accounting.balance

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

Annotations already declare readOnlyHint, idempotentHint and closed-world behavior, so the safety profile is covered. The description adds real substance beyond them: empty entries are treated as zero, amounts are Decimal strings, and the account field is inert — all behaviors an agent would otherwise have to guess.

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?

Front-loaded with the purpose, then input shape, then return values, then the scope caveat. Short Korean sentences with no filler; the caveat is placed last where it reads as a qualifier rather than burying the main point.

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?

The tool is a single-parameter validator with an output schema, so return-value documentation is not strictly required, and the description supplies it anyway plus input semantics and scope limits. Nothing an agent needs to invoke it correctly is missing.

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 coverage is 0% and the schema only says 'array of objects', so the description carries the burden and largely meets it: it specifies the {account, debit, credit} item shape, the Decimal-string amount format, and the zero-default for empty values. It does not address optionality of debit/credit or what additional keys do, leaving a modest gap.

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?

States a specific verb and resource: validating that the debit total and credit total of a journal-entry list match. It also scopes itself out of per-account balance checking, which separates it from the other accounting.* tools such as accounting.income_statement and accounting.ratios.

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 closing sentence gives an explicit when-not-to-use: the account field is ignored in the totals, so it cannot verify per-account balances. That is strong exclusion guidance, but no named alternative is offered for the per-account case.

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