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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, covering the safety profile. The description's 'Check' aligns with read-only behavior and adds the return structure (dict with credits_remaining and uploads_remaining), which is useful context. However, it does not disclose any additional traits like rate limits or authentication prerequisites beyond the parameters. With annotations in place, this is adequate but minimal.

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?

The description is concise and well-structured: a clear first sentence stating the purpose, followed by Args and Returns sections. It is front-loaded with the main action and does not contain verbose or redundant phrasing. The repetition of schema parameter descriptions is minor and typical, but it does not detract from overall efficiency.

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 simple read-only balance-checking tool, the description is complete: it states what it does, the required inputs, and the output structure. It does not cover error conditions or alternative usage, but these are not critical for a basic operation. The return values are specified, and the tool's simplicity makes this sufficient for an agent to call it correctly.

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?

The description's Args section repeats the parameter descriptions exactly as they appear in the input schema ('Account email (for Basic auth).'). Since schema coverage is 100%, the baseline is 3. The description adds no additional meaning or context about the parameters beyond what the schema already provides.

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 a specific action ('Check remaining credits and uploads') on a specific resource ('for the authenticated account'). This distinguishes it from siblings like check_account_status, which would cover broader account status. The verb and resource are explicit and unambiguous.

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 guidance on when to use this tool versus alternatives such as check_account_status. It only describes the function, so usage is left to inference. There is no mention of exclusions or context that would help an agent decide between get_balance and other account-related tools.

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