plaid-mcp

get_balances_tool

Retrieve live account balances from financial institutions via Plaid. Optionally filter by account ID to target specific accounts.

Instructions

Live balance lookup. Filter by account_id if given.

Tool call template

This tool declares no required parameters. Add optional parameters from the input schema as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {},
    "name": "get_balances_tool"
  }
}

Input Schema

Name	Required	Description	Default
`account_id`	No

Output Schema

Name	Required	Description	Default
`result`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Sep 8, 2026

TDQS

B3.3/5.0

Behavior2/5

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

With no annotations provided, the description carries the full burden. 'Lookup' implies a read-only operation, but the description does not explicitly state that there are no side effects, permissions required, or other behavioral traits. It is not misleading, but lacks explicit transparency.

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 a single concise sentence with no redundant information. It uses clear, direct language and is efficiently structured for quick comprehension.

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

Completeness4/5

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

Given the tool's simplicity (one optional parameter) and the presence of an output schema (not shown but indicated as true), the description is largely sufficient. It covers the core purpose and the only parameter. It does not mention edge cases or result format, but that falls under the output schema's responsibility.

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

Parameters4/5

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

The description adds meaning to the sole parameter `account_id` by explaining it is a filter and optional ('if given'). This is beyond the schema's type and default, compensating for the 0% schema description coverage. It does not elaborate on the semantics of the account_id value itself, but that is inferable from the domain.

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

Purpose4/5

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

The description 'Live balance lookup' clearly states the tool's function (retrieve balances) and the optional filter by account_id. It is distinguishable from sibling tools like get_liabilities_tool or get_holdings_tool, though 'lookup' is slightly less explicit than 'get' or 'retrieve'.

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

Usage Guidelines2/5

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

The description provides minimal guidance on when to use this tool versus alternatives. It mentions 'Live' implying real-time data, but does not explicitly contrast with other balance-related tools or state conditions for selection. No usage scenarios are given.

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