ynab_update_transaction

Instructions

Implementation Reference

• src/ynab_mcp_server/server.py:365-403 (handler)

  The async function that handles the 'ynab_update_transaction' tool. It builds an updates dict from optional fields, converts dollars to milliunits if amount is provided, calls client.update_transaction(), and returns a formatted result string.

  async def ynab_update_transaction(params: UpdateTransactionInput) -> str:
      """Update an existing transaction. Only specified fields will be updated."""
      try:
          updates = {}
          
          if params.amount is not None:
              updates["amount"] = dollars_to_milliunits(params.amount)
          if params.date is not None:
              updates["date"] = params.date
          if params.payee_name is not None:
              updates["payee_name"] = params.payee_name
          if params.category_id is not None:
              updates["category_id"] = params.category_id
          if params.memo is not None:
              updates["memo"] = params.memo
          if params.cleared is not None:
              updates["cleared"] = params.cleared.value
          if params.approved is not None:
              updates["approved"] = params.approved
          
          if not updates:
              return "Error: No fields to update. Specify at least one field to change."
          
          async with YNABClient() as client:
              transaction = await client.update_transaction(
                  params.budget_id,
                  params.transaction_id,
                  **updates,
              )
          
          result = "## Transaction Updated\n\n"
          result += f"- **ID**: `{transaction['id']}`\n"
          result += f"- **Date**: {transaction['date']}\n"
          result += f"- **Amount**: {format_currency(transaction['amount'])}\n"
          result += f"- **Payee**: {transaction.get('payee_name', 'N/A')}\n"
          
          return result
      except Exception as e:
          return format_error(e)

• src/ynab_mcp_server/server.py:355-363 (registration)

  The @mcp.tool() decorator that registers 'ynab_update_transaction' as an MCP tool with annotations for title, readOnlyHint, destructiveHint, idempotentHint, and openWorldHint.

  @mcp.tool(
      name="ynab_update_transaction",
      annotations={
          "title": "Update Transaction",
          "readOnlyHint": False,
          "destructiveHint": False,
          "idempotentHint": True,
          "openWorldHint": False,
      }

• src/ynab_mcp_server/models.py:136-145 (schema)

  Pydantic model UpdateTransactionInput defining the schema for the tool's input parameters: transaction_id (required), plus optional fields amount, date, payee_name, category_id, memo, cleared, approved. Extends BudgetIdInput which provides budget_id.

  class UpdateTransactionInput(BudgetIdInput):
      """Input for updating an existing transaction."""
      transaction_id: str = Field(..., description="The transaction ID to update")
      amount: Optional[float] = Field(default=None, description="New amount in dollars")
      date: Optional[str] = Field(default=None, description="New date (YYYY-MM-DD)", pattern=r"^\d{4}-\d{2}-\d{2}$")
      payee_name: Optional[str] = Field(default=None, description="New payee name", max_length=200)
      category_id: Optional[str] = Field(default=None, description="New category ID")
      memo: Optional[str] = Field(default=None, description="New memo", max_length=500)
      cleared: Optional[ClearedStatus] = Field(default=None, description="New cleared status")
      approved: Optional[bool] = Field(default=None, description="New approved status")

• src/ynab_mcp_server/models.py:96-100 (schema)

  ClearedStatus enum used by the schema, with values CLEARED='cleared', UNCLEARED='uncleared', RECONCILED='reconciled'.

  class ClearedStatus(str, Enum):
      """Transaction cleared status."""
      CLEARED = "cleared"
      UNCLEARED = "uncleared"
      RECONCILED = "reconciled"

• src/ynab_mcp_server/server.py:40-42 (helper)

  Helper function dollars_to_milliunits used in the handler to convert dollar amounts to YNAB milliunits (1000 milliunits = $1.00).

  def dollars_to_milliunits(dollars: float) -> int:
      """Convert dollars to YNAB milliunits (1000 milliunits = $1.00)."""
      return int(round(dollars * 1000))