — https://policylayer.com/tools/acato-ebay-mcp/get-won-items.md
- `list_hosts` — Read — https://policylayer.com/tools/acato-ebay-mcp/list-hosts.md
- `search` — Read — https://policylayer.com/tools/acato-ebay-mcp/search.md
- `server_info` — Read — https://policylayer.com/tools/acato-ebay-mcp/server-info.md
- `add_to_watchlist` — Write — https://policylayer.com/tools/acato-ebay-mcp/add-to-watchlist.md
- `complete_user_auth` — Write — https://policylayer.com/tools/acato-ebay-mcp/complete-user-auth.md
- `remove_from_watchlist` — Write — https://policylayer.com/tools/acato-ebay-mcp/remove-from-watchlist.md

## For agents

This record is a snapshot. Live verdicts and the full registry:

- Check every server in your MCP config at once: `npx -y policylayer stack`
- Vet a server before you add it: install the mcp-precheck skill — `npx skills add https://policylayer.com` (skill text: https://policylayer.com/skill.md)
- Query the registry over MCP: endpoint `https://api.policylayer.com/mcp` — tools `check_mcp_server`, `check_mcp_stack`, `check_tool`, `search_registry`, `get_change_events`

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Source: the PolicyLayer MCP registry — one continuously verified record per MCP server. Full record: https://policylayer.com/registry?q=acato-ebay-mcp · API: https://policylayer.com/registry/api · Policy library: https://policylayer.com/policies/acato-ebay-mcp