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

Annotations already convey the read-only, idempotent, non-destructive nature. The description adds useful behavioral context by detailing what is returned (currencies, fees, exchange spread, convenience features) and the default sorting by score when no filters are applied. No contradiction with annotations.

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 concise sentences: the first communicates purpose and output content, the second clarifies default behavior. No redundancy or fluff, and the most important information is front-loaded.

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 search tool with a fully self-describing schema and clear annotations, the description sufficiently covers purpose, output fields, and default behavior. It does not need to explain return structure in depth since it already mentions key output attributes.

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% with detailed descriptions and defaults for all 7 parameters. The description adds minimal extra meaning beyond the schema—the no-filters behavior is essentially implied by the defaults. Thus it does not elevate above the baseline.

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 it 'Search[es] and compare[s] foreign currency accounts' in Poland, using a specific verb and resource. It distinguishes itself from sibling account-search tools by focusing on currency accounts, not personal, savings, or business accounts.

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 provides clear context on when to use the tool (searching/comparing currency accounts) and even explains the default no-filters behavior. However, it does not explicitly mention alternatives or situations where sibling tools would be more appropriate, so it lacks explicit exclusions.

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