open-banking-io MCP Server

get_balances

Retrieve booked or available balances for a specified account. Provide the account ID and choose an ISO 20022 balance code such as ITBD or ITAV to identify the balance type.

Instructions

Get the balances (booked, available, ...) of one account.

type is the ISO 20022 balance code: ITBD = booked (interim), ITAV = available. account_id comes from list_accounts.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "account_id": "<account_id>"
    },
    "name": "get_balances"
  }
}

Input Schema

Name	Required	Description	Default
`account_id`	Yes

Output Schema

Name	Required	Description	Default
`result`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Aug 20, 2026

TDQS

A4.3/5.0

Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

No annotations are provided, so the description must carry the behavioral disclosure burden. It explains that the tool returns multiple balance types and defines the type codes. It does not explicitly state that the operation is read-only, but that is implicit and acceptable for a get operation. It adds useful context beyond the schema, such as the source of account_id.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is succinct and front-loaded, using two sentences and a brief code block for the type codes. Every sentence adds value with no redundant text.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given that an output schema exists (not shown in detail), we don't need description of return values. The tool is simple (one required parameter) and the description covers the essential semantics, including the meaning of type codes. It is complete for a straightforward get-balances endpoint.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 0%, so the description must compensate. It does explain account_id (source from list_accounts) and defines the type parameter even though 'type' is not present in the provided schema. This discrepancy between description and schema introduces potential confusion about whether the type parameter is actually accepted, lowering the score.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states 'Get the balances (booked, available, ...) of one account' which uses a specific verb and resource, and distinguishes it from sibling tools like list_accounts, get_transactions, and list_connections. The mention of ISO 20022 balance codes adds specificity.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description provides a clear prerequisite: 'account_id comes from list_accounts', guiding the agent to obtain the identifier from a specific prior step. It also explains the meaning of the optional type parameter, though it does not explicitly state when to use this tool versus alternatives, which is fairly obvious given the sibling set.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Deploy Server