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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is clear. The description adds value by stating it also reports 'plan's operational limits (max pages per upload, max upload size, daily spend cap)', which goes beyond the basic read-only nature and helps set expectations for the returned data. This is useful context beyond what annotations provide.

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 yet information-dense. It opens with the core definition, then provides usage examples, a critical clarification, and a note about additional returned data. Every sentence serves a purpose with no fluff, and the structure is front-loaded with the most important information.

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 no-parameter, read-only tool with an output schema, the description covers all needed context: what it returns (credits and limits), when to use it, and how it relates to batch sizing. The presence of an output schema means return values are already documented, and the description fills in the operational intent. Nothing essential is missing 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 tool has zero parameters, so there are no parameter semantics to describe. The schema covers 100% of parameters (none), and the baseline for a 0-parameter tool is 4. The description does not need to add parameter-level details, and it correctly focuses on the returned information.

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 precisely states the tool returns 'remaining Bankstatemently credits' and explicitly distinguishes these from 'credit/debit transactions', eliminating a common confusion. It names the resource and the verb, and the clarification that it is a processing quota makes it distinct from potential sibling tools that might handle transactions.

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 concrete use cases ('how many credits do I have, remaining pages, plan limits, quota, how many pages can I upload') and explicitly warns it is NOT for credit/debit transactions. It also advises using it before starting a multi-file batch to size correctly. However, it doesn't mention when to prefer this over specific siblings, though the sibling tools are clearly distinct in purpose.

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