Sleeper API and MCP server Let your AI agent manage your Sleeper teams.

ToolWhat it doesAccess

• list_leagues List the leagues the signed-in account plays in. read

  Returns each league with its name, the team you manage and its status. The agent calls this first to get the league_id the other tools take. Leagues you archived are not listed.

  MCP callsleeper_read → list_leagues

  REST endpointGET https://cotlet.dev/api/v1/sleeper/leagues

  Parameters

  Parameters: list_leagues

  Name	Type	Description
  season string	string	Season year, for example 2026. Defaults to the current season.

  Example response

  {
    "leagues": [
      {
        "league_id": "L-5521",
        "name": "Sunday Scaries",
        "team": "Gridiron Ghosts",
        "status": "In season"
      },
      {
        "league_id": "L-7710",
        "name": "Office Dynasty",
        "team": "Waiver Wire Wizards",
        "status": "In season"
      }
    ]
  }

• get_lineup Read your starters and bench in a league. read

  Returns your starting slots in the order the Team tab shows them, then your bench and any injured reserve. Each player has a position and the injury status shown in the app. It reads the roster as it is now and does not look ahead to future weeks.

  MCP callsleeper_read → get_lineup

  REST endpointGET https://cotlet.dev/api/v1/sleeper/leagues/{league_id}/lineup

  Parameters

  Parameters: get_lineup

  Name	Type	Description
  league_id string required	string	League to read, from list_leagues.

  Example input

  {
    "league_id": "league_8c41d2"
  }

  Example response

  {
    "league_id": "L-5521",
    "starters": [
      {
        "slot": "QB",
        "player": "Dean Mercer",
        "status": "Active"
      },
      {
        "slot": "RB",
        "player": "Jamal Okoye",
        "status": "Out"
      },
      {
        "slot": "WR",
        "player": "Eli Brandt",
        "status": "Active"
      }
    ],
    "bench": [
      {
        "player": "Tyrese Boone",
        "position": "RB",
        "status": "Active"
      }
    ]
  }

• list_matchups Read the matchups and scores of one league week. read

  Returns each pairing with both team names, their records and their points so far. Scores of a live week change until the games end. Weeks that have not started show no points.

  MCP callsleeper_read → list_matchups

  REST endpointGET https://cotlet.dev/api/v1/sleeper/leagues/{league_id}/matchups

  Parameters

  Parameters: list_matchups

  Name	Type	Description
  league_id string required	string	League to read, from list_leagues.
  week integer	integer	Week to read. Defaults to the current week.

  Example input

  {
    "league_id": "league_8c41d2"
  }

  Example response

  {
    "league_id": "L-5521",
    "week": 8,
    "matchups": [
      {
        "teams": [
          "Gridiron Ghosts",
          "Blitz Brothers"
        ],
        "record": [
          "5-2",
          "4-3"
        ],
        "points": [
          131.4,
          118.9
        ]
      },
      {
        "teams": [
          "Waiver Wire Wizards",
          "Fourth and Long"
        ],
        "record": [
          "3-4",
          "2-5"
        ],
        "points": [
          102.2,
          97.6
        ]
      }
    ]
  }

• set_lineup Move players between starting slots and the bench. write

  Puts the player in the slot and moves the old starter to the bench. It refuses a player whose game has already started, because Sleeper locks those players. It reaches no one and one more call undoes it, so it does not wait for your approval.

  MCP callsleeper_write → set_lineup

  REST endpointPUT https://cotlet.dev/api/v1/sleeper/leagues/{league_id}/lineup

  Parameters

  Parameters: set_lineup

  Name	Type	Description
  league_id string required	string	League to change, from list_leagues.
  slot string required	string	Starting slot to fill, as get_lineup names it.
  player_id string required	string	Player to start in that slot, from get_lineup or list_free_agents.

  Example input

  {
    "league_id": "league_8c41d2",
    "slot": "slot",
    "player_id": "player_8c41d2"
  }

  Example response

  {
    "league_id": "L-5521",
    "slot": "RB",
    "started": "Tyrese Boone",
    "benched": "Jamal Okoye",
    "status": "saved"
  }

ToolWhat it doesAccess

• list_free_agents List players that no team in the league has rostered. read

  Returns available players the way the Players tab lists them, with the injury status and whether the player is on waivers. Players on waivers can only be claimed, not added at once. The list is capped at the first page the app shows.

