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

With no annotations provided, the description carries the full burden of behavioral disclosure. It only mentions 'Browser-based tool', which hints that it is an interactive UI rather than a typical API, but does not explain what happens when invoked, whether it requires internet access, what output it returns, or any side effects. The description lacks details about the tool's behavior beyond its core function, leaving the agent to guess at runtime behavior.

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 a single, efficient sentence that front-loads the most important information: supported regions, the comparison feature, and the browser-based nature. Every phrase earns its place, with no filler or redundancy. It is optimally concise and well-structured.

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 no parameters and no output schema, the description is moderately complete. It covers the core purpose and the fact that it's browser-based, which is the key contextual clue. However, it does not explain how the agent should interact with it (e.g., launch a browser, wait for user input) or what the expected result is (e.g., a displayed result, a report). For a tool with zero annotations, this leaves some gaps in understanding the full invocation flow.

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, and the schema is empty with 100% coverage (trivially). Per the baseline rule, a score of 4 is appropriate. The description adds the 'Browser-based tool' note, which clarifies that this is not a parameter-driven API but an interactive tool, providing meaning beyond the empty schema. This is sufficient for a tool with no parameters.

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 that this is a simulator for national health insurance premiums, supporting specific regions (20 designated cities + Tokyo's 23 wards) and offering instant comparisons between municipalities. It uses a specific verb ('simulate') and resource ('national health insurance premiums'), making the purpose evident. However, it does not explicitly contrast with sibling tools like social-insurance-calc or resident-tax-calc, so it doesn't fully differentiate itself, but the regional specificity and comparison feature set it apart enough.

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 guidance on when to use this tool versus other insurance or tax calculators. It does not mention any prerequisites, exclusions, or alternatives. An agent would have to infer that this is for national health insurance specifically, but there is no explicit statement about when this is the preferred tool over similar calculators. This is a significant gap for a tool with no other context.

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