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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, so the agent knows it's a safe read operation. The description adds value by specifying exactly what data is returned (balance, rates, sender, mode, status) and the context of cost estimation. However, it does not elaborate on response structure or any edge cases (e.g., what 'status' means). Given annotations cover safety, a 3 is justified as it provides some behavioral context without contradiction.

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 front-loaded with the purpose ('Get account'), then lists key data points, and ends with a usage directive. Every sentence earns its place, but the title 'Konto i saldo' is duplicated in the description's first line without adding new info. Minor redundancy, but overall efficient. A 4 is fair.

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?

Given the tool has zero parameters, no input complexity, and a relatively simple purpose, the description covers what the agent needs: what it does, what data is returned, and when to use it. An output schema exists (likely detailing the return structure), so the description doesn't need to explain return values. It adequately covers the context for correct invocation, so 4 is appropriate.

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 tool has zero parametersainer, so schema coverage is 100% (no parameters to describe). The description still adds import context about the tool's purpose (prepaid balance, rates, etc.), which is useful for understanding the return value. Since there are no parameters, a baseline 4 is appropriate because the description compensates for any lack of parameter info by explaining the output context.

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 states a specific verb and resource ('Get account') and lists concrete data returned (prepaid balance, rates, sender, mode, status). However, it does not explicitly differentiate from siblings; while siblings like 'get_message' and 'get_report' exist, the description's focus on account/balance makes it distinguishable, but a brief mention of what it is not would improve clarity.

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?

It gives a clear usage directive: 'Call this before estimating send cost.' This tells the agent when to use it (pre-cost estimation). However, it does not mention scenarios where it should not be used or alternatives, though given the unique purpose (account info), this is a minor gap. Thus a 4 is appropriate.

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