Retrieve bank account balances, optionally filtered by bank nickname or specific account ID, to check available funds across linked UK banks.
Balances. bank is a nickname (omit for all banks); account_id narrows to one account.
| Name | Required | Description | Default |
|---|---|---|---|
| bank | No | ||
| account_id | No |
| Name | Required | Description | Default |
|---|---|---|---|
No arguments | |||
Changes observed during successful MCP inspections.
v0.1.2Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnly, idempotent, non-destructive and open-world, so the safety profile is covered. The description adds essentially nothing behavioral beyond the implicit fact that omitting `bank` aggregates across all banks; it says nothing about freshness, result shape, or failure behavior for an unknown nickname.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Two short clauses with zero filler and the aggregation rule stated up front. The terseness borders on under-specification rather than verbosity, but nothing is redundant.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
An output schema exists, so return values need not be explained, and both parameters get some meaning. Still, a two-parameter read tool whose entire purpose statement is the single word "Balances" leaves an agent guessing about scope and about when this beats list_accounts.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema description coverage is 0%, so the description must carry the load, and it does partially: it clarifies that `bank` is a nickname rather than an ID and that omitting it aggregates, and that `account_id` narrows scope. It leaves the accepted `account_id` format and the interaction between the two filters unstated.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
"Balances." names the resource but supplies no verb and no scope statement; an agent must infer that this retrieves account balances. It is distinguishable from the list_* siblings by subject matter, but only weakly, since nothing says how it differs from list_accounts.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The only guidance is parameter-level ("omit for all banks", "narrows to one account"). There is no statement of when to call this versus list_accounts or list_transactions, and no prerequisites or exclusions are mentioned.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.