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Whistle hosts a remote Model Context Protocol server at: 
https://whistle.huddleup-sports.com/api/mcp
  • Transport: streamable HTTP (the standard MCP HTTP transport). This is not SSE-only and not a stdio server — connect with any MCP client that supports HTTP transports.
  • Auth: the same partner API key as the REST API, sent as Authorization: Bearer whk_…. Unauthenticated requests get 401 {"error":"unauthorized"}.
  • Tools: 20 tools mirroring the REST API’s 20 resource operations (whistle_list_leagues, whistle_create_games, whistle_assign_official, …) — everything except the GET /api/v1 index, which has no tool. Tool results are the REST response’s data payload; REST errors surface as tool errors with the same error code.
  • Scoping: the server forwards your bearer token to the REST API, so every tool call runs as you — the same source scope and attribution as direct REST calls.

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Connect from Claude Code

Use an environment variable — don’t paste the key into the command history: 
claude mcp add --transport http whistle \
  https://whistle.huddleup-sports.com/api/mcp \
  --header "Authorization: Bearer $WHISTLE_API_KEY"
Then ask Claude to list Whistle leagues to verify the connection with a read-only tool.

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Connect from a generic MCP client

Any MCP client configuration that supports HTTP servers with custom headers works. For clients using the common JSON config shape: 
{
  "mcpServers": {
    "whistle": {
      "type": "http",
      "url": "https://whistle.huddleup-sports.com/api/mcp",
      "headers": {
        "Authorization": "Bearer ${WHISTLE_API_KEY}"
      }
    }
  }
}
Check your client’s documentation for how it interpolates environment variables into headers — the goal is that the literal key never lands in a config file you might commit.

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The 20 tools

Read (safe)Write (confirm first)
whistle_list_leagueswhistle_create_league
whistle_get_leaguewhistle_update_league
whistle_list_gameswhistle_create_games
whistle_get_gamewhistle_update_game
whistle_list_officialswhistle_cancel_game ⚠️
whistle_list_assignmentswhistle_add_official
whistle_list_paymentswhistle_remove_official ⚠️
whistle_list_webhookswhistle_assign_official
whistle_list_webhook_deliverieswhistle_unassign_position ⚠️
whistle_register_webhook
whistle_delete_webhook ⚠️
Tools marked ⚠️ are destructive — agents should summarize and get human confirmation before calling them. See Errors & agent safety for the full rules, and Task recipes for end-to-end flows (each recipe notes its MCP tool equivalents).
One schema quirk to know: whistle_create_games accepts startsAt, sport, location, payDollars, label, externalId per game. Unlike the REST endpoint, the MCP tool schema does not take latitude/longitude.
Last modified on July 10, 2026