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

Annotations already declare readOnlyHint=true and destructiveHint=false. The description adds useful context beyond annotations: equity includes net income to date and the sheet always balances, which sets expectations about data behavior. It does not mention currency or basis handling, but annotations reduce the burden.

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 sentences, no redundant fluff. Front-loads the core function and includes a key behavioral nuance. Very efficient and well-structured.

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?

With a read-only tool, output schema present, and annotations, the description covers the essential purpose and a key data quirk. It doesn't need to explain return structure. Minor gaps in parameter detail and alternative usage pull it below 5.

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 only 25% (companyId's wrapper). The description does not explain basis, currencyCode, or asOfDate semantics. It loosely references 'as of a date' but doesn't specify formats, defaults, or how basis affects the report. Since coverage is low, the description fails to compensate.

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?

The description clearly states the tool returns assets, liabilities, and equity balances as of a date, with the specific note that equity includes net income to date. This distinguishes it from siblings like profit_and_loss or trial_balance by explicitly defining the balance sheet structure.

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 description provides no explicit when-to-use or alternative guidance. It implies use for point-in-time balance sheet queries but does not contrast with period-based reports like P&L or trial balance. Clear context but no exclusions or named alternatives.

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