balance_history

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

Annotations already declare readOnlyHint=true, so the read-only behavior is covered. The description adds context that it returns a running balance at transaction dates, but does not clarify what 'key transaction dates' means or any aggregation or pagination behavior. This is adequate but not rich.

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?

A single, well-structured sentence with no filler. The verb and resource are front-loaded, and the description is immediately scannable.

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?

For a read-only tool with one required parameter and no nested objects, the description plus schema and annotations is largely sufficient for selecting and invoking the tool. The main gap is the vague 'key transaction dates' and lack of explicit output shape, but no output schema exists and the tool is simple.

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 100%: all three parameters are described in the input schema. The description adds no parameter-level meaning beyond what the schema already provides, so the baseline 3 is appropriate.

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?

Description uses a specific verb ('Track') and resource ('an account's balance changes over time'), and clarifies the output concept ('running balance at key transaction dates'). It does not explicitly name sibling tools, so differentiation from get_transactions or get_category_balance is implicit rather than direct.

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 implies the tool is for balance-over-time queries, but it gives no explicit when-to-use guidance or alternatives among the many sibling tools. There is no exclusionary routing like 'use get_transactions for raw transaction lists'.

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