DESTRUCTIVE: modifies your real Yahoo roster. Adds a free agent, drops a rostered player, or does both at once. Provide addPlayerKey to add, dropPlayerKey to drop, or both for a simultaneous add/drop. Player keys look like 431.p.10642. Defaults to your configured team. Always confirm the players ...
AI agents use add_drop_player 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 |
|---|---|---|---|
force | boolean | — | Set to true to attempt the action even though write access is not officially supported |
teamKey | string | — | Team key; defaults to configured team |
addPlayerKey | string | — | Player key to ADD (free agent), e.g. 431.p.10642 |
dropPlayerKey | string | — | Player key to DROP from your roster |
Parameters from the server's own tool schema.
This tool modifies a real Yahoo Fantasy Baseball roster by adding and/or dropping players. While labeled 'DESTRUCTIVE' in its description, dropping a player from a fantasy roster is reversible (you can add them back if available), making this better classified as Write rather than truly Destructive.
From the tool's definition Adds a free agent, drops a rostered player, or does both at once. Provide addPlayerKey to add, dropPlayerKey to drop, or both for a simultaneous add/drop. Always confirm the players with the user before calling this.
Attacks that exploit this kind of access
DESTRUCTIVE: modifies your real Yahoo roster. Adds a free agent, drops a rostered player, or does both at once. Provide addPlayerKey to add, dropPlayerKey to drop, or both for a simultaneous add/drop. Player keys look like 431.p.10642. Defaults to your configured team. Always confirm the players with the user before calling this. 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.
add_drop_player accepts 4 parameters: force, teamKey, addPlayerKey, dropPlayerKey. 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 add_drop_player: 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.
add_drop_player 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 add_drop_player 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 add_drop_player. 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.
add_drop_player 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.
add_drop_player 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.
Teams ship this data inside their own products. See what a licence covers →