  MCP callsleeper_read → list_free_agents

  REST endpointGET https://cotlet.dev/api/v1/sleeper/leagues/{league_id}/free-agents

  Parameters

  Parameters: list_free_agents

  Name	Type	Description
  league_id string required	string	League to read, from list_leagues.
  position string	string	Filter by the position names of the Players tab.
  query string	string	Part of a player name.

  Example input

  {
    "league_id": "league_8c41d2"
  }

  Example response

  {
    "league_id": "L-5521",
    "players": [
      {
        "player_id": "P-3301",
        "name": "Tyrese Boone",
        "position": "RB",
        "status": "Active",
        "on_waivers": true
      },
      {
        "player_id": "P-2189",
        "name": "Colt Reyes",
        "position": "RB",
        "status": "Questionable",
        "on_waivers": false
      }
    ]
  }

• list_transactions Read the processed adds, drops and trades of a league. read

  Returns the moves of the league newest first: who added or dropped whom, trades and the FAAB bid that won a claim. The app shows full bid details for a processed waiver; the tool returns the winning move.

  MCP callsleeper_read → list_transactions

  REST endpointGET https://cotlet.dev/api/v1/sleeper/leagues/{league_id}/transactions

  Parameters

  Parameters: list_transactions

  Name	Type	Description
  league_id string required	string	League to read, from list_leagues.
  week integer	integer	Week to read. Defaults to the current week.

  Example input

  {
    "league_id": "league_8c41d2"
  }

  Example response

  {
    "league_id": "L-5521",
    "transactions": [
      {
        "type": "waiver",
        "team": "Blitz Brothers",
        "added": "Colt Reyes",
        "dropped": "Mo Vance",
        "bid": 9
      },
      {
        "type": "trade",
        "teams": [
          "Fourth and Long",
          "Gridiron Ghosts"
        ],
        "summary": "Two players for one and a 2027 round 3 pick"
      }
    ]
  }

• list_waiver_claims List your pending waiver claims in a league. read

  Returns the claims shown under Team, then Transactions: the player, who you drop and the bid in leagues with FAAB. Claims with the same bid keep the order you set. A processed claim moves out of this list into the league transactions.

  MCP callsleeper_read → list_waiver_claims

  REST endpointGET https://cotlet.dev/api/v1/sleeper/leagues/{league_id}/waiver-claims

  Parameters

  Parameters: list_waiver_claims

  Name	Type	Description
  league_id string required	string	League to read, from list_leagues.

  Example input

  {
    "league_id": "league_8c41d2"
  }

  Example response

  {
    "league_id": "L-5521",
    "claims": [
      {
        "claim_id": "C-9041",
        "add": "Tyrese Boone",
        "drop": "Mo Vance",
        "bid": 12
      }
    ]
  }

• submit_waiver_claim Claim a player on waivers, with a drop and a bid. writeasks first

  Creates the claim the way the waiver icon in the Players tab does. Bids are blind: other managers cannot see yours. The claim stays pending until the league processes waivers, and you can cancel it before then. By default you confirm each call; you can switch that off for this tool.

  MCP callsleeper_write → submit_waiver_claim

  REST endpointPOST https://cotlet.dev/api/v1/sleeper/leagues/{league_id}/waiver-claim/submit

  Parameters

  Parameters: submit_waiver_claim

  Name	Type	Description
  league_id string required	string	League to change, from list_leagues.
  add_player_id string required	string	Player to claim, from list_free_agents.
  drop_player_id string	string	Player to drop if your roster is full.
  bid integer	integer	FAAB bid in dollars. Leave out in leagues that do not use FAAB.

  Example input

  {
    "league_id": "L-5521",
    "add_player_id": "P-3301",
    "drop_player_id": "P-1180",
    "bid": 12
  }

  Example response

  {
    "league_id": "L-5521",
    "claim_id": "C-9041",
    "add": "Tyrese Boone",
    "drop": "Mo Vance",
    "bid": 12,
    "status": "pending"
  }

• cancel_waiver_claim Cancel one of your pending waiver claims. write

  Removes the claim from Team, then Transactions, and returns the bid to your budget in FAAB leagues. It reaches no one and you can place the claim again, so it does not wait for your approval. A claim that already processed cannot be cancelled.

