Begin or resume setup ('fantasy login' / 'fantasy start'). Shows how to create a Yahoo app if needed, and returns the authorization link once credentials are known. Optionally pass clientId/clientSecret to save them.
AI agents use fantasy_login to create or update resources in Yahoo Fantasy Baseball — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Yahoo Fantasy Baseball environment.
| Parameter | Type | Required | Description |
|---|---|---|---|
clientId | string | — | Yahoo Client ID (Consumer Key) |
clientSecret | string | — | Yahoo Client Secret (Consumer Secret) |
Parameters from the server's own tool schema.
This tool initiates an OAuth authorization flow and optionally saves client credentials (clientId/clientSecret). Saving credentials is a write operation with moderate severity, as it stores sensitive authentication data. It does not execute code, delete data, or involve financial transactions.
From the tool's definition 'Begin or resume setup', 'returns the authorization link once credentials are known', 'Optionally pass clientId/clientSecret to save them'
Attacks that exploit this kind of access
Begin or resume setup ('fantasy login' / 'fantasy start'). Shows how to create a Yahoo app if needed, and returns the authorization link once credentials are known. Optionally pass clientId/clientSecret to save them. It is categorised as a Write tool in the Yahoo Fantasy Baseball MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
fantasy_login accepts 2 parameters: clientId, clientSecret. The full parameter table on this page comes from the server's own tool schema.
Register the Yahoo Fantasy Baseball MCP server in PolicyLayer and add a rule for fantasy_login: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Yahoo Fantasy Baseball. Nothing to install.
fantasy_login is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the fantasy_login rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.
Set action: deny in the PolicyLayer policy for fantasy_login. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.
fantasy_login is provided by the Yahoo Fantasy Baseball MCP server (yahoo-fantasy-baseball-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
fantasy_login is one line of Yahoo Fantasy Baseball's registry record.
The record carries the whole server: verified identity, auth posture, risk grade, every tool classified, recommended policy — re-checked continuously.
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