  MCP callsleeper_write → cancel_waiver_claim

  REST endpointPOST https://cotlet.dev/api/v1/sleeper/leagues/{league_id}/waiver-claim/cancel

  Parameters

  Parameters: cancel_waiver_claim

  Name	Type	Description
  league_id string required	string	League of the claim.
  claim_id string required	string	Claim to cancel, from list_waiver_claims.

  Example input

  {
    "league_id": "league_8c41d2",
    "claim_id": "claim_8c41d2"
  }

  Example response

  {
    "league_id": "L-5521",
    "claim_id": "C-9041",
    "status": "cancelled"
  }

ToolWhat it doesAccess

• list_trade_offers List trade offers sent to you or by you. read

  Returns each open offer with the teams, what each side gives and who still has to accept. Sleeper shows offers on the Trade screen of the Team tab. Offers that were accepted, declined or expired are not listed.

  MCP callsleeper_read → list_trade_offers

  REST endpointGET https://cotlet.dev/api/v1/sleeper/trade-offers

  Parameters

  Parameters: list_trade_offers

  Name	Type	Description
  league_id string	string	Only this league. Defaults to every league.

  Example response

  {
    "offers": [
      {
        "trade_id": "T-3120",
        "league_id": "L-5521",
        "from": "Fourth and Long",
        "gives": [
          "Eli Brandt"
        ],
        "gets": [
          "2027 round 2 pick"
        ],
        "waiting_on": [
          "Gridiron Ghosts"
        ]
      }
    ]
  }

• propose_trade Send a trade offer to one or more teams in a league. writeasks first

  Opens the offer from the Trade screen. Sleeper lets a trade include players, current and future draft picks and FAAB dollars. If every side accepts, the trade goes to the league review period before it is processed. By default you confirm each call; you can switch that off for this tool.

  MCP callsleeper_write → propose_trade

  REST endpointPOST https://cotlet.dev/api/v1/sleeper/leagues/{league_id}/trade/propose

  Parameters

  Parameters: propose_trade

  Name	Type	Description
  league_id string required	string	League of the trade.
  partner_team string required	string	Team to trade with, as list_leagues or list_matchups name it.
  give array required	array	Player ids, draft picks or FAAB dollars you give.
  get array required	array	Player ids, draft picks or FAAB dollars you ask for.

  Example input

  {
    "league_id": "league_8c41d2",
    "partner_team": "partner team",
    "give": "give",
    "get": "get"
  }

  Example response

  {
    "league_id": "L-5521",
    "trade_id": "T-3144",
    "to": "Blitz Brothers",
    "gives": [
      "Jamal Okoye"
    ],
    "gets": [
      "Colt Reyes"
    ],
    "status": "sent"
  }

• respond_to_trade Accept or decline a trade offer made to you. writeasks first

  Answers the offer the way the Trade screen does. Accepting hands over players and picks once the review period of the league ends. Declining tells the other manager. By default you confirm each call; you can switch that off for this tool.

  MCP callsleeper_write → respond_to_trade

  REST endpointPOST https://cotlet.dev/api/v1/sleeper/trades/{trade_id}/replies

  Parameters

  Parameters: respond_to_trade

  Name	Type	Description
  trade_id string required	string	Offer to answer, from list_trade_offers.
  decision string required	string	accept or decline.

  Example input

  {
    "trade_id": "trade_8c41d2",
    "decision": "decision"
  }

  Example response

  {
    "trade_id": "T-3120",
    "decision": "decline",
    "status": "declined"
  }

• send_league_message Post a message in a league chat. writeasks first

  Posts as you in the league chat, where every manager reads it. Messages cannot be edited by the tool. By default you confirm each call; you can switch that off for this tool.

  MCP callsleeper_write → send_league_message

  REST endpointPOST https://cotlet.dev/api/v1/sleeper/leagues/{league_id}/message

  Parameters

  Parameters: send_league_message

  Name	Type	Description
  league_id string required	string	League whose chat to post in.
  text string required	string	Message text.

  Example input

  {
    "league_id": "league_8c41d2",
    "text": "text"
  }

  Example response

  {
    "league_id": "L-5521",
    "message_id": "M-8801",
    "status": "posted"
  }